Review of Ruddle on Retreatment

Amy Beth Dukoff, D.M.D. Management of Blocks, Ledges, Transportation, and Perforations A Review of Ruddle on Retreatment

Amy Dukoff r. Cliff Ruddle is the founder and director of Ruddle videotapes Advanced Endodontics. He gives lectures, presents hands-on workshops, and has a micro endodontic training center. This tape will show these techniques and provide more information. This videotape reviews previously taught endodontic techniques with alternative methods of treatment. In this tape, the techniques are demontrated with plastic models, extracted teeth, operating on patients and 3-D animation. Amy Dukoff Each segment is organized, explanatory, and well thought- out. Dr. Ruddle outlines his approach to a case’s treatment plan and his rationale for it. For example, crown-down is explained visually, and and Dr. Ruddle explains why it is important to open the coronal third before the apical third. He explains how opening the coronal one-third facilitates the apical instrumentation. MTA is described with its use and application. Furthermore, Dr. Ruddle incorporates CollaCote in his treatment plans. He says that he makes a “breakdown into a breakthrough.” Of course, tooth selection along with great access is a must. The video is worth watching. He reveiws techniques and basic concepts well. I highly recommend this tape. Dr. Ruddle has a very positive attitude in support of his process. His encouraging style of teaching the material enhances the tape.

11/02/1999

ENDO TIP You can reach Dr. Ruddle at:

Advanced Endodontics 227 Las Alturas Road Santa Barbara, CA 93103 Phone: (800) 753-3636 Fax: (805) 965-8253 www.endoinfo.com

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Amy Beth Dukoff, D.M.D. Vicoprofen: Effective Pain Relief? A Product Review

Amy Dukoff icoprofen combines two widely used analgesics. It produces a wonderful combination for the management of dental pain. The additive effect provides the doctor with an alternative for the patient seeking pain relief. The Vicoprofen tablet is 7.5 mg of Hydrocodone Bitrate with 200 mg of Ibuprofen. Hydrocodone Bitrate is a semi- synthetic, central acting opoid. Ibuprofren is a non-steroidal anti-inflammatory, peripheral acting drug. It is supplied in a fixed combination orally for short term usage (usually less Amy Dukoff than 10 days). Any contraindications and warnings for Ibuprofren are the same for Hydrocodone and Ibuprofen respectively. Knoll Pharmaceutical Company provides research describing the analgesic. They claim that there is a rapid onset of 11.0 to 16.2 minutes with its maximum effect in one hour. They also claim that most adverse reactions were mild and moderate with gastrointestinal reactions common. The manufacturer recommends 1 tablet every four to six hours with a maximum dosage of 5 tablets for a 24-hour period. Their study found that one Vicoprofen (7.5 mg) was equal in relieving pain to two tablets of acetaminophen with codeine (300 mg/30 mg x 2). The suggested prescription is Vicoprofen #40 Tabs. I usually dispense #12—#16, with instructions to take one tablet every 4-6 hours as needed for pain. I give this product a Four Star rating. I like hydrocodone for some of my patients because they tolerate it better than codeine. Some patients don’t like the side effects of codeine but aren’t allergic to it and would like pain relief similar to codeine’s narcotic effects. Ibuprofen has also been shown to be effective in treating inflammation. In the past, I have had the patients alternate between Tylenol with codeine and Advil. Vicoprofen in this combination seems to be effective and worth trying. 11/02/1999 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Amy Beth Dukoff, D.M.D. Pro Root Instructional Video A Product Review

Amy Dukoff RO ROOT is an instructional video by Densply and Tulsa Dental. Its subject is MTA (Mineral Trioxide Aggregate), which is a new material with a variety of uses. MTA can be used as a repair material for the root structure. One application is for procedural errors. MTA adheres well to the root wall. Also, it seals in cases of internal resorbtion and furcal communications. In addition, the video shows cases of success during apexification, pulp-capping pulpotomies, and as a root end Amy Dukoff seal. The video discusses MTA’s properties. The video states that MTA allows for normal healing, new cementum growth, adequate setting time, and the “least” leakage. They give supporting research. The video is informative and direct. I recommend viewing the video, and I also recommend the clinical use of MTA. MTA has been an adjuct in my practice. I have found that MTA does seal and repair well, but my method of dispensing the material for each use differs from the method shown in the video. I am more frugal, using only a small amount of the powder with a correspondingly small amount of distilled water. I use the packet for more than one procedure, and it works well. On the whole, the video is a good educational tool.

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Amy Beth Dukoff, D.M.D. Celebrex and COX-2 A Product Review

Amy Dukoff ELEBREX IS A COX-2, nonsteroidal, anti- inflammatory drug. Celebrex is made by Searle/Pfizer and is the brand name for celecoxib. The recommended dose is 200 mg daily or 100 mg twice a day. COX-2 is an isoform of cyclooxygenase (COX). Cyclooxygenases are used in the cyclooxygenase pathway of the inflammatory process. Cyclooxygenases occur in two Celebrex isoforms: COX-1 and COX-2. They are used in the metabolism of arachidonic acid to produce prostaglandins. Amy Dukoff COX-1 affects upper gastrointestinal tract mucosal protection and platelet aggregation. COX -1 is seen in many tissues, yet COX-2 presence may go unnoticed. They both are important in mediating inflammation and pain. Celebrex inhibits COX-2 and not COX-1. Therefore, the upper gastrointestinal mucosal protection remains, and studies have shown that COX-2 non-inflammatory drugs have a lower incidence of gastrointestinal ulceration than conventional non-steroidal anti-inflammatories. Celebrex does have some limitations. It cannot be taken with Bactrim or Septra. Also, if your patient is on Librium, you should be cautious with its use, Furthermore, for some patients the expense can be a factor, since Celebrex costs $2.50 per pill. As with all non-steroidal anti-inflammatories, one must take heed of the contra-indications for this family of drugs.

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Amy Beth Dukoff, D.M.D. The Importance of Diagnosis

Amy Dukoff IAGNOSIS IS ESSENTIAL before initiating root A good mutual canal therapy. A separate appointment is often needed understanding to diagnosis accurately. If the patient’s need is odontogenic, the patent will be grateful that the right tooth is treated so that of the his symptoms are dissipated. If it is not odontogenic, the treatment and proper referral or treatment is needed. proper The patient’s symptoms and the patient’s description of what he or she thinks has happened to the tooth are diagnosis is important, of course. However, after a patient explains why important in Amy Dukoff he feels it is a specific tooth, the patient may pinpoint another attaining a tooth. A complete diagnosis is needed for an understanding successful of the patient’s chief complaint; that diagnosis includes objective findings of clinical and radiographic examination outcome. and clinical tests. Clinical findings are not limited to pulp vitality tests, intra-oral or extra-oral exam. One must also evaluate for TMD ( tempromandibular disorder). Furthermore, evaluating for bruxism, clenching, and abnormal habits can lead to additional clues to conditions that might affect the patient’s symptoms. Finally, radiographic examination and evaluation are required. All the pieces are put together in order to make an accurate diagnosis. Radiographic evaluation is very dependent on your subjective evaluation and observation. Certain findings are indisputable, such as the number of teeth, restorations present, and gross findings—a radiolucency or grossly short obturation of the root canal space, for example. Some observations may be considered subjective. For example, the obturation in a premolar maybe “thin” to one practitioner yet acceptable to another. Also, canal in the mesial buccal root of a first molar that seems well obturated to one practitioner may reveal a missed MB2 to another practitioner. In many cases, calcified bodies in the pulp chamber can be a sign of pulpal changes and necrosis to some practitioners. Other practitioners may view these changes as normal since there maybe no periapical pathology found. Radiographs are a wonderful aid. However, their interpretations are subjective to the practitioner’s eyes. The consultation visit is extremely important. A good mutual understanding of the treatment and proper diagnosis is important in attaining a successful outcome.

May-June 2001

[ﺩﻡﺡﻡ file:///D|/HEALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/ad05diagnosis.html[2/21/2011 10:24:51 The Importance of Diagnosis

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Amy Beth Dukoff, D.M.D. Beware of the Groove

Amy Dukoff HE TOOTH’S ROOT SHAPE is sometimes Evaluate the overlooked. A root may have many cross-sectional external shapes, and the shape can change at different places on the root. Many times, a radiograph does not indicate any anatomy before aberration in the root form. However, as instrumentation instrumenting. takes place from within, the practitioner must have a mental note of the outside root form. The radicular form changes shape. In maxillary lateral incisors, the radicular cross-sectional pulp chamber varies Amy Dukoff from ovoid to conical. In maxillary premolars, there are many irregularities in the root form. These irregularities may be the result of fused roots with separated canals, fused roots with webbing, fused roots with a common apical foramen, or three-rooted tooth. The tapers and the apical portion can be very narrow and curved. When instrumentation takes place, one must monitor how wide to prepare the canal. Otherwise, you can strip and perforate unintentionally. Maxillary molars and mandibular molars may have invaginations in their root walls. They can have different root wall thickness. In the case of some mandibular molars, the distal wall may be thin and may have an additional problem of an external invagination. One must take heed of any external invagination while instrumentation takes place. The problems that may be encountered if overinstrumentation takes place where a groove or external invagination is present include stripping and lateral wall perforation. Furthermore, the walls can become more prone to fracture during some obturation techniques and some restorative procedures. Over-instrumentation will take away too much tooth structure. Care must be taken in instrumentation with respect to both internal and external structure. It is important to evaluate the external anatomy before beginning instrumentation. Radiographs are a wonderful aid in viewing the root structure in two dimensions. However, the external anatomy with its external invaginations requires constant attention.

July-August 2001

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Amy Beth Dukoff, D.M.D. How Trauma Affects the Nerve

Amy Dukoff EETH REACT to trauma in various ways. Their Keen response can cause immediate changes or delayed observation and changes that can take weeks or years to become apparent. The traumatic experience may cause gradual changes in the close root-canal system that do not become apparent until years examination later. are imperative. A good dental history is important to identify the type of trauma. Trauma can be due to abnormal occlusal contacts. It may have been caused by a recent blow to the tooth in Amy Dukoff question. Further investigation may reveal an injury that occurred many years earlier. When you are taking the history, it is important to determine how, when, and where the injury occurred. The corresponding symptoms at the time of injury are also important, along with the progression of symptoms. The patient will usually provide the important facts if prompted carefully and thoroughly. The clinical examination has many parts, proceeding through neurologic, external, intraoral soft tissue, hard tissue, and radiographic phases of examination. Vital tests are also needed. After all the information has been gathered, a diagnosis can be made. Trauma will cause a pulpitis. Determining whether the pulpitis is reversible or irreversible may take more than one appointment. Sometimes in a recent trauma with percussion tenderness alone and in normal occlusion, the symptoms may resolve and no treatment will be needed. At other times, if the pain is intermittent over a year, then irreversible pulpitis may be suspected. And at still other times, you may see a change in the shade of the clinical crown over the span of years. Furthermore, on radiographic interpretation, calcification or internal resorbtion may be seen. Keen observation of the tooth in question is imperative. Close examination is a must for diagnosis and subquent treatment.

September-October 2001

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Amy Beth Dukoff, D.M.D. Internal Resorption

Amy Dukoff OOTH RESORPTION may go unnoticed for many Management years. Often, the patient is unaware of it because of the and treatment lack of symptoms. Usually, the practitioner will discover the resorption in an unusual radiographic finding upon a routine are essential. examination when periapical radiographs are taken. Treatment of internal resorption begins with proper identification. Diagnosis differentiates internal resorption from external resorption. It is important in treatment to know if the resorption is purely internal, initiating within the pulp Amy Dukoff chamber and not communicating with the periodontal ligament. If the resorptive area is communicating, then it is an internal-external resorptive case, and the prognosis is questionable. Internal resorption can be the result of many factors:

partial removal of the pulp caries trauma pulp capping with calcium hydroxide a cracked tooth

The patient’s history will give the practioner clues to when the tooth was last worked on and whether trauma was involved. The resorptive process can progress at different speeds and with different periods of activity. Internal resorption can be managed with conventional non- surgical root-canal therapy. Prognosis is good; however, the patient must be recalled, since the resorptive defect can recur. If there is a perforation of the root to the periodontal ligament, then repair must be undertaken to create a barrier. Calcium hydroxide has osseous reparative properties that make it a good choice to create a barrier. Internal resorption is a problem all practitioners come across in practice. Successful treatment requires proper diagnosis and a good history. Management and treatment are essential.

November-December 2001

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Amy Beth Dukoff, D.M.D. Isolation

Amy Dukoff ROPER endodontic access is crucial to the success of This crucial the final treatment. The access openings can help the step is often practitioner overcome many technical difficulties that he or she may encounter during treatment. Before access is overlooked or gained, isolation is essential. This crucial step is often not given its overlooked or not given its proper attention. proper Isolation is attained with the placement of a rubber dam. Ideally, the dam is placed only on the treatment tooth. attention. However, in cases where there is gross subgingival decay and Amy Dukoff placement is precarious, it is better to use the two adjacent teeth as anchors. This method of anchoring the dam will facilitate the practitioner’s removing the gross decay, controlling gingival bleeding, and performing the procedure. The rubber dam, of course, is designed to help prevent the entrance of germs into the pulp cavity, assuring the safety of the patient. The Endodontic access opening can be affected by the rubber dam placement. It is important to evaluate the inclination of the tooth and projected root structure before placing the rubber dam. Getting a visual orientation of the tooth in its position in the arch is critical before initiating the access opening. Often, the practitioner will lose sight of vital information and clues to the location of the canal once the rubber dam is placed. This is especially true with calcified or inclined teeth. It is sometimes necessary to make small reference marks on the tooth for orientation to facilitate the access-opening procedure. At times, other procedures—such as crown lengthening, periodontal evaluation or treatment, or removal of a wisdom tooth—may be needed before the access opening. If the decay is subgingival, crown lengthening may be needed. Many times periodontal treatment—such as osseous recontouring, gingival recontouring, root resection, or hemisection—is needed as part of therapy. Wisdom tooth extraction may be needed if there is a pericoronitis, swelling that limits mandibular opening, or swelling with an inclined tooth. These are just a few situations in which other treatments are needed before beginning the isolation procedure. The importance of isolation in an endodontic procedure is often overlooked. Yet it is an important factor in the outcome of the treatment. Isolation is required before

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initiating the treatment.

January-February 2002

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Amy Beth Dukoff, D.M.D. Breakage of Instruments

Amy Dukoff reakage of instruments is a common problem for all practitioners. Breakage can occur for a multitude of reasons. The operator can be as careful as possible and still an instrument may separate. The challenge then becomes how to turn this into a positive and successful situation. Handling the occurrence with confidence gives the patient the comfort of knowing that all will be well. Fractures can occur with K-files, Hedstroms, reamers, NiTi, and rotary instruments. Generally, instruments should Amy Dukoff be discarded if one of the following occurs:

There are unwound flutes on the instrument. The instrument has seen excessive use. The operator had to place excessive bending or precurving. You see corrosion on the instrument.

Instruments may separate for any of several reasons. They can break due to the operator’s overworking the file. One cannot force an instrument to the desired length. Instruments may also break due to advancing from a smaller to a larger instrument, skipping steps in the progressive sequence. Some instruments, especially the NiTi and rotary instruments, separate more easily than stainless steel. One can check NiTi instruments by bending them in one’s hand before use. Rotary instruments may break without warning during use. Once an instrument is separated, the operator must inform the patient of the occurrence. Speaking to and informing the patient is usually the most difficult task. We want to transform the reaction of the patient from fear to comfort. Figure 1 Many times, a matter-of-fact approach is best, simply stating that an instrument separated because of the metal’s weakness. Speaking with confidence, demonstrating that you are in control of the situation, instills a feeling of comfort in the patient. One clinical example is the following. I was referred a patient with a separated file in the MB1 canal. The other canals were calcified. (See Figure 1.) The patient was asymptomatic and aware of the occurrence. The patient was referred to me to complete the case. Upon accessing the case, I found an MB2 that bypassed the instrument and had a common apex. Also, I found the DB canal. (See Figure 2.) The patient remained asymptomatic throughout the treatment.

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In the final post-operative radiograph , the separated instrument could not be noted. The result was a success. FIGURE 1: A separated (See Figure 3.) file in the MB1 canal.

Figure 2 Figure 3

FIGURE 2: An MB2 was found that FIGURE 3: In the post- bypassed the broken instrument operative radiograph, the and had a common apex. instrument is not visible.

Breakage or separation of instruments are problems that all practitioners experience. No matter how hard one tries to avoid this occurrence, it usually will occur at some point. Sometimes the instrument is simply used as part of the obturation system. At other times the instrument is bypassed, or, during further instrumentation, the separated file is removed using one of a variety of techniques. Managing the situation will provide the patient with added confidence and trust in you.

May-June 2002

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Amy Beth Dukoff, D.M.D. Orthodontics and the Root

Amy Dukoff RACES ARE A FACT OF LIFE for many adolescents. Malocclusion is esthetically and functionally undesirable. Most parents are concerned about how their children will look in their teen and adult years. However, when orthodontics is being considered, the long- term effect on the root is sometimes a forgotten consideration . Roots respond to orthodontic movement. The forces from the orthodontic movement cause disturbances in the Amy Dukoff circulation of the pulp. Circulatory disturbances can result in the degeneration of the odontoblast. Pulp changes are associated with orthodontic forces applied beyond the tolerance limit of the tooth. The results of orthodontic movement can be seen on a radiograph. Resorption may occur, and the root ends may become shortened and blunted. Even though these changes are present, pulp vitality may not be affected. Orthodontics is important when needed for correct alignment. However, teeth with complete apices may have more severe degeneration of the odontoblasts the Endo Tip incompletely formed root apexes. In most cases, damage to the pulp is reversible and does not result in a need for endodontic therapy.

Changes are proportional to the amount of force that is applied. The greater the force, the greater the disturbance in If a Peeso breaks the pulp chamber. The odontoblasts respond in many ways. in the canal, just Some odontoblasts will degenerate. Others may increase the touch the shaft deposition of reparative dentin. It is important to monitor the with any rotating duration and degree of pain the patient experiences after each high speed bur. orthodontic procedure. The spinning bur Orthodontics produces wonderful results. Understanding will either loosen how orthodontic procedures affect the pulp will improve the the Peeso up or treatment’s final result and ensure that the pulp remains actually spin it out healthy. of the canal. September-October 2002

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Amy Beth Dukoff, D.M.D. Missed Appointments

Amy Dukoff ISSED APPOINTMENTS can play havoc with a doctor’s schedule. Besides the down time, the loss of income can be a strain on the practice. One-visit endodontics is the key to reducing the number of missed appointments. Many patients are anxious about the endodontic procedure because of their previous experience or because of what a friend has said about the procedure. Pain motivates the patient to come for treatment. After the pain has been relieved, many patients miss the follow-up appointment. Amy Dukoff Completing the procedure in one visit eliminates the need for the patient to return to complete the treatment. Furthermore, completing the procedure in a single visit eliminates the patient’s risk of an incomplete treatment with possible re- infection or breakage of the coronal structure. One-visit endodontics creates a positive environment for the patient — especially the apprehensive one. Certainly, keeping the patient’s interest in the treatment is key. Undoubtedly, many patients have very busy, complex lives that match the bustling pace of city life. Just getting a patient to commit to a time or treatment plan can be quite an arduous task. Completing the endodontics in one visit can enhance the general dentist’s treatment plan, for the restorative can begin so much sooner. One-visit endodontics is wonderful for the patient—who is delighted that the procedure is over—at the same time that it reduces the likelihood that the patient will miss the next appointment. There will always be some patients who do not keep their appointments. Learning to make good use of the “empty” time that results is a constant struggle. Discipline is needed to utilize the time properly. Managing your time in the office is key to making a missed appointment’s time into a productive period. There is always work to do in the office. Having a to-do list for one’s self keeps wasted time to a minimum. Missed-appointment time is a good time to review accounts, inventory, and patients’ histories. It’s time for catching up on reading and correspondence. These unexpected holes in one’s schedule can become valuable to the practitioner. Missed appointments are always an unwelcome surprise. Making the “down time” into positive, productive time is challenging. It becomes rewarding when the time is well spent.

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November-December 2002

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Amy Beth Dukoff, D.M.D. Did You Know Where Rx Came From?

Amy Dukoff OR YEARS I SAW the symbol Rx and used it without Figure 1 knowing what it meant or symbolized. Finally, I stumbled upon the meaning of it and took note. The symbol Rx is derived from the major lines in the symbol of the Eye of Horus. Horus was an Egyptian god, the god of Nekhen, a village in Egypt, and god of the sky, of light, and of goodness. He was the son of Isis, the nature goddess, and Osiris, the god of the underworld. Osiris was murdered by his evil brother Seth, the god of darkness and evil. Horus Figure 2 Amy Dukoff sought to avenge his father’s death by challenging his uncle Seth to a fight. Seth cut out Horus’s eye, but Thoth, a god associated with wisdom and compassion, magically restored the eye. Horus did defeat Seth, finally. Horus’s eye, also called the wadjet eye, became a symbol for health. The Egyptians considered it a symbol of good and restored health.

The symbol was passed along through the ages. As William Osler wrote in 1910, “In a cursive form it is found in mediaeval translations of the works of Ptolemy the astrologer, as the sign of the planet Jupiter. As such it was placed upon horoscopes and upon formula containing drugs made for administration to the body, so that the harmful Figure 3 properties of these drugs might be removed under the influence of the lucky planet.” There is another theory of Rx’s origin. In that version, Rx is an abbreviation for the Latin word recipere, which means “take” or “take thus.” Long ago, this would not have been a direction to a patient but to a pharmacist, preceding the physician’s “recipe” for preparing a medication. That may be, but the shape of the symbol is a strong argument in favor of the Eye of Horus as its origin. If you look closely at the major lines of the eye of Horus, TOP TO BOTTOM: The you can see the elements of the symbol Rx. Eye of Horus, the symbol for Jupiter, and the Rx symbol share similar February-March 2003 elements.

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Amy Beth Dukoff, D.M.D. HIPAA Is Here

Amy Dukoff HE ACRONYM HIPAA stands for Health Insurance Portability and Accountability Act. Congress passed this act in 1996 to improve the effectiveness of the health care system. The goals of HIPAA are to protect our patients’ privacy, maintain patient information and billing in accordance with the national standards, and keep our patients’ charts secure. The privacy of a patient’s medical history and billing are to be protected. In the words of the U. S. Department of Health and Human Services, “The new Amy Dukoff privacy regulations ensure a national floor of privacy protections for patients by limiting the ways that health plans, pharmacies, hospitals and other covered entities can use patients’ personal medical information. The regulations protect medical records and other individually identifiable health information, whether it is on paper, in computers or communicated orally.” The fines for failure to comply are stiff, from $25,000 to $250,000 with criminal penalties. HIPAA’s policies may take time to digest, but adapting to their new set of standards does not really require much of a change in what one is currently doing. All it takes is a new awareness of what HIPAA is protecting and what we as health care providers must do to comply. I have adapted the following list of key provisions of these new standards from the Department of Health and Human Services guidelines: Access to Medical Records

Patients generally should be able to see and obtain copies of their medical records and request corrections if they identify errors and mistakes. Doctors generally should provide access to these records within 30 days and may charge patients for the cost of copying and sending the records. Notice of Privacy Practices

Doctors must provide a notice to their patients how they may use personal medical information and their rights under the new privacy regulation. Doctors are expected to provide the notice on the patient’s first visit following the April 14, 2003, compliance date and upon request. You generally should ask patients to sign, initial, or otherwise acknowledge that they

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received this notice. Limits on Use of Personal Medical Information

The privacy rule sets limits on how doctors may use individually identifiable health information. The rule does not restrict the ability of doctors, nurses, and other providers to share information needed to treat their patients. In other situations, though, personal health information generally may not be used for purposes not related to health care, and you may use or share only the minimum amount of protected information needed for a particular purpose. Confidential Communications

Under the privacy rule, patients can request that their doctors take reasonable steps to ensure that their communications with the patient are confidential. For example, a patient could ask a doctor to call his or her office rather than home, and the doctor’s office should comply with that request if it can be reasonably accommodated.

HIPAA affects the dentist and the entire practice team. Part of the dentist’s responsibility is to educate the dental team and employees. The front desk area becomes an area of concern when a patient’s privacy is considered. For example, the support staff must keep a low tone of voice so that other patients cannot overhear conversation with or about a specific patient. Also, computer screens should be placed and angled so that patients cannot view them easily. HIPAA requires that you take steps to protect the information you write and send electronically about a patient. Faxes and emails should have privacy warnings on them. To gain more information on HIPAA, you can contact the ADA. You may be able to attend an informative seminar on compliance, as I did. The U. S. Department of Health and Human Services has a helpful website where you will find guidelines and technical assistance with compliance at http://www.hhs.gov/ocr/hipaa/. Healthcare Compliance Solutions, Inc. (HCSI) located in Sandy, Utah, can help you accomplish compliance. Their fax is (801) 943-6658 and telephone (801) 947-0183. Their website is at http://www.hcsiinc.com/. They helped our office take the necessary steps to be compliant. All of us work hard at providing the best care for our patients. HIPAA is another way to ensure that each patient’s privacy is more closely monitored and to increase out awareness in this area.

May-June 2003

Cavit washes out. Use ZOP or

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glass ionomer as temporary material.

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Amy Beth Dukoff, D.M.D. Young Bui, D.D.S. The Apex Locator: Essential, but Not Infallible

Amy Dukoff HE “END” of the root canal is what we are looking for. Finding the end is the desired result one must achieve before instrumentation. When one begins a case, the tooth must be evaluated to see how to find the apical limit needed for instrumentation. Knowing the correct apical limit allows one to determine the correct working length. The practitioner who does not know the correct working length may inadvertently

Amy Dukoff create an apical perforation over-instrument over-extend obturation material under-prepare the root canal space with inadequate obturation

Biomechanical preparation with obturation that is not based on an accurate determination of the apical limit could lead to postoperative pain and complications. Determining the correct working length is essential. An apex locator is a useful tool for finding the apical foramen. The apical foramen is usually not at the anatomical apex. The apical foramen and the anatomical apex usually differ by approximately 0.5 mm to 1.0 mm. In older people, the deviation can be greater. The apical foramen is not visible on radiograph. The apex locator locates the apical foramen with a great deal of accuracy. The readout on the apex locator locates the apex or apical foramen and the apical constriction. (The apical foramen is also called the major diameter while the apical constriction is called the minor diameter.) Between the two locations, the readout is colored green. The practitioner needs to decide which value is to be the working length. The apex locator reliably gives the correct values. The radiographic vertex is often used as the working length; however it does not always correspond to the actual apical foramen. In the case of maxillary molars, the palatal root is often a good example of the fact that the radiographic vertex does not always coincide with the apical foramen. Drs. Melanie Kim- Park, Linda Baughan, and Gary Hartwell clearly illustrate this in “Working Length Determination in Palatal Roots of Maxillary Molars,” an article in the Journal of Endodontics.

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They show that in palatal canal curves greater than 25 degrees there is a statistical difference between the actual and radiographic lengths. Since the palatal root does curve buccally in a majority of the cases, the radiographic working length may be short. This is just one example in which the radiographic working length is not the same as the actual working length Knowing the exact apical terminus is vital in achieving a good result. Biomechanical preparation is improved and postoperative discomfort is decreased when the correct working length is known and used. N APEX LOCATOR is a very useful device in root- Figure 1 canal therapy. It can save you time and prevent giving your patients unnecessary doses of radiation. The apex locator will give you a reading when the reamer reaches the apical constriction, thus preventing you from over- instrumenting. It has a 95 percent accuracy. Sometimes, the apex locator gives you a wild reading just Young Bui as soon as the reamer enters the canal. This often occurs in FIGURE 1: The gutta- wet canals or in a tooth with a large metal filling or crown percha point is about 2 mm short and there is a because the readings rely on relative differences in electrical large puff of cement conductivity. The apex locator will give you the most extruding to the side of the accurate reading when the canal is dry and the reamer fits canal. snugly in the canal. If the apex locator has a built-in reset button, you can quickly and easily recalibrate the reading. The Endex by Osada is one such device widely used by the Figure 2 doctors in our office. With all this in mind, I had a false reading by my apex locator this morning when I was treating an upper left second premolar. The reading for the buccal canal was 18 mm. The canal was dry, and the reamer used for the measurement fit snugly in the canal. I got the same reading with the SafeSiders 25/.08 NiTi file after instrumentation was FIGURE 2: Working-length completed. Upon fitting the gutta-percha point, I noticed that x-ray. the point was about 2 mm short and there was a large puff of cement extruding to the side of the canal as seen in Figure 1. There appears to be a horizontal fracture or a large lateral Figure 3 canal at the level of the puff. I decided to take a working- length x-ray, Figure 2, to see where the canal ended. The working length was 20 mm. I cleaned and shaped the buccal canal again and dried it with paper points. There was no blood stain on the point tip, indicating that the working length was not out of the apex. Figure 3 shows the final x-ray with FIGURE 3: The canal filled the proper working length, lateral puff, and the puff of to the apex. cement extruding from the apex. The apex locator is a very dependable device. It makes root canal treatment a lot simpler and saves you a lot of time that would be spent in taking unnecessary x-rays. Although the reading is usually quite accurate, there are times when the anatomy of the tooth will cause the locator to provide a false reading, as in the case above. That is why I always prefer to take a mastercone x-ray before closing the tooth. This preview of the finished product will give you the opportunity

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to make any adjustment before you let the patient leave.

September-October 2003 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Amy Beth Dukoff, D.M.D. To Retreat or Not to Retreat?

Amy Dukoff ETREATMENT today is the standard of care . . . in the In discussing right cases. What used to be an easy decision to retreat retreatment with today is more complex. Each case must be evaluated patients it’s radiographically and symptomatically in order to decide important to whether retreatment is appropriate. In every case, the patient emphasize that a has to be well informed of his or her options. The risks that tooth’s requiring are involved must be explained as well as the prognosis and retreatment is not costs. a treatment The retreatment decision is made on a case-by-case basis. failure. Amy Dukoff If symptoms and disease are present, retreatment is usually indicated. Even without symptoms, retreatment may be indicated to prevent a future emergency. A common clinical finding that favors retreatment would be the presence of an incompletely obturated root canal system. Sometimes, a history of sporadic symptoms pointing to the tooth in question will indicate the need for retreatment. In rare cases, even the most perfectly executed non-surgical root canal therapy may need to be redone if the patient continually complains, “it just never felt right.” Sometimes, it’s hard to understand why the tooth hurts, but if the tooth does hurt, it’s important to listen to the patient and decide whether retreatment is indicative from a clinical or patient management perspective. The success rate for retreatment is lower than the rate for initial treatment. Moreover, there can be obstacles that compromise retreatment. These obstacles may be calcifications, complex morphology, ledges, blocks, separated instruments, and the thinness of the root dentin. In addition, the periodontal condition of the surrounding bone can affect the prognosis. The patient must be advised of alternative treatment options with their respective costs and success rates. Given the success rates for implants, they are often the preferred alternative to retreatment. In any discussion of retreatment with patients, it’s important to emphasize that a tooth’s requiring retreatment is not a treatment failure. If symptoms and disease are present, then treatment of the apical periodontitis is necessary. It may be the case that the root canal procedure went well but disease pathology is present. It may also be the case that radiographs show a treatment that was less than “textbook” perfect, requiring retreatment even though the patient

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considers the procedure successful and is not experiencing symptoms. Therefore, the need for retreatment is usually not caused by the failure of a root canal procedure and should not be presented to the patient from that perspective.

November-December 2003

Cavit washes out. Use ZOP or glass ionomer as temporary material.

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Amy Beth Dukoff, D.M.D. Endodontics and the Immature Tooth

Amy Dukoff HEN ENDODONTIC therapy is required on an Maturogenesis immature tooth with an open apex, ensuring is the treatment maturogenesis is the treatment of choice. Until the tooth is fully mature, the apex is open and the root canal of choice. walls are thin. Closure of the apex is needed in the root development of immature teeth, but continued root development and dentin formation are also needed. We want to allow not just apexogenesis—the closure of the apex—but maturogenesis—the continued maturation of the tooth, the Amy Dukoff normal process of root and apex formation with eventual closure of the apex, and continued dentin formation along the root walls to increase their thickness and length. Canal walls need thickness and an appropriate internal shape if the mature tooth is to be strong. The thin canal walls and open apex make root-canal therapy on an immature tooth extremely difficult. Keeping the pulp alive and allowing the tooth to mature is preferred because the mature tooth is a much better candidate for successful root-canal therapy. If the pulp is necrotic, apexification may be required. In this procedure, necrotic tissue is removed, and apex closure is induced. The desired effect of apexification is a calcified barrier across the open apex to allow for obturation with gutta-percha. However, apexification does not allow for the development of the root-canal walls. To achieve apexification, the canal must be free of infection. Calcium hydroxide is used to promote apical closure by stimulating the formation of a calcified barrier. The successful formation of the hard-tissue barrier is usually determined by tactile sensation. Mineral trioxide aggregate (MTA) can also be used to create an artificial apical barrier. MTA is placed into the canal to create an apical plug of 3?4 mm. Once the MTA is set, the canal can be obturated with gutta-percha. Encouraging maturogenesis is the desired treatment. If maturogenesis cannot be achieved, then apexification by calcium hydroxide or artificial closure using MTA must be utilized. The ultimate success can be determined only on recall with the absence of pain and pathology.

February-March 2004 FEEDBACK? We welcome your responses and questions.

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Amy Beth Dukoff, D.M.D. Cracked Teeth

Amy Dukoff RACKED TEETH are usually difficult to diagnose, but they are commonly seen in practice. Naturally, we see them in older patients, since their teeth have been in use for a long time, subjected to years of the stresses and strains of mastication. However, in practice, I have seen them in patients of all ages, since a crack may be caused by a single incident as well as cumulative stresses. Often, the patient who has a cracked tooth reports eating hard foods, such as hard candies, ice, popcorn, hard breads, nuts, or dried Amy Dukoff peas. Continued mastication of hard objects very often causes fatigue of the tooth structure, which could lead to cracks. Also, occlusal aberrations can weaken the tooth structure and eventually create a crack, as can such habits as clenching and grinding. Many times a “crack” sound is heard immediately, but the crack may actually have been present but undetected for a while. When a crack occurs in a tooth with a restoration, or in a tooth near one that has a restoration, the patient may jump to the conclusion that the pain he or she feels is the fault of the dentist. Diagnosis can be a frustrating experience for the practitioner, who may be unable to see anything “wrong” with the patient’s tooth restoration. The patient and the dentist have to come to a mutual understanding about the condition of the tooth and the nature of the crack. When a cracked tooth requires treatment, the nature, location, and severity of the crack may suggest a variety of treatment options with a variety of prognoses. The anatomy of certain teeth makes them more susceptible to cracks. The cuspal height and shape may increase the force on the tooth’s structure, leading to cracks. Keeping a tooth “healthy” is important in preventing cracks; therefore, care should be taken as to all aspects of the tooth. In diagnosing a crack, transillumination, microscopic evaluation, x-rays, staining techniques, and a bite stick are important. Transillumination helps the dentist to visualize the crack by the difference of the transmitted light through the tooth since the crack blocks light, causing a dark appearance. Microscopic evaluation helps to clinically detect the extent of the crack when it is near or in the root. Radiographs can show the bone breakdown around the tooth, which can help determine the size of the crack. Various stains, such as

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methylene blue, may also help visualize the crack. Lastly, a bite stick could help reproduce the patient’s symptoms and thereby help in locating the crack. These are just a few aids used to identify cracks. Cracked teeth can be a diagnostic challenge. However, resolution of the patient’s problem is satisfying. Proper techniques in diagnosing and analyzing the clinical condition are likely to lead to a good result.

Summer 2004 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Amy Beth Dukoff, D.M.D. Sometimes It Just Is

Amy Dukoff OMETIMES a patient presents with a chief complaint that surprises the practitioner. The complaint may not correspond to the practitioner’s assessment of the patient’s condition. At times, the patient’s perception may be mistaken; at other times, however, complications such as hard-tissue changes or calcification may be affecting the practitioner’s diagnosis. In such cases, listening carefully to the patient and following the clues in the patient’s complaint are essential to making the correct diagnosis. Amy Dukoff Hard-tissue changes can make diagnosis difficult. Calcifications can make the diagnosis confusing. Extensive formation of hard tissue on the dentinal walls can occur along with the obliteration of the pulp chamber. This condition may be caused by trauma, caries, periodontal disease, or other irritants. Furthermore, pulp stones and diffuse calcifications can occur. Pulp stones usually occur in the pulp chamber, while diffuse calcifications occur in the radicular pulp. Calcification makes the location of the pulp chamber difficult to read, which may mislead the practitioner as to the proximity of the caries to the pulpal chamber. Listening to the patient will give the practitioner important clues to lead the practitioner to the right tooth or area in question. When a patient presents with pain on a tooth with hard tissue changes, the practitioner should be alerted to the likelihood that changes occurred due to pulpal reactions. Many times caries may be present, but since the pulp chamber is obliterated, the depth of the caries in relationship to the pulp chamber can be misleading. Also, if a crack is present, the pulp chamber may become obliterated. Therefore, even if a shallow restoration is present or does not exist, pulpal obliteration can be caused by a crack. Lastly, trauma may also cause excessive stress, which in turn may initiate pulpal calcification. Evidence of calcification gives clues to the practitioner that the pulp has responded to an irritation. Therefore, if the patient is complaining in the region, a full evaluation of the teeth in question is vital. A tooth free of restoration may have a surprising result in response to pulp testing. As always, listening to the patient is key in accurate diagnosis.

Fall 2004

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Amy Beth Dukoff, D.M.D. Success for the Patient

Amy Dukoff IAGNOSIS is of paramount importance, and it is Having the dependent on the patient’s chief complaint. Because patient leave diagnosis begins with the patient, the essential requirement for an accurate diagnosis—and for establishing patient trust satisfied with —is the listening skill of the practitioner and the the treatment practitioner’s staff. Listening to the patient’s total needs, plan is a great understanding them, and responding to them are vital to achieving a proper treatment plan. The best plan satisfies the achievement. patient’s needs. Amy Dukoff Receptionists usually make the first step in diagnosis. They are the ones who initially greet patients and ask them to fill out the forms that provide needed information, including medical history, personal information, and financial information. Through these forms, the patient gives the medical team the first impression of the patient’s condition. When the patient is seated in the chair, the practitioner reviews the information that the patient provided. At this time, the patient also makes the practitioner aware of the condition, as the patient perceives it. The patient will also detail the history of the pain and the level of distress that accompanies the condition. Understanding the patient’s pain will help the practitioner diagnose the origin of the problem. The first few minutes will help establish confidence and trust between the patient and the practitioner. The patient’s financial and time constraints play a role in what the treatment plan will ultimately be. Patients may be limited to their insurance benefits or to their personal budget. It’s always wise to inform the patient of all the treatment options with their corresponding costs and long-term benefits. In addition to financial constraints, time may be a large factor, especially in our mobile society, since patients may be traveling frequently or planning to move. Depending on the patient’s level of pain and its severity, the treatment plan may be altered to fit the patient’s financial and time constraints. These two factors play a large part in deciding on a treatment plan for the tooth in question. Finalizing a treatment plan is the ultimate goal. Sometimes it takes a team of specialists working side by side with the practitioner to solve the patient’s individual needs. Having the patient leave satisfied with the treatment plan is a great achievement.

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Winter 2004 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Amy Beth Dukoff, D.M.D. Redoing an Office

Amy Dukoff HE DECISION to redo, renovate, redecorate, and update an office is usually a huge one. It is not just the financial commitment that makes the decision momentous, but also the amount of time and effort that is required to compete the task. Furthermore, the inconvenience to the doctor is enormous. However, to the patient, the changes are usually welcome. Patients are usually glad to see that their doctor takes pride in his or her work, profession, and surroundings. Many patients Amy Dukoff judge the doctor by the appearance of the office. An office that makes a good impression is extremely important for the first-time patient. In a specialty practice, such as ours, many of the patients are first-time patients, so the appearance of our office is especially important to them. We want them to be comfortable with the surroundings. Most patients are happy to see their doctor upgrading and recognize that the doctor cares about their feelings and the way that they perceive the office. Since technology is always changing, it is good for the patients to know that their doctor is staying in the forefront and keeping pace with what is new. Patients will tend to be forgiving during the transition phase. Timing is important. It is often good to decide to redo an office at the beginning of a new lease, as we did. The hardest part of the process is making decisions that everyone in the office likes. One must always remember that the “big picture” of completing a project is more important than the temporary inconvenience during the construction. With careful planning, the results will be worth the inconvenience.

January-March 2005 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Amy Dukoff, D.M.D. The Mandibular Second Molar Morphology

Amy Dukoff HE ABNORMALITIES of the mandibular second Achieving a molar are often not fully taken into account when root successful canal therapy is being considered. Usually, non-surgical root canal therapy is thought of as a routine endodontic result in root procedure. On first glance at a radiograph of a mandibular canal therapy second molar, the toooth often appears normal in on second morphology. However, when the procedure begins, very often the practitioner then realizes the extent of the molars presents difficulties that he or she may have to overcome. a challenge to Amy Dukoff The mandibular second molar is typically compared to the all clinicians. first mandibular molar. The differences are instructive. First, they are smaller coronally than the first mandibular molar. Second, they are more symmetrical than the first molar. Furthermore, the second molar’s roots have a tendency to be close together while being in a gradual curve. The first and second molars have similar access, which is in the mesial aspect of the crown extending just slightly distal. Of course, this access may have to be modified due to caries and coronal structure. Both molars must resist the forces of mastication. The second mandibular molars have some distinct characteristics. They are extremely susceptible to vertical fracture. Therefore, mesial-distal fractures if present have a very poor prognosis. Furthermore, the C-shaped root system is an anatomical variation of second molars. They can be seen with a fin or web connecting the root systems. The C- shaped canal may not be easily detectable on radiographic interpretation. In their article “C-Shaped Canal System in Mandibular Second Molars: Part II-Radiographic Features,” in the December 2004 Journal of Endodontics, Drs. Bing Fan, Gary Cheung, Mingwen Fan, James Gutmann, and Wei Fan, suggest that with close scrutiny one may possibly predict the presence of the C-shaped canal. The groove linking the canals may be so thin that one cannot see it by inspecting the radiograph. It’s important to be critical in looking at all second molar radiographs. Achieving a successful result in root canal threapy on second molars presents a challenge to all clinicians. It’s imperative to be critical before beginning and understand the case before proceeding.

April-June 2005

[ﺩﻡﺡﻡ file:///D|/HEALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/ad22mandibular.html[2/21/2011 10:25:01 The Mandibular Second Molar Morphology

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Amy Dukoff, D.M.D. To Retreat or Not When a Post Is Present

Amy Dukoff ECIDING whether to retreat an endodontically treated The decision is tooth can be difficult. The best course of treatment is dependent on not always clear from radiographs or from the patient’s symptoms. Making a careful diagnosis and discussing the many factors. treatment options with the patient usually produces the best results. The tooth may have a radiographic area that is asymptomatic. If disassembly would include post removal and possibly a new crown, many factors must be considered. Amy Dukoff First, one has to determine whether the post can be removed without causing a lot of structural damage to the tooth and weakening it. Then, the practitioner must determine whether the new post and core with a new crown will be functional. The new restoration must satisfy the patient’s needs. The type of existing post can help determine your decision. For example, a resin/fiber post could be more difficult to remove than a parallel post cemented with zinc phosphate. Also, the post’s proximity to the furcation or its length could contribute to the decision. In addition, the thickness of the post relative to the thickness of the dentin plays a role in the decision. Besides these concerns, the anatomical concerns must always be reviewed. These may include the proximity to the mandibular canal or the mental foramen. If the tooth is symptomatic, then a course of action must be determined and executed. Sometimes the patient will benefit from a course of antibiotics begun a few days before treatment to lessen the potential flare-up and make the procedure more comfortable for the patient. Because the patient will be more comfortable, removing any post system will be easier. Furthermore, the antibiotics may allow the effect of anesthesia to be more pronounced. Of course, the antibiotics may decrease the symptoms for a short term, making it more difficult to gain the input of other specialists if it is needed. Ultimately, the patient should decide with you on the best course of treatment. The decision to retreat an endodontically treated tooth is dependent on many factors and is very personalized. Discussing the risks and benefits with the patient is the best course to follow. Advise the patient and work with the patient to establish the final retreatment plan.

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July-September 2005 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Amy Dukoff, D.M.D. Education

Amy Dukoff DUCATION is key at all stages of practice. A practice Keeping up always in motion is vibrant and attracts the attention of with new its staff and its patients. The key to being and staying a success is always trying to better oneself. As endodontists, techniques we know that the more the referring doctor understands the changes the art of endodontics the more the patient benefits. way we The general dentist plays the key role in diagnosis of the tooth, but planning treatment in a case is difficult in itself. evaluate It’s hard to look at a radiograph and know whether the root previous root Amy Dukoff canal therapy failed due to a missed canal, underfilled canal, canal therapy. or a crack. Whether to retreat a case or just have the tooth extracted is usually a difficult decision. Diagnosing the cause of pain can be troublesome to the practitioner. As specialists, we believe that it is important to share new trends in endodontics with general practitioners, for they face a variety of different cases and treatment options. It is important for the specialist to work as a team with the general practitioner, sharing information. Staying current with the latest trends will allow the general practitioner to better evaluate teeth that have previously had root canal therapy, as well as diagnosing whether root canal therapy is indicated. Endodontics has changed in many ways. Keeping up with new techniques changes the way we evaluate previous root canal therapy. When one encounters an old silverpoint fill without a rarefaction or symptom, does that always mean that one should retreat? When a thin, filled case looks good yet still has thermal and percussion symptoms, does one retreat even if it looks “good” at first glance? Our evaluation of previous root canal therapy has also changed due to the way we now shape the canals. Today, we advocate enlarging the canal system to a .08 taper with nickel titanium versus the traditional step-back technique. Also, we encourage enlarging the apex with a # 35 SafeSiders® reamer. The larger apex size along with the greater taper allows for a cleaner and well shaped canal that tends to correlate to the architecture of the canal structure. Looking at a finished tapered canal is quite different from looking at a conventional 0.02 taper.

September - October 2005 FEEDBACK?

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We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Amy Dukoff, D.M.D. To Treat or Not to Treat

Amy Dukoff OME NEW PATIENTS come to your office after Making the having sought you out because they feel that you’re the right decision one who can solve their problems. They have been “all over” and no one has been able to find what is causing their creates a better pain. But they are sure that you can. The patient may bond between localize the pain to one side, and then it’s up to you. You are you and the in a difficult position. It’s tempting to tell the patient that what another practitioner did was not as good as what you patient. could do. Don’t give in to that temptation. In addition, don’t Amy Dukoff be too quick to treat a tooth. Take the time for a thorough evaluation and diagnosis, and take the time to establish trust and confidence between patient and practitioner. I had a patient present herself to my office with pain in the upper right quadrant. She had had three new posterior composites placed a few months earlier. She did not know the source of her pain. On her first emergency visit, it seemed that tooth #4 could easily be isolated as the source, due to her intense symptoms of thermal pain and the depth of her filling as revealed radiographically. However, the next day she returned with the pain continuing and hardly abating. Her two other molars, #2 and #3, seemed as if they might also need root canal therapy. However, with her wisdom teeth present and pressing on teeth #2 and #3, a consultation with an oral surgeon regarding the wisdom teeth was in order. Upon her visit there, the surgeon confirmed that both wisdom teeth would need extraction at a later date, and that tooth #2 did need root canal therapy. The patient returned the same day to initiate treatment. At that time, even though she would need root canal on tooth #2, and probably to tooth #3, she felt very comfortable with the treatment plan. A level of trust and confidence had been built between us because I had not rushed to initiate treatment on the teeth but instead took care to ensure that therapy was a necessity. In her case, root canal therapy was the answer. However, there are other reasons for odontogenic pain, which are not pulpal in origin. It is important to understand the other causes of odontogenic pain while diagnosing. The factors that can provoke pain include postural changes, occlusal disharmony, sinus involvement, and hormonal changes. Of course, an accurate history describing the pain must be taken; this can help in diagnosing non-odontogenic facial pain,

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which may be caused by trigemial neuralgia, cluster headaches, acute otitis media, acute maxillary sinusitis, or temporomandibular joint, to name a few. Making the right decision creates a better bond between you and the patient while the patient gains trust in your diagnostic skill.

November - December 2005 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Allan S. Deutsch, D.M.D. Broken Endodontic Instruments: Watch Out!

f all the complications that might occur while you are doing an endodontic procedure, one of the very worst is instrumentation breakage—in other words, “file separation” in the canal. Throughout my more than twenty years of practice, breaking an instrument in the canal has always been a major no-no for anyone doing endodontics. Recently, with the advent of rotary NiTi instruments, the manufacturers of these instruments seem to want us to believe that breakage is not such a problem anymore. Allan Deutsch Unfortunately, that is not the reality of the situation. Breakage is a problem, it remains a problem, and with the ENDO TIP advent of NiTi instruments it is becoming an even larger problem. If it were just the instrument’s breaking in the canal and there were no consequences, breakage would not really mean too much. However, when we break a small-size instrument To keep (#08 through #25), we effectively block the canal. When the canal is blocked, we cannot remove all the dead or infected breakage at a pulp tissue. Necrotic tissue in the canal leads to infection or minimum, chronic inflammation and endodontic failure. If we break or examine every separate a larger-size file, the broken section is usually easier file before use, to get around or bypass, and we can clean out the canal adequately. However, sealing the canal well may be difficult. don't overuse Poor sealing will also ultimately lead to endodontic failure. them, and don't By the way, there is really no foolproof way to remove overstress broken instruments. Removal must be approached on a case- them. by-case basis with a great deal of patience, skill, and luck in the equation.

The Strength of Stainless Steel STAINLESS STEEL instruments are the most resistant to breakage, and reamers are more resistant to breakage than files. Therefore, more than 25 years ago we switched over to using stainless steel reamers as the mainstay of our instrumentation. However, even these instruments break. In Figure 1, we see the most common form of deformation of the stainless reamer, “the shiny spot.”

FIGURE 1: The shiny spot on the reamer is caused by the unraveling of the reamer’s flutes.

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Figure 1

Here the flutes of the reamer (which form the cutting edge) are starting to unravel. The flutes usually unravel if the tip binds and we continue to rotate the reamer in a counterclockwise direction. If they are left to unravel more, they will eventually break. In Figure 2, just the opposite is happening. The flutes are knotting up. Once again the tip usually binds or wedges in the canal, and if we keep rotating the file in a clockwise direction the flutes will eventually break. FIGURE 2: Near the tip of Figure 2 the reamer we can see the flutes of the reamer knotting up like a twisted rubber band.

Only 1mm to 3mm of the instrument should be binding or doing work at the apical end. If more than that is binding, the instrument can easily lock into the canal and deformation can occur. Therefore, it is imperative to use the Peeso to prepare the coronal end of the canal, as described in the S.E.T. technique. The Peeso enlarges the canal so that the coronal end of the file or reamer does not engage the dentinal walls and hence the instrument only cuts at the apical 2?3 mm. This reduces the chance of breakage dramatically. Cutting in a wet canal also reduces the incidence of file or reamer breakage. Therefore, always keep the access opening wet with irrigating solution while you are debriding the canal. When stainless steel instruments do bind, luckily, we can see the deformation and act in time to throw out the instrument before it breaks in the tooth. Therefore, I strongly suggest that after each withdrawal of the instrument from the tooth the dentist should examine the file or reamer closely. Look for a shiny spot or a knot. If you see either of these, discard the instrument before it breaks in the patient’s root. Endodontic files and reamers should be considered disposable instruments. One to three uses and then out. Plan on spending approximately a total of $20 to $30 for all (SS and NiTi) instruments per endodontically treated tooth.

The Weaknesses of NiTi UNFORTUNATELY, the instruments least resistant to breakage are the NiTi files, especially the rotary files. It has been reported in the literature that NiTi begins to

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microfracture as soon as it is used in the root. No matter how light your touch, the NiTi microfractures. It is just a matter of time before the instrument fractures all the way. In the rotary handpiece, the combination of compressive and tensile stress causes the file to break even sooner. The faster you rotate the file and the more you bend the rotary instrument, the quicker it fractures. Unfortunately, NiTi instruments tend to fracture with no visible warning. The instrument may look perfectly normal, yet fracture in the tooth. In Figure 3, we are actually lucky enough to see a deformed NiTi file of “Greater Taper” before it has fractured in the root. This is a very rare event. Certainly, if we place this instrument back in the root it would fracture. FIGURE 3: Notice the Figure 3 slight deformation in the flutes near the apical end of the NiTi Greater Taper file. Next stop: breakage! We can do two things to help reduce the risk of NiTi fracture: Figure 4 1. Examine the file for deformations every time before placing it into the patient’s mouth. 2. Bend the file to at least an 80-degree angle, every time before placing it into the root, to see if it will fracture (see Figure 4).

If you are diligent and examine every file before use, don’t overuse them, and don’t overstress them, then you will keep your breakage to a minimum. If you use rotary NiTi files be FIGURE 4: Bending the very careful, because these are the easiest of all the NiTi file before placing it into the root. instruments to break. Good Luck!

November-December 2000

ENDO TIP Every time you remove a file or reamer from the canal, clean it off and examine it. If there are any shiny spots or knots, throw the instrument out. Consider endodontic instruments disposable!

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Allan S. Deutsch, D.M.D. Peeso and Gates Glidden Drills: They’re Not Just for Post-Hole Preparation!

bet that if you look on your bur stand you will find either a Gates Glidden drill or a Peeso reamer there. If you are like most of us, you have used them to make your post- hole preparations for years. These burs cut well, are reliable, and are relatively inexpensive. If they break, they break high up on the shaft next to the part that fits into the slow hand piece. Because they break so high up on the shaft they are usually very easy to remove from the tooth. Gates Gliddens and Peesos are not end-cutting, making them by definition Allan Deutsch reamers not drills. There is a nipple at the end of these instruments that prevents them from cutting at their tip. When the nipple engages the wall of a curved canal, the drill just spins and does not cut apically (see Figure 1).

Figure 1

FIGURE 1: Gates Gliddens and Peesos do not cut at their tips. Consequently, Gates Gliddens and Peesos will not Figure 3 perforate the canal in an apical plane. All in all they are very good instruments. Figure 2 shows a Gates Glidden drill on the left and a Peeso on the right. In Figure 3, we show an illustration of the main parts of each instrument. The differences are:

1. The cutting head is much smaller on the Gates vs. the Peeso. 2. The shaft is thinner on the Gates vs. the Peeso 3. The diameters of the heads are different for the same FIGURE 3: The main parts number instrument. of the Gates Glidden drill

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Figure 2

(left) and the Peeso (right). For example, the numbers on both the Gates and the Peeso are denoted by the number of circumferential grooves located on the shaft just below the cutout for the latch. FIGURE 2: A Gates Glidden drill on the left and Usefulness in Preparing Root Canals a Peeso on the right. Not only are these instruments good for making post-holes but they are exceptionally good for preparing root canals in an easy and reliable manner. They are especially good to use in a modified crown-down technique. Several years ago the “crown-down” method of root canal preparation was introduced. It stated that you should not prepare the apical end of the canal first, but rather that you should prepare the coronal end of the canal first. The dentist should use a large diameter instrument to go only 2-3 mm into the coronal end of the canal. Then the dentist should switch to a slightly smaller instrument and go a little deeper into the canal. This sequence is repeated until the apical terminus of the canal is reached with a small instrument. Over the years we have found this to be a very time consuming, not very predictable, and a fairly difficult technique to master. However, we did notice that Peeso and Gates reamers do offer a terrific way to use the crown-down technique to speed up instrumentation for the rest of the canal. Figure 4 The Crown-Down Technique in S.E.T. Figure 5 In other words, we use the crown-down technique as just one part of the overall S.E.T (Simplified Endodontic Technique). In essence, the Peeso and Gates Glidden drills represent the rotary instrumentation sequence in the Simplified Endodontic Technique. In the S.E.T. sequence, we first clean and shape the apex to a size number 20 (yellow) stainless steel instrument. If we would continue instrumentation without altering the canal at this stage, it would become more and more difficult to manipulate the larger number files or reamers in the canal. FIGURE 4: A typical This would occur because the coronal end of the canal would FIGURE 5: A larger file in mesial canal of a still be narrow, and the larger files would bind and work a typical mesial canal of a mandibular molar. along their entire length, both at the apical and coronal ends. mandibular molar. Figure 4 shows a typical mesial canal of a mandibular

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molar. It has a 60° curve within a very short or small radius. Figure 5 demonstrates a larger file in that canal. You can see that the file binds over almost the entire length of the canal and it is very bent or curved in that canal. Binding and bending are two situations that lead to instrumentation breakage. To lessen the chance of breakage, the file should only “work” or bind in the apical 2-3 mm of its flutes at any one time and the straighter the canal the better. This can easily be accomplished by using the Peeso or Gates to open up the coronal end of the canal to let the subsequent endodontic instruments do their job more easily. In essence we are doing a modified crown-down technique, using the Peeso or Gates. Figure 6 Straightening the Canal Once the apex has been instrumented to a size # 20 stainless steel instrument a number 2 Peeso or number 3 Gates is introduced into the canal. These instruments cut much better and more easily when used wet (Figure 6). If you do not have a slow speed with water spray use xylocaine, water from the triple syringe, or even irrigating solution. The instrument is introduced into the canal while it is spinning in the handpiece. Cut only 2-3 mm in depth, then remove the drill from the canal. Once the drill is out of the canal, clean the flutes of the drill with a wet gauze pad to remove the cut dentin. Now go back into the canal and cut another 2-3 mm deeper, as shown in Figures 7 and 8.

FIGURE 6: Peeso and Gates instruments cut Figure 7 better and more easily when used wet.

FIGURE 7: Cutting deeper into the FIGURE 8: Cutting deeper canal. still.

Continue in this manner until you have gone one-third to one-half of the way down the canal wall. The result will be that you have done two very good things:

1. You have lessened the curvature of the canal, usually from a 60° curve to roughly a 45° curve (see Figure 9).

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Figure 9 Figure 10

2. You have straightened out the canal, so there is less of a radius and the endodontic instruments do not have to bend as much.

The # 2 Peeso or number 3 Gates is equivalent to a # 90 FIGURE 9: Decreased instrument (0.90 mm). Therefore using these instruments curvature and a straighter opens the coronal 1/3 to 1/2 of the canal to 0.90 mm. This canal. will easily let any stainless steel instrument from # 25 to # 45 into the canal without binding in the coronal section of the FIGURE 10: Wider canal canal. results in less binding. Figure 10 illustrates a larger instrument in the canal that is loose in the coronal 1/2 of the canal. Because these larger stainless steel instruments now only bind in the apical 1/3 of the canal they can and do cut much or easily and with much less chance of breakage. Because they cut more easily, the instrumentation of the canal goes much faster. The instrumentation in general becomes much more predictable and easy. Predictable behavior and ease of use: a very good combination. Once the canal is instrumented in a step-back fashion (see “Introduction to Simplified Endodontic Techniques”) to a # 40 or # 45, the Peeso or Gates can be re-introduced into the canal to deepen the coronal flare closer to the apex by 1 to 2 mm if desired. The dentist can even widen the coronal flare at this point by using a # 3 Peeso or # 4 Gates if so desired. Figures 11 and 12 represent the canal in the before and after stages of Peeso or Gates preparation.

Figure 11 Figure 12

FIGURE 11: The canal before FIGURE 12: The canal after prepartation. preparation.

In Conclusion . . . The use of these drills results in several good things:

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easier preparation of the coronal half of the canal easier preparation of the middle third of the canal by larger-diameter instruments. overall, a more predictable endodontic preparation in a shorter length of time more easily and with less hand manipulation and fatigue.

So many positives—no negatives—what are you waiting for! FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Allan S. Deutsch, D.M.D. Endodontic Retreatment: Removing Posts

e have found that in the last five to seven years we are doing fewer and fewer endodontic-type surgeries, that is fewer apicoectomies. The endodontics is becoming more and more predictable, and with the advent of better technology conservative endodontic retreatment has become the procedure of choice. However, in many instances before we can redo the endo we must first disassemble the restoration. This disassembly procedure can oftentimes be tougher than redoing the root Allan Deutsch canal. We have found out that clinicians across the country are charging a separate fee for disassembly. Removing a post in order to gain access to the root canal system and still leaving a restorable tooth is no easy task. We used to just drill the posts out. However, the bur would often slip off the metal post and gouge out the post hole, sometimes dangerously thinning out the root to the point where it was not restorable. Now we have the microscope, and we are able to use a 1/2 or 1 round bur and see where to place it on the post. This has made drilling out the posts much easier. However it is still no picnic.

Initial Steps Before we begin removal, we must consider several factors in order to obtain a successful result. First, what type of post is it? Is it passive or active. Passive posts are held in with cement. Two typical passive post types are cast posts and paraposts. Active posts are typically threaded posts, like Dentatus, Vlock and Flexi-post. With both types of systems (active and passive), the first step is to expose the cement. Carefully remove all the core material around the post and expose as much of the post as possible right down to the coronal dentin of the post hole. Next, break the cement seal if possible or at least disturb it. It is at this stage that some new technology comes in handy. I just came back from Dr. Cliff Ruddles Endodontic retreatment course in Santa Barbara. He advocates, and we here on 57th street use, the “Spartan Ultrasonic” unit. Dr. Ruddle has designed a series of very thin and long Ultrasonic tips to be used in removing posts as well as separated endodontic instruments (see Figure 1). The Spartan ultrasonic is used dry at the lowest power setting. It cuts the dentin like the thinnest bur you can

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imagine. We now trough around the post and break up the cement. As you use this instrument, your assistant should be blowing air on the field to maintain your visibility. Naturally, since everything is so small you must use either some type of magnifying glasses or a microscope. In many instances, once the cement seal is broken the post will begin to vibrate and soon come out, if it is a passive post.

Removing Threaded Posts If it is a threaded post , you can now place either the wrench or a hemostat on the post and thread it out of the root. If the post is not moving, you can apply a thicker ultrasonic tip directly to the post and let it vibrate the post for several minutes. You can even hold the post with a forceps and touch the ultrasonic tip to the forceps and hence the post. If the post still won’t budge, you can use the Ruddle post removal system made by Analytic Technology. Here a trephine is drilled over the post to standardize the post’s diameter. Next, a tap is threaded onto the post. Finally, the extraction plier is placed onto the tap. At this point, an ultrasonic tip can be placed onto the tap and again loosen or disturb the cement seal. Now the extraction plier is activated and the post is removed. Yes, this really does work! The beauty of all these procedures is that the post is removed without “bombing out” the inside of the root. Because if you can’t restore it, what good are you really doing for the patient?

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Allan S. Deutsch, D.M.D., F.A.C.D. The New EZ-Change Overdenture Attachment: Maximum Retention with Minimum Stress

nlike most articles that appear in Endo-Mail, this article does not have anything to do with endodontics directly. However, when we developed the Flexi-Post, we also made an overdenture attachment to go along with it. That overdenture attachment is affixed to an endodontically treated tooth. Voila! That’s the connection between this article and endodontics. This simple ball-and-nylon-socket attachment has been successfully used around the world for the past fifteen years. Allan Deutsch Many articles about the attachment and the technique have been published in international dental journals. The EZ- Change Overdenture Attachment has been found to have the highest retention among all overdenture attachments being sold. Yet installing it is a very simple and direct technique to do. So why am I talking about it here? Recently, we have improved it and now offer it as an implant attachment. Advantages of the EZ-Change Overdenture Attachment Unfortunately, not every root canal is a success, and many patients come to us with only a few teeth left in the arch. In addition, there are implant cases that start out with many implants placed and end up with only a few that have integrated. Also, many patients would like the convenience and esthetics of fixed restorations, but can only afford removable restorations for their implants. The restoration of implants with fixed cases is a time-consuming procedure that is difficult for the dentist to master. The operatory and laboratory aspects of these cases are quite complicated, and the majority of dentists in the United States don’t perform restorations of implant cases yet. The placement of the EZ-Change Implant Overdenture Abutment Attachment (from Essential Dental Systems) truly is “easy.” It’s a simple technique even if you have not restored implant cases before. It gives your patient a restoration that looks great and works even better. The Placement Technique O.K., so what do you need to perform this technique? Well,

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Figure 1

you don’t need teeth. If your patient has an existing denture, even better. If not, hold on to the bridgework that the patient currently has as a temporary restoration until the implants have integrated and are ready to be loaded (usually approximately six to nine months). Talk to your oral surgeon or periodontist to determine which implant type they are most comfortable in placing. Generally, they will be placing either FIGURE 1: A healing FIGURE 2: H indicates the screw allows the gingiva to a; Branemark , 3i, SteriOss, Calcitek, IMZ, or Paragon implant. gingival cuff height. heal in the desired shape. We have overdenture attachments that are compatible with these implants. Once the implant has integrated, whoever placed it will now surgically uncover it. A healing screw can now be placed to allow the gingiva around the implant to heal in the desired shape. The shape that we want is just a parallel cylinder from the top of the implant to the top of the gingiva (see Figure 1). Once the gingiva has healed, you will need to know the height (thickness) of this gingiva to determine the gingival cuff height of the implant overdenture attachment (labeled H in Figure 2). When you know the implant type (Branemark, 3i, Paragon etc.), and the gingival cuff height of the attachment , you will be able to pick out the exact implant OVD attachment from the catalog for your case. Before placing the attachment, the denture is constructed. You can let the patient wear it for several weeks until all the soft tissue is compressed and any wear spots are relieved. You can now remove the healing screw from the implant and, using the appropriate wrench, screw in the E-Z Implant Overdenture Attachment into the implant (Figures 3 and 4). Then the rubber band is placed over the ball attachment to block out the height of contour of the ball and prevent the acrylic from locking under the ball. Once the rubber band is in place the EZ-Change nylon cap and keeper are placed onto the ball (Figures 5 and 6). Figure 3

Figure 4 Figure 5 Figure 6

FIGURE 6: The cap and FIGURE 4: Screwing the E-Z Implant keeper in place on the FIGURE 5: The EZ- Overdenture Attachment into the ball. Change nylon cap and implant. keeper. FIGURE 3: Removing the healing screw from the implant. Some marking paste or Occlude marking spray is placed

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on top of the keeper. The denture is seated and then removed. The marking paste indicates the area in the denture that must be relieved to make room for the female nylon cap and keeper part of the attachment. The denture is then relieved. The denture is placed over the attachments and checked to make sure that it seats passively in place (Figure Figure 7 7). Pink cold-cure acrylic is mixed and poured into the relieved areas in the denture. The denture is seated while the cold-cure acrylic sets. After eight to ten minutes, the denture is removed. The metal keeper that holds the nylon cap is now incorporated into the denture permanently. The excess flash is removed, and the denture smoothed and polished. You can now remove the rubber band that is still under the ball and dismiss the patient. FIGURE 7: The denture is The nylon caps last about eighteen months to two years placed over the before they wear out and lose their retention. At that time, a attachments and checked to make sure that it seats special wrench is used to unscrew the nylon cap from the passively in place. keeper and a new nylon cap can be threaded in its place. This takes about thirty seconds to do and is a really simple and easy technique to start you off with implants. The attachments have a fifteen-year clinical history of happy patients and, consequently, happy dentists.

11/02/1999 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

[ﺩﻡﺡﻡ file:///D|/HEALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/asd04ezchange.html[2/21/2011 10:25:04 Irrigation: The Key to a Clean Canal

Allan S. Deutsch, D.M.D., F.A.C.D. Irrigation: The Key to a Clean Canal

HE PROCESS OF cleaning and shaping the canal is one of the key components of endodontic therapy. Currently, we dentists seem to be devoting a very large amount of our time to learning which file or reamer to use and how to use them. With this emphasis on instrumentation, another aspect of endodontic cleaning is often overlooked. That aspect is irrigation. Why Irrigate? Allan Deutsch WE IRRIGATE for several important reasons.

1. to lubricate the canal to make instrumentation easier 2. to remove the debris that is generated from instrumentation 3. to dissolve the tissue that adheres to the canal wall and in the nooks and crannies 4. to kill any bacteria that are living in the canal and dentinal tubules

No one irrigant does it all, but there is one that comes close. That irrigant is the old standby sodium hypochlorite. This chemical is the real hero behind a successful endodontic treatment. It comes very close to doing all the things we just mentioned and doing them very well. Sodium hypochlorite has only one big contraindication. Do not get it past the apex! If the hypochlorite is expressed past the apex, it causes an immediate inflammatory reaction. The patient will be in great distress due to severe pain and almost immediate edema (swelling), along with the good chance of ecchymosis. These sequelae unfortunately have been very well documented. An Ounce of Prevention

THE BEST TREATMENT is prevention. When we understand how the irrigant works, preventing mishaps becomes easy. Our main aim is to really use the chemical nature of the irrigant to do the work. We do not want to wash the canal with the irrigant; we merely want to place the FIGURE 1: A 30 gauge hypochlorite atraumatically into the canal and let it sit there. needle, below, with a 23 We can most easily place it in the canal a few drops at a time gauge needle, above. using a 30 gauge needle. This needle (see Figure 1) facilitates

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placement of the irrigant far up into the canal. Just express one or two drops and let it sit there. According to the literature, it does its job in about ten minutes. The free FIGURE 2: The Vista oxygen and chlorine do the work, not the flushing action of syringe warmer; perfect for squirting it into and out of the canal. warming 5 ml syringes of Keeping the hypchlorite in the canal for ten minutes does hypochlorite. two things. One, it dissolves the tissue tags of pulp that are inaccessible to instrumentation (and there is a lot of this tissue around). Two, it will also kill all bacteria that it comes in contact with in this ten-minute period. The hypochlorite will work faster and better if it is warmed. A nice syringe warmer made by the Vista company in California (shown in Figure 2) will easily keep five 5 ml syringes at around 105 degrees F. The hypochlorite works very nicely at this temperature. The easiest way to keep the hypochlorite in the canal for ten minutes is to leave it in the FIGURE 3: Instrumenting access cavity while you instrument the tooth, as shown in through the irrigant that Figure 3. Each time you introduce an endo instrument into fills the access cavity of a the canal it goes through the hypochlorite and will drag some molar. along down into the canal by capillary action. It is a good idea to change the irrigant in the access cavity frequently, because it accumulates debris. I will sometimes change the irrigant each time I shift to a different size of file in a three-canal or four-canal molar. On the other hand, I may change the irrigant only once or twice in a single-canal anterior tooth. With irrigation, the more the better. Sometimes you may want to use different concentrations of the sodium hypochlorite. Straight from the Clorox bottle it is 5.25 percent. This is pretty strong and is good for treating lower second molars with “C” shaped canals. These canals are very difficult to clean well with files alone, because the canal is not oval or circular in shape. The canal may have a lot of fins and outpocketings and may even be a web shape anatomically. The 5.25 percent hypochlorite, if left for longer than ten minutes, will dissolve the tissue tags that it comes in contact with and give you a better, cleaner result. Believe it or not, irrigation is just as important for cleaning the canal as instrumentation. You can never over-irrigate, so the more the better. For disinfection and cleaning, irrigation is the key to success.

January-February 2001

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Endo-Tip

FEEDBACK? We welcome your responses and When the length of a tooth approaches the maximal questions. depth of a 25-millimeter instrument, the interference Please feel free to visit of tooth structure or a metallic restoration may make the Endo Forum and placing the probe of the apex locator difficult. In such add your comments cases, it is easier to attain proper measurement about any of the articles control using a 31-millimeter instrument rather than a in Endo-Mail. 25-millimeter instrument. —Doug Kase

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Allan S. Deutsch, D.M.D., F.A.C.D. New EZ-Fill® SafeSider™ Endodontic Instruments

E HAVE been explaining, demonstrating, and teaching a new sequence of endodontic instrumentation for more than three years now. This sequence of instrumentation uses stainless steel instruments, Peeso reamers and NiTi instruments. Unfortunately, these instruments had to be purchased separately from different manufacturers and combined to perform the sequence in the dentist’s office. Not only was this inconvenient, but the instruments did not cut any better or easier than any other conventional instrument. After several years of development and testing, Essential Dental Systems Allan Deutsch has developed an endodontic instrument with a different geometry. These new SafeSiders™ have a flat that extends uninterrupted the entire length of the cutting edge (see Figure 1). If we look at any other endodontic instrument in cross section, we see that it has a circular profile. When we look at the SafeSiders in cross section, we see that they look like the letter D because the circular configuration has one side that is flat.

Figure 1: An ISO #25 stainless steel instrument, showing the position of the flat.

What the Flat Does

THIS FLAT does several good things: it makes the instrument easier to use, prevents the accumulation of dentin debris, reduces stress on the instruments, and increases the flexibility of the instruments.

1. Because the flat reduces the amount of the instrument’s cutting surface in contact with the canal wall, less dentin is engaged during each cutting stroke. This decrease in the engaged area results in a slightly less efficient instrument but one that is easier to use in the canal because it is not fully engaging the canal wall circumferentially. You may have to turn the instrument a few extra turns to completely instrument the canal, but turning it within the canal is much easier now because the entire instrument is no longer cutting the root. You will notice much less hand fatigue. 2. The flat gives the dentin debris that is generated during cutting someplace to go. The debris accumulates in the space between the flat and the canal wall. Therefore, the debris does not wedge

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between the instrument and the canal wall making the instrument more difficult to turn in the canal. As the instrument is turned, the debris falls into the space created by the flat, and you do not have to work against the accumulated debris. Because less dentin is being cut at any one time and the debris has someplace to go, you will find that the clinical effect is that it feels about 25 percent easier to instrument the canal using the SafeSiders. 3. Because less of the instrument is cutting at any one time, less stress is placed on the instruments. Lowering the stress lowers the chance of instrument breakage, and consequently the instruments last longer. They do not have to be replaced as often as conventional instruments. 4. The flat is not cut deeply into the core of the metal of the instrument, so it increases the flexibility of the instruments without sacrificing strength. The flat removes some metal from the length of the cutting edge to the tip, resulting in more flexibility, but the durability and strength of the instrument are maintained. Two NiTi Instruments

FIGURES 2 AND 3 show the configuration of the two NiTi instruments in the series. The Orange 30/.04 is an ISO standardized #30 at the apex with a .04 taper up the shaft. The flat can easily be seen to extend the entire length of the cutting surface to the tip. The other NiTi instrument is the Brown 25/.08. It is an ISO standardized #25 at the apex with a .08 taper up the shaft. This is the last instrument in the sequence; once the canal is prepared with this instrument it is ready to be obturated with a medium gutta-percha point. Once again we can see the flat extending the entire length of the cutting edge of the shaft.

Figure 2: Note the flat extending the entire length of the cutting edge Figure 3: Note the flat extending the entire length of the cutting edge of the NiTi 30/.04 instrument. of the NiTi 25/.08 instrument.

The Proper Cutting Stroke

ALL THE INSTRUMENTS in the sequence are meant to be used with a circular cutting stroke. An up-and-down filing stroke is not the way to go! Use a “wrist-watch-winding motion” while applying slight apical pressure. During the clockwise winding motion, a point will come when you feel resistance from the flutes of the instrument cutting into the dentin. At that point, go to a counterclockwise motion. When you now rotate the instrument counterclockwise, you will cleave off the dentin that was engaged between the flutes, and the instrument usually will move about 0.5 mm closer to the apex. Remove the instrument from the canal, clean off any debris, and inspect the instrument for any deformation. If the instrument looks fine, repeat the cutting procedure until the instrument goes to the desired

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length in the canal. When the instrument is spinning freely (in a clockwise direction) and does not engage the dentin, it is time to move to the next size instrument in the sequence. Always cut wet! It will make instrumentation much easier. Keep the canal flooded with irrigant at all times. When the canal is dry, you will find that binding, ledging, and other bad things occur far too easily. Remember, there is a learning curve to all new techniques. After completing four or five anterior cases, you will be surprised at how much easier endo will have become.

March-April 2001 FEEDBACK? Endo-Tip We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

Never place a straight instrument into the canal. Always bend the instrument slightly. This will lessen the chance of ledging the canal wall.

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Allan S. Deutsch, D.M.D., F.A.C.D. May the Sequence Be with You

VEN OBI WON KANOBI and Darth Vader, who both had their light sabers, would have been nothing without the years of Jedi training that taught them how to use those weapons. We are much luckier; it will not take years to learn the correct use of the SafeSiders™ in endodontics. After you have used the SafeSiders on perhaps two or three anterior teeth, you will wield them with the skill of the StarWars characters. When you use the SafeSiders, it’s not the force that holds the key to Allan Deutsch success, but the sequence. First, unsheathe your number 08 or number 10 instrument to measure the length of the canal. The best and most accurate way to perform this measurement is with a third-generation apex locator (Endex or Root ZX). Next, instrument to the apex up to the EZ-Fill® SafeSider™ number 20. These stainless steel instruments up to a size 20 are as flexible as NiTi. Always use a “wrist-watch-winding” motion, never an up-and-down stroke. The up-and-down stroke is much more likely to push debris toward the apex and block it. That stroke can also more easily ledge, eliptisize, and distort the apex. SafeSiders Sequence

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When you have instrumented up to number 20, you are ready to open the coronal end of the canal with a number two Peeso reamer. This instrument widens and straightens the canal. Always use the Peeso wet. Go in with a pecking motion, never all at once, and slowly gain depth in the canal. When you are a third of the way to halfway down and feel resistance—stop. You can now recapitulate to the apex with a number 20 to make sure it is open. At this point, we use the “step back” technique. We instrument 1 mm from the apex with a number 25, then 2 mm from the apex with a number 30. We then instrument 3 mm from the apex with a number 35 and 4 mm from the apex with a number 40. This part of the procedure goes very quickly. We then take the Peeso again and go into the canal to gain another 1 or 2 mm in depth. We can then open the apex to the number 25 and then the number 30 instrument. We are then ready for the final shaping of the canal with the NiTi instruments. We use the Orange 30/.04 NiTi instrument to the apex, and then we use the Brown 25/.08 instrument to the apex to give the canal its final shape. This shape allows a medium or medium-large gutta-percha point to fit wonderfully well in the canal. Figure 1 summarizes the various steps in the sequence. Good luck, and may the sequence be with you! May-June 2001

FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Allan S. Deutsch, D.M.D., F.A.C.D. Summary of a Recently Published Study One-Visit Treatment Using EZ-Fill Root Canal Sealer

N THE COURSE OF the last twenty years, Barry Figure 1 Musikant and I have published well over 125 articles in the top dental journals around the world. We have had articles about posts, cores, endodontics, composites, and even hand cream published in journals ranging from the Journal of Dental Research, the Journal of Prosthodontics, and the Journal of Endodontics, to Dentistry Today. But just recently, we published what I consider to be one of the most interesting and relevant articles we have written in the last Allan Deutsch twenty years. The article, “A study of one-visit treatment using EZ-Fill root canal sealer” was published in the June 2001 issue of Endodontic Practice. This article is important for us on two levels. First, it validates the clinical techniques of doing endodontics in one visit and using the EZ-Fill technique. Second, it gives us a yardstick to measure how well we are doing for our patients (your patients) on a FIGURE 1: The EZ-Fill bi- success-versus-failure level. I find it interesting to note that directional spiral spinning we could practice for more than 25 years and not know the cement laterally, not scientifically how successful our treatment has been for our apically. patients. We could know it empirically from what we saw on a daily basis in our office, but here is our first opportunity to actually quantitatively tabulate our clinical results. It was Figure 2A interesting to note that most of the failures (9 cases) were due to fractured teeth. In the remainder of this article, I will give you the highlights of this recently published paper. Introduction

VER the last fifty years, endodontics has seen the FIGURE 2A: Tooth advent of many new techniques and devices that have number 30, old root canal, been aimed at making the procedure easier and under treated and increasing the success rate of the treatment. Some have underfilled. worked well; others appeared to work well when the academic literature was reviewed, but in clinical practice Figure 2B success was not apparent. 1 As with any technique in dentistry, clinical success is the acid test. Many investigators have reviewed the literature on endodontic success vs. failure and have reported similar ranges of results. Pekruhn in 1986 reported on 15 studies.2 He found a failure range of 2.3 percent to 30 percent. This corresponds to a success range of 70 percent to 97.7 percent.

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Friedman in 1997 reported on 37 success vs. failure studies FIGURE 2B: Root canal done from 1956 to 1996.3 He found a reported success retreated and refilled using range for these studies of 59 percent to 98 percent. Weiger EZ-Fill obturation et al. studied the literature and reported a success range technique. 4 between 70 percent and 90 percent. Hepworth and Friedman reviewed studies of orthograde retreatment and Figure 2C found a range of success of 70 percent to 90 percent.5 Success for single-visit endodontic treatment falls in the high end of the ranges studied by these authors. Pekruhn reported a failure rate of 5.2 percent or a success rate of 94.8 percent in his study on one-visit root canals. 2 Soltanoff in his single-visit study reported a success rate of 85 percent.6 Oliet reported a success rate of 89 percent for single visit 7 FIGURE 2C: Two-year endodontic treatment, and Jurcak et al. in their one-visit recall showing complete 8 study on soldiers also reported a success rate of 89 percent. healing. Naturally, the optimum success rate, the one we all strive for, is 100 percent success. Unfortunately, there are too many variables in treatment, materials, diagnosis, and reporting Figure 3A methods to make this a reality. Certainly new endodontic techniques that report success rates in the high end of the ranges previously reported should be considered clinically successful treatments. Obturation of the root canal space has always been an arduous task with unpredictable results in two aspects. One aspect is how to thoroughly fill the canal lumen and the other is how to accurately and repeatedly place the root canal FIGURE 3A: Typical vital filling to the anatomic apex of the root. Poor results in either case at completion. No of these two critical areas can ultimately lead to endodontic periapical pathology. failure.6,7 A new obturation technique, EZ-Fill epoxy resin root canal Figure 3B cement and bi-directional spiral system from Essential Dental Systems (S. Hackensack N.J.) has been developed. This technique achieves the desired results in a predictable easy fashion. The aim of this study is to evaluate completed EZ- Fill endodontic cases for a successful outcome over a six- month to two-year time period. Materials and Methods FIGURE 3B: Six-month recall showed no HE TEST SAMPLE consisted of 145 patients seen in a pathology developed, private endodontic practice in New York, New York. healed and asymptomatic. Non-surgical root canal therapy was performed on 153 teeth in one or more visits during the time period from 1/1/97 to 12/31/97 by three endodontic practitioners. Each endodontic Figure 4A specialist had more than twenty years of experience in a “very New York City” endodontic practice. The following patient factors were also collected: age; sex; whether or not the tooth was vital; if non-vital, whether there was PAR (periapical area of radiolucency); number of visits to complete treatment (1, 2, or more); radiographic findings; type of failure; fracture status; extraction status. The instrumentation technique for the endodontic FIGURE 4A: Typical

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procedure was the same in all teeth studied. All teeth were completion x-ray of a one- treated with a rubber dam in place using an aseptic technique. visit vital case using the Access was achieved and the working length was determined EZ-Fill obturation using the Endex apex locator (Osada, Los Angeles, CA) technique. During instrumentation the canals were irrigated frequently with 2.5 percent sodium hypochlorite. The apex was instrumented to a size #20 stainless steel .02 tapered Figure 4B instrument. Next the canal was widened with a number 2 Peeso reamer, no closer than 3 mm from the apex. Thereafter the step-back technique was used to taper the canal. A size #25 stainless steel Flexo-reamer (Dentsply/Maillefer, Tulsa OK) was used 1 mm short of the apex. Then a size #30 stainless steel flexoreamer was used 2 mm short of the apex. Next a size #35 stainless steel flexoreamer was used 3 mm short of the apex. Then a size #40 stainless steel flexoreamer FIGURE 4B: Nine-month recall x-ray showing intact was used 4 mm short of the apex and finally a size #45 lamina dura and healing. stainless steel flexoreamer was used 5 mm short of the apex. Once the canal had been grossly prepared, either an .06 or .08 nickel titanium file of greater taper (Dentsply, Tulsa OK) Figure 4C was used to give the final shape to the canal. This sequence of instrumentation is known as the “Simplified Endodontic Technique” or S.E.T.9-11 The canal was then filled with either a fine-medium or medium gutta-percha point. The canal was obturated using the EZ-Fill system, which consists of a bi-directional spiral paste filler and epoxy root canal cement. The cement is an epoxy resin based cement like AH-26 but much more radiopaque. It is also very FIGURE 4C: Two-year biocompatible.9-11 The bi-directional spiral of this system recall x-ray showing ensures that the canal walls are covered with cement and that normal bone anatomy there is no or minimal cement past the apex. This controlled being maintained. coverage is achieved because the spirals at the coronal end of the instrument spin the cement down the shaft toward the apex while the spirals at the apical end spin the cement Figure 5A upward toward the coronal end. Where they meet (about 3-4 mm from the apical end of the shaft), the cement is thrown out laterally (Figure 1). A prefitted single gutta-percha point was placed to the apex. The tapered shape of the canal lets the excess cement escape coronally. The cement in the canal 12 seals the apex and all lateral and accessory canals. The excess gutta-percha was seared off, and the access cavity was FIGURE 5A: Tooth sealed with either glass ionomer cement or zinc phosphate number 15 showing cement. excess EZ-Fill epoxy resin At the end of the appointment, the patient was given both cement past the apex of the cardiac dosage of antibiotic and 600 mg of ibuprofen for the palatal canal. pain management. The patient was then instructed to return to his or her general dentist, who would restore the tooth. Figure 5B Clinical and Radiographic Examination

RECALL CARDS were sent and telephone reminders were made to 363 patients. We were able to recall and evaluate 153 treatments in this study. At the recall examination, from six to twenty-four months

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after treatment, we recorded pain; tenderness to percussion, palpation, or both; fistula development; and swelling. FIGURE 5B: Two-year recall x-ray showing Radiographic examination, using the long cone technique complete resorption of with a Siemens Heliodent x-ray unit, was carried out using cement and healing. an x-ray film positioning device by Rinn (Rinn Corp., Elgin IL). Success was defined as: • On radiograph a preexisting lesion had gotten smaller or healed completely. • On radiograph no new lesion had formed where there was no lesion before. • The patient upon questioning at the recall examination was asymptomatic. • The patient was functioning well with the tooth. All radiographs were examined by a single endodontist, and patients were clinically examined at recall by the endodontist who did the treatment.

Statistical Methods

THE FISHER EXACT TEST was used to determine whether outcome (success, non-success), was associated with sex, number of visits, vital status, and, among non-vital teeth, presence of PAR. Due to the small number of unsuccessful outcomes, a multivariate analysis could not be carried out. Results

RECALL CARDS were sent and telephone reminders were made to 363 patients. We were able to recall and evaluate 153 treatments in this study. This was a recall rate of 42 percent.

Baseline Characteristics

MEAN AGE of the patients was 53 and ranged from 20 to 85. There were 61 percent females and 39 percent males in the study. There were 57.2 percent vital teeth and 42.8 percent nonvital teeth in the study. Of the non-vital teeth, 66 percent did not have a PAR and 34 percent did have PAR.

Outcomes

THE OVERALL TREATMENT estimated success rate was 94.1 percent. This was found at the exact 95 percent confidence interval: 89.1 percent to 97.2 percent. There was a frequency of 9 unsuccessful and 144 successful endodontic treatments. There was strongly no significant association between success rate and each of the following variables:

number of visits P = 0.442 vitality P = 0.757

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sex P = 0.707

Therefore there was a 94.1 percent success rate regardless of whether treatment took one or more visits, whether the tooth was vital or nonvital, and whether the patient was male or female.

Discussion

IT WAS STRONGLY FELT that clinical success was an important aspect of a successful outcome. Success rates reported over the last twenty years have ranged from 78 percent to 95 percent. Our result of 94.1 percent success fits well within this range. Differences in the definition of success most probably would alter the overall result of each study. However, it is difficult to determine by how much each study’s results would change. Our feeling is that individual studies may change slightly, but the overall range would most likely be the same due to other variables. These other variables include the skill of operators, who and how many people review the x-rays and cases, the techniques used, the materials used, and the time frame of the recall exam. In this study, three endodontists who each have more than twenty years of experience in private practice treated all the patients. This high level of clinical experience could possibly be one reason the success rate was on the high end of the scale. In a study by Sjogren et al., undergraduates at the University of Umea did the endodontic therapy and had a 91 percent success rate. 13 We used one endodontist to read the x-rays and evaluate the patients clinically. This helped reduce the variable of different opinions by different evaluators as described in the articles by Goldman and Seltzer.14,15 The authors tried to eliminate the variables of technique and materials in this study by using the same instrumentation technique and materials for each patient. We followed the S.E.T. technique for instrumentation and used the EZ-Fill epoxy resin root canal cement and bi-directional spiral obturation technique with a single gutta-percha point. Friedman et al. reported on a clinical study to assess the treatment results following endodontic therapy using a glass ionomer cement sealer (Ketac-Endo, ESPE Gmbh, Seefeld, Germany).16 They found a 78.3 percent success rate and concluded that their results were compatible with those found in the literature and that this supports the clinical use of Ketac-Endo as an acceptable endodontic sealer. In this study, EZ-Fill epoxy resin root canal cement (a derivative of AH 26 root canal cement) was used; Figure 5B illustrates complete resorption of excess cement after a two- year recall. The recall time frame shows the majority of patients at six months, with the next highest groups at one-year and two-

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year recalls. We were able to recall and evaluate 153 treatments out of 363 in this study. This was a recall rate of 42 percent. This correlates well with a mean recall rate of 43 percent for other studies as reported by Pekruhn.3 In agreement with other studies, there was strongly no significant association between success rate and: • the number of visits • vitality • patient sex Whether the tooth was treated in one visit or in more than one visit did not affect the success rate. Teeth treated in one visit were equally as successful as teeth treated in more than one visit. Whether the tooth was vital or nonvital did not affect the success rate, and whether the patient was male or female did not affect the success rate in this study. Interestingly, in a study by Vire of 116 extracted endodontically treated teeth, failure that led to extraction of these teeth occurred due to endodontic causes in only 8.6 percent of the population. 17

Conclusions

A SUCCESS RATE of 94.1 percent was found for this study using the EZ-Fill bi-directional spiral and epoxy resin root canal cement to obturate the canals. This correlates very well with reported success rates of between 78 percent and 95 percent in other studies. There was no significant association between success rate and each of the following variables: number of visits, sex, and vitality. These results support the clinical use of the EZ- Fill obturation system as an acceptable endodontic technique and sealer.

References

1. Orstavik D, Kerekes K, Eriksen HM. Clinical performance of three endodontic sealers. Endod Dent Traumatol 1987; 3:178-86. 2. Pekruhn, RB. The Incidence of Failure Following Single-visit Endodontic Therapy. J Endodon 1986; 12:68-72. 3. Friedman S. Success and Failure of Initial Endodontic Therapy. Ontario Dentist 1997; 74:35-38. 4. Weiger R, Axmann-Kremar D, Lost C. Prognosis of conventional root canal treatment reconsidered. Endod Dent Traumatol 1998; 14:1-9. 5. Hepworth M, Friedman S. Treatment Outcome of Surgical and Non-Surgical Management of Endodontic Failures. Journal of the Canadian Dental Association 1997; 63:364-371. 6. Soltanoff W. A Comparative Study of the Single-Visit and the Multiple-Visit Endodontic Procedure. J

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Endodon 1978; 4:278-281. 7. Oliet S, Single-visit Endodontics: A Clinical Study. J Endodon 1983; 9:147-152. 8. Jurcak JJ, Bellizzi R, Loushine R. Successful Single- Visit Endodontics During Operation Desert Shield. J Endodon 1993; 19:412-413. 9. Musikant BL, Cohen BI, Deutsch AS. Rethinking endodontics: Attaining total obturation of the root canal system with a simplified system. General Dentistry 1999; Jan-Feb: 73-82. 10. Seidman D. A General Dentist’s Viewpoint of Two New Endodontic Techniques. Compendium 1999; 20: 921-932. 11. Musikant BL, Cohen BI, Deutsch AS. Report of a Simplified Endodontic Technique. Compendium 1999; 20: 1088-1094. 12. Cohen BI, Pagnillo MK, Musikant BL, Deutsch AS. The evaluation of apical leakage for three endodontic fill systems. General Dentistry,1998; Nov/Dec:618- 623. 13. Sjogren U, Hagglund B, Sundqvist G, and Wing K. Factors Affecting the Long-term Results of Endodontic Treatment. J Endodon 1990; 16:498-504. 14. Goldman M, Pearson AH, Darzenta N. Endodontic success: who’s reading the radiograph? Oral Surg 1972; 33:432-7. 15. Seltzer S, Bender IB, Smith J, Freidman I, Nazimov H. Endodontic failures-an analysis based on clinical, roentgenographic, and histologic findings. Part II. Oral Surg 1967; 23:517-30. 16. Friedman S, Lost C, Zarrabian M, Trope M. Evaluation of Success and Failure after Endodontic Therapy Using a Glass Ionomer Cement Sealer. J Endodon 1995; 21:384-390. 17. Vire DE. Failure of Endodontically Treated Teeth: Classification and Evaluation. J Endodon 1991; 17:338-342.

July-August 2001

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Allan S. Deutsch, D.M.D., F.A.C.D. Fitting the Gutta-Percha Point

HE ENTIRE endodontic procedure, from diagnosis Figure 1 through instrumentation, can be said to be just a prelude to the “fill.” The filling of the canal with gutta- percha visually displays to everyone all your preceding efforts and work that have led to this last step in completion of the root canal therapy. The most important part of this last step is the fitting of the gutta-percha point. The point must fit well enough so that you know with the utmost FIGURE 1: Tapered gutta- predictability what the final result will look like, even before percha points. Allan Deutsch you complete the procedure. If the preceding instrumentation has been done well the point will be very easy to fit and the result will be predictably excellent. So, exactly what do we do in fitting the point? Figure 2 Constant modification of our instrumentation over the years has led us to the EZ-Fill® SafeSider™ technique. This sequence of instrumentation allows us to fill the canal with gutta-percha easily, effectively, and quickly. The key to the fill is to make sure that the last two nickel-titanium instruments, the orange 30/.04 and the brown 25/.08, go to the apex easily with no binding. Once this is accomplished, we can fit the gutta-percha point and fill the canal. I use the tapered gutta-percha points (Figure 1). The 25/.08 prepares the canal to a .08 taper. Therefore, I use a .06 tapered gutta-percha point. Each manufacturer’s point varies slightly from the others, but most of the .06 tapered points are very close to specifications. I use either a 25/.06 or a 30/.06 gutta-percha point. I select the point depending on how easy it was to instrument to the apex with the 30/.04. This instrument opens the apex to a #30. FIGURE 2: Gutta-percha I now take a gutta-percha point out of the box and place it point fitted in the canal. in the canal. I use a locking forceps and grasp and lock the point at my reference mark. I remove the point and measure it on a finger ruler. Let’s assume for demonstration purposes that the working length of the canal is 20 mm. When I measure the point, it will either be right on the mark, long, or short of the measurement. If it measures 20 mm (about 80 percent of the time) you are now ready to fill (Figure 2). If it is long (usually by about 1 mm), just take a pair of scissors and cut off the extra mm. Replace the point in the canal, lock it at the reference point, and measure it again. Usually it will now fit. If it does not, just repeat the cut step. If it is short by 1 to 2 mm, you have a little work to do.

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There is an area in the canal that is a little difficult to clean. It is located about 5 to 8 mm from the apex. With our technique, you have instrumented 4 mm short of the apex to a 40 and you have gone down as far as you can go with the #2 Peeso. This sometimes leaves a “no man’s land” in that 5 to 8 mm zone from the apex. This is usually where the gutta- percha point is binding. There are two ways to handle this :

Select a different gutta-percha point. They are not all exactly alike and one point may be more or less tapered than another. Reinstrument this 5 to 8 mm area.

You can reinstrument by :

1. going deeper with the #2 Peeso if possible 2. going 5 mm short of the apex with a #45 stainless instrument then 3. going 6 mm short of the apex with a #50 stainless instrument then 4. going 7 mm short of the apex with a #55 stainless instrument then 5. going back to the apex with the 25/.08.

Once the “no man’s land” is reinstrumented, a new gutta- percha point should fit to the measurement. Now that you have fitted the gutta-percha point to the canal, you are ready to place cement into the canal and permanently seal the root-canal system.

September-October 2001

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Allan S. Deutsch, D.M.D., F.A.C.D. Bead Sterilizers: An Endangered Species?

HERE IS A PROBLEM looming on the horizon. That Figure 1 problem is, “How will we sterilize our endodontic reamers and files?” You may answer, “That’s no problem. I’ll use my bead sterilizer.” (See Figures 1 and 2.) Herein lies the problem. Thanks to the local manicure salon, the FDA has stopped the sale of new bead sterilizers by the manufacturers. These nail salons were and are using bead sterilizers to sterilize large hand instruments. These instruments include nail scissors and cuticle cutters. Allan Deutsch Unfortunately, the beads did not do a great job on those instruments, and many customers had their nail beds infected by bacteria or fungus. Certainly, this was and is a problem. The FDA received enough complaints to warrant an FIGURE 1: One type of investigation. They determined that if a manufacturer wanted bead sterilizer. to make and sell bead sterilizers they would now have to file for a PMA (Pre-Market Approval) with the FDA. This requires rather large sums of money for testing. Many manufacturers logically decided that the expense was not worth it for a $100 device. Therefore, the manufacturers of Figure 2 bead sterilizers are no longer making these sterilizers for dental or nail use. So, what can you do? The problem isn’t a crisis yet. We still have a few years’ supply of bead sterilizers left. If you are worried, try to stock up on as many old units as you can. However, good luck, because there do not seem to be many around. And when our sterilizers burn out, what are our options?

We could pre-package setups of sizes 08 through 25/08 FIGURE 2: Another type of SafeSiders, in foam sponges in sterilizer bags. Along bead sterilizer. with the assorted sizes, we would need separate bags of perhaps three or four of one size of the smaller-sized instruments, in case they bend or become distorted. We could use covered metal sterilizer organizers. These are filled with assorted instruments, the cover is closed, and then the organizer is bagged. When the bag is opened after sterilization, the box and its contents are sterile. When you remove the cover and turn it over, it can be used as a sterile tray when placed on the bracket table. I used this type of setup when I first started to practice. It takes some getting used to.

The problem here is that unused instruments are exposed to

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repeated sterilization cycles. This tends to heat-harden the instruments and in many cases may make them more brittle. It seems to me that we will be going through a lot more instruments per case. All in all this is a problem that will not go away and is getting worse. What will the manufacturers come up with to help us out? If you have any ideas, please contribute them to our Endo- Mail Forum.

November-December 2001

The most common source of post-operative pain after FEEDBACK? endodontic treatment is pressure brought on by hyper- We welcome your occlusion. Before releasing your patient, be sure to check the responses and questions. bite with the patient in a reclined and upright position and Please feel free to visit relieve any high spots. If the tooth is going to be restored with the Endo Forum and full coverage, you can even take the tooth totally out of add your comments occlusion. about any of the articles in Endo-Mail.

[ﺩﻡﺡﻡ file:///D|/...LTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/asd10beadsterilizers.html[2/21/2011 10:25:07 Apex Locators: A Mechanical Method of Controlling Post-Operative Pain

Allan S. Deutsch, D.M.D., F.A.C.D. Apex Locators: A Mechanical Method of Controlling Post-Operative Pain

OR MANY YEARS, I thought the definition of Figure 1 endodontic esthetics was the filling of the root canal to the radiographic apex. Little did I realize that I was creating unneeded post-operative pain and possibly setting up a chronic inflammatory response, which might lessen the chances of a successful endodontic treatment for my patients. The inflammatory response triggers the type of pain that occurs immediately after the anesthetic wears off. This pain is characterized by a sharp intense quality with throbbing in Allan Deutsch the affected area. Where was I going wrong? The endodontic literature during the 1990s reported that the anatomic apex is often (at least 50 percent of the time) 0.5 to 1.0 mm short of the radiographic apex. The anatomic apex is usually defined as the apical constriction in the canal at the cemento-dentinal junction. If the canal is instrumented and FIGURE 1: Endodontic filled to this level, the instrumentation and filling material instrument past the will not impinge on the periodontal ligament or the alveolar anatomic apex going to the bone. radiographic apex. (Ouch!) The problem was that I was instrumenting and filling to the radiographic apex (Figure 1). Consequently, I was instrumenting at least 50% of the time from 0.5 to 1.0 mm past the apex and into the ligament and bone. For thirty to forty-five minutes, I was using my reamers to poke tiny holes Figure 2 and rip the periodontal ligament. The result of this was nasty pain as soon as the anesthesia wore off. Using an apex locator will enable you to determine accurately where the anatomic apex is located. An x-ray will not permit you to locate the anatomic apex. We do not routinely take working-length x-rays any longer. Because we are no longer instrumenting to the radiographic apex but rather to the anatomic apex, the amount of post-operative pain has been substantially reduced. Now that we are filling to the anatomic apex, we are experiencing an increase in success rate. Figure 2 shows a gutta-percha filling pushing through the anatomic apex, which is approximately 2.00 mm short of the radiographic FIGURE 2: The gutta- apex. We recently published our office success rate in a percha point is fitted to the study in the June 2001 issue of Practical Endodontics. In the radiographic apex and article we reported a 94.1 percent success rate. This is at the consequently it is 1 mm

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very high end of the reported literature. You never get 100 long. percent success because cases fail due to root fracture and inadequate or failing restorations. Figure 3 is a radiograph of a tooth that is rotated, showing the bucco-lingual view. You can see that the anatomic apex is at least 1 mm short of the radiographic apex. Figure 4 shows a dot of gutta percha at the apical end of the palatal canal. This dot is approximately 1 mm short of the radiographic apex. The dot tells us that the canal is curved at a 90-degree angle facing the buccal, so in actuality you are looking at the end of the gutta percha facing directly buccal. If you tried to reach the radiographic apex, you would have to perforate the root and come out the top.

Figure 3 Figure 4

FIGURE 4: The palatal canal is curved at a 90 degree angle to the buccal. The end of the gutta percha is seen as a dot.

FIGURE 3: The anatomic apex is at least 1 mm short of the radiographic apex.

The moral of this article is: if you do more than 3 or 4 root canals per week, go buy an apex locator. I recommend at least a third-generation locator, Endex by Osada, Root ZX by Morita, or the locator made by Analytic Technologies. Happy measuring.

January-February 2002

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Allan S. Deutsch, D.M.D., F.A.C.D. Which Burs to Use for Endo?

lthough completing a molar endo may take up to one Figure 1 hour, the time I actually spend drilling on the tooth is relatively short. Out of that one hour I may only take five to eight minutes drilling with my high-speed burs. However, like many other preliminary procedures those initial minutes are exceedingly important to setting up the final result. What do we want to accomplish when using our high- speed handpiece? Allan Deutsch 1. We want to gain access to the pulp chamber (without perforating the chamber floor). 2. This access will enable us to find all the canals (even the ones that are hiding!) 3. We want to have straight line access so that we can use FIGURE 1: The ceiling of our Peeso or gates to its full extent without having it the pulp chamber break. measured from an occlusal 4. We want to reduce the occlusion somewhat to avoid cusp corresponds to length post-operative biting trauma and inflammation. “L” of the bur.

In golf, a good grip enables a good swing, which gives us a good game (we hope). In endo, finding the chamber enables us to find the canals, which enables us to complete the root canal therapy. To this end I use two burs. These Figure 2 burs accomplish 95 percent of my drilling. The first is a high-speed carbide number 4 round bur. With this bur, I outline the chamber occlusally and remove enough dentin until I am in the pulp chamber. This bur can actually help you avoid perforations. Figure 1 shows the critical measurements on the bur. It turns out that the ceiling of the pulp chamber measured from an occlusal cusp corresponds to length “L” of the bur. When you hold the bur up over an accurate x ray you can see that when the ball is placed on the chamber ceiling the end of the taper of the FIGURE 2: The end of the shaft corresponds to the cusp tip (see Figure 2). I now for the taper of the shaft first time have a measurement guide as to how far down I am corresponds to the cusp to drill into the tooth with my #4 round bur. tip. When I look at the diagnostic x ray, one of things that I am looking at is the occlusal gingival height of the pulp chamber. If the chamber is calcified, and therefore very narrow, I know I will not feel a drop when my bur reaches the chamber. I therefore drill down to the line on the bur where the taper and parallel parts of the shaft meet and stop

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when this line is level with the cusp tip. I now know I am a little below the ceiling of the pulp chamber. This has given me the depth and a very rough outline of the chamber, I must now refine this preparation. I refine the preparation with the use of a high-speed coarse barrel diamond (Figure 3). I lean the diamond against the axial wall and go around the outline of the prep (Figure 4).

Figure 3 Figure 4

FIGURE 3: a high-speed coarse FIGURE 4: smoothing the wall barrel diamond used to refine the and allowing light into the preparation. chamber.

This smooths the wall and allows a great deal of light into the chamber. I next rinse the pulp chamber with Sodium Hypochlorite. I remove the irrigant with a high-speed endo suction tip. I can now easily see whether I have removed the entire ceiling of the pulp chamber. Now I first start looking for the canals. I also use this barrel diamond later to reduce the occlusion to avoid post-op pain due to prolongation of inflammation due to a high bite. The barrel diamond is also used to push back the mesio-palatal axial wall in maxillary molars. Along this mesio-palatal line in about 4060 percent of the cases there is an extra canal. This canal is called the MB2 or mesiobuccal prime canal. It is responsible for a lot of molar endo failures if it is missed and not cleaned out. Simplifying your armamentarium down to two burs will speed up and simplify your endodontics.

May-June 2002

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Allan S. Deutsch, D.M.D., F.A.C.D. Relief of Dermal Sensitivity Caused by Latex Gloves

INCE THE ADVENT of universal precautions Figure 1 against infection has led to the routine wearing of latex operating gloves, concern regarding hypersensitivity reactions to these gloves has been increasing. This concern can be seen in the numerous articles now being published on this topic. In November 1994, Gordon Christensen’s Allan Deutsch CRA newsletter reported on a survey of dermal FIGURE 1: Cracking of the skin due sensitivity. Twelve percent of 28,858 respondents to dryness. reported experiencing some type of reaction to

various types of operating gloves. Latex gloves

were by far the most common cause of problems,

but vinyl and nitrile rubber also caused some

problems. The most common reactions were

itching, redness on the contact area, or both dry skin on the contact area cracking skin on the contact area

What Causes “Dry” Skin?

IN HIS CLASSIC STUDY, Blank showed that lack of water, not lack of oil, was the primary cause of dry skin, proving that the softness and flexibility of the stratum corneum was a direct function of the moisture in it. Blank concluded that cornified epithelium required 10 percent to 20 percent water content to feel and look “normal,” since water was the most effective “plasticizer” for cornified tissue. Blank emphasized that neither an externally applied oil, nor the “natural” oils, can keep the stratum flexible without the aid of water.

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Figure 2

FIGURE 2: Layers of the epithelium.

Flesch in a discussion of the chemical basis of emollient in the horny layers, found evidence that the skin contains hydrophilic nitrogenous substances as well as other hydrophilic substances, which enhance the ability of the skin to hold water. When these substances are extracted from the skin, its ability to hold moisture is greatly diminished. In addition, in various skin conditions associated with scaling, the scales appear to have lesser amounts of these substances as well as a low capacity to bind moisture.

Figure 3

FIGURE 3: Structure of the skin. Recent work has brought to light a number of interesting facts concerning hydration of the stratum corneum. For example, it has been found that the stratum corneum contains water-soluble compounds responsible for the wetability, water-holding, and water-absorbing capacities of this tissue, which are called collectively the “natural moisturizing factor” of the skin, or NMF. Thus, the stratum corneum contains 58 percent keratin, 11 percent lipid, and 30 percent water-soluble NMF. Table 1 gives the chemical composition of NMF. The presence of NMF in the stratum corneum

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Table 1

serves a triple purpose:

1. It picks up moisture through its hygroscopic properties. 2. It lowers the surface tension of the skin surface, overcoming the normal water repellency of the keratin. 3. It will absorb liquid water present on the skin surface from perspiration or from outside sources.

We can conclude that NMF regulates the water content of the stratum corneum. Striase concludes, from all of the data disclosed, that an occlusive agent alone would not perform as the ideal moisturizer, nor would a hygroscopic moisturizer alone act as the ideal moisturizer. However, a proper balance of the two might achieve the desired result. Thus the “ideal” moisturizer should have the following properties:

It must regulate and maintain the water content of the stratum corneum, but not to such a degree as to induce superhydration. Its effectiveness should be independent of environmental changes. Its continued application must not cause damage to the stratum corneum by the removal of or interference with the natural moisturizers present therein. It must be nonirritating and nonsensitizing. It must be stable in cosmetic formulations. It must be economical and readily available.

At present, it is not certain which of the various components of MNF plays the most significant role. In the past, urea was apparently considered important, resulting in a plethora of dry skin remedies containing urea. Using in vitro experiments, Hellgren and Larson concluded that:

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The long-term use of urea-containing dermatologic preparations may “reduce” and damage the horny layer of the skin. Sodium chloride does not damage the skin. Sodium chloride has twice the water-binding capacity of urea and thus should be considered a superior moisturizing agent.

It has long been known that the presence of sodium chloride in water tends to retard its vaporization. The use of sodium chloride by Ljungstrom in 1941 predates the employment of urea for dry skin and ichthyosis by Rattner in 1943. Ljungstrom achieved good results in a patient with ichthyosis using baths containing 3 percent salt water, followed by inunction of 10 percent sodium chloride in lanolin. Gordon, employing Ljungstrom’s regimen in one case of ichthyosis vulgaris and in another of ichthyosis hystrix, reported that both responded dramatically. He claimed that the patient with ichthyosis hystrix, who looked like a “porcupine man,” was “rehumanized.” Despite such glowing reports, sodium chloride ointments were not employed extensively because patients were reluctant to consent to the use of the thick, greasy ointments then available. “Dead Sea Salt” Cream for Dry Skin (Glove’n Care™)

BECAUSE topical preparations containing urea were not particularly effective in some patients with dry skin and also sometimes caused stinging, burning sensations, we undertook an investigation of the use of creams containing sodium chloride, which have been shown to be more effective and less irritating than creams containing urea. Without understanding the exact physiology of healing, we do know that the Ancients discovered the beneficial effects of the waters of the Dead Sea more than four thousand years ago. These benefits included a therapeutic improvement in such skin disorders as psoriasis and eczema as well as an enhancement of normal skin. The Dead Sea was actually the site of a major cosmetic industry in Ancient times. Queen Cleopatra enjoyed the benefits of Dead Sea cosmetics so much that she persuaded Mark Antony to establish control over portions of the sea and then give them to her as a gift. Because Europe was the focal point of western culture, the Dead Sea remained for a long period obscure and almost unknown in the backwaters of a

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provincial people. It was not until the formation of the modern state of Israel that the waters of the Dead Sea became recognized worldwide for their therapeutic value. Today more than 600,000 tourists travel to the Dead Sea annually. In fact, for those traveling from Northern Europe, a trip to the Dead Sea is a recognized medical expense. Goldberg and Sagher state that the Dead Sea has no drainage and therefore contains a very high concentration (up to 30 percent) of minerals, including sodium, potassium, magnesium, calcium (and halogens), chlorine, bromine, and “others.” At the suggestion of Essential Dental Systems, a processed and purified concentrate of Dead Sea water (5 percent) was incorporated into a water- based emulsion. The emulsion was water-based so that it would not compromise the integrity of the latex glove or interfere with adhesive dentistry. It is of interest that Glove’n Care hand cream contains all of the minerals present in NMF (see Table 1). From theoretical and practical viewpoints, Glove’n Care hand cream has many of the virtues that Striase enumerated as the properties of an ideal moisturizer:

It contains an effective hygroscopic moisturizer: water of high saline content. It does not cause burning, stinging, or other unpleasant sensations and is well tolerated on the lips and skin. It is nonsensitizing and nonirritating and does no damage to the stratum corneum, even after repeated applications. By hydrating the stratum corneum, it quite effectively relieves the scaliness, dryness, and pruritus associated with dry skin, with resultant softening and increased pliability of the skin. It is stable chemically and physically for long periods of time, requires no preservatives, and is free of perfume, thus lessening the possibility of allergic contact dermatitis from such added ingredients. It is inexpensive. It seems to prove that the dermatologists of “the good old days” were correct when they claimed that sodium chloride is an excellent “moisturizer.” It contains the electrolytes present in NMF- sodium, chloride, calcium, potassium and magnesium. It contains a high concentration of sodium, which possibly enhances the moisturizing effect of PCA in NMF, since it is sodium

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PCA, not PCA alone that is hygroscopic.

References

1. Blank JH: Factors which influence the water content of the skin. J Invest Dermatol 18: 433, 1952 [BACK] 2. Flesch P: Chemical basis of emollient function in horny layers. Proc Sci Sect TGA 40: 12, 1963 [BACK] 3. Flesch P, Jackson-Esoda EC: Deficient water-binding in pathologic horny layers. J Invest Dermatol 28: 5, 1957 [BACK] 4. Striase S J: The search for the ideal moisturizer. Cosmet Perfum 89: 57, 1974 [BACK] 5. Hellgren L, Larson K : On the effect of urea on human epidermis. Dermatologica 149: 289, 1974 [BACK] 6. Ljungstrom C E: A simple and effective treatment of ichthyosis. Acta Med Scand 108: 98, 1941 [BACK] 7. Gordon H: Treatment of ichthyosis. Arch Dermatol 52: 178, 1945 [BACK] 8. Goldberg L H, Sagher F: Psoriasis treatment at the Dead Sea. Cutis 16: 61 1975 [BACK]

September-October 2002

Endo Tip Do not use Septocaine™ on patients who are allergic to sulfur medication. The sulfur compound from the preservative in Septocaine is different from the sulfur compound in other anaesthetic solutions. Septocaine contains sodium metabisulfite, a sulfite that may cause allergic reactions including asthmatic episodes in susceptible people.

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[ﺩﻡﺡﻡ file:///D|/...ALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/asd13dermalrelief.html[2/21/2011 10:25:09 Replacement Insert Makes Denture and Post Connection Easier

Allan S. Deutsch, D.M.D., F.A.C.D. Replacement Insert Makes Denture and Post Connection Easier

OR MANY RESTORATIONS in dentistry, what fits Figure 1 so well initially may, depending on a patient’s occlusion, deteriorate over time. The weak point in all overdenture systems is the connection between the denture and the post. It wears out and must be replaced. The Flexi-Overdenture® System from Essential Dental Systems is no different. However, an Allan Deutsch ® addition to the system, the EZ-Change Keeper and Cap Insert (Figure 1), allows for replacement in less than one minute. Following is the placement procedure for the post, keeper, and cap insert: Figure 2 1. Prepare the initial post hole with Gates Glidden reamers (Figure 2). 2. Size the post hole with the primary reamer of choice. Note that you can eyeball the choice by placing either a post or a template over an undistorted X-ray. The minimum requirement for placement is 1 mm of lateral tooth structure at the FIGURE 1: The EZ- Change Keeper and Cap most apical placement of the post within the root Insert. (Figure 3). 3. After you have created the primary post hole, use Figure 3 the countersink/root facer to form the final post- hole shape (Figure 4). Because the countersink/root facer is not self-limiting, you can drill the dual preparation (preparation for the flange and second tier of the Flexi-Overdenture post) fairly deeply into the root. Drilling deeply has the FIGURE 2: Prepare the major advantage of shortening the lever arm of the initial post hole with Gates attachment to a bare minimum. The shorter the Glidden reamers. lever arm, the less the forces of occlusion are magnified. Having a short lever arm may become particularly important if the abutment root is periodontally compromised. 4. Assuming that the primary reamer went the full length, make a trial seating of the post to its full depth (Figure 5). 5. If the post hole is prepared short of its full length, the post will not completely seat. To ensure seating

[ﺩﻡﺡﻡ file:///D|/.../DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/asd14replacementinsert.html[2/21/2011 10:25:09 Replacement Insert Makes Denture and Post Connection Easier

Figure 4

of the post’s flange, shorten the post apically enough to allow for full insertion plus an additional FIGURE 3: Size the post 1 mm to make sure that the blunt apical end of the hole with the primary post does not impinge on the tapered end of the reamer of choice. post-hole preparation (Figure 6). Figure 5 6. Before cementing the post, place an assembled EZ- Change keeper and cap insert onto the ball of the attachment (Figure 7). Place marking paste onto the keeper and place the denture over it. Remove the denture and see where the marks are impinging the denture (Figure 8). If the keeper impinges to the point where the denture must be perforated for FIGURE 4: Use the the keeper’s clearance or the keeper impinges in an countersink/root facer to aesthetically compromising fashion, you may form the final post-hole deepen the preparation into the root with the shape. countersink/root facer to gain an extra millimeter or Figure 6 two. 7. After you have established clearance, place Flexi- Flow Cement with Titanium into the canal with a lentulo spiral reamer. Place about three increments of cement with an up-and-down motion; this technique will ensure complete coating of the canal walls. In addition, coat the shank of the post. The FIGURE 5: Make a trial cement acts as a lubricant, further easing the seating of the post to its insertion of the post (Figure 9). full depth. 8. Before cold-curing the keeper into the denture, FIGURE 6: Shorten the make sure that the rubber band covering the post apically enough to allow for full insertion plus undercut of the ball attachment is in place. Place pink acrylic into the denture and seat the denture an additional 1 mm. for about five minutes or until the acrylic sets. 9. Remove the denture and relieve the excess acrylic around the keeper (Figure 10). You can now safely remove the denture from the undercut of the ball attachment. With this system you may never need to cold-cure any worn-out attachments again. 10. Place the denture in the patient’s mouth. The relationship should be the same as before cold curing the keeper into the denture. 11. If at some point the cap insert wears out, take the two-pronged wrench provided in the kit and place it in the holes inside the cap insert and rotate out the old cap with a counterclockwise motion (Figure 11). At times the cap insert may wear out in such a way that the internal prong holes wear away. If this is the case, heat the wrench in a flame until the prongs are red and then insert the wrench anywhere

into the nylon cap insert. Wait several seconds while the melted nylon solidifies around the prongs and again rotate counterclockwise for removal. 12. To place a cap insert (figure 12) , place the prongs of the wrench into the holes inside the insert, line up the thread of the insert with that of the keeper and rotate in with a clockwise motion. You will feel a tactile click when the cap is fully inserted. Replacement is complete within about 30 seconds chair time and there is no need for cold curing. 13. Reseat the denture. It should fit as before without any change in alignment.

Figure 7 Figure 8 Figure 9 Figure 10

FIGURE 8: Remove the FIGURE 10: Remove the denture and see where the denture and relieve the marks are impinging the excess acrylic around the denture. FIGURE 9: Place cement keeper. FIGURE 7: Before cementing the into the canal, coat the post, place an assembled EZ- shank of the post, and Change keeper and cap insert onto insert the post. the ball of the attachment. Figure 11 Figure 12

FIGURE 11: Use the two-pronged wrench to rotate out the old cap. FIGURE 12: To place a cap insert, rotate in with a clockwise motion.

November-December 2002

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Allan S. Deutsch, D.M.D., F.A.C.D. Restoring a Tooth with Little or No Coronal Dentin

HE FLEXI-FLANGE patented split-shank threaded Figure 1 post system provides maximum retention and minimum insertional and functional stress in cases with little or no coronal dentin. Following are step-by-step instructions for restoring a tooth with little or no coronal dentin using the Flexi-Flange system (Figure 1).

Allan Deutsch 1. Use the depth gauge in conjunction with an x-ray to determine proper post size. 2. Begin the post-hole preparation by removing the root filling material. Use a Gates Glidden drill to establish 100 percent of the post-hole length and 90 percent of the post-hole width. Figure 2 3. Use the primary reamer to achieve 100 percent of the post-hole width. Note: Because the Flexi-Flange fits optimally within a concentric hole, the number of FIGURE 1: Flexi-Flange entries into the post-hole with the primary reamer post system. should be limited. Lubricating the canal with water or another suitable wetting agent makes post-hole Figure 3 preparation easier. 4. Use the countersink drill (Figure 2) to cut two tiers in one operation; this prepares a seat for the second tier and the seat for the flange. 5. Determine full seating of the post by making certain FIGURE 2: The that the flange fits flush within the preparation (Figure countersink drill creates a 3). Note: To achieve complete seating in highly curved second tier and a flange canals, use a diamond disk to remove sufficient apical seat. post length to allow full seating of the second tier and flange. Shorten only the legs of the post after trial Figure 4 seating to ensure the creation of threads in the canal with minimal stress. FIGURE 3: Fully seat 6. Trial-insert the Flexi-Flange with the appropriate flange into the dentin. wrench. 7. Unthread the post from the canal completely and place Figure 5 Essential Dental Systems’ Flexi-Flow Cem composite resin cement in the post-hole and on the post shank. 8. Thread the post back into the post-hole with light pressure. Note: The post will seat completely with minimal resistance. 9. Remove excess cement to prepare for the core buildup. 10. Use a bonding agent to facilitate retention between the coronal dentin, the post, and the core buildup material.

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FIGURE 4: Use an Note: Use an opaquing agent for aesthetic restorations opaquing agent for (Figure 4). FIGURE 5: Example of Ti- aesthetic restorations. 11. Using a core matrix, place and shape Essential Dental Core Natural core buildup. Systems’ Ti-Core Natural core buildup material Figure 6 (Figure 5).

Figure 6 shows the final x-ray of the Flexi-Flange split-shank threaded post system in place. The Flexi-Flange system is designed for cases with little or no coronal dentin. It is a variation of the Flexi-Post system, which has brought practitioners clinical success for decades. These post systems provide maximum retention with minimal insertional and function stress. February-March 2003

FIGURE 6: The Flexi- Flange split-shank threaded post system in place.

ABOUT: Flexi-Flange®

Flexi-Flange

Flexi-Flange® patented split shank post incorporating a flange to provide additional stability in situations where there is inadequate coronal dentin and excessive occlusal forces anterior and posterior.

Features • Stabilizing Flange maximizes dentin-to-metal contact, distributing functional stresses over a larger area to minimize stress concentrations at any one point. • Split shank design closes on insertion to deliver maximum retention with minimal stress. • Triple tier design provides resistance to post loosening and root/post fracture.

Manufacturer Essential Dental Systems, Inc. 89 Leuning Street South Hackensack, NJ 07606

[ﺩﻡﺡﻡ file:///D|/HEALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/asd15restoring.html[2/21/2011 10:25:10 Restoring a Tooth with Little or No Coronal Dentin

Toll Free: 800-223-5394 Tel. 201-487-9090 Fax: 201-487-5120 [email protected] www.edsdental.com

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Allan S. Deutsch, D.M.D., F.A.C.D. Product Review VibraJect

THINK THAT all of us have wanted to learn how to give a painless injection. I certainly have. Long ago someone The VibraJect taught me to shake and push and rotate the mucosa that the needle was going to penetrate. This effectively was using the “Gate Control Theory” of pain as first proposed by Melzak and Wall in the 1970s. It works well for the maxillary arch, where you can grab the mucosa, but not too Allan Deutsch well for a mandibular block injection. Now the first major advancement in this area is being marketed. It is a device called the VibraJect. The VibraJect FIGURE 1: The VibraJect. clips onto any type of syringe that you are currently using for anesthesia. It causes the entire syringe to vibrate . The vibration feels like that from a pager or cell phone, but the amplitude is not as large. The device appears to vibrate at a high frequency and does not affect the positioning of the needle at all. I have been using it for approximately three months now. The vast majority of patients report either not feeling the mandibular block injection or just feeling it ever so slightly. Certainly, that represents a vast improvement over the reduction in pain from a preliminary topical and a little shaking. This device is now part of my regular armamentarium and remains on the bracket table at all times. It has not been relegated to the “drawer of useless devices.”

The VibraJect clipped in place on a syringe

FIGURE 2: The VibraJect clipped in place on a syringe.

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The VibraJect is an excellent product, and I recommend it highly if you want to reduce the pain of injections in your practice. The price is around $250. It can be purchased from:

Ron Wasserman Metropolitan Dental Supply, Inc. 35-02 Crescent Street Long Island City NY 11106 Phone: (718) 706-6677.

May-June 2003

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Allan S. Deutsch, D.M.D., F.A.C.D. Three-Rooted Bicuspids (They’re Out There)

T HAS BEEN my experience that the most common cause of clinical failure in endodontics is missed or uninstrumented canals. In other words, anatomy is king in endodontics. If you do enough root canals and you are on the lookout for three-rooted maxillary bicuspids, you will see them. The key is to get into a routine that makes it easy to spot them. Allan Deutsch I recommend that you take two starting films for each tooth. These x-rays have a twofold purpose. The first is for diagnosis and to establish etiology that justifies root-canal therapy as the correct treatment for this tooth. The second purpose is to gain as much information about the tooth as possible in order to facilitate the treatment. You will want to know:

How big is the pulp chamber? Are the canals open or calcified? How many roots (and canals) does the tooth have? Does decay go directly into the canal? This will make the canal orifice harder to find. Are there any bent or malformed or malposed roots in the tooth?

One of these x-rays should be straight on, preferably using a Rinn aiming device, and the other x-ray should be angled from the mesial or distal to look for extra roots. Teeth that commonly have extra roots are: mandibular molars, mandibular bicuspids, and maxillary bicuspids. This case report deals with a maxillary first bicuspid (tooth #12). The patient presented with hot and cold sensitivity and sensitivity to biting and tapping on the tooth. A new composite inlay had been placed one month earlier. Diagnostically, the tooth was yelling for endodontics. On the starting x-ray (Figure 1) we could see a hint of three roots. This does not occur too frequently. We took another x-ray, angled this time. However, my regular assistant was on vacation and my temporary assistant’s x-ray was overlapped and diagnostically useless. Rather than expose the patient to more x-rays, I made the assumption that this was a threerooted bicuspid and decided that I would look for all three canals when I opened the tooth. When looking for extra canals or roots it is almost mandatory to employ some type of optics. I use Designs for

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Figure 1

Vision loupes. I use a 2.5 x wide-field to find the mouth, and a 4.5 x wide-field when I am looking for canals. The microscope comes in handy for calcified canals. These optics will save you subsequent visits and consequently earn you more money on your cases. FIGURE 1: The starting x- I made the access cavity in the standard oval shape for a ray showed a hint of three bicuspid. The oval went from just before the buccal cusp tip roots. to just in front of the palatal cusp tip (Figure 2). I used a number 4 round bur to make the rough prep, and then I used a non-end-cutting barrel diamond to smooth and shape the Figure 2 axial walls of the access prep. A drawing of the floor of the pulp chamber when I first opened it up can be seen in Figure 2. Upon initial opening, I could probe only a single canal. I found it in the mesial buccal area of the chamber floor. “O. K.” I said to myself, “I’ve got one canal. Where are the others?” If this was truly a “minimolar,” there should be a palatal canal somewhere. On the palatal side I just saw a dark line (Figure 2). Since most canals are found directly under the FIGURE 2: Showing the cusp tips and along the dark lines, I decided to push the access cavity and the floor access opening more toward the palatal. I was happy to find of the pulp chamber. the canal directly under the cusp tip where it should have Figure 3 been. I then proceeded to clean out and instrument both the MB and palatal canals. I have found that once the canals are instrumented the large orifices make it easier to place and find the missing canal. Also, during the course of instrumentation, the sodium hypochlorite cleans out all the debris and stops any bleeding. This gives you a very clear field to look for the missing canal. All canals in general can be found in or along the dark line or area found on the chamber floor. I now took my barrel diamond and opened the area around the dark line on the disto-buccal side of the tooth. Since there was vital tissue in FIGURE 3: Showing the the canal, I could see a blood spot. The rest of the floor had instrumented floor of the been cleaned by the sodium hypochlorite. That was the canal. canal. I now instrumented it fully using the EZ-Fill® SafeSiders® technique. The instrumented floor of the canal can be seen in Figure 3. The tooth has a compressed molar Figure 4 appearance. The orifices for the buccal canals were about 1.5 millimeters apart in a mesial distal direction. The tooth was filled with gutta percha and EZ-Fill resin cement using the EZ-Fill bidirectional spiral. The tooth was closed with glass ionomer cement, the patient was sent back to the referring general dentist for a permanent restoration, and Figure 4 shows the end of another happy tale of FIGURE 4: The end result. endodontic therapy.

September-October 2003 FEEDBACK? We welcome your responses and questions.

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Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Allan S. Deutsch, D.M.D., F.A.C.D. Esthetic Post Placement

OSTS are not generally considered an esthetic part of Figure 1 restorative dentistry, merely the foundation for what the dentist hopes will be esthetically pleasing. However, there are times when roots are thin and the metal of a post may show through the exposed root or even the thin gingival layer over the root, making for less-than-ideal esthetics. In the same fashion, many of the restorations built on Allan Deutsch endodontic posts are ceramics that allow light and the metallic color of the posts to show through. FIGURE 1: Flexi-Flow Natural Composite Flexi-Flow & Ti-Core Cement.

Recognizing the need to improve these situations, Essential Dental Systems, Inc., developed tooth-colored, long-term Figure 2 (>10 years), fluoride-releasing composite cements and core materials: Flexi-Flow Natural and Ti-Core Natural (Figures 1 and 2). Together with an opaquing layer, such as C&B- Metabond (Parkell), these products mask the color of the metal post (Figure 3) and improve its esthetics (Figure 4). In addition, Ti-Core and Flexi-Flow also come in gray (reinforced with titanium) to differentiate from the lighter tooth structure when necessary. FIGURE 2: Ti-Core Natural Core Material. Stability Figure 3 One might ask, “Why bother with metal posts that require masking when a new generation of ceramic posts has been introduced that are tooth-colored to start with and do not need masking?” The answer is that the first and most important function of the post is not esthetics, but supporting the restoration with the greatest long-term stability. Stability is based on the degree of retention and the even distribution of insertional and functional stresses. The most efficient way to gain higher retention is to engage the dentin via a threaded shank. However, conventional solid-threaded shanks, whether tapered or parallel, create stresses that could lead to fracture. FIGURE 3: The color of Flexi-Post & Flexi-Flange the metal post is masked.

Flexi-Post and Flexi-Flange, also manufactured by Essential Dental Systems, Inc., are split-shanked, parallel-threaded

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Figure 4 posts with the proven ability to achieve maximum retention with insertional stresses no greater than those of a passive post. Of equal importance is the ability of the post to distribute the functional stresses along the entire length of the shank—a requirement that the parallel-threaded, split-shank design of the Flexi-family fulfills most efficiently. “Bendability” FIGURE 4: The esthetic When the posts are made of stainless steel, they impart a results are improved. “bendability” almost equal to the flexibility of dentin, reducing the chances of gap formation between the core and the body of the root. The bendability of a material is a function of the modulus of elasticity and the cross-sectional area of the material being tested. These dynamics are quite different from the limited resilience of ceramics. Because of the nongiving nature of the ceramic material, ceramic posts transmit most functional stresses to the root rather than absorbing them in the material itself. Highest Recorded Retention

The split-shank design of Flexi-Post and Flexi-Flange ensures that the threads engage the dentin with minimal lateral stress, yet produce the highest recorded retentions found in the literature. The even distribution of stresses optimizes the long-term success of the underlying support and makes the final restoration more predictable. Conclusion

Success is the ultimate esthetic challenge. Nothing looks worse than a fractured root. Loosened or fractured posts do not look good either. Like beauty, esthetics is truly in the eye of the beholder but the esthetic success of a restoration is usually noted and enhanced when form follows function. The split-shank design of the Flexi-family of posts creates an architecture that integrates the needs of a supportive post and high retention with those of the root, minimal insertional stresses. Harmony like this can also be called esthetic.

November-December 2003 FEEDBACK? For infected cases—instrument fully, We welcome your open the tubules with 18 percent responses and questions. EDTA and let Peridex® (Chlorhexidine) sit in the canal for 10 Please feel free to visit minutes, then obturate. This the Endo Forum and procedure will disinfect most infected add your comments cases, with resulting healing of the about any of the articles lesion. in Endo-Mail.

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[ﺩﻡﺡﻡ file:///D|/HEALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/asd18esthetic.html[2/21/2011 10:25:11 Irrigation Update

Allan S. Deutsch, D.M.D., F.A.C.D. Irrigation Update

ECENTLY, several new articles have been published that add valuable information as to which irrigant to use and for how long. Currently, I use the following protocol:

1. I irrigate with 5.25 percent sodium hypochlorite into the canals and leave Allan Deutsch some irrigant in the pulp chamber when using all the stainless steel SafeSiders, from size #08 to size #40. 2. I change the irrigating solution in the canals and in the pulp chamber every time I change the instrument size. 3. When I reach the NiTi SafeSiders (30/.04 and 25/.08), I flood the canals (which have already been opened with the number 2 Peeso, with 17 percent EDTA in an aqueous solution. 4. I now intrument the final canal shape with the EDTA in the canal and the NiTi SafeSiders. This will remove the smear layer and open up the dentinal tubules. 5. After instrumentation, I give the canal a final rinse with 5.25 percent hypochlorite to remove and neutralize the 17 percent EDTA. 6. I dry and fill the canals next. 7. However, if this is a retreatment, or if there has been a longstanding infection (longer than 3 months), I will now irrigate with 0.12 percent chlorhexidine (Peridex®). I let the chlorhexidine sit in the canals for approximately five minutes. 8. After five minutes, I dry the canals with paper points and fill the canals with GP and cement. I do not irrigate with NaOCl.

In a study reported in the International Endodontic Journal, N. Habahbeh, et al, reported that all concentrations of NaOCl were effective in the elimination of E. faecalis but that different concentrations required different lengths of time to achieve the result; 5.25 percent was the most effective, killing 100 percent of bacterial cells in two minutes. The time required by 2.5, 1.0 and 0.5 percent was 5, 10 and 30 minutes respectively.1

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In another study, L. M. Sassone, et al, showed that 0.12 percent chlorhexidine (CHX) did not eliminate E. faecalis in any time interval. One percent CHX eliminated all strains, as did NaOCl at both 1 percent and 5 percent concentrations. Therefore, under the conditions of this study, a 0.12 percent CHX solution was ineffective at killing E. faecalis.2 A third study, reported by O. Oncag, et al, compared the antibacterial properties and toxicity of 5.25 percent NaOCl, 2 percent chlorhexidine gluconate, and 0.2 percent chlorhexidine gluconate plus 0.2 percent cetrimide (Cetrexidin®: Vebas, San Giuliano, Milan, Italy). In the laboratory study, the 2 percent CHX gluconate and Cetrexidin were significantly more effective on E. faecalis than the 5.25 percent NaOCl at 5 minutes. Similarly, in the in vivo study, 2 percent CHX gluconate and Cetrexidin were significantly more effective on anaerobic bacteria than the 5.25 percent NaOCl at 48 hours. The authors state that “2 percent CHX gluconate and Cetrexidin had more antibacterial effect on anaerobic bacteria than 5.25 percent NaOCl because of their active cationic properties, which enable their adsorbtion by the dentine surface and their substantive antibacterial effect.”3 It is surmised that this cationic effect leaves a long-acting antibacterial action on the dentinal tubules. After reading these articles I must now say “Oops!” My NaOCl protocol is OK. I am certainly leaving my 5.25 percent solution in the canal for greater than two minutes. This will kill almost all the bacteria and remove the tissue debris and consequently the organic load. However, I am certainly not leaving the 0.12 percent chlorhexidine Peridex (Figure 1, left) in the canal long enough. According to the article by L. M. Sassone, et al, 0.12 percent CHX would never entirely get rid of the bacteria, no matter how long you left it in the canal! To get rid of 100 percent of the bacteria within five minutes you need a solution of CHX greater than 1 percent. Consequently, I have now bought 2 percent chlorhexidine by Vista (Figure 1, right). I have retained the same protocol as above with the exception of using 2 percent chlorhexidine instead of 0.12 percent. Let’s hope this kills all those bugs! References

1. Habahbeh N, Drucker DB, Qualtrough JE, Korachi M. Abstract R95. International Endodontic Journal 2003;36(12):950. 2. Sassone LM, Fidel R, Fidel S, Vieira M,

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Figure 1

Hirata R, Jr. The influence of organic load on the antimicrobial activity of different concentrations of NaOCl and chlorhexidine in vitro. International Endodontic Journal 2003;36(12):848-852. 3. Oncag O, Hosgor M, Hilmioglu S, Zekioglu O, Eronat C, Burhanoglu D. Comparison of antibacterial and toxic effects of various root canal irrigants. International Endodontic Journal FIGURE 1: 0.12 percent chlorhexidine from Peridex 2003;36(6):423-432. and 2 percent chlorhexidine from Vista.

February-March 2004 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Allan S. Deutsch, D.M.D., F.A.C.D. IADR Meeting in Honolulu

T WAS TOUGH DUTY, but somebody had to do it. That is, go to the IADR Figure 1 (International Association of Dental Research) meeting in balmy, 80-degree, downtown Honolulu, Hawaii. Naturally, I volunteered for this assignment. Every year the international dental research community holds its Allan Deutsch annual conference at a city somewhere around the world. This year we were lucky that the host city was Honolulu; next year it will be not-so- balmy Baltimore. Researchers submit abstracts of their research in the year preceding the convention. The FIGURE 1: Posters set up before abstracts are reviewed and either accepted or viewing time. rejected. The accepted abstracts are presented at the convention either as fifteen-minute oral presentations or as poster presentations. This Figure 2 year we gave two poster presentations (Figures 1 and 2). Instrumentation Time: Conventional Instruments versus Non-interrupted Flat-sided SafeSiders

B. L. Musikant, B. I. Cohen, and A. S. Deutsch, Essential Dental Systems, South Hackensack, NJ, USA FIGURE 2: Previewing hours, with the crowd starting to come in. BARRY MUSIKANT’S RESEARCH showed that flat-sided SafeSiders reamers are much faster at instrumenting the canal than Figure 3 conventional files or even conventional reamers. Therefore, less engagement with the dentin as a consequence of the flat-sided SafeSiders reamer actually decreases the time needed to clean the canal. As we have seen clinically for more than ten years, the SafeSiders are very fast; for me, they are even faster than rotary!

Objective

The purpose of this in vitro experiment was to FIGURE 3: The PulpOut Bur, showing

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compare the time (in seconds) needed to create the flat and the 7 mm fixed stop. an .08 tapered canal preparation utilizing conventional hand instruments versus a new non- interrupted flat-sided hand instrument design, the Figure 4 SafeSiders (EDS).

Method

This study was divided into four groups with ten samples per group; group 1, conventional files (Dentsply), group 2, SafeSiders files, group 3, conventional reamers (Dentsply) and group 4, SafeSiders reamers. Rectangular blocks made of a resilient acrylic resin that mimics the physical properties of dentin were used. Time to the apex Figure 5 was measured under four experimental conditions. One-way analysis of variance (ANOVA) was used to compare mean times across conditions. Upon finding a significant difference, the Newman-Keuls (NK) test was used.

Results

ANOVA showed a significant difference between groups (P < 0.0001). NK tests showed FIGURES 4 and 5: Discussing the that the conventional files in group 1 (275.2 ± research with anyone who would listen. 42.19) had significantly longer times than the conventional reamers in group 3 (183.9 ± 42.24) or SafeSiders files in group 2 (182.5 ± 17.70) Figure 6 (those two groups not being different from one another), and that SafeSiders reamers in group 4 (128.3 ± 14.07) had the shortest times, which were different from all of the other instruments.

Conclusion

The conventional designs for both reamers and files result in slower, less-efficient instrumentation to the apex compared with their SafeSiders counterparts. The SafeSiders design FIGURE 6: Only in Hawaii! reduced dentinal engagement, reduced resistance of the instruments within the canal, and shortened the time needed for canal preparation. Morphological Measurements of Molar Pulp Chambers

A. S. Deutsch, B. I. Cohen, and B. L. Musikant, Essential Dental Systems, S. Hackensack, NJ, USA

MY RESEARCH, although simple in design, led to some amazing findings. We found that on all

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molar teeth the distance from the cusps to the ceiling of the pulp chamber is very constant. This distance is approximately 6.50 mm. With this number in mind, we designed a new dental instrument that we named the PulpOut Bur. This bur is a number 4 round bur with a flat side and a fixed stop at 7 mm (see Figure 3). The flat lets the bur cut exceedingly well, and the fixed stop will prevent the dentist from perforating into the furcation. Say goodbye to iatrogenic furcation perforations! Even on calcified canals, the PulpOut Bur will place you at the level of the chamber without worrying about perforations. Pretty amazing stuff.

Objective

The aim of this in vitro study was to determine and measure critical morphological anatomy of pulp chambers.

Method

One hundred random human maxillary and one hundred random human mandibular molars were used. Each molar was affixed to a millimeter x- ray grid and x-rayed in the mesio-distal plane using a parallel long cone technique. The x-rays were examined under a stereomicroscope and the measurements were read to the nearest 0.5 mm.

Results

Maxillary = Max, Mandibular = Mand, Mean (mm): Pulp Chamber Floor to Furcation; Maxi = 3.05± 0.79, Mand = 2.96 ± 0.78; Pulp Chamber Ceiling to Furcation; Max = 4.91 ± 1.06, Mand = 4.55 ± 0.91; Buccal cusp to Furcation: Max = 11.15 ± 1.21, Mand = 10.90 ± 1.21; Buccal cusp to pulp chamber floor; Max = 8.08 ± 0.88, Mand = 7.95 ± 0.79; Buccal cusp to pulp chamber ceiling; Max = 6.24 ± 0.88, Mand = 6.36 ± 0.93; pulp chamber width; Max =1.88 ± 0.69, Mand = 1.57 ± 0.68. The pulp chamber ceiling was found at the level of the cemento-enamel junction in Max = 98%, Mand = 97% of the specimens. The measurement with the highest percentage of variance was the width of the pulp chamber (Max = 37% and Mand = 43%).

Conclusion

The measurements obtained were very similar for both maxillary and mandibular molars. The measurements with the lowest percentage

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variance were: buccal cusp to furcation (approximately 11%) and buccal cusp to pulp chamber ceiling (approximately 14%). The pulp chamber width varied the most, due to various types of calcifications found in the pulp chamber.

Figures 4 and 5 show me (in the Hawaiian spirit) talking about our research (to anyone who would listen). After a few hours of talking I was feeling no pain. (Wonder why? See Figure 6.)

Summer 2004 FEEDBACK? When using the PulpOut We welcome your responses and Bur to gain access, always questions. cut wet to prevent the Please feel free to visit the Endo nylon fixed stop from Forum and add your comments melting. about any of the articles in Endo- In endo, cutting wet is a Mail. good idea for all burs. Every bur will cut better when wet, even slow speed burs.

To smooth and remove excess Cavit, use a Q-Tip wet with water.

To smooth and remove excess glass ionomer or zinc oxyphosphate, use a Q-Tip wet with alcohol.

Allan Deutsch

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Allan S. Deutsch, D.M.D., F.A.C.D. Don’t Perf Out . . . PulpOut!

N THE SUMMER 2004 issue of Endo-Mail, I talked about the research we presented at Figure 1 the IADR meeting in Honolulu. The morphological research on molars was just published in the June issue of The Journal of Endodontics (2004;30(6):388-390). This research showed that there are some very Allan Deutsch consistent measurements when it comes to molar pulp chambers. These measurements in conjunction with the use of the PulpOut bur will allow you to gain access to the chamber (even in calcified chambers), easily, quickly, and without perforating into the furcation. FIGURE 1: The pulp chamber ceiling is Some measurements to remember are: found at the level of the C. E. J. 98 percent of the time. 1. The pulp Chamber Ceiling is just about always at the level of the CEJ! See Figure Figure 6 1. Figure 2 2. The height of the pulp chamber is between 1.5 mm and 2.0 mm for the average non- calcified tooth. See Figure 2. 3. The average distance from the floor of the pulp chamber to the furcation is about 3.0 mm. See Figure 3. 4. Last but not least—the distance from the cusp tips to the ceiling of the pulp chamber in molars is approximately 6.30 FIGURE 2: The average height of a pulp mm. See Figure 4. This is the most chamber (F) is 1.5 to 2.0 mm. FIGURE 6: Cutaway view. critical distance of all. Using this measurement, we have developed an instrument that will allow you to find the Figure 3 pulp chamber in all teeth, (normal or calcified)!

That instrument is the PulpOut bur. It is a number four round bur with a hard plastic non- movable stop fixed at 7.0 mm from its tip. See Figure 5. The 7 mm distance enables you to gain access to the pulp chamber without risk of going through the pulpal floor and into the furcation. For teeth with average-size pulp chambers, the PulpOut bur will place you somewhere in the FIGURE 3: The distance between the middle of the pulp chamber. See Figure 6. pulpal floor and the furcation

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Figure 7

For teeth with calcified chambers, it will place (measurement A) equals 3.0 mm on you on the floor of the chamber. See Figure 7. average for both mandibular and FIGURE 7: The PulpOut As we age, the pulp chamber normally maxillary molars. bur in a calcified pulp calcifies from the floor up. Therefore, the 7 mm chamber. distance will place the bur in what used to be the middle of the chamber but now is the floor. This Figure 4 Figure 8 will then enable you to find the canals much more easily. Once the general outline of the access is made with the PulpOut bur, the diamond shaper is now used. The diamond shaper is a non-end-cutting coarse barrel diamond. It is placed against the axial walls and moved around the entire access opening. This will smooth the axial walls and let more light in to the floor. See Figure 8. The diamond is extra long so that the entire FIGURE 4: The mean distance (E) from the cusp tip to the pulp chamber ceiling axial wall from floor to occlusal surface can be is 6.36 mm in mandibular molars and cut in one operation. The non-end-cutting tip of 6.24 mm in maxillary molars. the shaper will not cut or gouge the floor of the chamber. Once these burs are used, finding canals without Figure 3 perforating the furcation becomes very predictable and easy.

FIGURE 8: Preparing the axial walls of the chamber. Fall 2004

FIGURE 5: The PulpOut bur’s non- movable stop is fixed at the critical 7.0 mm pulp chamber depth.

FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Allan S. Deutsch, D.M.D. Don’t Perf Out . . . PulpOut . . . for Bicuspids, Too!

N THE FALL 2004 ISSUE of Endo-Mail I described the clinical technique for use of the PulpOut™ bur in Figure 1 molars. The technique is based on our recently published research (June 2004) in the Journal of Endodontics. This research shows that the distance from the cusp tip to the ceiling of the pulp chamber in molars is approximately 6.5 mm. That 6.5 mm distance is very consistent in all molar Allan Deutsch teeth. We made the fixed stop on the PulpOut bur at 7 mm. Locating the stop there assured that access into the chamber would always be made without perforating the floor of the pulp chamber. We have just had our second morphological research paper accepted for publication in the Journal of Endodontics. We reasoned that if all furcated molars had a very consistent measurement from the cusp tip to the pulp chamber ceiling, maybe the furcated bicuspids did also. We got a little fancier in this study and used the Trophy RVG digital imaging system to radiograph the bicuspids. Once the digital x-rays were processed, we measured them using the Digipan FIGURE 1: An example of measuring mode of the Trophy system (Figure 1). the measurements for a We measured the same anatomic landmarks for bicuspids bicuspid, taken in a buccal as we did for molars. These measurements can be seen in palatal view. Figure 2. The measurement that we were most interested in is D. This is the measurement from the cusp tip to the chamber Figure 2 ceiling. This measurement in bicuspids was 6.94 mm. Although this number is statistically different from the average of 6.3 mm for molars, it is smaller than the 7.0 mm of the PulpOut bur. Consequently, the PulpOut bur will work very nicely for bicuspids as well as for molars. Statistically, based on a bell curve, there will always be some bicuspids in which the PulpOut bur will get very close to the ceiling of the bicuspid but not penetrate it. In these instances, you will be only about 0.6 mm away from penetrating the ceiling. Clinically, the PulpOut bur will get you very close to your objective. As an aside, it is very interesting to note that the one measurement that was the same for molars and bicuspids was measurement B. Measurement B is the distance from the pulp chamber ceiling to the furcation. This seems to be a constant number for all teeth with furcations. Why this is so, FIGURE 2: Anatomic I have no idea. measurements for bicuspids.

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So remember: Don’t perf out . . . PulpOut!

Winter 2004 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Allan S. Deutsch, D.M.D. New Material, New Use

SSENTIAL DENTAL SYSTEMS recently released an upgraded and improved Ti-Core®. This new material Figure 1 is called Ti-Core Auto E. The “Auto” stands for auto- mix and the “E” stands for esthetic. This composite core material is a dual-cured hybrid composite reinforced with the lanthanide series of metals. Using proprietary chemistry and manufacturing processes, we were able to keep Allan Deutsch approximately 90 percent of the physical properties of the original Ti-Core natural yet make Ti-Core Auto E less viscous. The lower viscosity enables us to package the material in a dual-barrel syringe with an auto-mix stator and very small delivery tip (See Figure 1). This material can easily be extruded and mixed all in one operation. The Vita A2 color enables the material to be used in any situation where esthetics is a concern. A 24 mm increment will light- cure in approximately 20 seconds. The material will finish FIGURE 1: Ti-Core Auto self-curing in approximately six minutes. E. I have been working with this material for several months now. About two months ago, it occurred to me that since this material was so easy to use and relatively inexpensive there was another great use for it in addition to building up cores. I have been using Ti-Core Auto E as a temporary material to close the access opening. I etch all the dentin and surface enamel with 37.5 percent phosphoric acid for approximately 20 seconds. This procedure removes the smear layer and opens up the tubules. It also etches the intertubular dentin itself. Since the composite has a low viscosity and flows very well, it will flow into the tubules and also form resin tags into the etched intertubular dentin. The net effect of all of this is a very good seal. This seal will stop coronal leakage after the endodontics is completed. Sometimes the patient does not have the tooth restored for months. If the temporary material leaks or wears away during that time and the root becomes infected, the endodontics must be redone. Ti-Core Auto E will not leak since it is mechanically bonded into the tubules and the intertubular dentin, and since it is a hybrid composite it certainly will not wear away in a matter of months. Cavit also seals well coronally. However, the problem with this material is that it is rather soft and prone to wear. Sometimes when used as an occlusal seal between visits it washes out, and the tooth often becomes infected between

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appointments. We long ago stopped using Cavit as a primary interappointment sealing material because there were too many unnecessary infections. The clinical technique is very simple and quick. First fill the entire access cavity with the 37.5 percent phosphoric acid (Figure 2). Let this etch the dentin and coronal enamel for 20 to 30 seconds. Then wash off the etchant with water. Assemble the syringe and express the Ti-Core Auto E through the auto-mix syringe and small placement tip, directly into the access cavity (Figure 3).

Figure 2 Figure 3

FIGURE 3: Express the Ti-Core Auto FIGURE 2: First fill the E through the auto-mix syringe and entire access cavity with small placement tip, directly into the the 37.5 percent access cavity. phosphoric acid.

Smooth and shape the occlusal surface with an instrument. Light-cure the Ti-Core Auto E for 20 to 40 seconds, depending on the thickness of the temporary seal you want to create (Figure 4).

Figure 4 Figure 5

FIGURE 4: Light-cure the Ti-Core Auto E for 20 to 40 seconds, depending on the thickness of the temporary seal you want to create.

You are now done! This is a very quick and easy approach to temporization of the access cavity for any root-canal treatment. No fear of infection, and esthetically pleasing results also!

January-March 2005 FEEDBACK?

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We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Allan S. Deutsch, D.M.D. Hands-On Lectures at HODEC

ODEC, our hands-on lecture facility, has now been operating for Kudos for HODEC about six months. We have given half-day, full-day and two-day courses. From our point of view and from the point of view of Treat yourself to a those who have attended, HODEC is an unconditional success. course with Barry All courses, no matter the length, have both a didactic and hands-on Musikant who will component. The lectures are to the point. That is, they describe the teach you more in techniques that the dentist participant will practice and perform in the 2?3 hours than you Allan Deutsch hands-on section that occurs immediately after the lecture. will learn in a year. He has made my The half-day course (four hours) lets the dentist get a taste of one-visit endo much more endo using the SafeSiders® technique with the reciprocating Endo- enjoyable. Express™ handpiece. After instrumentating a natural bicuspid tooth, the Louis dentist then obturates the instrumented canal with the EZ-Fill® single- Malchmacher, DDS cone technique. Lastly, the participant gets to close the access opening Bay Village, OH with Ti-Core Auto E, a dual-cure metal-reinforced composite, and learns how to place a Flexi-Flange post and build up the core. The morning The course was flies by as we do all these procedures. designed so that The one-day and two-day courses give the students more of everything participants felt and in greater detail. The didactic part of the course goes into the where confident performing procedures as and why of doing endo quickly and easily while maintaining excellent taught immediately. results with a high success rate for the patient. The focus of the hands-on Robert Saukas part of the courses is to shorten the learning curve for doing SafeSiders Stanton, MI cases using the reciprocating Endo-Express handpiece. The dentist accomplishes this by instrumenting multiple bicuspid and curved molar Success!!! Yes!!! teeth. After the teeth are instrumented, they are obturated using the EZ- You gave an in- Fill single-cone technique. Once the endodontic procedure is completed, house lecture back we take digital x-rays of the finished teeth. The digital x-ray is then in December and I highly magnified and displayed using our LCD projector. The dentists wanted to let you know how things can then immediately see how their technique is improving. The are going. I am on participants at HODEC have all loved this instant feedback teaching aid. cloud nine today. I Once you see how you are doing, it is very easy to modify your technique feel like I can be to achieve the best results possible. In these longer courses we also offer confident that I can the opportunity to try the endo microscope and ultrasonics, important deliver a superior adjuncts in learning a sound endo technique. service to my If you want to do one-visit endo using the SafeSiders/Endo-Express patients with your technique and earn CE credits, HODEC in South Hackensack is the place technique. for you. It is extremely close to New York City, just ten minutes over the Lance Fallin, DDS Zachary, LA George Washington Bridge. Call us at 201-487-9090 or see us on the web at edsdental.com. Very informative, I know these courses will pay for themselves after you have done just practical & one or two endo cases in one visit in your own office. enjoyable. I feel confident enough to See you at HODEC. use the procedure first thing Monday morning. This is the best I’ve ever taken!

Ronald Petrosky, Tuckerton, NJ

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Thanks so much for your generosity in offering your course and I’d recommend that anyone contemplating endo or a new way of doing such, take Barry’s course as it was worth the trip. Ron Schalter, DDS Hudson, MI

Best endo course I’ve ever taken. Ed McElroy El FIGURE 1: Allan Deutsch overseeing FIGURE 2: Hands-on instruction Paso, TX hands-on practice at HODEC. is “up close and personal.” Run, don’t walk, for the chance to meet and listen to Barry! Howard Farran, DDS, Phoenix, AZ

The best endodontic course I’ve attended.

Alan Stott Lancaster, CA

FIGURE 3: Barry Musikant lecturing at HODEC.

April-June 2005 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Allan S. Deutsch, D.M.D. Simple Overdenture Technique, Lasting Results

MPLANTS have, in the last 15 to 20 years, paved the way to restoration of the edentulous and partially edentulous mouth. However, many patients cannot afford the time or money required to complete this treatment successfully. Making an Overdenture (OVD) using a simple ball-and-socket type of attachment for extra retention is a proven and easy alternative treatment to implants. Allan Deutsch The Flexi-Overdenture® attachment is based on the patented split-shank Flexi-Post® for the highest retention of the post in the root and the fewest problems. The ball-and- socket attachment delivers high retention for full and partial dentures, providing a simple, inexpensive overdenture at chairside. The Flexi-Overdenture supports a nylon attachment that is incorporated into an overdenture (Figure 1). Alternatively, and for great ease of replacement, a threaded version of the nylon attachment can be threaded into an EZ- Change® metal receptacle (keeper) that in turn is incorporated into the denture (Figure 2). The post allows the dentist to utilize remaining roots to support the retention of a denture.

Figure 1 Figure 2

FIGURE 1 FIGURE 2

The Steps for Placement of the Flexi- Overdenture

Try to retain two canine teeth in each arch for the abutments for the OVD. If canines are not available, try to use bicuspids next. However, any tooth—even just one tooth—

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will provide additional retention for the OVD.

Determine the optimum post size by placing the plastic template over an undistorted x-ray. There should be at least one millimeter of lateral tooth structure at the most apical placement of the post.

After determining the correct post size, prepare the post hole, using a sequence of Gates Glidden drills followed by the color-coded primary reamer exactly correlated to your post size (Figures 3 and 4).

Figure 3

FIGURE 3 Figure 4

FIGURE 4

After using the correct primary reamer, prepare the countersink/root facer preparation with the countersink/rootfacer drill (Figure 5).

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Figure 5

FIGURE 5

Try placing the post that corresponds to your preparation. It should be fully seated (Figure 6).

If the post does not seat fully, shorten the apical end of the post the appropriate amount for full seating (Figure 7).

Figure 6 Figure 7

FIGURE 6 FIGURE 7

Coat the internal surface of the post hole and the shank of the post with Flexi-Flow Auto® reinforced composite cement and place the post into the root.

Let set for four minutes.

Place the nylon cap on the ball of the Flexi-Overdenture attachment. Make sure that the colored rubber band is on the ball of the attachment. The rubber band blocks out the undercut of the ball (Figure 8).

Mark the top of the nylon cap with a disclosing paste and place the denture over the root (Figure 9).

Figure 8

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Figure 9

FIGURE 8 FIGURE 9

Remove the denture, noting where it has been marked with the paste (Figure 10).

Figure 10

FIGURE 10

Relieve enough acrylic from the denture to allow the denture to sit passively over the nylon cap (Figures 11 and 12).

Figure 11 Figure 12

FIGURE 11 FIGURE 12

Once you have confirmed that the denture is sitting passively supported only by the ridges, place a doughy mix of acrylic into the relieved site, place the nylon cap over the acrylic and keep it in position until the acrylic hardens (Figure 13).

Remove the denture and relieve the excess underlying acrylic

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(Figure 14).

Figure 13 Figure 14

FIGURE 13 FIGURE 14

The denture now has the added retention supplied by the ball-and-socket attachment provided by the Flexi- Overdenture attachment. Over time, the nylon attachment will wear, out reducing the amount of retention it provides. The nylon attachment can be replaced by drilling out the old attachment and cold-curing a new one in. To reduce the time and effort necessary for replacement, Essential Dental Systems, Inc., has developed the EZ-Change attachment for rapid replacement of the worn nylon attachment. To incorporate it into the denture do the following:

Instead of the nylon attachment, place the EZ-Change attachment, which consists of a metal receptacle (keeper) and a threaded nylon attachment within it (Figure 15).

The two components of the EZ-Change attachment are incorporated into the denture in the same manner as the original nylon cap.

When the nylon attachment now wears out, it is a simple matter to use the EZ-Change wrench to unthread the worn- out nylon cap from the metal insert and thread in a new one (Figure 16). No cold-curing is necessary, the entire process taking only a few seconds.

Figure 15

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Figure 16

FIGURE 15 FIGURE 16

The ball-and-socket is very user-friendly for the patient. It snaps in easily, the patient can both hear and feel when the ball is seated, and there are no components to bend or break. This is a viable and time-tested alternative technique for those who cannot have implants.

July-September 2005 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Allan S. Deutsch, D.M.D. Basic Research Points the Way to Improved Results

HY do some cases fail even if all the canals were found and the mechanical instrumentation and shaping were successful? The answer is usually quite simple: infection. In the article “Effect of endodontic procedures on enterococci, enteric bacteria and yeasts in primary endodontic infections,” in the International Endodontic Journal 2005, 38;372-380, Ferrari, Cai, and Bombana concluded that enterococci, enteric bacteria, and yeasts were present in primary endodontic infections. Enterococci, particularly Enterococcus faecalis and E. faecium were resistant to removal by root canal preparation followed by intracanal dressing. Allan Deutsch This article could very well explain the results obtained by Siqueira and Rocas. In their article “Polymerase chain reaction-based analysis of microorganisms associated with failed endodontic treatment, OOO, 2004 97;85-94, Siqueira and Rocas concluded that microorganisms occurred in all cases of root-filled teeth associated with periradicular lesions, which lends strong support to the assertion that treatment failures are rather of infectious etiology, caused by persistent or secondary intraradicular infections. E. faecalis was the most prevalent species, followed by four other anaerobic species: P. alactolyticus, P. propionicum, D. pneumosintes and F. alocis. All examined samples harbored at least one of the following gram-positive bacterial species: E. faecalis, P. alactolyticus, or P. propionicum. So the evidence is mounting that E. faecalis is a very nasty bug and probably responsible for most endodontic failures and problems. The question then becomes, how do you get rid of it clinically? Since Ferrari et al. showed that instrumentation did not get rid of all the bacteria, it is up to the irrigants we use to do the job! The key questions are “What should we use?” and “How should we use it clinically?” We know that we must use sodium hypochlorite, because it has the greatest efficacy in removing tissue debris. However it does not kill E. faecalis. This was shown in an article by Menezes et al. “In vitro evaluation of the effectiveness of irrigants and intracanal medicaments on microorganism within root canals,” International Endodontic Journal 2004,37;311-319. In this article they concluded that 2 percent CHX solution was more effective than 2.5 percent NaOCl against E. faecalis. We are starting to build a case for 2 percent CHX (chlorhexidine gluconate). See Figure 1.

Figure !

FIGURE 1: Two percent CHX solution was more effective than 2.5 percent NaOCl against E. faecalis.

It turns out that the percentage of CHX is crucial! Sassone et al. in their article “The influence of organic load on the antimicrobial activity of different concentrations of NaOCl and chlorhexidine in vitro,” International Endodontic Journal, 2003,36;848-852 concluded that a 0.12 percent CHX solution did not eliminate E. faecalis at any time interval. One percent CHX eliminated all strains. The 0.12 percent is equivalent to “Peridex” mouthwash. Many other articles point to a 2 percent solution for clinical use in endodontics. At a 2 percent level the antimicrobial effect of CHX can be achieved in 12 minutes of contact. At this point you may be saying to yourself, “This is very nice, but I still like to put calcium

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hydroxide in the canal in between visits to kill the bacteria.” Really amazing research has just been published concerning calcium hydroxide. Kayaoglu et al. in their article “Growth at high pH increases Enterococcus faecalis adhesion to collagen,” International Endodontic Journal, 2005,38;389-396, conclude that a minor increase in pH up to 8.5, which may be a consequence of insufficient treatment with alkaline medicaments such as calcium hydroxide, increases the collagen-binding ability of E. faecalis, in vitro. This can be a critical mechanism by which E. feacalis predominates in persistent endodontic infections. Wow! Taken clinically, if you don’t get enough calcium hydroxide into the canal to raise the pH enough, you make the infection worse (harder to get rid of). An additional two articles (Lin et al. JOE, 2003,29;565-566 and Basrani, OOO, 2003,96;618-624) showed that CHX was effective against E. faecalis and Ca(OH)2 was not. So for me, no more calcium hydroxide antibacterial therapy; it may make matters worse, not better! The article “Effect of root canal dressings on the regeneration of inflamed periapical tissue,” by Dammaschke et al. in Acta Odontologica Scandinavica, 2005, 63;143-152, concluded that chlorhexidine used as an intracanal medicament showed good periapical regeneration, suggesting that this may be an alternative to calcium hydroxide root canal dressing. OK, now we know that the tissue heals with this stuff! There is a bonus effect with chlorhexidine use. Rosenthal et al. in “Chlorhexidine substantivity in root canal dentin,” OOO, 2004;98:488-492, concluded that the results of their study indicate that CHX is retained in root canal dentin in antimicrobially effective amounts for up to 12 weeks. A fabulous property for an antimicrobial agent! They also said, “CHX is known to be particularly effective against many strains of bacteria found in infected root canals, including E. faecalis.” In a study comparing common endodontic disinfectants, 0.5 percent CHX was also significantly more effective at killing C. albicans than Ca(OH)2, 5 percent and 0.5 percent NaOCl and 2 percent IKI. While these substantive and antimicrobial properties of CHX found here are promising, it does not have the tissue-dissolving properties of NaOCl. Although NaOCl is still considered the irrigant of choice, the use of CHX may be considered advantageous as a treatment prior to obturation, an alternative irrigant during retreatments, or even incorporated into antimicrobial dressings. The take-home lesson is that CHX is good stuff, but how should we use it clinically? It appears that the key is the use of 1517 percent aqueous solution of EDTA before the use of CHX. A large percentage of the bacteria causing the problem reside in the dentinal tubules. After instrumentation, the bacteria are covered by the smear layer of dentin. If we do not remove this layer, our 2 percent CHX cannot get to the bacteria and consequently will not kill them. Conversely, as shown by Clark-Holke et al. in “Bacterial penetration through canals of endodontically treated teeth in the presence or absence of the smear layer,” Journal of Dentistry, 2003, 31;275-281, when the smear layer is removed and the canal is obturated with gutta percha and an epoxy resin cement (like EZ-Fill®), there was no leakage of bacteria through the apical foramen. The presence of the smear layer resulted in leaking in 60 percent of the model systems over the experimental time period. So it is a good thing to remove the smear layer:

1. before CHX application 2. before obturation with an epoxy cement. Clinical Procedure in Conjunction with SafeSiders® / Endo-Express® Technique

1. While instrumenting from #08 to #40 Stainless steel SafeSiders, use NaOCl 5 percent as the irrigant 2. While instrumenting with the 30/.04 and 25/.08 NiTis, use 17 percent aqueous EDTA (removes the smear layer) 3. Rinse out EDTA with water or anesthetic. Both EDTA and NaOCl form a precipitate and inactivate CHX! Therefore, do not let the CHX contact either EDTA or NaOCl. 4. Irrigate with 2 percent CHX and let sit in the canals for at least two minutes. 5. You can leave the canal slightly damp with CHX if obturating with EZ-Fill sealer. The epoxy EZ-Fill will set even under water. This will ensure prolonged maximum antibacterial activity. 6. Obturate the canals.

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Figure 2

September-October 2005 FEEDBACK? If the canal has a difficult curve, you can pre-bend a stainless We welcome your SafeSiders instrument (08-40), place it in the canal, and then insert it responses and questions. into the reciprocating handpiece (after the instrument is in the canal). Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Allan S. Deutsch, D.M.D. New Diagnostic Cat Scan Great for Endo

hile I was in Philadelphia for the 2005 Figure 1 ADA Convention, Dr. Victor Sendax (inventor of the mini temporary implant) introduced me to Imtec’s Iluma FlashCT scanner. The machine itself is about the size of a Panorex and is entirely open. The total radiation dose is slightly more than a Panorex. However, Allan Deutsch the amount of information is mind blowing. You can see the entire head with all the blood vessels and soft tissue. You can see just the hard tissue in 3D. You can see how the roots curve and in what plane and direction. However, the best information for me is that you can slice the teeth in the horizontal plane in 0.1mm sections and see:

1. the actual canals in the root 2. whether there is an MB2 in the maxillary FIGURE 1: A 3D picture of all the bony molars and hard structures. 3. how many canals are in a bicuspid (max and mand) Figure 2 4. whether the canals are calcified 5. whether any canals were missed in retreatment cases 6. PARs while they are still confined to the medullary bone (wow!)

This instrument is a major step forward in endodontic diagnosis! What makes this all work is the pricing of the machine by Imtec. Instead of a flat dollar price or lease for the machine, you can opt for a dollar amount for each scan that is taken. There is a FIGURE 2: A slightly magnified view of minimum of $3,000 per month. On this page are the maxillary arch in a horizontal slice. some examples of what we have to look forward to. Figure 1 shows a 3D picture of all the bony and hard structures. This view can be rotated and moved in any plane to see the relationship of various anatomic landmarks. Figure 2 shows a slightly magnified view of the maxillary arch in a horizontal slice. Each slice is 0.1 mm thick. The resolution is amazing.

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Figure 3

Tooth #3 shows the MB2 canal. On tooth #2 I cannot see the DB canal. Figure 3 shows a greatly magnified view of teeth numbers 2 and 3. The MB2 on tooth #3 is very evident. When I scrolled through the slice, FIGURE 3: The beginning of the I could see that the MB2 joined the MB near the maxillary sinus. apex. At the apex there was only one MB canal. Figure 4 This is very good information to know. Figure 4 shows the beginning of the maxillary sinus. As we scroll through the slices, we can see whether the root tips are in the sinus or not. We can also see whether the sinus is cloudy or not. If there were a PAR between the root tip and the sinus, we could see that also. This instrument promises to kick endodontic diagnosis and treatment into the 21st century. We are currently on a waiting list for delivery of our new diagnostic instrument. November-December 2005 FIGURE 4: A greatly magnified view of teeth numbers 2 and 3.

FEEDBACK? It is important to We welcome your responses and continually disinfect the questions. surface of your finger Please feel free to visit the Endo ruler. Placing an Forum and add your comments instrument from an about any of the articles in Endo- infected canal on the Mail. surface to check or change the measurement control can lead to cross- contamination of new instruments and gutta- percha cones. Doug Kase

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Alan Winter, D. D. S. Product Review NewTom® 9000 Accuracy

ENTAL CAT SCANS are becoming endo friendly! New technology and software are allowing a virtual 3- D view of the roots and surrounding bone. Better diagnosis makes better treatment. Dr. Alan Winter, a New York periodontist whom many of you know, describes it in detail below. —Allan S. Deutsch THE NEWTOM® 9000 is not a GPS guided missile system, but it does have pinpoint accuracy. NewTom is an abbreviation for new tomography, a technology with great promise. Until now, computed tomography (CT) imaging, also known as CAT (computed axial tomography) scanning, has been ordered primarily by dentists who place implants, and in certain diagnostic situations where 3-D imaging helps formulate a diagnosis. Dental CT scans reformat a series of spiral images into recognizable dental structures. The result is a series of transaxial and axial views that enable us to locate the mandibular nerve, observe the size and shape of the maxillary sinus, determine whether a cyst has broken through the cortical plate, note the dimensions and placement of atrophic ridges, and do so much more as well. What does the NewTom 9000 offer beyond all that? Plenty. Accuracy

The first thing that impresses us is NewTom’s accuracy. Although dental CT scans provide detailed information, dimensions can be off by as much as 1.5 mm. That may not seem to be much, but when there is only 10 mm above the mandibular nerve, technical errors on the magnitude of 1.5 mm cannot be overlooked. Why does the error occur? Dental CT scans take a series of parallel spirals and convert them into specific images by sophisticated algorithms. The computer compensates for the small gaps between the spirals, but these gaps accumulate into a margin of error. The manner in which a technician places the patient’s head also contributes to the error. The NewTom differs from a traditional dental CT scan in the way it captures an image; it does so by cone beam volumetric tomography. The X-ray tube revolves around the

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patient’s head in a single spiral, capturing a volume with each of the 360 degrees it rotates. Added together, the volumetric cone images are reformatted without any discernible error. In fact, the NewTom is accurate to 0.1 mm. Reduced Radiation

Accuracy is good, but what else separates the NewTom from a traditional dental CT scan? In two words, less radiation. While a dental CT scan takes ten minutes of working time and exposes the patient to two minutes of radiation, the NewTom scan takes 70 seconds and exposes the patient to 17 seconds of low-dose radiation. The radiation from a NewTom scan is comparable to the radiation from a single Panorex, while a dental CT scan is roughly equivalent to 6?8 times that amount, depending on bone density. More Information

Another difference is that a dental CT scan shows only what is prescribed: either the mandible or maxilla. If a patient needs both a maxillary and mandibular CT scan for implants, the total radiation is equivalent to about 15 Panorexes. The NewTom, however, takes both the maxilla and mandible with a radiation dose equivalent to that of a single Panorex. In addition to both jaws, the NewTom scan displays both TMJs and the sinuses, as well. Another advantage of the NewTom is that the fees are much less for much more information. Tomographic Images and Endodontics

Okay, so we’re talking about greater accuracy, more information, less radiation, quicker scans, but why would endodontists be interested in dental tomographic images? The answer is evident once you see what this machine is capable of doing. For example, consider the following:

An axial cut on the NewTom easily identifies a second hidden canal in the MB root of a maxillary first molar. Actually, the axial cuts of the NewTom cut through each root, millimeter by millimeter, depicting every canal of every root of every tooth.

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Transaxial cuts reveal hidden roots or untreated roots that require endodontic treatment.

Coronal cuts are so specific that they can separate the MB from the DB root of a maxillary molar, permitting an accurate diagnosis of which root has periapical pathology and which doesn’t. Extrapolate this to the next step, and the NewTom distinguishes between sinus and dental infections.

You can see why we are so excited about the NewTom. It gives more information about the teeth, the root canals, condyles, mixed dentitions, impacted teeth, and supernumeraries than conventional CT imaging does, and it helps detect and diagnosis pathology with greater accuracy than anything else currently out there. It won’t solve every problem for us, but in an age that demands greater precision and predictable results, the NewTom brings us one step closer to the elusive gold ring of 100 percent detection and diagnosis that we all strive to grab. For those needing one more reason to try this technology, the NewTom 9000 can produce studies in both NewTom and SimPlant¨ formats. Implant studies can be ordered along with views of the TMJ; chronic pain sufferers can get specific pictures along with detailed panoramic cuts; and patient studies are always on file for future review. If the NewTom interests you as much as it has captivated us, call me at APW Dental Services, PC, (212) 838-8302, and request a descriptive brochure. Not only do we have the first NewTom 9000 in New York City at APW, but we have the only one on the East Coast. We are located in a historic townhouse at 34 East 62nd Street, and we would be pleased to have you visit our office or arrange for a personal in-office demonstration. Dr. Herbert Frommer, director of radiology at

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NYU Dental Center and the only board-certified oral and maxillofacial radiologist in New York City, reads every scan for pathology including the structures of both jaws, the sinuses, airway space, and temporomandibular joints. APW is a radiology lab run by dentists for dentists.

May-June 2003 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Alan Winter, D. D. S. A New Standard of Care?

T HAS BEEN SAID that an endodontic filling is equivalent to an angiogram; each depicts the nuances, constrictions, and patency of its respective organ. Graphic representations of a three-dimensional anatomic structure, be it an accessory canal or collateral circulation, will provide more information and data to help diagnose or treat both medical and dental problems than will conventional X-rays. With the increasingly common placement of dental implants, the use of three-dimensional data from computed tomography (CT) and cone beam volumetric tomography (CBVT) is invaluable in dental implant treatment planning, temporomandibular joint (TMJ) dysfuntion, pathology, and orthodontic evaluations. While CT scan technology has been available for twenty years, a number of considerations limit its use in dentistry. In addition to inflicting high-dose radiation exposure on the patient, CT scans only take one arch at a time. A patient who needs the opposing arch scanned would be exposed to the same exposure again (equal to ten panoramic films). CT scans create so much scatter that it may limit the quality of an image and make visualizing atrophic ridges or key anatomy difficult. By comparison, the CBVT scanner (e.g., the NewTom 9000) significantly reduces the radiation exposure (by 80 to 90 percent). In addition, it significantly reduces scatter from existing restorations. The NewTom 9000 CBVT scanner takes both arches at the same time, reduces the patient’s exposure to unnecessary radiation, is available for future studies, and saves a great deal of time. APW Dental Services, located in midtown Manhattan, is the only dental radiology center in the tri-state area that has the NewTom 9000 CBVT scanner. Their tomographic services exceed expectations when it comes to providing scans for comprehensive treatment planning, TMJ, endodontic lesions, orthodontics, pathology, third molar cases, and pre-surgical considerations for dental implants. In fact, so much information is included in their cone-beam 3D volumetric tomograms that it may very well become a new standard of care for pre-surgical analysis for dental implants, chronic dental pain, recalcitrant endodontic lesions, TMJ dysfunction, and more. Like a well (laterally) condensed root canal, a 3D

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tomogram can give more information than any of us may have dreamed of when it comes to seemingly routine clinical situations. Consider Figure 1; the bridge had failed and the dentist wished to place implants in the edentulous area. This is a panoramic view of a 3 mm slice with a 12 mm trough. This means that everything 12 mm buccal and lingual to the center 3 mm cut is captured in this view.

Figure 1

FIGURE 1: A panoramic view of a 3 mm slice with a 12 mm trough.

Consider that the information in these 25 mm is more precise than a conventional panoramic radiograph, and that both are good screening devices to observe impacted teeth, supernumerary teeth, retained root tips, most periapical radiolucencies, and most anatomic structures. But is this image, along with a dental periapical X-ray, enough to place a dental implant? Perhaps not. Figures 2 and 3 represent a 1 mm slice with a 1 mm trough, which equals a 3 mm view through the mandible.

Figure 2

FIGURE 2: A 1 mm slice with a 1 mm trough. Figure 3

FIGURE 3: Showing major and minor branches off the nerve.

Notice how well-defined the mandibular nerve is and notice what appear to be major and minor branches off the nerve. Figure 3 marks these branches, which can easily be seen in

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transaxial (sagittal) slices. Based on the analysis and report provided by APW Dental Services, the dentist informed the patient that nerve damage could be expected if implants were placed. Instead, an alternative treatment plan was designed for the patient that would not jeopardize the nerve. In a different but similar case, teeth were removed in the mandibular left. In preparation for implant placement, the dentist referred the patient to APW for a 3D tomographic study. While the panoramic view (Figure 4, which is a 3 mm slice with a 12 mm trough) did not raise any alarms, the 1 mm slice with the 1 mm trough (Figure 5) indicated that placing an implant in the area of the mental foramen, which the dentist intended to do, could be a problem.

Figure 4

FIGURE 4: A 3 mm slice with a 12 mm trough. Figure 5

FIGURE 5: A 1 mm slice with a 1 mm trough.

The transaxial (Figure 6) cut demonstrates an atypical mental foramen that extends to the lingual cortical bone.

Figure 6

FIGURE 6: Transaxial cut demonstrates an atypical mental foramen that extends to the lingual cortical bone.

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The distance from the crest to the nerve was 9.3 mm. When the dentist indicated that he planned to place a 10 mm implant, it was suggested that he alter his treatment plan. In the past, this dentist had used only periapical films to determine where to place a dental implant. With this added information, he was able to prevent a potential problem and render better care to his patient. In less than a year, APW Dental Services has brought a welcome change, enabling tri-state dentists to provide better, more accurate pre-surgical analyses for their patients. Not only are implant patients better served, but APW has assisted surgeons in isolating impacted teeth, cysts, retained roots, oral-antral communications, and more. When it comes to implant cases, APW provides a unique service: they highlight and identify the mandibular nerve in the 1 mm panoramic frames and in all transaxial views. Upon request, they will provide measurements of the amount of bone above the mandibular nerve in appropriate sites. In addition, a formal oral radiological report (provided by Dr. Herb Frommer, director of radiology at the New York University College of Dentistry) may be requested for each patient. APW Dental Services is located in a historic landmark brownstone at 34 East 62nd Street. APW’s fees are highly competitive, and they offer one-day service. They are open Monday through Friday and can be reached at 212-838-8302.

February-March 2004 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D. Thoughts on Recent Academic Proceedings

Barry Musikant he speakers at the Fifth International Symposium on Endodontic Biology included academic researchers of world renown. The meeting was dedicated to the discussion of single-visit versus multiple-visit endodontics. In a certain sense, it was like going back in time, because as researchers they were discussing sterile and non-sterile canals, which brought up the specter of culturing, something that most of us considered a nightmare in dental school.

Researchers’ General Conclusions While the speakers were not recommending culturing, they Barry Musikant generally came to the following conclusions:

1. All vital cases should definitely be done in one visit for less post-operative pain. This conclusion is partially based on the following one. 2. All temporary filling materials leak; cavit allows the least amount of leakage. 3. In multiple visits, any reduction in bacteria as a result of the first visit will be repopulated with bacteria by the second visit. 4. The toughest cases to achieve success are not bacterially infected but fungally infected. 5. If some bacteria are left after adequate obturation, they are generally entombed subjected to reduced nutritional conditions incapable of reaching vital tissues rendered non-viable by the canal medications in a small percentage of cases, capable of survival and able to prevent healing

The survival of fungi offer the poorest long-term success rate because fungi interact with the macrophage cells periapically to increase the release of calcium inducing bone and root resorption. This is often a low-grade chronic process occurring over a number of years, often without symptoms.

Researchers’ General Recommendations The reality of endodontic therapy is that we do not know if we have all of the bacteria or fungi in the root canal after treatment and if we do, what specific organisms they are. The

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researchers generally offered these recommendations:

1. Widen the apices of canals to at least a #30 instrument with a significant coronal flare. This not only physically removes bacteria and disengages dentin, but allows adequate space for NaOCl irrigation. 2. Have an excellent coronal seal, because data shows that long-term success is as dependent on the prevention of coronal leakage as it is on an apical seal. 3. Prevent gutta percha from going over the apex. Most of us originally learned that one of the reasons gutta percha makes an ideal filling material is its inert nature when in contact with periapical tissues. Research was presented that shows gutta percha over the apex has the potential to also interact with the macrophage cells to induce bone and root resorption. This detrimental effect is enhanced when the gutta percha has been degraded into a less stable structure as a result of chemical softening with chloroform or the application of heat during thermoplastic obturation procedures. 4. NaOCl is used in concentrations ranging from 2.6% to a full 5.25%. The higher the better as long as the application does not allow for periapical extrusion under pressure. 5. Ca(OH)2 is a good inter-visit medication when a case is highly infected.

My Conclusions Some of my own thoughts on what I heard at this meeting include:

1. Our practice is on the right track in using our Simplified Endodontic Technique, (S.E.T.) as our endodontic guide because it widens and tapers the canals enough to efficiently irrigate them with NaOCl 5.25%. 2. S.E.T. places a gutta percha point thoroughly coated with an epoxy resin (EZ-Fill) into the confines of the canal. Because it is a single cone system, the gutta percha is not subject to vertical or lateral condensation that could force the point into the periapical tissues, inducing a macrophage interaction resulting in bone and root resorption. 3. Epoxy resins have their own anti-bacterial and anti- fungal properties as the material sets, rendering any remaining bacteria and fungi less viable. 4. Epoxy resin cements offer the most resistance to coronal leakage due to their polymer structure, unlike ZOE based cements that are particulate in structure and disintegrate far more readily in the presence of moisture.

Single-Use Endodontic Instruments

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One of the researchers brought up the idea of using endodontic instruments for only one visit and then discard them because they incrementally dull with usage and are more prone to fracture over time. I strongly object to this idea! The advent of Ni-Ti instruments has given the dentist an armamentarium that has increased the cost of each instrument from approximately $.70 per instrument to $7.00 per instrument. Unlike tough and inexpensive stainless steel, Ni-Ti is vulnerable to fracture, especially when instrumenting curved canals. Yet the instrumentation of curved canals are where they are most needed to prevent canal distortions such as transportations and zipping. The fact that Ni-Ti instruments have their greatest potential to fracture in these situations where they are most needed represents an ironic paradox set before us. The manufacturers of these Ni-Ti instruments would love us to use systems composed of expensive and vulnerable instruments and to dispose of them after one visit to reduce the fracture incidence during their usage and the potential for subsequent lawsuits. Rather, I strongly believe that using a hybrid system of stainless steel and Ni-Ti that takes advantage of the strengths of each and de-emphasizes the weakness of each represents a far more rational system than the wholesale replacement of Ni-Ti files after a single usage.

S.E.T. specifically addresses these issues. Those using the system have found that fracture of the few Ni-Ti files used is a rare occurrence and when it does occur it is generally in your hand and not in the root. The simple bending test that we do before placing a Ni-Ti instrument into the canal quickly determines if the instrument has enough strength for use in shaping the canal without fracture. Because of our emphasis on stainless steel and the high number of times we can use Ni-Ti instruments before discarding them, the cost of S.E.T. instrumentation is minimal compared to all of the systems being advocated today. Interestingly, the viewpoint of single usage derives from the academic circles where instruments are often donated to the dental schools by the manufacturers in the hope of influencing dental students to become future customers. It is far easier to advocate single usage when the economic impact of that decision does not hit you directly. I know that I am not alone in rebelling against a system that increases the cost more than ten-fold without any effort to see whether the end point of the instrumentation, namely the shape of the canal, could be attained in a more efficient and economical manner as advocated by S.E.T. We are far better off as practitioners when we exchange and develop information about techniques rather than rely solely on “facts” that are presented by manufacturers and marketers. FEEDBACK?

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We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D. We Use What Works

Barry Musikant e have all taken many courses in our quest to do things better, easier, or faster. Yet, often we never incorporate what we recently learned. Certainly, I took a number of endodontic courses over the years that emphasized rotary Ni-Ti instrumentation and thermoplastic obturation. They did not become part of my techniques and I started to analyze why this was the case.

Departures from Established Procedures One of the main reasons we do not apply new information is is that it may represent a sharp departure from the existing Barry Musikant knowledge base. For example, a switch from manual step- back endodontic instrumentation to a rotary crown-down technique, or lateral condensation with a change to a heat- carrying applicator. Both represent a significant departure from the way things were done. Rotary crown-down presents itself as a superior technique, but is it better, easier or faster to learn, and is it truly superior enough to justify its incorporation into your daily routine? The rotary Ni-Ti crown-down technique has requirements that the step-back technique does not, including:

1. a light touch that never binds the instrument to the point where it cannot be pulled out or drawn in 2. a technique that requires constant motion of the instrument 3. frequent replacement of instruments even though you do not see obvious distortion to them 4. a technique that requires clear tactile perception of when and to what degree the instrument is binding

Some thermoplastic obturation techniques require the following to be newly incorporated:

1. the application of a high heat source for a very short time; approximately 2 seconds to a fitted gutta percha point followed immediately by 2. a 3 mm apical push for 5 seconds more after the heat has been applied followed by 3. reapplication of high heat and withdrawal of the instrument

It Takes Time and Practice

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Time and practice are required to achieve the skill to incorporate these new procedures. Poor application of any of these skills severely affects the outcome of the procedures. In other words, these new techniques that might produce a superior result over more traditional techniques also carry with then the burden of a narrow window of success. A series of difficult tasks must all be performed well to get a good result. Potential negative results from the rotary crown-down techniques include instrument fracture and subsequent blockage of the canal. Potential negative results from heat application techniques include excessive heat to the root and periodontium producing pain and tissue necrosis, possible extrusion of softened gutta percha, and shrinkage of the heated gutta percha mass yielding a poor dentin-cement interface, something that may occur without the dentistís awareness of it. Therefore, the desire to accept a new technique and, thus, be motivated to learn it, at some point is determined at least in part by the difficulty of the technique with all its potential drawbacks versus the predictability of higher quality results. The greater the predictability of excellent results the more likely the technique will be used again. If the quality of the results vary widely, the poor predictability of the technique makes for less acceptance by the practitioner. The advantages of rotary Ni-Ti crown-down over step back include:

the avoidance of hand fatigue the elimination of distorted curved canals

The advantages of thermoplastic obturation over lateral condensation include:

better adaptation of the gutta-percha to the walls of the root (discounting shrink-back) less mechanical stress to the root during obturation better looking x-rays, often including lateral canals in non-vital cases

The Ultimate Decision Ultimately for any procedure, the practitioner must decide whether the advantages outweigh the disadvantages. For endodontics, the practitioner can make this decision in light of the EZ-Shape and EZ-Fill techniques that are easy to learn. These techniques vary little from the previously known manual step-back techniques, yet deliver wider tapered canals. These canals are shaped to exactly fit a fine-medium or medium gutta percha point. This precise shaping allows the canals to be obturated with a single room-temperature master point and an epoxy-resin cement of varying thickness that is routinely delivered as an interface between the gutta percha and the walls of the root. The simple reason that EZ-Shape and EZ-Fill are being

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adopted by the dental community is that they are in phase with previously learned knowledge, doing away with traditional shortcomings and adding those few features that allow the dentist to predictably do endodontics as well as the best endodontist simply, quickly, and cost effectively. 11/02/1999 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D. Proper Diagnosis of Teeth: Making Sure You’re Doing the Right Tooth!

Barry Musikant lthough Simplified Endodontic Technique (S.E.T.) gives you a cookbook approach to achieving excellent endodontics, the original diagnosis is critical in applying S.E.T. to the right tooth. A sequence of twelve steps helps you correctly diagnose most teeth.

1. Take a good history. Listen to everything the patient wants to say. Not only will you get useful information, but you are letting the patient know that you have time and concern for him or her. Depending upon the information the patient supplies, you Barry Musikant can often shorten the diagnostic procedure. Good questions to ask are:

What do you think the problem is? Does it hurt to hot or cold? Does it hurt when you’re chewing? When does it start hurting? How bad is the pain? Does anything relieve it? How long has it been hurting?

2. Take a radiograph. It may show a periapical or periodontal area, decay, resorption, deep fillings, fracture, or thickened PDL. Radiographs are indispensable. No diagnosis should be made without them.

3. Employ percussion-tapping. Percussion-tapping with the mirror handle on the tooth in a vertical direction often allows you to identify the tooth that has inflammation in the ligament and, consequently, hurts the most to tapping. If two teeth together hurt to tapping, immobilize one with your finger while tapping the other and then reverse the process. Often you will find that one hurts significantly more than the other and will be the more suspicious of the two.

4. Employ palpation. Press into the fold above the apex of the root or roots. Often

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the endodontically involved tooth will be more tender than the others if the inflammation has extended into the periapical region, and palpating in this way will produce a greater sensation. You should also be able to detect any swellings or fistulas that may be present. Palpate the lingual of teeth with the same goals in mind

5. Apply the cold test. This is simply done with cylindrically shaped ice sticks. Make them by placing water in empty anesthetic carpules and adding a piece of dental floss that extends to the bottom of the carpule and has a handle on the open end of the carpule. Keep them in the freezer and withdraw the frozen cylinder when needed. A good site of cold application is generally the buccal surface as close to the cemento-enamel junction as possible. If a metal crown restoration is on the tooth, attempt to apply the ice on the lingual metal collar, an area where the cold travels most easily. If a tooth has irreversible pulpitis it will either give a prolonged response, possibly after some delay, or no response. Transient pain (less than ten seconds) after the application and removal of ice is normal. No response may mean the tooth is endodontically involved, especially if all other teeth respond to cold. If sharp transient pain occurs that is greater than the pain felt in surrounding teeth, check to see if the bite is high. Root canal is probably not needed and the bite adjustment will eliminate the hyper response to cold.

6. Apply the heat test. Using a ball of hot gutta percha on the tip of a plastic instrument, place the gutta percha onto the tooth the same way you would the ice. Wait approximately 15 seconds between teeth to assess the possibility of a delayed, but, prolonged response. Compare the results from other tested teeth. If one tooth gives a prolonged response, whether immediate or delayed, it is a most suspicious candidate for endodontics. If the pain is immediately relieved by cold, the tooth probably needs root canal.

7. Apply the electric pulp test (EPT). This test should be used when the hot and cold tests fail to give clear information on the state of vitality of the tooth. Again, the information supplied by the electric pulp test must be weighed against the response from other teeth. the fact that a tooth does not respond to the EPT has little meaning if all the other teeth also do not respond, unless of course this is the only tooth with a well-defined area at the apex or is quite tender to percussion.

8. Use bite sticks.

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Use bit sticks to check for incipient fractures that are causing pain to a tooth when under function. By having a patient bite on each cusp and laterally move the lower jaw, each cusp is subjected to lateral stresses. If a section of the tooth under a cusp has an incipient fracture it will often hurt when pressure is applied. If a fracture does exist, the tooth may not need endodontics if the fracture does not extend into the pulp. The pain generally disappears if the fractured portion of the tooth can be cleaved off.

9. Employ transillumination. Transillumination often confirms the portion of the tooth that has the fracture. By placing the transillumination light source on the lingual side of the tooth and turning out the chairside light source, fractures may be picked up as a dark horizontal line against a light amber background. Transillumination can sometimes differentiate between vital and non-vital teeth with the non-vital appearing duller than the surrounding ones when the light source is applied.

10. Use the binocular microscope. It is excellent for picking up incipient fractures simply because you can look at teeth magnified up to 30 X with excellent illumination.

11. Apply selective anesthesia. It should be applied with an intraligamentary gun. If specific anesthesia to one tooth makes all pain disappear for a short time and the effect is repeatable, the anesthetized tooth is probably endodontically involved.

12. Drill a test cavity. If you believe that a non-vital tooth is causing symptoms, but cannot confirm non-vitality with assuredness, a test cavity without anesthesia may allow entry into the pulp without any pain, thus confirming your suspicions.

Even after using all these tests we may find at times that we are still not confident in making a definitive diagnosis. Realize that some pain that appears to be dental in origin is not. Problems involving the temperomadibular joint, sinuses and the trigeminal nerve often mimic endodontic pain, but, will not disappear after treatment. If you suspect non-dental causes, refer the patient to the appropriate specialist (medical or dental) unless you are knowledgeable in these areas yourself. Good diagnosis comes from using as many of the above tools as are necessary to confirm as solidly as possible your opinion on what should be done. My experience is that patients truly appreciate the time you take to confirm what should be done. This is especially true when a patient comes in with a strong feeling that one specific tooth is the source of the

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problem, but your diagnosis says that it is another and after treatment you are right. If it turns out that you are wrong, that is the subject of another article!

11/02/1999 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., Brett I. Cohen Ph.D., Allan S. Deutsch D.M.D., F.A.C.D. The Fallacies of Non-Metallic Posts

Barry Musikant t would appear that the recycling of old ideas packaged in the guise of new technology shows up every now and then to make a case for its superiority over proven techniques and devices. Non-metallic posts are an excellent example of this process. Unsupported claims are made that the retention is optimal because the posts take advantage of the greater adhesion produced by etching and bonding, something all passive posts do.

The Modulus of Elasticity Fallacy In addition, a marketing innovation includes great emphasis Barry Musikant that the post are made of materials that endow them with a modulus of elasticity equal to that of dentin. This implies that because of the similarity, the post will bend in unison with the tooth, reducing functional stresses to the root that would have been far greater if a metal post had been inserted into the canal. The claim of similar flexibility of the post and the tooth is very attractive for the long-term success of the post- supported restoration. The reality of the concept is false, however, and not supported by the logical analysis of its claims. First of all, when claims are made that the materials Allan Deutsch have the same modulus of elasticity, it means that the samples tested have the same cross-sectional area. This should immediately become clear if one realizes that a redwood tree and a redwood tooth pick both have the same modulus of elasticity. The tree is immovable, while the toothpick can be snapped in two between your fingers. Obviously, the cross-sectional area affects the resistance to bending. A post going into the root of a tooth has by necessity a much smaller cross-sectional area than the root it is being placed into. The smaller the cross-sectional area, the greater the flexibility, just as in the case of the toothpick. Because all posts are thinner than the roots they are going into, a similar modulus of elasticity will produce a post that bends far more than the root it is in. The claim of similar moduli of elasticity is a weakness, not a strength, and a post that bends significantly more than its supporting root will not bring longevity to the overlying restoration. More specifically, the modulus of elasticity of dentin is 8. The diameter of the shank of the average post going into a

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root is generally between 20 and 25 times smaller than the host root. To compensate for this smaller diameter, the modulus of elasticity should be proportionally higher, producing a stiffer material. A stiffer material that has a thinner cross-sectional area could bend in a fashion similar to the bending of the root, if it has the proper modulus of elasticity. The modulus of elasticity of stainless steel is 200, 25 times that of dentin. Yet, if the cross sectional area of the stainless steel post is about 25 times thinner than the root, the bending of both the post and the root will be the same when subjected to an outside force (200 / 25 = 8). A careful analysis of the original claims for non-metallic posts not only demonstrates that they bend far more than the roots that they are in, but also that stainless steel, rather than being too stiff, has in fact an excellent modulus of elasticity for compatibility between a post and supporting root.

The Composite Core Fallacy While claiming the benefits of a lower modulus of elasticity, a further part of the technique includes the addition of a composite core. the claim is made that the combination of the two creates a mono-block that bends like a tooth, something that the post was supposed to be able to do on its own. The term mono-block implies a homogeneity of materials, suggesting that the post and core are so similar that they act as one unit. However, the post—though flexible—is highly resistant to fracture because of carbon fibers palced in parallel in the matrix. The composite core is not endowed with such fracture- resistant components and is subject to degradation under function from a post that bends far more than the root. In fact, the first area of degradation would be along the composite core dentin interface producing a gap formation susceptible to decay and further widening. For the concept to produce longevity, the core would also need the incorporation of parallel carbon fibers, a product that does not exist today.

The Superior Esthetics Fallacy A newer generation of non-metallic posts which are composed of either a reinforced composite or ceramic are making claims of superior esthetic results. They are being advocated when the teeth are being restored with the new ceramic crowns. The solidity of the final restoration is based on the bonding ability of the new adhesives. As any endodontist will tell you, endodontically treated teeth do not make ideal abutments! If possible when they are used, additional teeth that have not had endodontics are incorporated into a restored span for greater stability. It is traditional, unchallenged knowledge that when endodontically treated teeth are crowned, the margin should include a long bevel onto the root surface to create a superior ferrule effect. The new ceramic crowns, like their predecessors, require a butt joint. These restorations should

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not be placed on endodntically treated teeth, especially those with a post-supported core. If the better restoration is a porcelain fused to metal crown with a long bevel, the need for an esthetic post does not exist, and the post that is placed can have higher retention and better stress distribution pattern than any of the non-metallic posts can deliver. The one area where a tooth-colored post might have some irreplaceable benefit is thin roots covered by a thin labial gingiva where the color of the metallic post might show through. The incidence of this particular situation is very small and even there can be modified by the use of opaquing cements over the shank of the metal post when it is placed within the root.

Conclusions In summary, the claims made for non-metallic posts are not supported by the logic of many laboratory studies. Further, the use of esthetic non-metallic posts with butt joint full coverage restorations is counter-productive and should be avoided. Well designed stainless steel prefabricated posts (Flexi-Post and Flexi-Flange) are more compatible with functioning roots, producing far higher retention, minimum stress upon insertion, and even distribution of stress under function. It would appear that the even distribution of stress under function is enhanced by a post that bends very similarly to dentin, the result of a significantly higher modulus of elasticity, such as that of stainless steel.

11/02/1999 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D. How to Instrument and Obturate Canals Superbly and Economically

Barry Musikant ost dentists instrument canals with .02 tapered stainless steel reamers or files. They may open the apex anywhere from a #15 to a #40. Having instrumented with .02 reamers or files, they then obturate the canals with .02 tapered gutta-percha or standardized (I.S.O.) or (standardized points). Generally, the canals and the point are coated with cement and the pre-fitted point is placed into the canal, followed by the addition of extra points in a combination with vertical and lateral condensation. Barry Musikant As you may know, although the fit film is placed accurately to the apex, the final film often shows gutta-percha over the apex. You might logically decide that you used too much vertical force. What you should understand is that you are placing an almost parallel gutta-percha point into an almost parallel preparation. An .02 taper is very close to parallel. Is it any wonder, therefore, that a small amount of condensation then results in overfill? An alternative is to shape your canals with greater taper and place points of greater taper, making it more difficult to drive the points over the apex, even if you apply significant vertical condensation. Because of this greater resistance, you will have fewer unpleasant discrepancies between your trial fit and final cementation. Buchanan designed a set of files of greater taper going from .06 mm/mm to .12 mm/mm. These tapered files correlate almost exactly to various tapered gutta-percha points. For example, the .06 file of greater taper correlates to a fine-medium point. The .08 file of greater taper corresponds to a medium point. Both Buchanan files will bind exactly at the apex. As good as these files are for creating proper shapes, they should not be used from the start of instrumentation because they would be subjected to considerable stress

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Since they are made out of Ni-Ti, they can break without warning despite showing no signs of wear. Using Ni-Ti Instruments Without Fear of Fracture To take advantage of these Ni-Ti instruments without fear of fracture, shape your canals first with a step-back sequence using the .02 tapered stainless steel reamers. The sequence consists of the following steps:

1. Determine the distance to the apex. (We obtain greater accuracy from an apex locator than x-rays. We’ve used a unit from Osada for years) 2. Coat all files and reamers with RC Prep and irrigate copiously with with 5.25 percent NaOCL delivered with a 30 gauge needle used with very light pressure.

A 30 gauge needle allows you to irrigate efficiently near the apex as the shaping progresses. The light pressure prevents the solution from going peripically. Remember, only a few drops are necessary apically to thoroughly fill the canal space with fluid, and time is necessary for the NaOCL to digest the organic debris and kill residual bacteria. 3. Instrument to the apex through a #20 reamer using a rotational motion. 4. Track the canal 1/3 to 1/2 its length with a #2 Peeso reamer, tapering the canal in the process. Minimal force assures no ledging or blocking. 5. Recheck your apical patency with the #20 reamer. 6. Go 1 mm short of the apex with a #25 stainless steel reamer. 7. Go 2 mm short of the apex with a #30 stainless steel reamer. 8. Go 3 mm short of the apex with a #35 ENDO TIP stainless steel reamer. 9. Go 4 mm short of the apex with a #40 stainless steel reamer. 10. Go 5 mm short of the apex with a #45 stainless steel reamer. A key point in using Ni- Ti instruments is to Checking your patency after each reamer prevent heavy hand is a good idea. Having used the stainless pressure and binding. If steel reamers through #45 in a step-back fashion, you now have created a canal shape you use light hand with a .05 taper using .02 tapered

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pressure, the binding is instruments! The increasing stiffness of the minimal. You will remove thicker stainless steel reamers have not distorted the canal shape because as the less tooth structure at reamers become progressively wider, they any one time, but will be go diminishing distances. This sequencing is compensated for it by an excellent safety device. increasing the number of If by chance you initially over-instrument, you will not compoud the problem by instrumentation cycles. repeatedly injuring the peripical tissues because the technique requires you to pull back. At this point in the process, you are more than halfway to achieving an .06 or .08 tapered canal space. 11. Employing a balanced-force technique, use Buchanan’s .06 file of greater taper to the apex without applying a lot of pressure. The final shape, going from a .05 taper to a .06 taper should take less than 30 seconds. 12. Once an .06 taper is achieved, you can automatically fit a fine-medium point, or you can choose to shape the canal with an .08 file of greater taper, which should take you no more than an additional 90 seconds followed by a trial fitting of a medium gutta-percha point.

A key point in using Ni-Ti instruments is to prevent heavy hand pressure and binding. If you use light hand pressure, the binding is minimal. You will remove less tooth structure at any one time, but will be compensated for it by increasing the number of instrumentation cycles. A higher number of cycles combined with reduced hand pressure prevents the Ni-Ti instrument from reaching its elastic limit. Distortion occurs only after reaching its elastic limit, and Ni-Ti easily fractures when reaching this point without any tell-tale signs. An additional advantage is that as delicate as Ni-Ti is, it will last almost indefinitely, if the elastic limit is not violated.

The Bi-Directional Spiral The placement of a well-coated tapered gutta- percha point into a well-coated tapered canal drives the cement into accessory invaginations if they exist and ensures the safe release of excess cement coronally. The bi-directional spiral (BDS) is the most effective way to safely place cement on all walls of the preparation. The BDS creates lateral movement of the cement while preventing it from going over the apex.

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EZ-Fill cement is used to coat the canals and the prefitted tapered gutta percha point. It has the following advantages:

It is non-toxic and non-inflammatory. It is eugenol-free. Because it is an epoxy resin, it’s compatible with composite chemistry It bonds to dentin and gutta-percha. It is highly radiopaque. It neither shrinks or expands. More than 45 years of research back its use.

After coating the canal, coat the last 4-5 mm of the tapered gutta-percha point, place it into the canal, and sear off the excess material. A single tapered gutta-percha point is all that is required. Coronally, the thicker cement seal stays perfectly intact. Displacing it with further point placement will achieve nothing. The time requirements for this sequence from start to finish on a non-calcified single canal should be less than 20 minutes (with practice). The money invested in this technique is minimal because the emphasis is on inexpensive traditional stainless steel reamers and regular tapered gutta-percha points. We believe that this technique is truly the best of both worlds, resulting in superbly shaped canals, a well-fitted gutta-percha point with a continuous epoxy resin interface that has been driven into any invaginations that may have existed, produced in a time-efficient and economical manner. Nothing else comes close!

11/02/1999

Instruments used in this procedure are available from the following sources:

Buchanan Files

Tulsa Dental . . . (800) 662-1202 MDKD&V Logo

EZ-Fill Endodontic Cement Bi-directional Spirals

EDS . . . (800) 223-5934 If you would like a Endodontic Reamers demonstration of this Tapered gutta-percha points technique, e-mail us or call

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our offices at (212) 582-8161. L. D. Caulk . . . (800) 532-2855

Peeso Reemers #2 NaOCI(Clorox)

Standard Items

FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo- Mail.

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Barry L. Musikant, D.M.D. Thoughts on Nickel-Titanium Instrumentation

Barry Musikant egular readers of our newsletters will notice an increased emphasis on simplified endodontics. I have taken many courses on new techniques available for instrumentation and obturation, and have concluded that needless complexity and expense has evolved from the insight that there is not a single canal, but rather a system that may include various accessory invaginations. To clean and obturate this system, leading endondontists determined that all canals had to Barry Musikant be thoroughly debrided and obturated. Opening the canals to a wider taper allows them to be cleaned and irrigated more efficiently. Shaping to a greater taper allowed the canals to be obturated with thermoplasticized gutta-percha without pushing the gutta-percha over the apex. These innovations, wider taper and thermoplastic obturation, are improvements over the traditional .02 tapered canal shaping and obturation with standardized points. Improvements Brought Complication and Expense While these innovations are improvements, many of the instruments and techniques used to achieve them are complicated and expensive. The introduction of Ni-Ti files of different designs to achieve a wider taper requires the implementation of a crown-down technique ENDO TIP because of their metallurgic characteristics. Although Ni-Ti has super elasticity to negotiate curved canals without distorting them, it has little

tolerance for deformation without fracturing. To minimize instrument distortion, the crown- Have you ever opened the down technique requires the use of thicker files chamber of a pulp and first with thinner ones used sequentially in a experienced a fetid odor? I crown-down direction. This technique is delicate, have. Using a mouthwash in requiring keen tactile sense and patience. In the a syringe to irrigate the pulp process of switching from stainless steel to Ni- canal works to eliminate that Ti, the cost of the average instrument increased odor. Many times I'll leave from $1 to over $6! This, without any promise the rinse inside the chamber

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that the Ni-Ti instruments would last even as for a few minutes. Afterwards, long as stainless steel ones. The increased use of I'll rinse with sodium Ni-Ti that must be replaced frequently to achieve hypochloride. Then the odor the continuously tapered canal shape is common will dissipate. Patients who to most of the techniques employing crown- smelled the initial odor feel down preparations. terrific, for there is no longer Replacing lateral condensation with various an odor. Furthermore, they thermoplastic techniques also produced a major feel that you, as a practitioner, increase in the cost of obturation. $6 have "really" done something thermoplastic points replaced $.07 gutta-percha points. Heating systems costing thousands of for them. I hope you have as dollars replaced Bunsen burners and lateral much success with this condensation. One method of thermoplastic technique and patients' obturation requires placing a red-hot spreader acceptance of it as I have. within 5 mm of the apex, releasing the heat ring, Amy Dukoff, D.M.D. and further advancing it another 3 mm over a matter of seconds, reheating the spreader, and releasing it from the gutta-percha followed by further obturation with a gutta-percha glue gun. Are the improved results justification for the increase complexity and expense? I do not believe so.

Simple and Economical Alternatives Read the accompanying article on this site entitled “How to Instrument and Obturate Canals Superbly and Economically” for alternative methods that are simple and economical. We have employed them in our office for ten months with immense success, characterized by reduced flare-ups, excellent radiographic results and ease of operation. The techniques described in this article are in full conformity with the latest research in endodontics. The sealing ability was at least the equal of thermoplastic and lateral condensation techniques. These techniques have reduced cost and time. The increase in complexity and expense to achieve superior results has proved not to be inevitable after all; it has been short-circuited by a little creativity and common sense.

11/02/1999 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D. X-Tip, Where “X Marks the Spot” Product Review

Barry Musikant ractical Endodontics (800.215.4245) lives up to its X-Tip Step 1 name by introducing the X-Tip anesthetic system. It is a system that eliminates the weaknesses of Stabident. Both systems create a hole into the trabecular bone approximately 5 mm apical to the buccal papilla. The anesthetic solution is then injected under low pressure into the trabacular bone mesal to the tooth that is being treated. The problem with the Stabedent system was finding the hole, which was made through the attached gingiva to inject the anesthetic. X-Tip solves this problem by making X-Tip Step 2 Barry Musikant the drill itself a hollow tube through which a 28 gauge needle can pass. The initial drill stays in place, allowing the anesthetic to then be placed without hunting for the hole that was just created! What I like most about this system is the fact that the guide (your drill), stays in place for the entire procedure, allowing for more anesthetic to be placed if necessary. Because extra anesthetic can be delivered so effortlessly,

there is never a need to include adrenaline in the X-Tip Step 3 anesthetic, which prevents tachycardias and other unwanted events. The safety and convenience of this tool will give every dentist the ability to give adequate anesthesia, generally one of the first prerequisites for successful endodontics.

FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.C.D., Brett I. Cohen Ph.D., Allan S. Deutsch D.M.D., F.A.C.D. New Post Designs and Applications

Barry Musikant uch has been written about new post designs that bend like the tooth structure and, through the use of bonding agents, have very high retention values. One study has stated that the new composite posts create no stress under function because they bend like the tooth. Other “passive” post systems are ceramic, look like tooth structure, are bonded into place with high retention and are, consequently, said to be superior. From a review of literature, and from our own clinical experience, we hope to clarify the situation. First of all. There is no thing as a “passive” post. They still Barry Musikant distribute functional stresses to the walls of the root. They may have the advantage of not inducing insertional stresses, but if not designed properly still have the potential of distributing functional stresses in a concentrated fashion. In fact, the only passive post is the one in the box! Another point to remember is that to date, no combination of etchants, microabrasion, bonding agents, or cements has proven to be as resilient or as strong as dentin. A threaded post with even a weak cement still offers more tensile resistance than any passive post because the thread is locked into the dentin. The resistance that dentin offers is far greater Allan Deutsch than any cement developed to date. More importantly, the fatique charachteristics far exceed that of any composite cement. Research has made it abundantly clear that threaded posts have the potential of creating high levels of insertional stresses. We could not agree more! The concept of the split flange, a characteristic of the Flexi family of posts, was developed to mitigate the stressful effects of the thread while maintaining its retentive advantages. Many independent studies confirm the combination of high retention with minimal insertional stresses and the even distribution of functional stresses associated with the split- shank concept. One relevant clinical question is when to use the Flexi- Post versus the Flexi-Flange. First, it is important to know that the Flexi-Flange exists. It is the third tier that was designed to give the post greater stability when no coronal tooth structure exists. The flange creates a broader metal-to-dentin surface. Under function, all posts put tensile stress on the cement

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interfaces between the shank of the post and the walls of the root. A large flange offers vertical resistance to the post’s lateral movement, consequently preserving the cement interface along the post shank. Added reinforcement is not necessary when adequate coronal tooth structure exists, but is a necessity when it doesn’t. To take advantage of the multi-tiered design, the post may be fully seated. If the flange is not seated, it is the same as not being there! Depending on the amount of dentin remaining, either a Flexi-Post or a Flexi-Flange is our choice when it has been determined that a post is necessary. During our courses on Simplified Endodontic Techniques, we practice instrumentation on plastic blocks. If you wish to practice placing Flexi-Post or Flexi-Flange in these blocks, let us know, and we will accommodate you.

11/02/1999 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D. How to Judge a Safe Endodontic system

SYSTEM of endodontic instrumentation is created to provide a shape to a canal that assures that it has been thoroughly cleansed by both the instruments used and the irrigating solutions applied with them. The system is composed of a series of instruments used in a specific sequence delivered to the canal either manually or by a powered handpiece. Each of those instruments should ideally have a design that optimizes its usage. The design, delivery, and sequence (DDS) of the instruments should support one another in the most efficient and safest way possible. Barry Musikant Design CANAL SHAPES with tapers of .06 mm/mm or greater are more likely to be cleansed than the traditional .02 mm/mm tapered canals because greater tapers remove more pulp tissue, increase the ability to place irrigating solutions closer to the apex, and increase the intimate contact of the irrigating solutions with the walls of the canal. As the taper of the canal increases, the surface tension between the walls of the canal and the irrigating solutions decreases, allowing greater flow of the irrigating solution producing more effective cleansing action.

Delivery LEARNING TO USE these instruments in a safe manner requires the ability to develop a light touch that prevents excess engagement at any one time. The “touch” that one must develop has no clear parameters other than it must “feel right.” Poorly defined parameters mean that fewer practitioners will get it just right. Long-rooted teeth with tight canals and one or more curves further complicate successful instrumentation. Most problematic is the fact that NiTi reamers and files are prone to fracture when subjected to levels of torque, flexure, and fatigue that are close to the normal forces that must be applied. Consequently, NiTi rotary instrumentation is a technique with a very narrow window of success. If the technique is not performed exactly right, the result may be a fractured instrument locked into the canal space.

Sequence THE SEQUENCE of the instruments should be compatible

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with their strengths. If a rotary NiTi reamer is used in a crown-down fashion, the potential of high dentin engagement exists. The greater the engagement, the greater the stress to the instrument, stress that is magnified further if the instrument is negotiated around a curve. Proper sequencing ensures, first, that the extra work each instrument must do falls well within its ability to do it without fracturing and, second, that the practitioner can easily tell when to progress from one instrument to the next. The design of each instrument in the sequence should further enhance its ease of use.

Results THE RESULT of properly designed instruments used in the correct sequence is a system that shapes canals safely, simply, predictably, effectively, and economically. The impact upon you personally is far less stress, greater pleasure in performing the procedures, and more free time—meaning either greater financial productivity or increased leisure time.

To learn more about properly designed systems that eliminate the endodontic stress in your life, e-mail me.

November-December 2000 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.C.D. The Future Is Coming

OME OF THE DENTISTS I speak to praise the nickel-titanium rotary crown-down technique. They say that it eliminates the most significant problems of traditional endodontics: there is no more hand fatigue, there are no more distorted canals, and instrumentation sizes the canal to a tapered gutta-percha point. The unpredictable flimsy fills of traditional endodontics have given way to a standardized taper that allows the dentist to place a much bigger gutta-percha point producing dramatically improved radiographs. Barry Musikant Given this picture of progress, I have at times felt like a Cassandra when I talk about the shortcomings of this highly praised and highly advertised technique. My biggest concern regarding rotary NiTi instrumentation is the increased potential for instrument fracture. More often than not, dentists tell me that they used to fracture instruments when they first began using the nickel- titanium rotary crown-down technique, but since they have Endo Tip become more familiar with the techniques, fracture is very infrequent and is further reduced by replacing the instruments before they weaken to the point where fracture is likely. That response might have ended further discussion, but thinking about my own emotions when I When the length was going through the NiTi rotary phase, I ask them of a tooth whether they worry about the possibility of fracture even though the instruments rarely do fracture. And the approaches the response is always the same. They always worry. maximal depth of This consistent response from dentists, most of them a 25-millimeter significantly younger than I am, made me think that perhaps there are generational differences toward stress. instrument, the Maybe the younger you are, the more comfortable you are interference of with stress. I don’t think so. More likely, the dentists who tooth structure or accept this stress do so because they see no alternative to a metallic doing excellent endodontics and, therefore, that is the price they must pay. I believe I would have done the same restoration may except that I had a crying need to produce excellent results make placing the in a simplified manner, eliminating the stress that seemed probe of the apex as if it would lie ahead of me for the rest of my locator difficult. In professional life. The result of my attempt to lessen that stress was the such cases, it is development of the EZ-Fill bi-directional spiral, which easier to attain coats the canals thoroughly in a controlled manner, and a proper

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sequence of eight stainless steel hand reamers and two NiTi hand files, which allow the dentist to perform one- measurement visit endodontics in less than an hour with results that are control using a indistinguishable from thermoplastic obturation techniques. 31-millimeter instrument rather Most dentists react quite positively to these new techniques even if they are doing rotary NiTi crown- than a 25- down. The idea of eliminating the fear of fracture while millimeter reducing overhead by at least a factor of ten will generally instrument. gain someone’s attention. However, some dentists actually take mild offense when shown an easier way, especially —Doug Kase when they have made a large investment in time and money to learn the so-called modern techniques. The contemporary term for the anxiety that they feel when they recognize the superiority of the new techniques but reject the idea of adopting them is cognitive disonance. Like jealousy and envy, cognitive dissonance does little to improve our ability to take in new information. We are in an irritating era for endodontics. Every time we think we’ve got our act together, along comes new information that unsettles the applecart, even if it doesn’t quite upset it. Take heart. In these pages, over the next few months, we are going to show you complete endodontic systems—simple in design, affordable, and efficient—that will give you the ability to do endodontics as well as the best endodontists.

January-February 2001 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.C.D. The Introduction of the EZ-Fill® SafeSider™ Instrumentation System

PPROXIMATELY seven years ago, after attending rotary nickel-titanium hands-on courses by Drs. Ruddle and Buchanan, I implemented these systems into my practice. Although many of my results improved due to the greater tapered shapes these techniques produce, I felt subjected to increased stress because of the higher incidence of fractured instruments and the fear of not knowing when I might fracture an instrument. Higher stress levels are exactly what I did not need at that stage of my professional life, and my desire to eliminate that stress was the prime motivation Barry Musikant for my searching for a sequence of instruments that would do away with it. As most of you probably know, this search led to the development of Simplified Endodontic Techniques (SET). SET transformed our practice, allowing us to become at least twice as productive, producing radiographic results at least as good as rotary nickel-titanium, and removing the fear of fractured instruments. Beyond SET

AS GOOD AS SET IS, it was still a sequence of existing instruments not specifically designed to optimize instrumentation. After two years of development, we are finally able to introduce the SafeSiders™, a sequence of ten hand instruments that will allow you to instrument an average canal in less than five minutes and a difficult, curved canal in less than eight minutes, making one-visit endodontics a readily achievable goal. (See Figure 1.) The name of the game in endodontics is to get to the apex as easily and quickly as possible without blocking or distorting the canals. The sequence of SET maximized this process for the instruments that existed until now.

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FIGURE 1: The EZ-Fill SafeSider Instrumentation System. The Effect of the Flat

THE SAFESIDERS improve upon SET by having along their entire working length an uninterrupted area of relief, called a flat, that does not engage the dentin when the instrument is negotiated to the apex (see Figure 2). The flat is one of those simple design changes that has a profound effect on instrumentation. Any canal can now be quickly instrumented to receive a medium or medium large gutta-percha point. I would say that the SafeSiders improve instrument efficiency by about 25 percent.

FIGURE 2: EZ-Fill SafeSider flat on the 30/.04 NiTi instrument.

The increased taper encourages better irrigation with 5.25 percent NaOCl. The flat creates an open space for debris. While the flutes on one side are relieved, the central core of the instrument is not, leaving the instrument essentially as strong as it was before. Yet the rotational force needed to negotiate apically is significantly reduced, allowing total instrumentation with a “light touch.” (Dr. Deutsch discusses the flat in more detail in “New EZ-Fill SafeSider Endodontic Instruments.”) Less engagement means less resistance. The small reduction in cutting ability is compensated by rotating the instrument an extra turn, something the dentist does automatically anyway. The net result is that the instruments glide through the tooth, reaching the apex quickly and efficiently. The first eight instruments are tough stainless steel, and the last two instruments in the sequence are nickel- titanium. They are used to size the canal to accommodate the tapered gutta-percha point that is to be placed. Unlike rotary nickel-titanium, the relieved nickel-titanium SafeSiders may be used many times without replacement because the SafeSiders are not subject to high degrees of torsional stress. They are never rotated beyond resistance. In

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addition, we perform a simple manual bending test that assures the dentist that if the instruments do not break in the hand they will not fracture in the tooth. In conjunction with the EZ-Fill Obturation System, SafeSiders will give you a great sense of control and, with time, the confidence to take on more difficult cases. Personally, it gives me great satisfaction to introduce an instrumentation system that meets our needs, is economical, produces results that are at least the equivalent of rotary nickel-titanium, and does away with all the insecurities and expenses that those “modern” systems impose. As always, we are ready to help you learn these new skills. In the past, we’ve taught many of you how to use SET; we now encourage you to take the new course with the SafeSider instruments and see the difference. (Click here for the course announcement.)

March-April 2001 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.C.D. Fractured Instruments in Rotary Nickel-Titanium Endodontics

ITH INCREASING momentum, modern endodontics Making the is being defined by rotary nickel-titanium formerly endodontics. There is no question that these “modern” techniques have solved the problems associated unacceptable with traditional endodontics, including canal distortion, hand acceptable is a fatigue, weak underfills, overfills, fractured roots, damage to definition of the periodontal ligament, and iatrogenically blocked canals. The shift to rotary nickel-titanium also brings with it the lowered potential for increased incidence of fractured instruments as standards. well as strip perforations in thin, curved roots with Barry Musikant concavities. To reduce the incidence of fracture, manufacturers strongly recommend replacing the instruments after only limited use. In addition, torque sensing handpieces have been developed that autoreverse when a set amount of torque is exceeded. Glickman and Koch state that

nickel-titanium utilization requires special precautions. [Nickel-titanium instruments] should only be used to resistance and never be forced. Limiting factors associated with NiTi include the inability to bypass or remove ledges, a steep learning curve, high expense, and the universal concern for file separation.

They further state that

NiTi rotary files are no more susceptible to breakage than stainless steel so long as all principles of rotary instrumentation are strictly adhered to, clinicians understand and master the respective systems prior to clinical usage, and proper disposal schedules are developed for NiTi. Aberrant canal anatomy, instrument fatigue, and improper usage patterns can contribute to file separation. It is much more critical in a rotary technique to fully comprehend the canal anatomy of each canal. For example, NiTi files should be avoided in canal systems where two canals come together, when a canal bifurcates or where there is an S curve. During use, clinicians should continually observe for

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instrument fatigue, as overuse or abuse of files will predispose them to failure. How a file is used and the type of canal form it is used in are probably just as critical as how many times a respective file is used; for example, calcified canals will logically stress NiTi files more than patent straighter canals. Usage and constant monitoring is additionally important because these files need to operate at the proper RPM and in a consistent manner. NiTi’s Narrow Window

LICKMAN AND KOCH’S list of caveats shows how narrow the window for success is in nickel-titanium endodontics. If canals were not curved, there would be no need for nickel-titanium. Yet the greater the curve the more susceptible nickel-titanium instruments are to fracture. Manufacturers recommend frequent replacement of rotary nickel-titanium instruments, but they do not shed light on the interactions between the canal and the rotating NiTi file that rapidly produce the defects in the instrument that lead to fracture. It is an empirical rule to reduce the separation of instruments within the canals without truly understanding the causes of separation. Innovative methods of controlling torque are being added to the technique because fractures still occur despite increased and highly expensive precautions. Another phenomenon is starting to appear: the rationalization of the entire problem of fractured files. Articles have recently appeared that minimize the problem. One paper states that if an instrument fractures in the tooth, the tooth will often heal anyway or a simple apical procedure will solve the problem. An apicoectomy on a mandibular second molar in close proximity to the inferior alveolar nerve is not a simple apical procedure. Nor is any apical surgery simple for the patient. If endodontic failure occurs because the dentist who performed the procedure is not able to cleanse and seal a canal with a fractured instrument in it, the dentist may be responsible for that tooth and any restoration supported by that tooth even though the doctor informed the patient that the instrument had fractured in the tooth when it happened. Progress?

RACTURING A SEGMENT of an endodontic instrument is no less a problem for dentists today than it was 25 years ago. Any suggestion to the contrary potentially misleads dentists, reducing their ability to make wise decisions concerning the endodontic techniques they wish to use. From a historical perspective, any attempt to mollify concerns about fractured instruments tends to make more acceptable the techniques that lead to fractures. Making the formerly unacceptable acceptable is a definition of lowered

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standards. Standards should not be lowered as a way of being less critical toward a new system. Any new system should meet and exceed consistently held standards. That is a definition of progress. The advantages of manual and rotary nickel-titanium instruments must be balanced against their disadvantages. The same principle applies to stainless steel instruments. Deciding which type of instrument to use is not an either-or situation, but rather an effort to incorporate the advantages of NiTi with the advantages of stainless steel into a system that eliminates the weaknesses of both. The result would be a new system that would benefit from the best of both worlds: it would cause no hand fatigue or canal distortion, and it would be predictable, controllable, simpler, far less prone to fracture, and significantly less expensive. Advocates of rotary nickel-titanium techniques claim that there has been a paradigm shift in endodontics. There has been a paradigm shift, but it is defined by the final result, not the methods by which that result is attained.

May-June 2001 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.C.D. When Science and Empiricism Go Hand-in-Hand

N THE August 2001 issue of the Journal of Endodontics, authors Kuhn et al. analyzed the potential reasons for the incontestable increase in fractured instruments when using engine-driven rotary nickel-titanium instruments. The article fascinated me because it gave a scientific explanation for these fractures and indirectly supported many of the concepts we developed for the EZ-Fill® SafeSider™ Instrumentation System. The points they make include these:

1. Superelastic metals such as nickel-titanium flex far Barry Musikant more than stainless steel instruments yet in clinical use have a much higher incidence of fracture. 2. The incidence of nickel-titanium fracture is related to defects from: work hardening of the alloy before machining surface defects produced during machining propagation of existing surface defects by cyclic fatigue, making the metal more brittle as the defects become larger and more numerous

The authors used x-ray diffraction, scanning electron microscopes, and microhardness tests to observe the initial state of the nickel-titanium instruments as well as the degradation that took place with use. They came to the same conclusions scientifically that we reached empirically. Nickel-titanium instruments are most prone to fracture when instrumenting curved canals. The greater the curve, the more stress the nickel-titanium instrument undergoes, producing a greater number of crystalline defects within the alloy as well as an increased number of growing surface defects that make the instrument more brittle and prone to fracture. Nickel- titanium alloy differs markedly from stainless steel, which distorts and fractures due strictly to plastic deformation and not because it becomes more brittle with use. Score One for Empirical Reasoning

THE EMPIRICAL reasoning behind the manual SafeSider Instrumentation Technique was to develop a system that would create a canal space equivalent to the best shape produced by engine-driven rotary NiTi instruments while also replacing the vulnerable, unpredictable NiTi alloy with tough, predictable stainless steel wherever possible.

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To further enhance the ease, simplicity, and predictability of the SafeSider Technique, we designed a sequence of relieved flat-sided cutting-edge instruments that promote rapid negotiation to the apex. Stainless steel instruments compose the first 80 percent of the system. Only the last two instruments in the sequence are composed of nickel-titanium, and they, too, incorporate the SafeSider relieved flat. By shaping 90 percent of the canal space prior to the use of NiTi instruments, the remaining 10 percent puts little stress on the subsequent NiTi hand instruments. The forces applied to the NiTi instruments are further reduced by a significant straightening of the canal prior to their use. Because they are never rotated beyond resistance, the amount of stress the instruments are subject to is limited. Finally, the NiTi instruments are first test-bent in the hand approximately 90 degrees. If they do not break in the hand, they will not break in the tooth if used in the prescribed manner. If they do break in the hand, breakage is the ultimate confirmation that discarding the instrument at this point was the proper thing to do. The bending test is highly significant in light of Kuhn’s paper, which states that crack propagation increases, rendering the instruments more and more brittle. The SafeSider Instrumentation System replaces and compensates for an engine-driven rotary NiTi system, delivering comparable shaping in less time and at far less cost. The entire SafeSider System consists of ten instruments plus the No. 2 Peeso reamer used in a completely safe fashion. The first four instruments enlarge the canal to the apex to a No. 20 stainless steel reamer, which is usually the starting point for all NiTi rotary systems. After this only six more instruments and under four minutes are usually needed to produce a canal shape that accepts a medium or greater gutta-percha point. A tremendous amount of marketing money has been spent convincing dentists to use the rotary NiTi systems. Despite all the expensive secondary innovations to reduce the incidence of fracture plus the support of large segments of the endodontic community repeating the mantra that rotary NiTi is the new paradigm, there are more caveats today in the use of these systems than for any other systems. The Kuhn paper clearly defines the basic weaknesses of rotary NiTi endodontics. With full appreciation of the superior shaping results that can be attained, the SafeSider Instrumentation System delivers those results without yielding to rotary NiTi’s disadvantages. Stress and the Thermal Gradient

IN ANOTHER PAPER, titled “The effect of thermal change on various dowel-and-core restorative materials,” published in the July 2001 issue of the Journal of Prosthetic Dentistry, Yang et al. demonstrated that the stress level developed in the restoration and the surrounding dentin was closely related to the degree of thermal gradient. The nonmetallic dowel and

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cores generated greater thermal stresses than metal dowel and cores. The combination of a resin core with a carbon-fiber dowel generated the highest stress in the cement layer core and metal-ceramic crown. Thermal stresses generated from the thermal gradients of the nonmetallic dowel-and-core materials generated additional stresses in the cement and its interface. With increasing thermal expansion, stresses in the restorations and coronal portion of the dentin increased more markedly than did stress levels in the supporting bone. As I often point out in my lectures, to me the worst restorative combination is a carbon fiber post with a full composite core surrounded by a ceramic crown ending in a butt joint onto dentin. The Yang paper states that the cement layer between the core and the crown undergoes the highest degree of degradation, opening up the margins. Open margins lead to secondary decay and internalized micromovement in a vicious cycle that shortens the life of the restoration The esthetic goals that prompt the use of a full ceramic restoration—which, in turn, requires a nonmetallic post—may be more functionally met by the use of a Captek-like restoration with a feathered metal margin that allows the use of a fully functional metal post without compromising esthetics. The Flexi-Post and Flexi-Flange design have a metal dowel and a supporting core that is generally about 75 percent metal after the core has been prepared. The small amount of additional composite should limit the amount of heat absorbed by the core material. In addition, if Ti-Core with titanium is used, the metal component of the post and core is even greater, mitigating the thermal gradient of the composite portion of the core. As founders of Essential Dental Systems, we obviously support the products we developed and market. However, it is nice to see that as the years go on the latest data from independent researchers support concepts that we have incorporated and, in turn, critically review concepts and designs that we have rejected. These products were first developed for our own use and, if they worked as we planned, we then made them available to the profession. It is a simple concept that still seems to work. An Interesting Insight

THE OTHER DAY, the suction in my rooms went down and I had to use another room. The slow speed handpiece was different from the one I am used to, and I found using the No. 2 Peeso in this room more difficult than in my own. Here are the particulars: In both my rooms I use a Titan slow speed unit. It is connected to a rheostat that allows low rotations with good torque. A slight depression of the foot rheostat starts the Peeso slowly rotating exactly as it should. However, in the other room, a Viper handpiece from Kinetics did not operate as smoothly. Depressing the rheostat slightly did not start the handpiece slowly. The rheostat had to be

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depressed more to make the handpiece start, and then it went faster than I wanted. Once it had started, I could back off on the speed, but this movement did not give me the same control I have with the Titan unit. In addition, despite the greater speed I did not have as much torque. Ideally, I want slow speed and high torque to give me optimum control of where to remove circumferential dentin. Bottom line: it did not give me the same control that I have with the Titan handpiece. Certainly, you can use the Viper and get used to it. Perhaps, the Viper handpiece can be better adjusted. However, I believe in making life as easy as possible, and using the Titan makes my life easier. If this little insight strikes a chord with you, check out the Titan. It can’t hurt, and it might help. P.S. I used Amy’s room. Since then she has switched to the Titan slow speed handpiece and also finds life a lot easier.

September-October 2001 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.C.D. Design and Sequence Determine Endodontic Success

UCCESSFUL ENDODONTICS results in teeth that Figure 1 are comfortable under function and regrow bone where bone loss has previously occurred. Inflammation within the periodontal ligament is usually the reason endodontically treated teeth are uncomfortable. Inflammation is incompatible with bone regeneration. Inadequate debriding, overinstrumentation, and overfilling either initiate inflammation or do not resolve preexisting inflammation. Fractured instruments are one cause of inadequate Barry Musikant debriding. If the apical portion of the canal is blocked early on by a fractured file, irrigating and cleansing apical FIGURE 1: Fractured to the broken instrument will be impossible unless the instrument blocking apical dentist can remove or negotiate around the separated portion of the canal. segment (Figure 1). The incidence of fracture is directly related to the instrument’s resistance to torsional and Figure 2 flexural stress, which in turn is related to the sequence of instruments used. The greater the amount of dentin each instrument must cut, the greater stress that instrument may encounter. Crown-down rotary NiTi poten-tially subjects the initial instruments to excessive torsional and flexural stresses. The torsional stresses increase as the instrument engages and cuts a greater length of canal. The flexural stresses increase as the instrument deviates from a straight line (Figures 2 and 3). Torsional and flexural stresses together create a stress load that is greater than the sum of their individual loads. NiTi offers far less resistance to these stresses than stainless steel. NiTi is flexible, but soft. Where stainless steel can selectively cut into dentin in a directed fashion, NiTi can only mill dentin away while staying centered. A centered canal preparation is far more likely to encounter a strip perforation on the distal aspect of a mesiobuccal root than is a canal prepared by a No. 2 Peeso purposefully directed FIGURE 2: Flexural stress away from the furcation and the distal aspect of the increases as the mesiobuccal root. instrument deviates from a The sharper and harder the metal, the easier the task of straight line; the arrow cleaving dentin from the canal wall during indicates the point of instrumentation. Stainless steel is approximately four to stress and potential five times harder than NiTi. NiTi can cut dentin only in fracture. very small increments. If it engages more than the

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minimum amount of dentin at any one time, it is unable Figure 3 to cleave the dentin from the canal walls. Rather, the dentin engages the flutes of the file or reamer and “sucks” the instrument into the tooth without cleaving off the dentin, subjecting the instrument to excessive torsional and flexural stresses. This potential stress problem is aggravated by the crown-down sequence of instrumentation. Crown-down implies going from thicker to thinner instruments as the canal is negotiated apically. How far apically to go with the initial instruments is not well-defined. If a .12 tapered rotary NiTi instrument .20 mm at the tip initially negotiates 6 mm into the canal, the diameter of this instrument at the orifice is 0.92 mm (6 x .12 + .20). This width can only be gained gradually and carefully by using a light touch and a rapid up-and-down motion of the instrument, making certain never to engage too much dentin at any one time. A system that uses a sequence that does not define a FIGURE 3: Flexural stress will be increased if the clear-cut method of instrumentation, further limited by its instrument must negotiate lack of strength and cutting efficiency, is one that cannot past an overhang; arrow A predictably shape the great variety of canal curvatures, indicates overhang lengths, and widths that will be encountered. Inadequate preventing continuous instrumentation that results from separated instruments straight line access; arrow would logically increase the incidence of inflammation in B indicates point of the periodontal ligament, leading to success rate lower greatest curvature on than that for teeth shaped to the same taper without outside wall of canal. instrument separation. Although the traditional step-back sequence of Figure 4 instrumentation required modifications to produce a wider tapered canal preparation, step-back defines the amount of dentin to be removed at any one time much more specifically than crown-down does. For example, if the canal is already opened to the apex to a No. 20 reamer or file, the width of the apical 12 mm of the canal are as shown in Figure 4. If the canal is sequentially widened from No. 25 through No. 40 using a 1 mm step-back technique, the maximum amount of dentin removed from instrument to instrument is .03 mm/mm, as shown in Figures 5 through 8, below. This is less than 1/10 th the incremental dentin removed with the initial crown-down rotary NiTi instruments (see Figure 9, below). Furthermore, the instruments doing the cutting are tough, inexpensive stainless steel, highly resistant to fracture. The step-back also minimizes hand fatigue and canal distortion because the instruments go a shorter distance as they become FIGURE 4: Showing a thicker and stiffer. canal opened to the apex Optimization of the modified step-back technique is to a No. 20 reamer or file; encapsulated in the EZ-Fill® SafeSider™ Instrumentation arrow indicates the System, a series of predominantly stainless steel thickest, most engaged instruments that are designed with a patented non- part of NiTi, most prone to fracture. interrupted continuous flat along the entire cutting

length. The flat further facilitates rapid negotiation to the apex in the following ways:

The instrument does not engage the dentin along the flat. Less engagement means less resistance, which allows for a lighter touch while negotiating more rapid access to the apex. Two vertical blades are created that sweep the dentin from the flutes into the open space. The instrument is more flexible, allowing it to negotiate curves more efficiently. Instruments last longer because they are used with less force and in conjunction with the No. 2 Peeso reamer.

The last two instruments in the sequence are NiTi and are used manually. They too have the flats and are used in such a way that they are subject to minimal torsional and flexural stress. The EZ-Fill SafeSider System provides a hand test to determine whether or not the NiTi instruments are strong enough to be used in the tooth without fracturing. If they do not fracture in the hand when bent approximately 90 degrees, they will not break in the tooth if used in the prescribed manner. The two NiTi instruments quickly provide an .08 taper that is consistent with complete debridement and thorough irrigation, standard requirements for endodontic success. The SafeSiders provide a design and a sequence that together give the dentist the ability to perform complete shaping to at least an .08 taper, fit a medium gutta-percha point, and, with the use of the bi-directional spiral and EZ-Fill Epoxy-resin cement, create a total three- dimensional obturation that is at least the equivalent of far more expensive and complicated techniques. Every aspect of the EZ-Fill SafeSider Instrumentation and Obturation System falls well within the safe capacity of each instrument to perform its task. Consequently, excellent results are easily, speedily, economically, and predictably achieved.

September-October 2001

Figure 5 Figure 6

Figure 7 Figure 8

FIGURES 58: Maximum dentin removed from instrument to instrument in 1 mm step-back technique. Figure 9

FIGURE 9: Showing amount of dentin removed by initial crown- down rotary NiTi instruments. FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.C.D. “No Man’s Land”: Endodontics’ Last Frontier

OR THOSE OF YOU who have followed the discussion The concept of of the EZ-Fill® SafeSider™ instrumentation techniques, “no man’s land” it is obvious that straight canals are a lot easier to shape than gives the dentist curved ones. In fact, the greater the curve, the harder the a clear shaping process. If you think about it, and probably even if understanding of you don’t, the reasons are also obvious. the potential of The straighter the canal, the greater the depth that the No. 2 the No. 2 Peeso Peeso can gain before it meets resistance. If a canal reamer. measures 21 mm to the incisal edge and is perfectly straight, Barry Musikant at some point in the instrumentation the No. 2 Peeso, can attain the depth of 19 mm, its complete extension from the slow-speed handpiece. The only portion not shaped by the No. 2 Peeso would be the most apical 2 millimeters. On the other hand, if a 21 mm canal is highly curved, as in a molar, the Peeso will go a shorter distance down the root. The pulp chamber might take up 11 mm of the length, leaving 10 mm for the canal. Of that length, the Peeso may only be able to go down 4 mm, leaving a distance of 6 mm to the apex. In both the straight and curved canals, a .05mm/mm taper would be prepared with a 1 mm stepback from instruments sized 25 through 40 in the most apical 4 mm of the canal. In the straight canal, the No. 2 Peeso would be able to go so far apically that it would prepare the canal space into the stepback area. In the highly curved canal, a space would exist between the most coronal extension of the stepback (4 mm from the apex) and the most apical extension of the No. 2 Peeso reamer, a length of 2 mm. (The full canal length is 21 mm minus the 11 mm of pulp chamber access minus the 4 mm the Peeso was able to go apically minus the 4 mm coronal extension from the stepback; 21 - 11 - 4 - 4 = 2 mm.) I call this space “no man’s land.” For whatever length “no man’s land” has, its taper is 2 mm/mm, starting at .40 mm. If the length is 2 mm, the coronal extension of this space is .44 mm in width. (.40 mm + [2 x .02 mm] = .44 mm). The final shaping instruments in the SafeSider technique include 30/.04 and a 25/.08 manual reamers. The longer “no man’s land” is, the more these greater tapered NiTi instruments must cut. This is not a problem, but it is something the dentist should be aware of. Fortunately, canals that are so curved that they prevent the

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No. 2 Peeso from approaching the coronal end of the stepback are rare. When they do occur, the remaining NiTi instruments must do more work, but the technique and sequencing is designed to minimize the stress developed within these instruments and produce the final taper quickly, efficiently, and predictably. (Remember: you should always test-bend the instruments before using them in the canal.) The concept of “no man’s land” gives the dentist a clear understanding of the potential of the No. 2 Peeso reamer. While this instrument cannot be forced around a curve, the No. 2 Peeso reamer should extend as apically as possible in a straight line at right angles to the occlusal surface of the tooth. With a light touch, the No. 2 Peeso will find its own depth for each canal without any fear of perforation or ledging. Combining the No. 2 Peeso reamer with the SafeSider sequencing allows the dentist to shape all canals to at least an .08 mm/mm taper, generally in five minutes per canal or less. As usual, if any dentist wants help in attaining these skills, just call me at (212) 582-8161 and I’ll set up an evening to teach you. I never teach more than two dentists on any given night, so I do get booked up at times. The course takes about an hour and a half, after which you won’t believe how straightforward and simple the technique is. There is no charge for this course. I have been doing it as an exercise in good will for the last six years and personally enjoy it. I believe you will too.

November-December 2001 FEEDBACK? ENDO TIP Perforation of a molar does not We welcome your mean that the tooth is a lost cause. responses and questions. You can use MTA to seal the Please feel free to visit perforation and get a good the Endo Forum and prognosis. MTA is biocompatible and allows for add your comments bone and tissue healing against it. It sets nicely in a about any of the articles moist environment. in Endo-Mail.

By mixing the material a little on the wet side, you can manipulate it a little easier and help it to set quicker.

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Barry L. Musikant, D.M.D., F.A.C.D. SafeSiders® Produce Superior Post-Hole Preparations

E HAVE OFFERED several articles on the benefits of the EZ-Fill® SafeSider™ instruments for safely and quickly shaping canals that have a taper similar to that of engine driven nickel-titanium systems without the accompanying fear of fracturing instruments. In addition, the EZ-Fill SafeSider Instrumentation System allows the practitioner to create a coronal space that is more compatible to post placement, particularly in molars. In past articles we described how the SafeSiders do this. In this article we describe how superior post placement is another result of the Barry Musikant EZ-Fill SafeSider technique. Nickel-titanium instruments are approximately 75 percent to 80 percent softer than stainless steel and far less resistant to torsional stresses. Consequently, when entering a curved canal, it does not straighten it (Figure 1). Rather, it centers itself within the canal and widens the inner wall (toward the furcation) and outer wall (away from the furcation) evenly (Figure 2).

Figure 1 Figure 2

FIGURE 1: A C-shaped FIGURE 2: A C-shaped canal that has canal that has yet to be been widened, demonstrating the widened. removal of tooth structure from the inner wall.

The result is a curved canal that is uniformly wider. In single-rooted teeth this feature might be considered advantageous. However, in a molar protecting the tooth structure between the inner wall and the furcation is very important in order to avoid strip perforations particularly in MB roots of maxillary and mandibular molars. NiTi can do

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no differently because it lacks the hardness and torsional strength to allow it to selectively cut dentin away from the furca to straighten the coronal portion of the canal. When a post is to be placed, drills are finally used that will straighten the coronal path of the canal to give the post straight-line access and greater depth. Because tooth structure has been needlessly removed on the furcal side of the canal, the newly prepared straight-line coronal access has resulted in a canal space that may be significantly wider than it needed to be (Figure 3). If a cast post is to be placed, it will have a wider taper that makes it that much more of a potentially destructive wedge (Figure 4).

Figure 3 Figure 4

FIGURE 3: A picture of the canal FIGURE 4: A wide tapered space after tooth structure has been cast post with a wide removed from the outer wall, producing coronal cement interface. a coronal canal space with a wide taper.

If a parallel prefabricated post is placed, a lack of coronal fit will result in a large cement interface that has lower retention and is more prone to breakdown (Figure 5). If the practitioner chooses not to straighten the coronal canal path, the length of the post will be shorter, concentrating more functional stresses over a smaller area and the post will not be in line with the long axis of the tooth, resulting in more functional stresses being distributed laterally within the root containing the post. The EZ-Fill SafeSider, on the other hand, create straight- line access early in the instrumentation process. Coronally, dentin is selectively removed from the outer wall, turning C- shaped canals into J-shaped canals (Figure 6).

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Figure 5 Figure 6

FIGURE 5: A parallel FIGURE 6: The C-shaped canal prefabricated post with a opened up early on with a No. 2 wide coronal cement Peeso to attain straight-line access, interface. showing where the dentin is selectively removed.

Not only is a J-shaped canal far easier to instrument, because you are dealing with one curve and not two, but the canal shape needs little modification to accept a conservative cast or prefabricated parallel post. The cast post will have a thinner taper, making it less of a wedge (Figure 7). The parallel prefabricated post should fit fairly accurately within the prepared canal space along its entire length, assuring greater retention and a longer-lasting cement interface (Figure 8). Straight-line access assures that the dentist can create adequate length as well as post placement in line with the long axis of the root.

Figure 7 Figure 8

FIGURE 7: A thinner tapered cast FIGURE 8: A parallel post in the canal with a thin prefabricated post with a thin coronal cement interface. coronal cement interface.

This discussion is an example of taking a concept that was first enunciated by engine-driven NiTi proponents, namely that greater tapered shapes are superior to those produced by

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conventional endodontic techniques, and achieving those results in a far simpler, more efficient, and more economical way. As usual, we welcome discussion on any points that you may agree or disagree with and we will be happy to publish the insights gained from those discussions. I personally prefer discussion by phone at (212) 582-8161, but if e-mail is to your liking, by all means use it.

January-February 2002 FEEDBACK? ENDO TIP We welcome your Would you like to learn an easy, responses and thorough, and economical technique questions. for obturating canals? Please feel free to visit Take our free hands-on endo course. the Endo Forum and add your comments Click here for details. about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.C.D. Knowing the Research Makes All the Difference

ECENTLY, a local endodontist distributed a newsletter A body of quoting research from an article by Pommel et al stating research has that obturation with a single gutta-percha point produces the greatest amount of leakage. From their conclusions he determined that extrapolated the further conclusion that the EZ-Fill® the use of an Obturation System (Essential Dental Systems, Inc. S. epoxy-resin Hackensack, NJ) would perform badly because it too is a single-point obturation system. The quoted authors conducted cement . . . is at their research using a zinc-oxide-eugenol cement as the least as interface. They noted that zinc oxide, unlike the epoxy resin effective as Barry Musikant used in EZ-Fill, hydrolizes in water. The authors conjectured every other that zinc oxide would be prone to cement washout over time because the setting reaction is reversible in the presence of method of water, resulting in a degradation of the material and leaching obturation. of hydrolized eugenol and unreacted zinc oxide. They concluded that the large volume of sealer used for the single- cone technique is more prone to shrinkage than the small volume used for compaction techniques. However, epoxy resin’s setting reaction is not reversible in the presence of water, and because it is a polymer it is far tougher than the particulate zinc-eugenol cement. The endodontist would not have come to the erroneous conclusion he reached if he had been aware of the differences in cement interfaces between zinc oxide eugenol and epoxy resins. Furthermore, several studies comparing single-cone techniques using epoxy-resin cements have attained different results. Wu, Ozok and Wesselink compared the sealer- coated canal perimeter at 3 mm and 6 mm from the apex and found significantly better seals after the single-cone obturation (with no condensation) than after vertical or lateral condensation. Antonopoulous, comparing lateral condensation with lateral condensation, found similar sealing abilities. Spangberg tested single-cone, lateral-condensation, vertical-condensation Thermafil and Ultrafil and found them all statistically the same, with the single-cone technique having the least deviation in results. In a study published this year, Hata et al compared the apical sealing ability of System B, lateral condensation, and the EZ-Fill obturation technique, using a one-way analysis of variance, and found no significant difference among the groups. However, the authors stated that the root canals obturated with the EZ-Fill technique showed the least dye penetration. Baumann et al

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compared the leakage of five different single-cone techniques with lateral condensation and concluded that some single- cone techniques with thermoplastic gutta percha and sealer or cold gutta percha and a new sealer application tool (EZ-Fill) can be an alternative to lateral and vertical condensation. Cohen et al compared the leakage of single- point fills using epoxy resins to lateral condensation and Thermafil and found them all statistically equal, with the single-point fill having the least leakage in absolute terms. In a study that addresses the long-term sealing ability of an epoxy-resin cement interface, Kontakotis, Wu, and Wesselink compared the performance of five sealers before and after storage in water for two years. They concluded that Roth and Pulp Canal Sealer, both zinc-oxide-eugenol cements, allowed more leakage in thick layers than thin, whereas no significant difference was found between the thin and thick layers for the epoxy-resin cement. Cohen et al confirmed the weakness of zinc-oxide-eugenol cements compared with epoxy-resin cements. The shear bond strength of the zinc-oxide-based cement was literally zero, while that of the EZ-Fill epoxy-resin was 323.9 psi. No more-adhesive endodontic cement exists. Furthermore, Cohen determined that the free eugenol found in all zinc-oxide cements prevents the polymerization of composites and their bonding agents by scavenging the free radicals that initiate the polymerization process10. From a clinical point of view, using the EZ-Fill Obturation System, Deutsch et al reported a success rate of 94.1 percent over two-and-a-half years. A body of research has determined that the use of an epoxy-resin cement as an interface of varying thicknesses over at least two years is at least as effective as every other method of obturation. From a mechanical point of view, one may believe that a single-point fill cannot obturate accessory canals. Yet, obturating with EZ-Fill often shows lateral canals filled. Unlike thermoplastic obturation, in which the canals are filled with gutta percha, the EZ-Fill technique predictably fills these canals with epoxy-resin cement. The filling of these canals is clearly observed because the epoxy- resin cement is radiopaque. The canals have been debrided both mechanically and chemically with NaOCl and are sufficiently open to allow the extrusion of material into these spaces. There is no innate superiority of gutta percha over epoxy- resin. In fact, Lee has demonstrated that thermoplastic gutta percha contracts as it cools from a minimum of 45 minutes to 10 hours, shrinking approximately 4 percent in the process. Epoxy-resin, on the other hand, goes into the canal at room temperature and expands approximately 1.75 percent as it warms from room to body temperature. Not only does shrinkage continue far longer than the 10 seconds popularly believed, but very little cement can even be used during thermoplastic obturation. Because the coronal escape route is closed off when obturating thermoplastically, any excess

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cement in the canal would be forced over the apex under significant pressure. The single-point technique allows the safe coronal extrusion of excess cement and, consequently, cement can be used liberally both in the canal and on the point itself. Hall demonstrated that at best 62.5 percent of curved canal spaces are coated with cement with the traditional applicators, obviously less when thermoplastic techniques are used. Therefore, combining a thermoplastic technique with an inadequate cement interface produces a result far removed from the three-dimensional claims made for it. To understand the EZ-Fill obturation system, you must appreciate the mechanics behind the bi-directional spiral. The coronal spirals drive the cement apically while the three apical spirals drive the cement coronally. These two cement flows collide and are driven laterally. The spiral is used with an up-and-down hand motion, driving the cement against the canal walls and any accessory canals that may reside there, along its entire length. The cement is driven further laterally when the coated tapered gutta-percha point is placed into the canal. The EZ-Fill SafeSider instrumentation system rapidly shapes the canal to a minimum of an .08 mm/mm taper, which corresponds to a medium gutta-percha point. The greater the taper of the gutta percha, the more the cement interface is driven laterally, which is why so many lateral canals are filled with this instrumentation and obturation system. Some other points to be considered: Floren et al noted that System B represented a narrow window of success because it is possible to cause thermal damage to the ligament if the temperature rise exceeds 10 degrees C, something that is more likely in canals with thin roots. Saw et al demonstrated that thermoplastic techniques not only caused a temperature rise in the tooth and ligament, but that this rise created dentinal stress and could lead to premature fracture. Jurcak et al reported that Touch N Heat produced increases in temperature from 8 to 67 degrees C and that this was a concern. E. M. Hardie reported on similar concerns for the same reasons. To further appreciate the utility of the EZ-Fill system, consider the following research: Zidan et al state that it appears that leakage is independent of the method of obturation when an adhesive sealer is used. This can be attributed to the ability of the adhesive sealer to wet the walls of the canal, bond to the dentin, and seal the residual volume between gutta percha and the canal wall. In fact, the literature shows that an epoxy-resin has strong adhesion to dentin and the gutta-percha point without the need of a dentinal bonding agent. Opening the dentinal tubules of the canal with EDTA significantly increases the bond strength of the epoxy-resin cement to the dentinal walls. Gettleman et al compared the adhesion of three cements—AH-26, Sultan, and Sealapex—to dentin with the smear layer intact and the smear layer removed. AH-26 has the highest adhesion to

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dentin when the smear layer is removed. Limkangwalmongkol et al compared the sealing abilities of four root-canal cements, including Apexit, Sealapex, Tubli- Seal and AH-26. AH-26 demonstrated a significantly better apical seal than the other sealers. The authors note that from the findings of other studies AH-26 appears to have many advantages over other sealers. It mixes easily, flows well, has ample working time, good radiopacity, comparable solubility, good adhesion and good biocompatibility. It has also been shown to adhere to dentin that has been maintained in a moist state. Of the materials tested in this study, AH-26 had the best working characteristics. Wu et al, in comparing the leakage of four sealers stored in water for one year, determined that AH26, Ketac-Endo, and Tubli-Seal showed a reduction in leakage over time and gave significantly less leakage than Sealapex. The authors also noted that AH26 gave a long-lasting seal when used as the sole material, showing its possible multiple applications. Those dentists who try the EZ-Fill Instrumentation and Obturation Systems will quickly find that they have the ability to produce the highest quality results more easily, quickly, simply, and far less expensively. I hope that this detailed response to wayward conclusions sets things straight. The research and our seven years of clinical results speak for themselves. In the past you may have felt that you had to invest in complex, complicated, and expensive endodontic systems, but you can bring about a major reduction in your level of stress and financial costs if you adopt the EZ-Fill SafeSider Instrumentation and Obturation systems.

References

1. Pommel L, Camps J. In Vitro Apical Leakage of System B Compared with Other Filling Techniques. J Endodon 2001;27:449-51. [BACK] 2. Wu M-K, Ozok R, Wesselink P R. Sealer distribution in root canals obturated by three techniques. International Endodontic J 2000;33:340-345. [BACK] 3. Antonopoulos K G, Attin T and Helwig E. Evaluation of the apical seal of root canal fillings with different methods. J Endodon 1998;24;655 [BACK] 4. Dalat D M, Spangberg LSW. Comparison of apical leakage in root canals obturated with various gutta- percha techniques using a dye vacuum tracing method. J Endodon 1994; 20:315-9. [BACK] 5. Hata G, Imura N, Matsuda T, Kato A, Souza F J, Toda T. Apical sealing ability of the EZ-Fill obturation technique. J Endodon 2002; 28:260. [BACK] 6. Baumann M A, Loy R, Behrens O. Dye penetration of five different single cone techniques compared to lateral condensation. Abstract IADR/AADR/CADR 80th General Session March 2002 [BACK] 7. Cohen B I, Pagnillo MK, Musikant B L and Deutsch A

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S. The evaluation of apical leakage for three endodontic fill systems. Gen Dent.1998; Nov-Dec: 618-23. [BACK] 8. Kontakiotis E G, Wu M-K, Wesselink P R. Effect of sealer thickness on long surface of the tooth during the thermo-mechanical compaction technique of root canal obturation. International Endodontic J. 1986; 19:73-77. [BACK] 9. Cohen B, Volovich S, Musikant B and Deutsch A. Shear bond strength for four endodontic sealers. Endodontic Practice; 3:9-14. [BACK] 10. Cohen BI, Volovich Y, Musikant B L and Deutsch A S. The Effects of Eugenol and Epoxy-Resin on the Strength of a Hybrid Composite Resin. J Endodon; 2:79-82. [BACK] 11. Deutsch A S, Cohen B I, Musikant B L, Kase D. A study of one-visit treatment using EZ-Fill root canal sealer. Endodontic Practice 2001 4:29-36. [BACK] 12. Lee C Q, Chang Y, Cobb C M, Robinson S, Hellmuth E M. Dimensional Stability of Thermosensitive Gutta- Percha. J Endodon; 23:579-582. [BACK] 13. Hall M C, Clement D J, Dove S B, Walker lll W A. A Comparison of Sealer Placement Techniques in Curved Canals. J Endodon 1996; 22: 638-642. [BACK] 14. Floren J W, Weller R N, Pashley D H, Kimbrough W F. Changes in Root Surface Temperatures with In Vitro Use of the System B HeatSource. J Endodon 1999; 25:593-595. [BACK] 15. Saw L-P, Messer H H. Root Strains Associated with Different Obturation Techniques. J Endodon 1995; 21:314-320. [BACK] 16. Jurcak J J, Weller R N, Kulild J C, Donley D L. In Vitro Intracanal Temperatures Produced during Warm Lateral Condensation of Gutta-percha. J Endodon 1992; 18:1-3. [BACK] 17. Hardie E M. Heat transmission to the outer surface of the tooth during the thermo-mechanical compaction technique of root canal obturation. International Endodontic J. 1986; 19:73-77. [BACK] 18. Zidan O, Al-Khatib Z, Gomez-Marin O. Obturation of root canals using the single cone gutta-percha technique and dentinal bonding agents. Internatinal Endodontic J 1987; 20:128-132. [BACK] 19. Gettleman B H, Messer H H, ElDeeb M E. Adhesion of Sealer Cements to Dentin with and without the Smear Layer. J Endodon 1991; 17:15-20. [BACK] 20. Limkangwalmongkol S, Burtscher P, Abbott P V, Sandler A B, Bishop B M. A Comparative Study of the Apical Leakage of Four Root Canal Sealers and Laterally Condensed Gutta-percha. J Endodon 1991; 17:495-499. [BACK] 21. Wu M-K, Wesselink P R, Boersma J. A 1-year follow- up study on leakage of four root canal sealers at different thicknesses. International Endodontic J 1995;

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28:185-189. [BACK]

September-October 2002 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.C.D. Changing Endodontic Perceptions

AVING LECTURED in the Carolinas and Kentucky The EZ-Fill® recently, I thought I would give you my impressions SafeSider® of the state of endodontics from the viewpoint of many of the practitioners I met. Many dentists still perform instrumentation traditional endodontics for three reasons: they understand that system and EZ- rotary NiTi instruments sometimes separate in the canals, Fill obturation especially when they are curved; NiTi systems are very expensive; and the dentists truly are not displeased with the system produce results that they have been getting. Another group, perhaps the superior larger than the first, has switched from traditional endodontic results of rotary Barry Musikant techniques and instruments to some form of rotary NiTi. NiTi without the Many of these dentists were at first very enthusiastic about the new systems because they gave them far better results fear of without hand fatigue and canal distortion. Those who have instrument used these systems for a couple of years readily admit that separation. they have separated some files. However, in general their results are so improved that despite the occasional separated instrument they continue to use these systems. Ultimately, they believe that they have no choice because they do not want to return to the poorer results produced by traditional techniques. I asked one attendee who uses rotary NiTi what he does about curved canals and he said he sends patients with curved canals to a specialist. I noted that given the chance of instrument separation while shaping curved canals that was probably a wise choice. This dentist is really saying that he recognizes the limitations of the system and is in turn limiting himself from gaining further expertise. I think that a system should not put barriers in the way of growing. Certainly the rotary NiTi system should not present such a barrier, since rotary NiTi was originally designed to shape the curved canals that time and experience had proven risky. The EZ-Fill® SafeSider® instrumentation system and EZ- Fill obturation system are alternatives that produce the superior results of rotary NiTi without the fear of instrument separation and take no more time to complete the process. The SafeSiders® are designed to treat all teeth, from the simplest to the most complicated. Shaping a canal will take on average two to seven minutes from the time of measurement depending upon the canal curvature and how far apically the No. 2 Peeso can go. The axially relieved SafeSiders coupled with the No. 2 Peeso reamer negotiate to

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the apex more quickly because they engage less dentin, are more flexible, take a curve with greater ease, remove debris from the flutes, and require less hand pressure. The beauty of the EZ-Fill SafeSider system is that only two NiTi instruments, used manually with a reciprocating hand motion, are required to produce an .08 mm/mm taper, the space needed to fit a medium gutta-percha point. Moreover, the two NiTi instruments are used only after 95 percent of the canal space has been shaped with tough inexpensive stainless steel instruments. The coronal 1/2 to 2/3 of the canal space has been shaped to straight-line access, limiting any negotiated curves to the apical 1/3. The fact that the two NiTi SafeSider instruments are used manually in a reciprocating motion allows them to be “bend- tested” before they are placed into the tooth. If they do not break when bent 90 degrees in the hand, they will not break in the tooth if used in the prescribed way. The bend test gives the dentist a rational way to decide whether to discard expensive NiTi instruments rather than replacing them automatically after one or two uses. Quite simply, if they break in the hand you know for sure that they must be replaced. The EZ-Fill SafeSider instruments represent a manual system that, nevertheless, shapes 85 percent of the canal with the rotary No. 2 Peeso reamer or the No. 2 and 3 Gates Gliddens, leaving the apical 1/3 to be efficiently shaped with the simple sequence of relieved EZ-Fill SafeSider reamers or files.

November-December 2002 FEEDBACK? Endo Tip I am always pleased to conduct a no- We welcome your cost hands-on session for anyone responses and who wants to learn how to use the questions. SafeSiders for efficient and excellent Please feel free to visit results. Click here for information the Endo Forum and about our next in-house hands-on course, or add your comments contact me at (212) 582-8161 if the scheduled date about any of the articles is not convenient for you. in Endo-Mail. Barry Musikant

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Barry L. Musikant, D.M.D., F.A.C.D.; Brett I. Cohen, Ph.D.; Allan S. Deutsch, D.M.D., F.A.C.D. Long-Term Fluoride-Release Restorative Materials

OMPOSITE RESINS have replaced many of the Because many materials that were formerly used in dentistry. people now Posterior and anterior composites and resin cements used with the appropriate bonding agents are now substitutes drink bottled for amalgam, glass ionomers, and zinc phosphate. An water, which important element associated with long-term success of these does not newer materials is the release of fluoride. Fluoride is dynamically incorporated into the hydroxyapatite matrix contain forming the more acid- resistant fluorapatite and thereby fluoride, . . . rendering the tooth structure less susceptible to subsequent using long-term Barry Musikant decay. Fluoride has also been shown to reduce the cariogenic fluoride- 1 potential of bacteria by inhibiting their metabolism. releasing Cohen, et al., recently reported in Oral Health a ten-year fluoride release of four reinforced composite resins; theirs is restorative the only study found in the literature for this duration. The materials in composite resins included in the study are Ti-Core and Ti- areas of Core Natural (Essential Dental Systems, South Hackensack, New Jersey), two core materials that are approximately 80 restoration that percent filled and have incorporated titanium and lanthanides abut dentin is respectively to produce compressive strength equivalent to essential. that of dentin.2 The other two composite resins were Flexi-Flow and Flexi- Flow Natural (Essential Dental Systems), cements that are 60 percent filled to allow for greater flow and also incorporate titanium and lanthanide respectively. The four composite resins have continued to demonstrate release of fluoride over a ten-year period. The higher filled Ti-Core samples released fluoride in a burst effect over the first two years and then settled down to a lower level of continuous release. The Flexi-Flow composite resins, on the other hand, released fluoride at a low level from the beginning. The different release patterns make sense because the more densely filled Ti-Core resins leave less room for the efficient incorporation of fluoride while the less densely filled Flexi-Flows have room to incorporate the fluoride more efficiently, consequently releasing it over time in smaller quantities. (See the graphs.)

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Graph 1

Graph 2

Although the mechanics of fluoride release are interesting, the important fact is that fluoride release does not weaken the Ti-Core and Flexi-Flow polymer structures over time. In contrast, glass ionomers and resin-modified glass ionomers weaken as the fluoride is released over time. In real-world dentistry, the fluoride release should occur only when the polymer is exposed to moisture; such exposure occurs at the composite-dentin interface, because dentin is 30 percent water. The amount of fluoride released in these situations is far less than the amount released when the composite resins are completely immersed in water for test purposes. Ti-Core core material and Flexi-Flow cement will release their fluoride only at the composite-dentin interface if there is no marginal leakage under the crown. If leakage does occur, more fluoride will be released at the very time when it is most needed. Since we do not expect leakage to occur on the first day of post-and-crown placement, the effective release of fluoride should last far longer than the ten-year release period reported in this study, which subjected the composite resins to an immersion bath. Because the incorporation of the fluoride into dentin is dynamic, meaning that it is a reversible reaction, the fluoride must be released continuously to prevent the eventual loss of the fluoride from

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tooth structure and the conversion of the fluorapatite matrix back to the hydroxyapatite matrix—and, of course, to maintain its inhibitory effect on bacterial metabolism. Hence, the significance of this long-term fluoride release study. Fewer people are exposed to fluoride because many people now drink bottled water, which does not contain fluoride, rather than public water, which does. Despite the beneficial effects of the low-level mass exposure to fluoride in many public water systems, a number of people avoid municipal water supplies for fear of exposing themselves to lead and arsenic. Given this reality, using long-term fluoride-releasing restorative materials in areas of restoration that abut dentin is essential.

References:

1. Nouri M-Reza, Titley KC. A Review of the Anitbacterial Effect of Fluoride. Oral Health 2003;93(1):8-11. 2. Cohen, BI, Musikant BL, Deutsch S. Ten Year Fluoride Release from Four Reinforced Composite Resins. Oral Health 2002;92(9):44-52.

February-March 2003 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.C.D. DentalTown.com Is a True Home on the Web

THOUGHT THAT it would be a good idea to tell you The cyberspace about my experiences at DentalTown.com, the website of dental the magazine DentalTown, the brainchild of Dr. Howard Farran. DentalTown.com is the most comprehensive and community easy-to-use dental website I have ever seen. It covers just starts and ends about every subject of interest and doesn’t cost a penny. with the Joining and becoming an active participant are both easy. When I joined, two years ago, DentalTown.com had about participants, so 9,000 members. Currently, it has more than 20,000 it is no better or members. There must be a reason why so many people are worse than the Barry Musikant joining. integrity of the DentalTown.com’s most outstanding feature is an array of message boards on which you can interact with other dentists who dentists. If you wish, you can start a new subject to learn the participate. I views of others. I believe that the grassroots nature of these have found it message boards is the basis of this site’s success. A true well worth my community is being formed in cyberspace for the benefit of all. As the slogan of the site puts it, “With DentalTown.com time. . . . no dentist will ever have to practice solo again.” The cyberspace dental community starts and ends with the participants, so it is no better or worse than the integrity of the dentists who participate. I have found it well worth my time. In addition to message boards, DentalTown.com includes an extensive area of the site for case presentations in any discipline that is likely to interest you. If you have a scanner, you can upload cases in a matter of a few minutes and then have other dentists discuss the particulars of your presentation. DentalTown held the first meeting for participating dentists this past February in Las Vegas. I was among the more than 800 dentists who attended the three-day meeting. Although most of us had never met any of the other participants, we did not feel like strangers because of all the previous contacts we had had through the various message boards. Many of the dentists active in DentalTown.com are involved with other organizations and interests. Many include in their messages a link to an active website of their own. Just by clicking the link, you can go to the participant’s site, permitting you to travel freely not only within the DentalTown website, but laterally to many other sites with useful information of their own. For example, recently I

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was reading a post on DentalTown.com from an endodontist who is involved with Roots, a web site devoted to endodontics. I clicked the link that he had included and was there in a moment. For a guy like me, DentalTown.com has become addictive. At this stage of my career I love to teach, and the constantly growing membership in DentalTown.com gives me a larger and larger audience that I can talk to. The advantages of SafeSiders® and EZ-Fill® obturation are not always immediately obvious to dentists. Most of them have been swayed by a combination of ineffective endodontic training in dental school and the intensive mass marketing of rotary NiTi systems. Two years ago, when I first started corresponding on DentalTown.com about the alternatives to rotary NiTi, thermoplastic obturation, and vertical condensation, I was met either with significant skepticism or —worse—with non-responsiveness. But repetition and the honing of these alternative presentations have increased the awareness and the acceptance of the SafeSiders and EZ-Fill. Short of spending a fortune on mass marketing (we cannot compete with Dentsply) I cannot think of a better way to get these new ideas across than a genuine grass-roots movement, such as the DentalTown.com message boards, where the acceptance of new equipment and techniques will be only as good as the validity of the arguments we make for them. Dentists sometimes tell me in DentalTown.com forums that they are looking forward to lectures that I am going to give in their areas, further increasing the sense of community. The relationship with a large number of dentists through DentalTown.com is ongoing and growing. The challenge of answering questions accurately and honestly makes any participant grow professionally. So, I would suggest that whether you are a casual reader of posts or an active dentist with information that you want to disseminate you should become involved in DentalTown.com.

April-May 2003

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Barry L. Musikant, D.M.D., F.A.C.D. SafeSider® Reamer Instrumentation and EZ-Fill® Obturation The Challenge of Changing Viewpoints and Attitudes

THOUGHT THAT it would be worthwhile to discuss the The SafeSider goals that we have set for ourselves and for the courses reamer we teach in endodontic techniques. We want to help all of you do far better endodontics with less stress and instrumentation significantly lower costs. We developed the SafeSider® and EZ-Fill reamer instrumentation and EZ-Fill® obturation systems as obturation the tools to accomplish these goals. We want to show as many open-minded dentists as we possibly can (and as many techniques not-so-many not-so-open-minded dentists) that the SafeSider virtually instrumentation and EZ-Fill techniques will change their eliminate Barry Musikant lives by virtually eliminating instrument separation and instrument reducing their overhead by about 90 percent without compromising the final results. separation and Many of you have taken the courses in which we teach reduce these simplified yet uncompromising methods. If you have overhead by taken one of our courses more than a year ago, I about 90 enthusiastically suggest that you take one again. We have streamlined our teaching techniques and the sequences we percent without use to produce excellence even more efficiently. compromising Demonstration and practice are now on natural teeth rather the results. than plastic blocks. If you have not taken our courses, consider doing so. It is not too strong a statement to say that the learning experience has the potential to change your life. I say this with growing conviction, based on comments from dentists who have taken the courses. I am very active on the Dentaltown.com forum, the largest forum for dentists on the Internet. There I offer dentists all over the world the opportunity to take hands-on courses with me. Many have taken me up on the offer and have then described their experiences for the membership. Their comments regarding the learning experience and their subsequent use of the two systems we teach have been so uniformly positive that we know we are accomplishing something that is unquestionably constructive. Please understand that undertaking and continuing the task of teaching SafeSider reamer instrumentation and EZ-Fill obturation techniques truly require the desire to fight the good fight. In part, we are working to overcome the negative results of misleading instruction in dental schools. For years, dental students were subjected to an inadequate and ineffective method of performing endodontics. They were

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taught that files were more efficient than reamers when, in fact, K-files are one of the least efficient ways to shape canals. They were taught to fear and avoid the use of Peeso or Gates Glidden reamers in canal preparations when, in fact, the smaller sizes can be used safely and simply. We are also working to overcome the misinformation promulgated by major dental companies. They have promoted rotary NiTi as the answer to all the deficiencies of traditional endodontics. Granted, traditional endodontics was so limited in its potential to produce adequate endodontic therapy that in contrast almost any other system looked good. Rotary NiTi instruments eliminate hand fatigue and canal distortion while producing shapes of greater taper that promise far better debridement and obturation. As it turns out, the advantages of these instruments come at the cost of certain disadvantages. One disadvantage is obvious. These instruments cost about 20 times as much as traditional endodontic instruments. The second disadvantage is far more discouraging. Rotary NiTi instruments do not have the strength and resilience of stainless steel and will break unpredictably, either from excess torque caused by apical binding or from cyclic fatigue brought on by rotation around a significant curve. The weakness of rotary NiTi instruments has been the impetus behind a whole second wave of innovation that has added to the cost of a system that is already 20 times more expensive than traditional techniques. Such expensive tools as autoreversing torque-sensing handpieces, reduction handpieces, and electric handpieces as well as the recommendation that NiTi instruments be thrown away after one use have added immensely to the costs. Yet, many of those who have mastered the rotary NiTi techniques rationalize higher expenses and occasional instrument separation by noting that they generally produce far better results more quickly than they ever did using traditional techniques. It is human nature not to abandon something that you believe has improved your life, and considering the state of traditional endodontics, rotary NiTi can certainly make that claim. People are even more likely to resist making a change when they believe that there is really no alternative that can further improve their present situation.

So, this is the great challenge that’s worth the good fight: To show that the SafeSider reamer instrumentation and EZ- Fill obturation techniques virtually eliminate instrument separation and reduce overhead by about 90 percent without compromising the results. These results are attained in a simplified, time-efficient manner that improves the productivity of the dentists who use the techniques. Possibly, the most basic question someone could ask is, “If the SafeSider reamers and the EZ-Fill obturation techniques are as good as you say, why isn’t everyone using them?” The converse of that question would be, “Since not everyone knows about them, why are those who do know so

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enthusiastic about using them?” The reality of the marketplace is that getting the message out takes time and money. The more money invested, the less time required. This is the route that the big rotary NiTi companies have taken. If one cannot invest millions in marketing, superior ideas and innovations must give a new product or technique the chance of having an impact in the dental community. Thanks to Dentaltown.com and its founders, Howard Farran and his wife Judith, we have had an opportunity to level the playing field with the “big boys” somewhat and present these innovative new approaches to a large number of dentists. Better yet, we’ve been able to get their feedback for the betterment of the entire profession. In fact, this peer- review feedback is readily available to anyone who joins Dentaltown.com (at no cost) and goes to its endodontic file section.

September-October 2003

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Barry L. Musikant, D.M.D., F.A.C.D. The Stability of Metal Posts

JUST ATTENDED a lecture by Dr. Ed McLaren in From a which he discussed the use of ceramic crowns and when functional point to use them. The factors that determine what is used as the overlying crown include: of view, fiber- reinforced What tooth structure is underneath the crown? If there posts work best is significant dentin then there is no problem in just bonding the overlying porcelain crown to that dentin. where they are What is the potential for flexure of the underlying not needed in core? The greater the potential for flexure is, the less the first place. Barry Musikant likely is a porcelain restoration to last. What type of stress is applied, and how much? Can the internal interface of cement be protected during function?

If you look at this short list for determining whether to use a purely porcelain-constructed crown it appears that the most important factor is the potential for flexure of the underlying core. This factor alone will determine how the stresses are tolerated and the long-term success of the cement interface. Flexure takes on increased significance when you are considering the restoration of an endodontically treated tooth where the coronal tooth structure, if any exists, has been weakened by the access opening, diminishing the strength and rigidity of the coronal tooth structure. To the extent that the coronal tooth structure has become compromised, the need to restore rigidity (reducing flexibility) becomes increasingly critical. Over the past several years, non-metallic fiber-reinforced composite posts have come into vogue. The primary claim made for them is that they have a modulus of elasticity similar to that of dentin, implying that they will bend like dentin under function. If this were true, they would not have too much flexibility, just the right amount of flexibility. However, the concept that materials having the same modulus of elasticity bend the same is a false one for the placement of posts. Having the same modulus of elasticity implies that two materials (dentin and the composite post) will bend the same only if they have the same cross-sectional area. However, a post is generally 10 to 15 times thinner than the root it is in and will, consequently, bend 10 to 15 times more than the root because it has the same modulus of elasticity. A quality

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that the manufacturers imply is a plus turns out to be a tremendous negative. From a functional point of view, the best that can be said about non-metallic fiber-reinforced posts is that if they are placed in a tooth with sufficient coronal dentin, it will be a case of the tooth’s supporting the post, not the post’s supporting the tooth. Or to say it another way, fiber- reinforced posts work best where they are not needed in the first place. A secondary advantage of these non-metallic fiber- reinforced composite posts is their color. They can be made of a tooth-like color that allows the placement of a porcelain crown without any dark shadow being cast from underneath. Yet, if they are used in these situations, the problem of excess flexibility becomes an issue for the long-term success of the porcelain restoration, which—though it looks esthetically pleasing—may not have enough stability. As McLaren stated, if the criteria for porcelain crowns are not present he will place a metallic post and restore with porcelain-fused-to-metal restorations, such as Captek. In fact, he showed a number of cases restored with porcelain-fused- to-metal restorations, and the esthetic result could not have been more pleasing. It should be stated that McLaren was not emphasizing endodontically treated teeth. Yet, he still found many situations where pure porcelain restorations were not good choices. Endodontically treated teeth have much less margin for error because there is that much less tooth structure and greater underlying flexibility. From my own experience, I would say that the minimum requirement for placement of a non-metallic fiber-reinforced post, followed by the placement of a porcelain restoration, is enough tooth structure to supply a minimum of an internal bevel 3 mm long to which the ceramic restoration can be bonded. However, if this much tooth structure exists, is it really necessary to place a post at all? Thus, we arrive again at the conclusion that non- metallic posts work best where they are not needed in the first place. Less dentin than this means that a porcelain- fused-to-metal crown must be placed. This in turn means that a stronger metal post should be used because esthetic considerations are of little or no significance. Another claim that is made for non-metallic fiber- reinforced posts is that they are able to absorb high impact without fracturing the tooth. This is said to be a direct result of their flexibility. One must understand that this data comes from experimental destructive compression tests done in a lab. If enough force is applied to a metal post, there will be a higher incidence of root fracture than if the same force is applied to a non-metallic fiber-reinforced post. However, the force that is applied experimentally is in excess of what the human jaws can generate. In fact, the only time in real life that this would have significance is when a tooth suffers the large sudden impact of a force from a blow. To use this as a criterion for placement while ignoring the routine functional

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stresses that can cause a non-metallic fiber-reinforced post and the overlying restoration to fail is completely missing the point. Excessive flexibility leads to open margins, secondary decay, and eventual failure of the restoration. The stability offered by metal posts prevents crown displacement, reducing the chances of open margins and their consequences. I would add one more point. For the highest rate of success on endodontically restored teeth, not only should a metal post such as the Flexi-Post or Flexi-Flange be used, but a porcelain-fused-to-metal restoration incorporating an external bevel of 23 mm would maximize stability for the long haul. Or, as my partner Allan Deutsch says, there’s nothing like wearing a belt and suspenders to make sure that your pants don’t fall down.

November-December 2003

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Barry L. Musikant, D.M.D., F.A.C.D. Education as a Means of Practice-Building

HIS ARTICLE is really directed more to endodontists When you teach than to the general practioner. When I was a good deal an effective younger and just starting out, I wanted to meet dentists so that I could build my endodontics practice. My father was a simplified well-known dentist in Manhattan, many of his friends were approach in dentists, and as a result I had been surrounded by dentists contrast to all since early childhood. So, when I had to meet dentists to build a practice it was not an uncomfortable situation for me the other to be in. techniques out I knocked on doors and introduced myself, and I also there, the Barry Musikant became an instructor at one of the local dental schools. In practice- addition, my partner Allan Deutsch and I started throwing singles parties for dentists, dental assistants, hygienists, and building anyone else remotely associated with dental offices. This potential is was easy to do when I was single. I don’t recommend this amazing. approach if you are married. We also gave many lectures at localities throughout the greater New York area. The standard we always attempted to reach was something that set us apart from the “others.” That was why we opened up seven days a week and twelve hours a day, because no one else was doing it. The same motivation was behind the the singles parties. When we lectured originally, it wasn’t on endodontics, but rather on post and core buildups, because no one else at the time was doing it. Today, we teach dentists how to perform efficient, inexpensive, and predictable endodontics by learning the SafeSider® instrumentation and the EZ-Fill® obturation techniques. When you teach an effective simplified approach in contrast to all the other techniques out there, the practice- building potential is amazing. It dwarfs whatever we had done over the preceding 25 years. Many times I speak to an endodontist and say that one of the things you probably do is to call up new dentists and ask them out for dinner. In effect, you are trying to charm them into sending you referrals. I understand that. I did plenty of that over the years. Now maybe I’m being cynical, but most dentists really don’t want to go out for dinner. I think most of them want to get home when the workday is done, and when they agree to go out with an endodontist (or any other specialist) it’s because they are being a nice guy (or gal). So here we are teaching dentists how to do much better endo simply and effectively without spending a lot of money

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and, in fact, virtually eliminating the chances of fractured instruments. We tell other endodontists, our potential competitors, how and why it works for us. And the results are amazing. Most endodontists believe that if they really teach an effective method of endodontics it will result in less work for themselves, so they don’t want the general practioner to learn these simpler, more effective systems. We tell them that, in reality, they are only half right. If they teach these systems, many of their referrers will send fewer patients because they can do more on their own; however, what these endodontists fail to see is that teaching the Safesider and EZ- Fill techniques will result in their meeting many new dentists whom they would have never met otherwise. By the way, most of the individual hands-on courses we give last two to three hours. That means that both the dentist and the endodontist get home earlier than if they had gone out to eat. In addition, you have not polluted yourself with alcohol and fat-drenched steaks, adding to your long-term good health. The endodontists who teach the techniques that allow the gp’s to make more income in a simplified fashion will get less work per dentist, but they will have many more dentists who send work. As for being charming, I tell them that if they teach a dentist to make $125,000 more a year, there are few things that are more charming. It certainly beats sending a case of wine or a dozen steaks from Omaha, not that we are telling those specialists to stop sending the wine and the steak. Teaching the SafeSider instrumentation and EZ-Fill obturation techniques is particularly timely, considering the fact that rotary NiTi has two things that are going on concurrently. Many recent graduates are coming out of dental school having been exposed to rotary NiTi techniques, and a low but persistent incidence of instrument separation keeps occurring. While the major manufacturers say that instrument separation is a result of the practioners’ techniques, the research clearly shows that instrument failure is directly connected to NiTi’s poor resistance to torsional and fatigue stresses. Studies have shown fracture rates between 2 and 9 percent, a level that translates into great inefficiency when attempting to remove embedded segments of broken instruments. Once the dentists see and understand the SafeSider alternative, they begin to appreciate the formerly inconceivable notion that rotary NiTi is truly an irrelevant departure from safe predictable endodontics, and its abandonment results in superior results and less anxiety.

Spring 2004

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FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.C.D. SafeSiders® and the Mindsets They Encounter

ENTALTOWN.COM has been a vital vehicle for SafeSiders SafeSiders growth. A wonderfully interactive dental have received site with close to 35,000 members who participate in a slew of varied message boards, the site is intuitive and easy to so many master. I recommend that everyone join. You will be a positive better dentist for it. That, however, while absolutely true, is testimonials not the thrust of this article. As the main advocate of this relatively new system, the that we could SafeSiders, I have encountered a variety of reactions from practically fill a the dental community. Most reactions have been positive, small book with Barry Musikant coming as they do from dentists who want to learn the them. technique to solve problems that they are having with some form of rotary NiTi or with their traditional techniques. SafeSiders have received so many positive testimonials that we could practically fill a small book with them. While I am grateful for those positive reactions, they are not the reactions that amaze me. Instead, I am amazed by the reactions of a handful of dentists, practically all of them rotary NiTi users, who somehow feel that an aggressive discussion of the SafeSider alternative is a violation of the status of rotary NiTi as the endodontic paradigm. These dentists assert the superiority of rotary NiTi by listing the assumed shortcomings of the SafeSiders, which—according to them—include the following:

The SafeSider system is a manual system and must, therefore, create far more hand fatigue than rotary NiTi and take much longer time to shape the canals. Canals cannot be shaped to a greater taper with SafeSiders. Gutta-percha points will not fit as well in canals shaped with rotary.

The assertions made by these dentists are inaccurate whether they come from endodontists (the strongest advocates of rotary NiTi) or general practitioners, who often quote the opinions of the endodontists they associate with. In truth, in the SafeSiders technique, 85 percent of the canal space is shaped with the number 2 Peeso reamer and the number 2 Gates Glidden in a crown-down fashion similar to, but a lot safer than, the crown-down technique used with rotary NiTi. The procedure is safer because it ensures that if the Peeso or the Gates breaks, the break will be in the coronal

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section of the shank and therefore the broken piece can be removed easily in seconds. Another reason for the safety of the technique is the fact that as the Peeso straightens the coronal curve it removes tooth structure from the outer wall of the canal, the wall away from the furcation. Compare this pattern of removal with that of the orifice openers of rotary NiTi instruments, which remove equal amounts of tooth structure from the inner and outer walls, and you quickly realize that the rotary NiTi instruments are more likely to cause strip perforations on the furcal side of the root. The widest diameter of a number 2 Peeso is 0.9 mm versus diameters as high as 1.6 mm for the rotary NiTi orifice openers. The SafeSiders create a .08 mm/mm taper with 95 percent of the shaping first done with tough, fracture-resistant stainless steel before the far more vulnerable NiTi is used. The remaining 5 percent is shaped manually, using NiTi SafeSider reamers with a reciprocating motion that prevents fracture. A simple manually applied bend test is used to confirm that the reamer can be used in the canal without fracturing before it is placed into the canal. The SafeSiders produce an .08 mm/mm taper, while the best that rotary systems create for the most part is an .04 to .06 mm/mm taper. NiTi instruments are limited to smaller tapers not because reduced tapers are superior, but because the dentist cannot create an .08 mm/mm taper using rotary NiTi without increasing the risk of separating an instrument around a curved canal. It is becoming increasingly obvious that the limitations of rotary NiTi have a direct impact on the results that can be obtained. Like rotary NiTi, the SafeSiders work quite efficiently in straight or mildly curved canals, producing a fully shaped canal in minutes. As the canals become more curved, nickel titanium’s weakness under torsional stresses and its low resistance to cyclic fatigue impose a whole set of safety rules on rotary NiTi instruments. Because the SafeSiders are predominantly stainless steel based, they are not nearly as subject to these stresses and have far less likelihood of fracturing in similar situations. The physical characteristics of these two metals means that in straightforward cases both systems will produce excellent results in minutes, but as the curves become greater and sharper the NiTi must be used with far more caution, and consequently take far more time, than the SafeSiders in similar situations. Given the .08 mm/mm taper produced by the SafeSiders, a medium gutta-percha point (preferably from Dentsply Maillefer) fits perfectly, and when combined with the EZ-Fill epoxy resin creates an excellent seal. If the canal is very elliptical, there is no problem placing a second or even a third well coated accessory point. Supporters of rotary NiTi often contend that the cause for concern about fractures really does not exist. They use data from their own offices to demonstrate a minuscule fracture rate of less than 1 instrument in 1000 used. While this is

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impressive, it does not come close to agreeing with the far more pessimistic feedback we constantly receive from dentists who are signing up to take the SafeSiders courses. The marketplace also belies these dentists’ appraisals of the safety of rotary NiTi. For example, the following products and procedures have been introduced in recent years to avoid or overcome fractured instruments:

a spate of new systems, each promising a design that is more resistant to fracture auto-reversing handpieces that reverse at the first signs of excessive torque electric handpieces that allow precise control of the rotation speed the concept of single usage increasing limitations on the types of cases that can be done with rotary NiTi as well as constant reinforcement of the meticulous technique that must be employed to prevent these fractures, as reported in a number of published articles methods of removing fractured instruments once fracture has occurred and finally, the contention in a number of articles that fractures generally are not that bad, that they rarely result in apical problems, and that when they do a “simple” apico wll suffice

This last point, in my mind, is a prime example of denial and a major impetus to turn the clock back by rationalizing events that should be occurring less frequently, not more frequently. The endodontic publications also belie the upbeat evaluations from rotary NiTi supporters. Not a month goes by without an article in one or more publications concerning the causes of rotary NiTi instrument separation and what is required to prevent it, so far to no avail. Publications would not give this much attention to a problem if it were virtually non-existent, as some endodontists claim. What it all boils down to is an example of the prejudice of those who have become quite good at rotary NiTi and don’t find the need or the desire to learn a new alternative, especially one that by comparison is so simple that it may detract from the effort and expense they have already made to master the complexities of rotary NiTi. I say prejudice because I have met very few advocates of rotary NiTi who have really learned the SafeSiders technique. Most say that it is a manual system and dismiss it as old technology without ever having tried it. My persistence in making all of the above points has also taken on a personal tone. Some, when they don’t like the message, attack the messenger, but such an attack does not make the message any less valid. Simply put, rotary NiTi has had all the time in the world to refine itself and show solid progress in preventing instrument separation. However, over the last 15 years or so, as more dentists have employed

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these systems, the fracture rate has continued. The most basic question should be whether you want to continue with these systems or consider systems that are predominantly based on stainless steel and virtually eliminate instrument separation while reducing the overall costs by at least 90 percent.

Summer 2004

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Barry L. Musikant, D.M.D., F.A.C.D. Post and Core Decisions Based on Fact, Not Fiction

IKE EVERY OTHER DENTIST, I read the latest The real test of articles in the dental trade journals and can certainly be a post is how influenced by them . . . with a few major exceptions. When I see products that are in direct competition with the well it will do things we have developed for Essential Dental Systems, such when little or as the Flexi-Post and Flexi-Flange, SafeSiders, and the EZ- no coronal Fill obturation system, I think extra-critically to determine in my own mind whether what they claim is mostly hype or is dentin exists. based on solid data that defines their products as a step forward. Barry Musikant One area of product development that has caught my attention is the introduction of new bonded fiber-reinforced composite posts. Claims have been made in one article or another that posts of this type actually strengthen teeth, that they seal the tooth better than root canal cement and gutta percha, and that they hold up at least as well as metal posts while dramatically reducing the incidence of root fracture associated with metal posts. If even one of these claims were true, these new products would represent major competition for the split-shanked metal post. Certainly, those claiming superiority for fiber- reinforced composite posts cannot do it on the basis of retention. The Flexi-Post and Flexi-Flange have retention values in the range of 300 pounds, while the maximum retention of a passive post—whether metal or fiber- reinforced composite—does not exceed 90 pounds, which is equal to the maximum cohesive strength of the strongest cements that exist today. A case could be made that fiber-reinforced posts will distribute less functional stress to the root than metal posts do because they are more flexible than metal posts of the same diameter. This is true, but in the literature it has been amply documented that the forces that the human musculature can generate are not sufficient to cause a passively seated metal post to fracture the tooth if there is a minimum of 1 mm of lateral tooth structure surrounding the post at its most apical placement. It has also been documented that the Flexi-Post and Flexi-Flange generate no more insertional stresses upon cementation despite their high retention than a passively placed post does. At the same time, the Flexi-Post and Flexi- Flange have the additional benefit of distributing functional stresses more evenly around the entire shaft of the post than

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is the case for a passive parallel metal post, where the functional stresses are concentrated apically. Recently one paper has definitively stated that a composite post in combination with a methacrylate resin cement will strengthen teeth if the cement is bonded to the dentinal walls via a primer. Yet the primer, which is drawn up into the dentinal tubules, has a hydrophilic nature and has been documented to continue to absorb water. This process leads to nano leakage and the weakening of the original bond. Although some authors have hyhpothesized that what is needed is a bond that is hyrodphilic prior to curing and hydrophobic after it cures, it also has been stated that these shifting qualities are beyond the present capabilities of the bonding agents and cements. As a result, any increase in strength is transient at best because the hydrophilic primer embedded into the dentinal tubules continues to attract the water molecules that accelerate the degradation of this bond. The results are a decrease in initial strength and the start of nanoleakage, which is a foot in the door in the process leading to microleakage. Furthermore, significant degradation of the bond of the post to the interface between cement and primer results from thermocycling, a process that is unavoidable in the mouth. In contrast, this degradation process does not occur when the threads of a metal post are embedded and cemented into the dentinal walls. At a minimum, independent research disputes the company-sponsored research claims of superior characteristics for the products they sell. However, once they have their research in print, companies will continue to make claims that are far from being universally accepted because they believe that those claims will sell the product. It is important for dentists to know what is real and to have the ability to differentiate it from what is claimed. Yes, one could read all the conflicting research and come to his or her own conclusions, but if we are honest we have to admit that this is not a likely scenario in most cases, where time is our most valuable asset. A shortcut approach, even though it is self-serving, is to read the viewpoints of those who, as I do, have competitive products and want to make sure that the alternative interpretations gain public attention. At worst, a protracted dialogue goes on, with each side defending its own position. Ultimately the winners are those who follow the dialogue. Lincoln had it right: You can fool all the people some of the time and some of the people all the time, but you cannot fool all the people all the time. So what can be said about fiber-reinforced composite posts? There is no question that they work when sufficient dentin exists, but so does every post—or, for that matter, no post at all. The only purpose of a post is to create a more stable and substantial core upon which to seat, so the real test of a post is how well it will do when little or no coronal dentin exists. In these situations the core must support the crown without the added stability of extra dentin. Without coronal dentin, the post must have high retention, because its

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anchoring is limited to the internal retention of the shank of the post within the root canal. If the post is passively held in by the strongest cement, it will have a maximum retention of 90 pounds. If it is held into the dentin with threads, like those of a Flexi-Post or Flexi-Flange, the post will have over 300 pounds of retention, mimicking the retention that a natural crown has to a natural root with far greater accuracy than a passive post, no matter what material it is made of. Many dentists have chosen to use fiber-reinforced composite posts because these posts don’t discolor the core, which in turn may affect the shade of the overlying ceramic crown. If a post is necessary, then insufficient dentin is present, which implies that the crown should have a ferrule, which means that the final restoration should be porcelain fused to metal. If this is the case, a full porcelain jacket that is incapable of creating a fine chamfered finish line is the wrong restoration. A porcelain to metal restoration allows the placement of the stronger, more retentive, metal post while supporting the core with a ferrule, a design feature that has been shown to be the most important aspect of a final restoration where minimal dentin exists. And the esthetics of the post are not an issue because the porcelain fused to metal restoration is not translucent. The worst situation would be to place a shoulder preparation around a core that is entirely or nearly entirely composed of a flexible fiber-reinforced composite core surrounded by a composite core material. A restortion of this design is most likely to open gaps under repeated functional loads of compression and tension. Gaps lead to leakage, which leads to secondary decay. The most that can be said for fiber-reinforced composite posts is that in the event of a traumatic blow a flexible post will absorb more stress than the stiffer metal posts and in so doing will reduce the chances that the traumatic force will produce a vertical fracture. While reducing the incidence of root fracture is a plus, employing a flexible post to prevent these rare events while increasing the chances of gap formation and secondary decay under normal function does not make for long-term success. Rare events should never be the criteria that determine the mode of treatment. Ideal treatment should reflect the elimination or minimizing of those events that are most likely to occur. Unless we realize this, we may make treatment decisions based on an overemphasis of unlikely events while missing the common-sense approach that will most likely succeed for the largest number of patients. This approach—working to eliminate or minimize the most likely events—applies to many aspects of dentistry, including endodontics in particular, which we will go into in further detail in future issues of Endo-Mail.

Fall 2004

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In canals where you need to place a curve or 45-degree bend at the end of the instrument to negotiate the apical dilacerations, line up the mark or notch on the rubber instrument stop with the bend of the instrument. This will ensure that the bend is facing in the right direction in relation to the apical curve every time the instrument is inserted into the canal.

Doug Kase

FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.C.D. At Last! The Hands-On Dental Education Center (HODEC)

N OCTOBER 8 AND 9, 2004, we acted as hosts for the first use of our new hands-on dental education center (HODEC); Kit Weathers and Mike Goldstein conducted a two-day course on rotary endodontics and associated subjects. HODEC is located in South Hackensack, New Jersey, and can accommodate as many as 40 participants in hands-on technique sessions. This facility has been a dream of ours for some time. We Kit Weathers lecturing at know that actually using new instruments and experiencing HODEC new techniques has a far greater impact than just listening to Barry Musikant someone talk about them. Unlike the workshops that we give one-on-one at our endodontic practice in Manhattan, we will have to charge for the courses conducted at HODEC. However, instruments and materials that we recommend during the full-day and two-day workshops will be included in the fee for all the courses. Those instruments would cost well over half the course fee if they were purchased separately. We know of no other continuing education courses that make this offer. We are providing this extensive armamentarium as a take- Barry Musikant explains home package to show in a dramatic way that dentists can get the advantages of the EZ- a topnotch educational experience and all the tools they will Fill obturation system need without having to make further payments for the instruments to perform the techniques they just learned. We want the knowledge and the instruments to be in your hands as soon as you complete these educational experiences. The techniques that you will learn will challenge any preconceived notions you may hold regarding the need for expensive rotary NiTi. We will show you how to prepare canals to an .08 mm/mm taper within minutes while virtually eliminating any chance of instrument separation. If you are presently using rotary NiTi, your ongoing costs will be reduced by at least 90 percent. If you are using traditional time-consuming techniques, your productivity will at least double, and you will achieve superior results in the process. You will understand the simple concept of relieved reamers and why they negotiate through tight curved canals far more easily than any other endodontic instrument. You will learn why thermoplastic obturation techniques add needless complexity and expense and why they will give more consistent results at a fraction of the cost and in a fraction of

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the time. In short, many of the concepts that have been promoted by massive marketing and recent dental school programs will be shown to be illogical, ill-conceived, and counterproductive. The overarching thrust of this two-day course is to address all these issues and the discussions that may ensue to clear up our thinking and demonstrate that rational thinking is far more important to excellent endodontics than some of the unproductive complex and expensive approaches that have been promulgated in recent years. The first two-day course will start in January 2005. Those taking this course will receive 17 CE credits. It will be a comprehensive endodontic educational experience including:

1. Diagnosis and case selection 2. Achieving safe and proper access with a simple new device that virtually prevents all perforations 3. Using releaved reamers in reciprocating handpieces that allow quick and easy shaping of even tightly curved canals to an .08 mm/mm taper within a few minutes per canal while virtually eliminating instrument separation 4. Obturation of the prepared canals in a procedure that incorporates the use of a bidirectional spiral to load the canals and coat the points with an epoxy-resin cement that binds chemically and physically to both the gutta percha and the dentin 5. Using digital imagery to confirm the accurate and thorough placement of the cement and gutta-percha points from both mesio-distal and bucco-lingual angulations 6. Placing a highly retentive post to insure a stable core for the long-term success of the final crown

While the emphasis will be hands-on, with at least half of each day being devoted to benchtop workshops, we will also present a solid case for these techniques as the very best and most practical ways to perform these phases of endodontics. We are prepared to discuss all other methods of instrumentation and obturation that the participants may be interested in and to demonstrate clearly why the methods that you will learn in this course are superior. In addition to the above disciplines, participants will be able to acquaint themselves with the endodontic microscope, apex locators, and ultrasonic and sonic units for the purpose of debriding and removing instruments broken while using other techniques. The two-day courses will include breakfasts and luncheons at the lecture site and an optional dinner on the first night of the two-day program for those who would like to relax informally with the group. In the future, we will also hold specialty courses emphasizing the microscope and its ability to aid in the removal of broken posts and instruments. You will learn the

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technical care and maintenance of the microscope as well as proper positioning to see every tooth in the mouth. For information on the growing list of these courses please CLICK HERE or call 888-5HANDS-ON. This is just the beginning of what we believe will be both a common-sense and revolutionary approach to endodontics with both the dental profession and the general public sharing the benefits.

Barry Musikant lecturing in the new Hands-On Dental Education Center

Winter 2004

Take an online tour of the Hands-On Dental Education Center (HODEC)!

CLICK HERE

FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.C.D. The Maturing of the SafeSiders® and Ourselves

BIT OF A DICHOTOMY exists when it comes to the The Endo-Express excellence in results produced by rotary NiTi with SafeSiders instruments. As Bill Watson, a well-known approach is endodontist from Kansas, has pointed out, there are often thoroughly collateral spaces that can harbor tissue. Finding these canals compatible with requires placing bends on instruments and probing the walls all endodontic of the canals. Yet placing bends in this way is difficult at situations from best with rotary NiTi instruments, which do not take bends the simplest to well and weaken substantially when they are bent, making the most routine usage of rotary NiTi instruments after bending a complex. Barry Musikant potential problem. Unfortunately, NiTi’s flexibility is directly related to its fragility, magnifying its dichotomous nature. NiTi’s flexibility is most needed in the shaping of curved canals, but that is where NiTi instruments are most vulnerable to functional separation. The problem of weakening upon bending is solved with the SafeSiders® approach. These instruments, which are all stainless steel until the last two in the sequence, may be prebent to more efficiently explore for collateral spaces. Once the spaces have been found with the reamer, the probing instrument can then be attached to a reciprocating handpiece, which will enlarge the space, debriding it in the process without any concern for separation of the instrument or distortion of the probed space because the motion is limited to 90 degrees. So I look at the SafeSiders from the viewpoint that they are designed for maximum manual exploration if so desired, yet retain the adaptability to be engine-driven for ease of use. This duality of usage gives the dentist the ability to comprehend the internal anatomy with excellent tactile perception yet not have to pay for that fine tactile perception with eventual hand fatigue when it comes to debriding these collateral spaces through sequential canal enlargement. In short, no other system that I know of gives the dentist instruments that are designed to have the least resistance to apical negotiation, bring debris coronally, be routinely prebent for fine probing and then attached to an engine that eliminates hand fatigue without producing distortions, excess torsional stress, or cyclic fatigue. The Endo-Express with SafeSiders approach is thoroughly compatible with all endodontic situations from the simplest to the most complex. The dentist does not have to know the degree of difficulty he

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or she is going to face before starting the case, which if you think about it, makes things much simpler in its own right. The SafeSiders produce a tapered canal preparation equal to or better than that produced by rotary NiTi instruments, but are far superior in finding those accessory canals that would be missed by a rotary system that stays centered in the main canal. A far better case can be made that the SafeSiders have a greater potential for thorough debridement than rotary NiTi because of NiTi’s strict limitation in probing sharp curves and the difficulty of then trying to shape them with a rotary system. The design of the rotary systems simply does not allow for this type of action. The fact that this limitation can be compensated for with the use of other systems does not minimize the inadequacies of the rotary NiTi approach to instrumentation. The ability to consistently produce excellent endodontic results in all the various anatomic challenges that confront us produces confidence in the operator whether that operator is a G.P. or a specialist. Consistently good results increase confidence in one’s own abilities as well as the system through which those abilities work. Because I teach the SafeSiders technique to so many people, I am constantly re- evaluating just what this system is all about. Over a period of four years of use and the last year of use with the instruments coupled to the reciprocating handpiece, I have found no shortcomings attached to this system. Some dentists voiced initial fears of the No. 2 Peeso that is incorporated into the system. Yet, when I show them the proper use of the No. 2 Peeso, the two fears they have (strip perforation into the furca and ledging) are no longer a concern. In fact, I learned early on in the teaching process that many of the fears that dentists have originate in their dental education at a point in time where they had no choice but to accept academic dogma because they were not in a position to test the inhibitions imposed by their teachers. Dogma left untested can solidify into hard held beliefs. That is part of the challenge when teaching dentists with diverse educational backgrounds. Teaching is our new mantra, whether we do it with the free hands-on workshops we offer in our dental office in Manhattan or the more formal intensive two-day courses we give at the Hands-On Dental Education Center (HODEC) in New Jersey. We find that dentists are hungry for effective methods of producing excellent endodontic results that are simpler, less stressful, and dramatically less expensive. The feedback on our educational courses has been so positive that we are in the process of expanding our commitment to hands-on education. We believe that ultimately our own success is directly dependent upon our commitment to the dental community and the degree of effort we put into constantly refining that commitment. It’s taken us more than 30 years to truly believe that we have something of significant substance to offer our colleagues. Active practice is an essential if we are to

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continue to innovate both in products and our teaching. When asked a question during our lectures, I always want to be able to relate what I did clinically the day before. When we tout endodontic reality, that reality must be backed up by daily practical experience. Without it, any dental lecturer would quickly become hollow, if not to the audience then to himself.

January-March 2005 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.C.D. Posts and Cores: Myths and Realities

I THOUGHT THAT it would be timely to once again compare the design of the Flexi-Post® and Flexi- Flange to the new concepts of post buildups, namely the use of fiber-reinforced composite posts. The supposed advantages of fiber-reinforced composite posts include:

1. They have a modulus of elasticity similar to that of dentin, implying that the post will bend similarly to the tooth in which it is embedded. Barry Musikant 2. They have high retention because they are bonded into the teeth. 3. They bend enough to absorb parafunctional forces without acting as a conduit for excessive stresses that lead to root fracture. 4. They eliminate the high insertional stresses associated with threaded metal posts because they are of passive design. 5. They impose no esthetic challenges because they have the color of teeth. 6. They strengthen the teeth.

Before challenging these supposed advantages, we should understand the parameters of post placement. Until the recent claims that bonded composite posts strengthen teeth, it was a well accepted fact that posts do not strengthen teeth, that they are used only to support the retention of a core that does not have sufficient coronal dentin to support occlusal function. Removing coronal dentin to support a post makes no sense because removing dentin weakens core support more than introducing a post supports it. As endodontists, we no longer subscribe to the philosophy that every endodontically treated tooth automatically must have a post. Today we will not hesitate to place or recommend the placement of a post if an inadequate amount of coronal dentin exists to support the core that in turn supports the overlying restoration. With that in mind, let’s examine some of the listed advantages of fiber-reinforced composite posts. 1. They have a modulus of elasticity similar to that of dentin, implying that the post will bend

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similarly to the tooth in which it is embedded. This claim made its way into post advertisements early on. The thrust of these advertisements is the illogical conclusion that posts made of materials with a modulus of elasticity similar to that of dentin will bend the same as dentin. In fact, materials with a modulus of elasticity similar to that of dentin will only bend the same if (and it is a crucial if) they have the same or similar cross-sectional area. When one realizes that a redwood tree and a redwood toothpick both have the same modulus of elasticity it becomes clear that the modulus of elasticity alone does not define deformation under function. In the case of teeth, a post with the same modulus of elasticity as the tooth is likely to have a cross-sectional area approximately 1/10 to 1/15 that of the tooth it is embedded into, making the post 10 to 15 times more deformable under function than the surrounding tooth. The differences in cross-sectional area of the tooth and post define the degree of deformation, unavoidably leading to increased compressive and tensile stresses within the core material simply because the core material is supported by the more highly deformable post. The effects of a deformable post on the core material are another issue that has not been accurately addressed. Advertisements claim that the post and core bond to one another, creating a monobloc that is stronger than either component alone. That might be true if the two materials were enmeshed in each other’s structures to such an intimate extent that a new composite material was created, such as occurs in airplane propellers. However, in the case of posts and cores the fiber-reinforced post stands as a separate entity and is then grossly overlaid with a composite material in which either no fibers are included or the fibers are randomly aligned, giving it minimal resistance to functional forces. The resistance to deformation and the resistance to cyclic fatigue degradation is defined by the strongest link in the chain, the fiber-reinforced post, which we have already demonstrated is 10 to 15 times more deformable than the root it is in. Adding a weaker composite overlay does nothing to strengthen the post’s resistance to deformation. The end result of the core buildup is stress to the core material as it undergoes repeated cycles of compression and tension because of the supporting post’s low resistance to deformation. To reinforce the above point, consider a post that is as flexible as a human hair supporting a core against lateral movement without any coronal dentin existing. The only resistance encountered is the minimal support of the post, a hair in this case, and the frictional resistance of the bonded composite to the relatively flat surface of dentin. In this example, it should be clear that the composite adds nothing to the strength of the post. The saving grace in this dismal scenario comes from the outer margins of the final restoration. As long as these circumferential margins stay intact, the weakness of the post-

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and-core construct will not be tested, allowing any type of underlying support or no underlying support at all to succeed. If and when the outer margins of the restoration degrade, as they often do over time, then all the functional forces will be directed internally and the weaknesses of the construct will take their toll. 2. They have high retention because they are bonded into the teeth. Advertisements make claims that bonded posts have unusually high retention, rendering the retention of threaded posts irrelevant. The factor that made threaded posts irrelevant was not the still-present need for high retention, but rather the inability to disassociate high retention from high insertional stresses. High retention is not acceptable even though it is needed if it must come with high insertional stresses because these stresses too often lead to root fracture. The maximum retention that a bonded passive post can attain is 90 pounds, far less than the 340 pounds attained with a threaded Flexi-Post and Flexi-Flange. Most importantly, both the Flexi-Post and Flexi-Flange attain their high retention values without introducing high insertional stresses, which are at a level comparable to those of passive posts. The split-shank design of these posts creates high retention by making the grooves for the threads in a sequential manner as it is screwed into the root. The posts themselves are, in effect, graduated taps that allow the dentist to enjoy the benefits of high retention, low insertional stresses, and an even distribution of functional stresses. 3. They bend enough to absorb parafunctional forces without acting as a conduit for excessive stresses that lead to root fracture. The one marginal advantage a fiber-reinforced post would have over a Flexi-Post or Flexi-Flange is the greater deformation displayed by the former when a sharp blow would be applied to the post-restored tooth. Under these unique circumstances, the increased bending would lead to a lower chance of root fracture than in a tooth with a metal post. However, short of these circumstances, namely during all the normal functions that dentition undergo, the rigidity of a metal post bending in unison with a root is far more likely to keep margins intact while supporting the external restoration. To design for traumatic blows while not meeting the needs for routine function is a poor choice of options in our opinion. 4. They eliminate the high insertional stresses associated with threaded metal posts because they are of passive design. Over the years, the split-shank design of the Flexi-Post and Flexi-Flange has shown that a metal post can be threaded

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into a tooth producing high retention and minimal stress at the same time. This fact alone makes the claimed advantages of a fiber-reinforced post non-existent. 5. They impose no esthetic challenges because they have the color of teeth. The problem of discoloration is pretty much nullified with opaquing bonding agents. I typically will opaque out the color of metal by coating the post, as it exits the root, with C & B Metabond opaquing agent. This same cement can be used even within the root to minimize any color that might show through the length of the root and the overlying gingival. Because this problem is eliminated so efficiently, esthetic considerations impose no limitation on the use of these split-shank metal posts.

6. They strengthen the teeth. This is a claim that is more apparent than real when first considered. To clarify logical thinking, consider a metal pipe that is strong enough to resist 300 pounds of force before bending. Now place a material within the pipe that alone resists 200 pounds of force before bending. Does it now require 500 pounds of applied force to bend the pipe filled with the 200-pound resistant material? On the contrary, the bending is still ultimately resisted by the pipe alone, which will bend after 300 pounds of force is applied even though the pipe is now filled with a 200 pound resistant core. In the same way, a post that bends far more easily than the tooth it is embedded into will not increase the resistance to bending of the tooth. The concept has a nice sound, but it is not backed up by fact.

OVER THE YEARS, from the use of reamers rather than files and now relieved reamers and their incorporation of a reciprocating handpiece rather than a rotary driving force, to the scientifically proven advantages of a split-shank design of threaded metal posts, we have attempted to demonstrate the connection between sound design and practical mechanics producing more successful techniques and restorative components. We hope this discussion is timely and helps dentists to think more critically when exposed to advertising claims that, in our estimation, do not reflect clinical reality.

April-June 2005 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.C.D. Post and Core Myths and Misconceptions

ALLACIOUS CONCEPTS encouraging the use of fiber-reinforced Figure 1 posts are not supported by a growing number of research articles and clinical experience. Unless the weaknesses of these concepts are well understood, they have the potential to propagate as valid approaches. The purpose of this article is to shed light on these misconceptions. Posts in teeth serve only one purpose: to supply extra support for a core when sufficient tooth structure does not exist to do it alone. Posts placed into teeth with sufficient dentin to support a core serve no purpose and are, at best, redundant. In fact, removing dentin in order to place a post may actually weaken the root. The placement of a post may give support to the Barry Musikant core, but it does not strengthen the root. Having the same modulus of elasticity as a root in no way assures that the post will bend to the same degree as the tooth in which it is embedded. Materials having the same modulus of elasticity will bend the same only if they have the same cross-sectional area. A post with the same modulus of elasticity as tooth, yet 1/15 the diameter of the tooth in which it is placed, will bend about 15 times more than the surrounding root, creating stresses in the supporting cement, the surrounding core buildup, and the post itself. In short, a post with greater flexibility than the tooth FIGURE 1: Split-shank parallel-thread posts. compromises the longevity of the overlying crown. Fiber posts are significantly more flexible than the roots in which they are embedded (1- 6). The concept that the core and post join together and create a monobloc stronger than either two of these components is a false notion. This is easily realized by making a post-and-core combination in which the post is no thicker than the diameter of a thread of hair. In this case, the post bends in the air and offers no support to the core. If such a post were placed in a root without the support of circumferential dentin, there would be virtually no resistance to lateral forces. In this absurd example, it becomes clear that the resistance to lateral movement is defined by the weakest element in the construct, namely the hair-thin post. As the posts become stronger, the resistance to lateral displacement increases. This resistance is always limited by the flexibility of the post, which is not enhanced by bonding to a stronger core material. In order for a post to bend like tooth in spite of its thinner cross- sectional area, the modulus of elasticity must be much higher than that of the surrounding root. In fact, because the post is about 1/15 the diameter of the root, the modulus of elasticity should be about 15 times higher than the tooth’s. Stainless steel and titanium fall into this category and will therefore bend much more similarly to the bending of the tooth in which they are embedded. Another false concept implies that bonding will increase the retention of a post beyond the cohesive strength of the cement holding the tooth in place. SEMs are often shown with fibrils of cement infiltrating the dentinal tubules by the millions as proof of the greatly increased retention. While this type of adhesion increases retention more than that of a non- adhesive cement, these millions of penetrating fibrils provide no additional strength to the bond beyond the strength of the cement. To date, this

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strength has never exceeded 90 pounds of tensile resistance (7-8). Research has demonstrated not only that retention is limited to the cohesive strength of the cement, but also that when subjected to thermal cycling fiber-reinforced composite posts degrade over time significantly more than metal posts do (9). Many studies conclude that metal posts offer more support for restoration than fiber-reinforced composite posts do. Metal posts are more resistant to bending and are far more resistant to thermal cycling. Those who support fiber-reinforced metal posts have attempted to turn a weakness into a strength by saying that fiber-reinforced posts are less likely to cause root fracture if subjected to excessive forces. The research has again clearly demonstrated that while this is true, it takes forces beyond human capacity to produce these fractures when metal posts are placed (10). On the other hand, the forces necessary to displace cores supported by fiber-reinforced composite posts fall clearly within the capabilities of human function. The best rationale for the use of fiber- reinforced posts would be to place them in order to avoid the increased chances of fracture when a tooth is subjected to a traumatic blow. This would, however, leave the restored tooth open to gap formation from normal function, an everyday occurrence. Once the strong case for the preference of metal posts over fiber- reinforced composites is established, an equally strong case can be made for the design of a split-shank parallel-thread post. (See Figure 1.) The split-shank design is the only threaded post design that produces the degree of retention that only threads embedded in dentin can provide while simultaneously minimizing the insertional stresses to those of a passive post (11). In effect, the split-shank design is a graduated tap that deepens the threads in a sequential fashion, never cutting more than .02 mm of dentin at any one time (Figure 2).

Figure 2

FIGURE 2: The split-shank design is a graduated tap that deepens the threads in a sequential fashion, never cutting more than .02 mm of dentin at any one time.

By limiting the removal of dentin, the stresses associated with that removal are also limited. The result is a post with retention of about 340 pounds, about four times higher than that of the most retentive passive post, but with stress levels no higher than that of a passive post. The retention of a natural crown to that of a natural root is at least 220 pounds, a result extrapolated from the research of Shimon Friedman. He demonstrated that it took at least 220 pounds to split a tooth in half along its long axis. Two hundred twenty pounds represents the weakest vector of strength for a tooth. As such, it is reasonable to expect that a natural tooth would have at least that much retention to a natural crown. The 90 pounds that the best passive post provides is inadequate to duplicate nature’s design. The split-shank design, on the other hand, is far more comparable to nature’s design. Not only does it supply 340 pounds of retention, it does so without generating high insertional stresses. Just as

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important, a parallel threaded post also distributes its functional stresses evenly around each of the threads. A passive parallel post distributes a good portion of the functional stresses in the apical region because the non-threaded parallel design offers no other area of resistance to these forces. Like all stresses, they are handled better when distributed evenly over a large area than they are when concentrated into a small area, as is the case with the passive parallel post design. From a restorative point of view, it is only the lack of coronal tooth structure that defines the need for a post. Therefore, once a post is required, external support by the crown is also required. The best way for the crown to supply this support is through the incorporation of a circumferential ferrule ending on the dentinal surfaces. The longer this ferrule, the greater the support the crown offers. To place a butt joint restoration on a tooth where most, if not all, of the axial wall is composed of a post supported by a composite core is to dramatically increase the functional stresses that will be directed against the axial wall. Knowing that this post-and-core buildup is subject to degradation, it is important to create a ferrule onto solid tooth structure that redirects most of these functional forces away from the axial wall and toward the external root surface. Summary

Establishing the greatest stability and longevity for restorations requires building a highly retentive and stable substructure. In turn, this requires the placement of a parallel threaded metal post. The split-shank design provides high retention with minimal stress, as well as even distribution of functional stresses. The crown should incorporate a ferrule and end on a long beveled dentin margin for maximum support. References

1. King PA, Setchell DJ, Rees JS. Clinical evaluation of a carbon fibre reinforced carbon endodontic post J Oral Rehabil. 2003 Aug; 30(8):785-9. 2. Drummond JL, Bapna MS. Static and cyclic loading of fiber- reinforced dental resin. Dent. Mater. 2003 May;19(3): 226-31. 3. Drummond JL In vitro evaluation of endodontic posts. Am J. Dent. 2000 May;13 (Spec No): 5B-8B. 4. Sidoli GE, King PA, Setchell DJ. An in vitro evaluation of a carbon-based post and core system. J Prosthet Dent. 1997 Jul;78(1):5-9. 5. Torbjorner A, Karlsson S, Syverud M, Hentsen-Pettersen A. Carbon fiber reinforced root canal posts. Mechanical and Cytotoxic properties. Eur J Oral Sci. 1996 Oct-Dec;104(5-6):605-11. 6. Yang HS, Lang LA, Guckes AD, Felton DA. The effect of thermal change on various dowel-and-core restorative materials. J Prosthet Dent. 2001 Jul;86(1):74-80. 7. Saunders, RD, Lorey RE, Powers JM, Sloan KM. A comparison of five post-cement systems for tensile retentive capacity. J Den Res 1988;67: IADR Abstract 304. 8. Stockton LW, Williams PT. Retention and shear bond strength of two post systems. Oper Dent 1999;24:210-216. 9. Yang HS, Lang LA, Guckes AD, Felton DA. The effect of thermal change on various dowel-and-core restorative materials. J Prosthet Dent 2001;86:74-80. 10. Wong EJ, Ruse ND, Greenfeld RS, Coil JM. Initial failure of post/core systems under compressive-shear loads. J De Res (IADR abstract #2269) 1999;78:389.

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11. Ross RS, Nicholls JI, Harrington GW. A comparison of strains generated during placement of five endodontic posts. J Endodon 1991;17:450-456.

July-September 2005 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.S.D.A. A Deeper Understanding of Endodontic Mechanics

N TERMS OF what is generally considered the state of This discussion the art of endodontic shaping, NiTi instruments used in a attempts to bring reduction-gear rotary engine are presently at the head of some deeper the class. Their use has certainly improved the results understanding to compared to what was routinely attained with the traditional the use of stainless steel files. Not only are the shapes more interconnection conducive to a better fill, but the shapes are gained without between the hand fatigue, a major plus when one compares the effort that design of went into shaping curved canals with hand files. instruments, the Rotary NiTi produced a quantum leap in quality while metals they are Barry Musikant reducing the effort needed to attain that quality. One could made of, and the say that the advocates of rotary NiTi actually popularized a forms of delivery standard for superior endodontics that, heretofore, was only that are used to attainable by a few highly skilled endodontists taking an make them excessively long time to produce. function. Rotary NiTi works because NiTi instruments have much greater flexibility than stainless steel files. It also works because the configuration of the NiTi files is really not that of files at all, but the configuration of reamers. The flutes on a NiTi file have the more vertical orientation one sees on k- reamers. This makes sense because the more horizontal flutes on a k-file are very inefficient when used with a rotary motion. Horizontal flutes tend to groove the dentin rather than remove it while also inefficiently planing the walls. It is still a mystery that all the rotary NiTi files have the configuration of reamers while the hand instruments used to establish the critical glidepath have the configuration of files. If the former is such a plus, which it is, why not use hand reamers initially? A secondary problem arises because of the efficient design of the NiTi files (which are really reamers). Attached to a rotary engine, these files have the ability to aggressively engage the length of the canal system. However, apical engagement potentially leads to torsional stress, a factor that NiTi is highly vulnerable to. Those who develop rotary NiTi techniques are well aware of this weakness and have established crown-down techniques that minimize the development of torsional stress. NiTi is also vulnerable to cyclic fatigue, defined as repetitive cycles of compression and tension to the shank of the NiTi instrument as it rotates around a curve. Excessive cyclic fatigue leads to separated instruments even if torsional stress is completely eliminated,

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which it never is. Minimizing cyclic fatigue for any given NiTi instrument is only possible by their frequent replacement with new instruments. Over the past two decades, the factors that lead to increased separation of NiTi include a direct relationship to the degree of curvature encountered, the abruptness of the curve, the thickness and taper of the NiTi instrument, and the speed of rotation. Eliminating the sources of rotary NiTi separation has become the paramount goal of the advocates and manufacturers of these systems. This goal is so dominant that it now supersedes the biologic needs of the teeth being instrumented. Where 20 years ago it was recommended to shape canals to a minimum of 35 and a taper of .08 or higher, as Dr. Schilder originally recommended to meet the biologic needs for cleansing the canal, today a mesio-buccal canal will most likely be shaped to a 20 or 25 with either an .04 or .06 taper, not because the shaping is adequate, but because shaping to a smaller apical diameter with a lesser tapered instrument produces a lower incidence of separated instruments. Tables exist that clearly show the average width of canals 1 mm, 2 mm, and 5 mm from the apex in the canals of all teeth. The mesio-distal width of a mesio-buccal canal of a first molar is over .40 mm. at the 1 mm level making a 20 or 25 preparation inadequate. Preparations to this level may look good on x-ray when they are obturated with a radiopaque material, but the walls surrounding that fill have not been properly cleansed according to the data established for the original dimensions of the canal before instrumentation. In short, fills of this sort are reminiscent of silver point fills two generations back. In their day, they looked good on x-ray, but they often did not do the job. Rotary NiTi is not only flexible to a far greater degree than stainless steel, but also has shape memory. It seeks to regain its straight-line configuration even after taking an appreciable curve. It is highly resistant to plastic deformation and when finally deformed NiTi instruments are far more prone to separation when exposed to torsional stress and cyclic fatigue. While flexibility is an excellent quality in an endodontic instrument, shape memory is not. Shape memory in instruments of increasing thickness and diameter forces these instruments to work more and more selectively on the outer walls of teeth, increasing the chances of canal distortion in the apical third and elliptical shaping at the apex. The distorting effects of shape memory along the walls of the canal along with the fear of separation due to torsional stress and cyclic fatigue have defined the more limited use of rotary NiTi in curved canals as the effects of their properties have become better understood. As we see, rotating NiTi exaggerates the weaknesses of this metal. If a 45-degree horizontal reciprocating motion were substituted for rotation, torsional stress and cyclic fatigue would be virtually eliminated. However, shape memory would still be a problem.

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On the other hand, the use of the reciprocating engine offers us the chance to reexamine the increased use of stainless steel. Unlike NiTi, stainless steel does not have significant shape memory. In other words, it can be pre-bent to more readily adapt to the canal being shaped. If a pre-bent stainless steel instrument were to be placed into a rotary handpiece, the increased stiffness of the stainless steel would tend to distort the apical preparation. However, when placed into a 45-degree reciprocating handpiece, the pre-bent instruments scribe an arc of 1/8 of a full rotation, not enough to produce apical distortion because the motion does not extend beyond the canal curvature that the instrument will shape and widen. Therefore, the stiffness, a negative quality of the stainless steel instruments, is compensated for by the use of the reciprocating handpiece and their having been pre- bent. Reciprocation is far closer to the balanced force technique of canal instrumentation that has been recommended as a way of keeping the instruments centered within the canal. In fact, it is safer than the balanced force technique because the back stroke with the reciprocating handpiece mills the dentin away rather than cleaving it, mechanics that induce far less stress in the instruments. The reciprocating engine substitutes a far larger number of reciprocating cycles with low amplitude rather than having very few cycles with very high amplitude that occur with balanced force. The end result is the same, only accomplished much more safely with the reciprocating handpiece. We hope we have established the fact that stainless steel when used with the reciprocating handpiece has far more versatility than rotary NiTi. The only challenge left is to design a reamer that has the most advantageous architecture to be efficient and safe. We already know that a reamer engages the dentin far less than a file and the vertically oriented flute design of a reamer is more efficient than the horizontally oriented flutes on a file when the motion is either rotation or reciprocation which is nothing more than a series of short rotations. The reamer can be designed to have even less engagement by placing a flat along the entire length of the shank, which reduces the engagement by an additional third. The incorporation of a flat creates two columns of chisels with one cutting in the clockwise direction and the other in the counterclockwise direction, making the instrument ideally designed for the reciprocating handpiece. The overall lack of resistance creates superb tactile perception either when used manually or in the reciprocating handpiece. And please be aware that these instruments, called the SafeSiders®, are designed to be used either manually or in the reciprocating handpiece. The reduced engagement along the entire length of the instrument’s shank affords the ability to have a cutting tip that will pierce tissue rather than impacting it apically. Apical resistance will let the dentist know if a sharp bend is being contacted, and the ability to pre-bend them, negotiate to the

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apex with the pre-bent instrument, and then attach to the reciprocating handpiece to produce effective apical shaping simply, safely, and efficiently, gives the dentist a tool that had not existed up until this time. Because they are relieved, they are also more flexible than non-relieved reamers. They are also more flexible because the reamer design means that they have fewer flutes, which means they are less work-hardened and even less prone than stainless steel files to distort and fracture. This discussion has attempted to bring some deeper understanding to the interconnection between the design of instruments, the metals they are made of, and the forms of delivery that are used to make them function. It is our opinion that the SafeSiders approach used with the EndoExpress® reciprocating handpiece is the most effectively designed system, bringing both efficiency and safety to the highest levels yet attainable. September-October 2005 FEEDBACK? Cavit washes out easily. Protect the We welcome your Cavit with a covering of Ti-Core® responses and Auto E. No mixing, it dispenses questions. directly into the access opening Please feel free to visit through its micro tip. Light cure for 20 the Endo Forum and seconds and no more worries about add your comments iatrogenic infections because the about any of the articles Cavit washed out. in Endo-Mail.

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Barry L. Musikant, D.M.D., F.A.S.D.A. Beyond Rotary NiTi: Eliminating Stress and Anxiety

THOUGHT that it would be good to let our readers know We believe that the number of courses that are available to learn the anyone who endodontic techniques we advocate and why these courses are unlike any other endodontic course they are likely familiarizes to take. himself or The most comprehensive courses we give are two-day herself with the affairs that cover in detail all the information necessary to successfully gain access to the pulp chamber, thoroughly use of the clean and obturate the canal system, seal it off coronally, and SafeSiders in build up a core where necessary. The attendees have a very the Endo- Barry Musikant good chance of absorbing all this information because the Express didactic is combined with more than ten hours of hands-on experience. One of the most positive reinforcing tools we use reciprocating is clinical repetition over two days. The opportunity to handpiece will “sleep” on what was learned from the first day and then quickly see that practice the second day is an effective method of inculcating rotary NiTi new knowledge both academically and clinically. The dentists have the opportunity to use the surgical microscope, instruments are apex locators, and sonic irrigatation techniques as well. not only not Unlike most courses that emphasize rotary NiTi, in which necessary, but, the learning curve can be defined as learning when not to use them, we teach alternative techniques that produce at a in fact, minimum equivalent results while virtually eliminating irrelevant. instrument separation. The SafeSiders® instrumentation technique used with the Endo-Express™ reciprocating handpiece eliminates torsional stress and cyclic fatigue, the two most important factors in rotary NiTi instrument separation. For those unable to take a two-day course, we offer a full- day course that includes at least five hours of hands-on. This course includes most of what is offered in the two-day course except that the attendees do not get as much practice. While the two-day and one-day courses are tuition-based, we also give a number of free 2-3 hour workshops held in our dental office in Manhattan. We are happy to give these free courses because they inevitably lead to use of the SafeSiders and generate a high degree of good will for our endodontic practice. Teaching these courses is a unique experience for Dr. Deutsch and me because we invented and continue to refine the SafeSiders system first for ourselves. When you have been an endodontist for as long as Allan and I, you know

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exactly what you are trying to accomplish when you develop a new system. The SafeSiders are designed not only to eliminate all the problems of traditional techniques, but also to eliminate the problems of rotary NiTi that surfaced as they were solving the problems of traditional techniques. Rotary NiTi at its best minimized the problems of overfills, weak apical fills, hand fatigue, canal distortion, fractured roots, and blocked canals. The SafeSiders in the reciprocating handpiece eliminate these problems at least as effectively as rotary NiTi. In addition, they eliminate the problems of separation and excessive expense that are a byproduct of rotary NiTi. In effect, the SafeSiders represent a third generation of endodontic instrumentation that brings relief from the shortcomings of the first two generations. The SafeSiders approach to endodontics can easily induce a state of cognitive dissonance in those who use rotary NiTi. The rotary NiTi user realizes that those instruments can break if not used correctly, if used too often, if a glide path is not first established, if sharply curved cases are negotiated, or if curved canals are opened beyond a fairly small apical preparation and taper beyond an 04 or 06. Rotary NiTi users have accepted all these limitations because the results when successful are far better than was routinely achieved with traditional techniques. The tradeoff of NiTi’s limitations for NiTi’s results was acceptable and logical until the SafeSiders were introduced. The introduction of the SafeSiders provides an alternative method of canal preparation. Included within the system is the establishment of a glide path accomplished far more easily with the relieved SafeSider reamers than the unrelieved files recommended as the glide path creators with rotary NiTi techniques. The SafeSiders technique incorporates the safe use of the No. 2 Peeso reamer to straighten the coronal curve, which makes all subsequent instruments less challenging, particularly in those cases with significant apical curves. This alternative technique also incorporates the use of the No. 2 Gates Glidden reamers to prepare the canals to a diameter of .65 mm to within 3 mm of the apex. NiTi instruments are not used with the SafeSiders technique until 95 percent of the canal has been shaped and the coronal curve has been straightened. The two NiTi instruments used have been hand-tested to assure their not fracturing during use and then are only employed in the 30 degree reciprocating handpiece which virtually eliminates the torsional stress and cyclic fatigue associated with separations in rotary NiTi techniques. Because the SafeSiders instruments cost about one-third that of rotary NiTi and can be used at least six times, the cost per instrument use is approximately 90 percent less than that of rotary NiTi. In fact, the danger resulting from over-using a SafeSiders instrument in the reciprocating handpiece is one of dullness, not separation. So, while the SafeSiders instruments should be discarded after using them on approximately 6?8 teeth, the downside of dullness represents a far smaller concern than that of the potential of separation.

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In short, we believe that anyone who familiarizes himself or herself with the use of the SafeSiders in the Endo-Express reciprocating handpiece will quickly see that rotary NiTi instruments are not only not necessary, but, in fact, irrelevant. This statement is so bold that the only way to prove it is for dentists to try the instruments and make their own assessments. It is for these reasons that both tuition-based and free courses are offered. To doubt these claims is more than understandable, especially when your endodontic techniques have been improved so much with the incorporation of rotary NiTi. Yet the third generation of endodontic instrumentation represented by the SafeSiders is designed to overcome all the disadvantages of the first two generations and we welcome anyone to critically appraise their use after trying them.

November-December 2005 FEEDBACK? It is important to change your gloves We welcome your intermittently during an endodontic responses and procedure, particularly in a non-vital questions. purulent case. If you do so, the Please feel free to visit possibility of cross-contamination the Endo Forum and from your glove’s finger tip to a add your comments sterilized instrument or gutta-percha about any of the articles cone will certainly be greatly reduced in Endo-Mail. if not eliminated.

Doug Kase

[ﺩﻡﺡﻡ file:///D|/HEALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/blm34beyond.html[2/21/2011 10:25:37 Alternatives to Management of a Horizontal Root Fracture

Claudia Hoffman, D.D.S. Alternatives to Management of a Horizontal Root Fracture

20-YEAR-OLD FEMALE presented with the chief complaint that “I fell off my bike two months ago and my tooth hurt for a while and has been loose ever since.” This was the patient’s first visit to the dentist since the accident. She had no significant medical history, no known allergies to medications, and was taking no medications daily. The patient had a history of regular dental visits every Claudia Hoffman year. The types of past dental therapy included root-canal therapy, restorations, extractions, fixed prostodontics, sealants, and implants. The patient had a history of trauma to the right anterior region four years earlier, and #7 had been lost and replaced with an implant. The extra-oral exam was within normal limits. The intra-oral exam was also within normal limits; there were no lesions, edema, or abnormalities noted. All probing depths were 3 mm or less, and oral hygiene was excellent.

The dental exam revealed that #10 had no response to cold or hot stimuli and was tender to percussion. Also, #10 was tender to palpation on the buccal gingiva at the mid-root level. There was class 2 mobility on #10. Multiple periapical radiographs of #10 were taken for evaluation. The horizontal root fracture in the middle third of #10 was evident (see Figure 1). Radiographically, the horizontal fracture appeared like a football-shaped radiolucency. There was no periapical pathology at the apex of #10. The space between the fractured segments appeared minimal. A widened PDL was apparent surrounding the fracture site, but the PDL remained intact. There was no significant bone loss in the anterior region.

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Figure 1

FIGURE 1: Showing the horizontal root fracture in the middle third of #10.

The angulation of the cone in radiographic detection of a horizontal root fracture is critical. In order to successfully diagnosis a horizontal root fracture the cone must be between 20 degrees and +10 degrees. Therefore, if you suspect a horizontal root fracture, it is a good idea to take multiple radiographs (see Figure 2).

Figure 2

FIGURE 2: Radiographs taken at various angles to a fracture (top row) produce images that reveal the fracture to varying degrees—or not at all.

Treatment

To facilitate pulpal and periodontal ligament healing, the coronal and apical segments were repositioned in as close proximity as possible, and a rigid splint of composite was placed on the buccal surface of #9 through #11. This was verified radiographically. The rigid splint should be placed for two to four months. If a long period has elapsed between the injury and treatment, it is unlikely

that the two segments can be returned to their original position, therefore compromising the long-term prognosis of the tooth. The tooth was isolated without anesthesia, and access was made. Upon entry into #10 no heme was noted. The patient was comfortable until the #10 file was placed beyond 15 mm. A radiograph was taken, and it showed that the file was at the fracture site. It was apparent at this point that the coronal segment was necrotic and the apical segment had maintained its vitality. Extirpation of the coronal pulp short of the fracture line was performed, using only sterile saline to maintain the vitality of the pulp tissue in the apical segment. Calcium Hydroxide was placed in the coronal segment to induce a hard tissue closure between the fractured segments. The patient was advised to avoid masticating in that area and to try to maintain a soft diet. When the patient returned on a six-week recall, she was asymptomatic. The splint was replaced and the calcium hydroxide was changed. A periapical radiograph showed no sign of periapical radiolucency. The patient returned for a twelve-week recall and was asymptomatic. Again, the rigid splint and calcium hydroxide were changed. The patient returned for a four-month recall. Tooth #10 was healing uneventfully, and no pathology was apparent at its apex. After splint removal, it was noted that #10 was now class 1 mobility. Upon entry into #10, the canal appeared clean and dry. The coronal segment was rinsed and re-instrumented to the fracture line. A hard tissue barrier was evident at the fracture site. The coronal segment was obturated with calcium-hydroxide-based cement (see Figure 3). The tooth was closed with composite, and the patient was placed on a six-month recall. At the six-month recall, the patient was comfortable and no pathology had developed.

Figure 3

FIGURE 3: Showing the obturation of the coronal segment.

Complications—such as pulp necrosis and root-canal obliteration—may arise, and every case is different. Clinical considerations to be evaluated for each case are age, degree of dislocation, mobility, level of fracture, type of fixation, and patient motivation. The success rate for treatment varies but has been reported to be approximately 74 percent. This case illustrates one alternative to treating and managing a horizontal root fracture. There are other options for treatment (see Figure 4).

Figure 4

FIGURE 4: Illustrating alternative treatments.

References

Andreasen JO, Andreasen FM, Bayer T. Prognosis of root-fractured permanent incisors-prediction of healing modalities. Endod Dent Traumatol 1989; 5:11-22. Andreasen JO, Hjorting-Hansen E: Intra-alveolar root fractures:radiographic and histologic study of 50 cases. J of Oral Surgery 25:414, 1967.

September-October 2003

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Claudia Hoffman, D.D.S. Solving the Mystery of Cracked Teeth

CRACKED TOOTH is often a mysterious case that As with any can be frustrating for the practioner and patient. A other case, a cracked tooth can present with a bizarre and inconclusive set of signs and symptoms. The diagnosis in thorough these cases may be the most difficult phase of treatment. history is Often the cracks are not identified until a restoration has been important. removed or a periodontal defect is identified. The following are the typical signs and symptoms that will Claudia Hoffman aid you in diagnosing a cracked tooth:

Patients feel inconsistent pain on mastication, particularly when releasing on biting. Patients tend to have trouble articulating their chief complaint and often have endured a long history of discomfort. The teeth may have had some treatment in the past that did not relieve the symptoms. Teeth may have pain on temperature extremes, mostly cold. Often there is no pain on percussion. If the pulp is involved, there may be signs and symptoms of irreversible pulpitis or periradicular pathosis.

A patient may present with one or all of the above signs and symptoms. As with any other case, a thorough history is important. The patient can provide the practioner with valuable information, such as a history of trauma in the area, a history of clenching or bruxism, or an oral habit, such as chewing on hard objects. During oral examination, the teeth should be dried carefully to help visualize any cracks. Multiple radiographs should be taken from different angles including a bite wing; this thorough imaging helps increase the chances of identifying the crack. Periodontal probing will identify a crack that has affected the periodontium and created a periodontal defect. Endodontically treated teeth may present with symptoms in the periodontium only because there is no vital tissue remaining. Transillumination, from a fiberoptic light, for example, can be a valuable diagnostic tool in identifying a cracked tooth. The light beam should be placed perpendicular to the tooth. Sound tooth structure will transmit light throughout the

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crown. In addition, staining dye can be placed into tooth structure to locate a potential cracked tooth. The treatment of cracked teeth will depend on the severity, location, and extent of the crack or fracture. A craze line, which is very common and often confused with a fracture, will transmit fiberoptic light and is considered normal with no treatment necessary beyond aesthetic concerns. Fractured cusps or cracked teeth should have full coverage to stabilize and protect the tooth. If the pulp is involved, temporizing the tooth as soon as the fracture is identified may be necessary to protect the tooth before endodontic treatment. If the tooth is split, the split usually is mesiodistal, crossing both marginal ridges and separating the tooth into two segments. In all cases of cracked teeth, the patient should be informed that the prognosis is guarded, and there are no guarantees.

Reference: American Association of Endodontics Colleagues For Excellence. Fall/Winter 1997.

February-March 2004

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Claudia Hoffman, D.D.S. Diagnosing a Radiolucent Lesion in the Posterior Mandible

S ALL DENTISTS KNOW, accurate diagnosis is Figure 1 crucial and can be challenging. A 46-year-old African American female presented to me with the chief complaint, “I went for my regular check-up, and my dentist told me I need a root canal.” The patient had an unremarkable medical history, and she had seen her dentist annually for the past 20 years. Upon clinical presentation, no nodes, masses, or swelling Claudia Hoffman were apparent. The patient had good oral hygiene with a dental history of endodontics, restorative, fixed, and FIGURE 1: Radiograph of #19, showing a large well- extractions. delineated periapical The patient was referred for evaluation of tooth #19. radiolucency at the apex of Radiographically, #19 had a large 2 cm well-delineated the distal root. periapical radiolucency at the apex of the distal root. The tooth had been restored many years earlier with a MOD Figure 2 amalgam. (See Figure 1.) The clinical exam revealed an asymptomatic molar that tested vital with a normal response to cold stimuli. Number 19 was negative to percussion and palpation. There was a mild buccal expansion at the apex of #19. The tooth exhibited no mobility and pockets less than 3 mm. The fact that the tooth tested vital was unusual, but there was the possibility that only the distal root had been necrotic and that the mesial roots may have remained vital. FIGURE 2: Showing the tooth at the time of the The patient was referred to an oral and maxillofacial four-month recall. surgeon for consultation regarding the lesion on #19. The oral surgeon evaluated #19 and reported that the lesion of the distal root was likely a granuloma with a small amount of buccal expansion with over-lying mucosa intact. The oral surgeon recommended root canal therapy and re-evaluation in three to six months; if the lesion increased or did not respond to treatment, #19 would receive an incisional biopsy, exploration, or both. The differential diagnosis for this radiolucent lesion in the posterior mandible is:

Periapical granuloma: involves a nonvital tooth Periapical cyst: nonvital tooth Periapical cemento-osseous dysplasia (early

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stages): mostly in African American females; usually apical to mandibular anteriors; teeth are vital Odontogenic keratocyst: unilocular radiolucency Ameloblastoma: especially in the posterior mandible; often associated with an impacted tooth (multilocular radiolucency) Traumatic bone cyst: mandibular lesion that scallops up between roots of teeth; usually in younger patients

The root canal therapy was performed as indicated, and upon access into the canals vital tissue was evident in the distal and mesial canals. The tooth was completed, and the patient remained asymptomatic. The patient was then referred back to the oral and maxillofacial surgeon for re- evaluation, and the pre-operative treatment was to biopsy the lesion and possibly to perform an apicoectomy on the distal root. The results of the biopsy would determine future proceedings. After the biopsy, the surgical report came back showing a diagnosis of viable bone and connective tissue consistent with a traumatic (simple) bone cyst in the area around #19. This is a benign, empty, or fluid-containing cavity within bone devoid of an epithelial lining, a pseudocyst. The lesion is more common than the literature indicates, and the etiology is uncertain. The typical presentation is a well-delineated radiolucent defect that can range from 1 to 10 cm, with domelike projections that scallop upward between roots. The treatment is surgical exploration and curettage, the prognosis is excellent, and reoccurrence is rare. Figure 2 shows the tooth at the time of the four-month recall, illustrating that the majority of the lesion has filled in.

Summer 2004

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Claudia Hoffman, D.D.S. A One-Year Roundup

T HAS BEEN approximately one year since I joined Barry, Allan, Doug, Amy, and Young in this practice. It is appropriate to say that I have been very lucky to work with such a talented and professional group of doctors, and I feel very fortunate. As with anything else in life, with experience comes knowledge. Therefore, I thought that I would share with all of you some of the things that I have learned and changed since Claudia Hoffman I started.

Reamers are much more effective than K-Files.

I had always used K-Files before I started with this practice. K-Files are tightly twisted square stainless steel wire instruments that encounter four points of contact in the canal. Reamers are loosely twisted trianglular wires that make three points of contact. Therefore, I understood the rational for reamers, but I had to experience the difference clinically to fully appreciate it. I started with reamers and switched back to files because I was comfortable with the quarter-turn and pull motion that I had used in my training. After a few weeks with files again, I was experiencing more hand- fatigue, more working time with each case, and more distortion of the canals. I truly realized how much more difficult it was to use files than reamers. The SafeSiders reamers offer an easier alternative; the reamer has a flat surface, decreasing the resistance to dentin in the canal. I can now say that, having experienced and utilized both techniques, I prefer SafeSiders to K-Files. Rotary NiTi has drawbacks and is not the ultimate answer!

This is very hard for me to admit, because I joined this practice as a fan of rotary NiTi instrumentation. I have done many wonderful cases using rotary NiTi, and it was difficult to try another technique. I have only separated one rotary NiTi file in my whole career, but the fear of instrument fracture is always there when using rotary NiTi. I was always careful not to push with the rotary NiTi instruments and therefore rarely took them all the way to the apex. I was doing most of my work with stainless steel hand files. After I

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started using Dr. Musikant’s technique with the SafeSiders incorporating the Peeso and the Gates, I saw results similar to those from rotary NiTi with less expense and much less anxiety. (You can refer to our website, www.endomail.com, for a full explanation of the SafeSiders technique.) As with anything else the Peeso and Gates Glidden have a learning curve before they feel totally comfortable. I have found that these instruments can do the same shaping as a rotary NiTi in the canals, and if these instruments break, they break at the top of the shank and the broken piece can be removed easily. I have less stress and anxiety and my cases are coming out just as nicely. Septocaine is a great adjunct to traditional anesthesia.

Septocaine is articaine hydrochloride 4 percent with epinephrine 1:100,000. We all encounter hot teeth, and these situations can be challenging for the doctor and the patient. I have always used 2 percent Lidocaine in most cases for mandibular blocks and infiltration. In some situations where obtaining anesthesia is difficult, I now use Septocaine to infiltrate and in a PDL injection around the hot tooth. I avoid Septocaine usage in patients with any significant medical history or allergy to sulfa drugs. I also do not use Septocaine in Mandibular blocks, due to reports of increased chance of paresthesia, although the chances are still very minimal. I find that using Septocaine in an infiltration and PDL injection will obtain anesthesia in a hot tooth. Correct diagnosis is the most important aspect in any case.

The medical and dental history is crucial. I always start in another quadrant than where I believe the problem lies. It is very easy to focus in on one tooth that the patient suggests, but it is important to examine the whole dentition. Although making multiple radiographs can be time-consuming, they are very helpful. I always take a periapical and bitewing radiograph of the tooth in question. If the correct diagnosis is not obvious or reproducible, schedule another appointment for the patient. Time may make the diagnosis easier and more accurate. Prescribing antibiotics and pain-killers temporarily is better than performing a questionable procedure on a tooth. Know when to stop and do not always try to be a hero.

Knowing when to say enough is a hard thing for all of us. We all want to be heroes and help save every tooth. Telling a patient that a tooth cannot be saved is a difficult thing. The patient’s expectations and the treatment plan have to be

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compatible. I have learned that being a hero in every case is not an option.

These are things I have picked up or changed over the past year, and I hope the process continues; in twenty years I should be doing things differently from the way I’m doing them today.

Fall 2004

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Claudia Hoffman, D.D.S. Internal Bleaching Techniques and Cervical Resorption

OOTH DISCOLORATION is a challenge that many Figure 1 dentists face, and internal bleaching is a practical treatment option. Internal bleaching is used to lighten a discolored tooth that has had root canal therapy. It involves placing a chemical oxidizing agent within the coronal portion of a tooth to remove discoloration. The etiology of tooth discoloration can be intrinsic, extrinsic, or both; it can involve dentin, enamel, or pulp; it may be brought on by diet, FIGURE 1: Illustrating Claudia Hoffman age, or habits; it may be local or systemic; and in some cases cervical resorption, number 11, etiology internal it may be iatrogenic. Discoloration can be caused by bleaching. endodontic filling materials or medications that the patient is taking. Discoloration associated with pulpal involvement can be caused by intrapulpal hemorrhage (in which case it is pink or brown), necrotic pulpal tissue, secondary dentin formation (in which case it is yellowish), and internal resorption (in which case it is a pink spot). Most bleaching agents are oxidizers that act on organic structures of the hard tissues and degrade them into smaller molecules that are lighter in color, such as C02, 02 and H20. Indications for internal bleaching are discoloration of pulpal origin, dentin stains, and stains not amenable to extra- coronal bleaching. Contraindications to internal bleaching are superficial enamel stains, defective enamel formation, severe dentin loss, presence of caries, and discolored composites. There are two techniques for internal bleaching: the chairside technique and the “walking bleach” technique. The chairside technique uses Superoxyl in 30 to 35 percent concentration, H202, and heat. This technique is highly effective, but the oxiding agent is strong and can burn. There is a six-to-eight percent chance of cervical resorption, increasing to 18 to 25 percent when the technique is used in conjunction with heat. The “walking bleach” technique uses a mixture of sodium perborate and water and may be utilized if the chairside results are inadequate or if you prefer to avoid the possibility of a higher chance of cervical root resorption. The sodium perborate when fresh is 95 percent perborate giving off 9.9 percent of available oxygen. This material is more easily controlled and safer than Superoxyl; therefore, it is the material of choice. The radiograph in Figure 1 shows a tooth that had root

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canal treatment and internal bleaching ten years earlier. The patient presented to our office with sensitivity in the gingiva in the area around the tooth. The patient presented with a complete history clearly indicating that he had received internal bleaching via the chairside technique. Internal resorption usually occurs at six months after internal bleaching, and after two years the tooth is usually not restorable, so recall accordingly.

Winter 2004

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Allan Deutsch

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Claudia Hoffman, D.D.S. Endodontic Pain or Acute Maxillary Sinusitis?

ATIENTS often present to our office with pain, under A sinus condition the assumption—correctly or incorrectly—that their is a very common discomfort is associated with a sinus infection. As cause of non- endodontists, we are supposed to be experts in diagnosing dental tooth pain; and relieving oral pain. Because of the complex anatomy in therefore, it can the head and neck region, conditions in this part of the body result in often cause referred pain that turns up in and around a tooth. unnecessary One anatomical structure that can be challenging to the dental treatment. Claudia Hoffman dentist is the maxillary sinus. The average dimension of the maxillary sinus is 40 x 26 x 28 mm (15 ml; Bailey 1998). The maxillary sinus is usually in the premolar to molar region and in rare cases may extend to the canine. The innervation is the maxillary division of the trigeminal nerve, the infraorbital nerve, and the anterior palatine nerve. The maxillary sinus is in close proximity to the maxillary teeth. A sinus condition is a very common cause of non-dental tooth pain; therefore, it can result in unnecessary dental treatment. Acute maxillary sinusitis (AMS) is a bacterial infection that needs to be correctly diagnosed. Patients with a sinus infection usually present with a chief complaint that involves dull aching pain that they are not able to pinpoint. The pain is usually lessened when the patient is standing up and worsens when the patient is lying down, so it may present as worse at night. Proper diagnosis starts with a complete medical and dental history. Non-invasive tests— such as radiographs, percussion, palpation, and thermal testing—should be performed. Does the patient have chronic allergies, a cold, or a history of sinus infections? Always ask patients if they have flown on an airplane recently. A true sinus infection usually increases in pain if the patient bends over and places the head below the knees. In addition, extra- oral palpation over the sinus area will usually cause discomfort. If the diagnosis is AMS, the dentist should prescribe analgesics, antihistamines, antibiotics, and nasal sprays. If it is truly a sinus infection, the patient should feel significantly better in twenty-four hours. If the pain recurs, the patient should be referred to an ear, nose, and throat physician.

January - March 2005

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Claudia Hoffman, D.D.S. Retreatment of Failed Surgical Endodontic Therapy

34-YEAR-OLD MALE presented to our office with The patient was the chief complaint “My tooth hurts off and on.” His given possible dental history revealed that endodontic therapy had treatment plans: been performed on tooth #6 two years earlier, due to a retreatment and carious lesion. The tooth was still symptomatic after the first observation, root canal therapy had been completed. Surgical endodontic retreatment and therapy was performed due to the persisting problem. The apicoectomy, or symptoms had never completely subsided. extraction. Claudia Hoffman The intra-oral and extra-oral clinical exams were within normal limits. Tooth #6 was sensitive to percussion and palpation. The tooth had no mobility or periodontal pocketing. Tooth #6 had endodontic therapy, which appeared adequate radiographically, and an amalgam retroseal. In addition, #6 had a screw post and the tooth had been restored with a composite that appeared to be leaking. There was no fracture evident radiographically or clinically. The treatment related to #6 was failing, and possible etiology was a microfracture or endodontic therapy failure due to orthograde root filling contamination, questionable apical seal, or microleakage from the coronal seal. Factors involved with a failure in endodontic surgery can include inadequate root end management, leakage, poor orthograde treatment, incomplete removal of cyst lining, and failure to recognize root fracture. The patient was given possible treatment plans: retreatment and observation, retreatment and apicoectomy, or extraction. The patient was advised that the prognosis for the tooth was guarded unless extraction was the chosen option. After careful consideration, the patient decided to try retreatemnt and observation. The post and gutta percha were removed under rubber dam isolation. The amalgam retro-seal was visualized under the microscope and the root was checked for fractures. The canal was irrigated with sodium hypochloride and chlorohexidine. After careful instrumentation to the retroseal, calci-um hydroxide was downpacked into the canal. The patient returned after ten days and was still symptomatic. The tooth was instrumented and irrigated again and packed with calcium hydroxide. After another ten days, the patient was contacted and stated that all the symptoms had disappeared. The treatment plan at this time is to obturate the canal and temporize the tooth for three to six

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months under observation.

April - June 2005

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Claudia Hoffman, D.D.S. C-Shaped Canals Are Challenging

EETH WITH C-shaped canals can be challenging and deceiving to dentists. C- shaped canals are usually found in mandibular second molars, and they represent 8 percent of second mandibular molars in the general population (Weine, 1998). There is an increased incidence in the Asian population, with 31.5 percent of second mandibular molars having C-shaped canals. The C-shaped root configuration is represented by fusion of mesial and distal roots. There are three categories of C-shaped canals (Melton et al, Claudia Hoffman 1991). Type I is a continuous C-shaped canal. Type II is a semicolon-

shaped canal, with dentin separating one distinct canal from a buccal or

lingual C-shaped canal. Type III is two or more separate canals. There are many clinical considerations when treating teeth with C- shaped canals. There is a higher incidence of lateral canals, fins, and apical deltas. Therefore, debridement and shaping will be more challenging. The use of ultrasonics with irrigation will help with debris removal. C-shaped canals can change configuration or morphology at different levels along the length of the root. The dentin thickness between the external root surface and the internal root canal wall is less than in other teeth, so be careful not to strip the walls during shaping or post placement. C-shaped canals can present challenges to the dentist in debridement, obturation, and restoration. Root canal therapy on these teeth generally has a lower rate of success, and patients should be advised of this before treatment begins.

I II III

FIGURE 1: The three types of C-shaped canal.

July - September 2005

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Claudia Hoffman, D.D.S. The Truth About MB2s

PATIENT presented to our office with the chief Figure 1 complaint, “I had a root canal started on tooth # 14 eight months ago, and it was just completed a month ago. I have been in agony ever since it was started.” The medical history revealed the patient suffers from trigeminal neuralgia on the left side. The clinical evaluation revealed a normal intra-oral and extra-oral examination, and there were no apparent Claudia Hoffman swellings or lesions. Tooth # 14 was very sensitive to FIGURE 1: an MB2 was located percussion and palpation, and the patient had pain on mesially lingually to the mesial

biting. The tooth tested negative to hot and cold buccal canal. sensitivity. Teeth # 13 and # 15 tested vital and asymptomatic. Radiographic evaluation of tooth # 14 showed a completed root canal therapy that appeared acceptable. Each of the apices had a puff of cement extruded past the radiographic apex. A puff of cement can be inevitable if the tooth is necrotic with no intact periodontal ligament upon obturation. All three visible apices had periapical radiolucencies evident, but without a pre-operative radiograph it is impossible to know if the PARs are healing lesions or new lesions. The diagnosis was a failed root canal therapy, and the etiology could be related to a crack, incomplete cleaning and bacteria removal, coronal leakage, or an accessory canal not treated. The patient was anesthetized and # 14 was isolated under a rubber dam. Upon access, the palatal, mesial buccal, and distal buccal canals were located and examined. The canals were obturated with gutta percha and appeared to be sealed coronally. Upon examination under the microscope, there were no cracks or fractures evident and the tooth appeared intact. Upon further examination, an MB2 was located mesially lingually to the mesial buccal canal. (See Figure 1.) Instrumentation was initiated on the MB2, and immediately the patient experienced discomfort. There was no vital tissue remaining in the MB2, but the patient was experiencing discomfort upon cleaning and shaping. The MB2 was a separate orifice and apex from the MB. I decided to clean and shape the MB2 to a 25/08 file and not retreat the other three canals at this time. Since the root canal

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looked adequate, I wanted to start with the MB2 and if the symptoms were relieved I would deduce the etiology of the pain was the accessory canal. Calcium hydroxide was packed into the MB2 for one week. The patient called the office three days later and stated that the pain was tapering off. Maxillary First Molar Anatomy

The maxillary first molar can be a very challenging tooth to treat, and has a very high endodontic failure rate. The maxillary first molar has three individual roots, ligual/palatal, the mesialbuccal, and the distalbuccal. These three root orifices usually form a tripod. The palatal canal is the biggest and easiest to locate. The canal can be flat and ribbon-like; therefore, careful debridement is necessary. The distalbuccal is usually straight, conical, and has only one canal. The mesialbuccal root of the first maxillary molar can be challenging due to the high incidence of MB2s. Weine’s 1969 classic paper showed a 50 percent incidence of MB2 canals. Pineda reported in 1973 that 42 percent of these roots manifested two canals and two apical foramina. Kulid and Peters’s paper in 1990 concluded that 95.2 percent of mesialbuccal roots had a second canal when the root was sectioned. The reported incidence of MB2s varies, but one thing is clear: MB2s are common; assume there are two canals until proven otherwise. Locating MB2 Canals

The orifice for the MB2 usually lies lingual to the mesialbuccal canal toward the palatal canal. The first thing a clinician should do is open the access from a triangle-shaped to a rhomboid-shaped preparation. The MB2 can be located mesial to the mesialbuccal canal. I got wonderful advice from a teacher who told me to sweep mesially from the mesial buccal canal toward the lingual. Fiber-optic illumination can aide in locating another canal. Magnification is a large factor in the success of locating an MB2. An ultrasonic tip can be used to sweep lingually from the mesialbuccal canal, and this may open up the developmental groove. Once a canal has been located, start with small instruments first; it is very easy to block yourself out from these canals. Oftentimes the MB2 orifice is angled, so the instrument will only enter at a mesial/lingual angle in the beginning. Do not try to straighten the orifice too early, because you do not want to ledge or block yourself out. Very often the mesialbuccal canal and MB2 exit through the same foramina.

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Second mesialbuccal canals can be very challenging and frustrating for practioners, and I hope this helps!

September - October 2005

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Claudia Hoffman, D.D.S. Possible Misconceptions Regarding Diagnosis

ISCONCEPTION 1: A patient with irreversible pulpitis has a painful response to hot and cold.

Irreversible pulpitis is often characterized by a painful, lingering response to cold. Irreversible pulpitis can be acute, subacute, or chronic; therefore, it can be partially or totally It is important to infected. The degree of inflammation in the pulp of a tooth continually disinfect with irreversible pulpitis is so diseased that root canal therapy Claudia Hoffman is the treatment of choice. The signs and symptoms can vary, the surface of your based on the extent and inflammation in the pulp; usually the finger ruler. Placing patient feels spontaneous, intermittent, or continuous pain. an instrument from The pain may be brought on by sudden temperature changes an infected canal (usually cold), and elicit prolonged episodes of pain. This on the surface to pain may be relieved by the application of heat or cold. check or change Reversible pulpitis does not involve spontaneous pain; the measurement therefore, it is reactive only when stimulated, and the control can lead to response does not linger after stimulus is removed. cross- Radiographs are not diagnostic in irreversible pulpitis contamination of because the inflammation is confined to the pulp. The new instruments radiographs can help with finding the etiology of the disease, and gutta-percha such as deep caries or restorations. In late stages of cones. irreversible pulpitis there may be a thickened PDL evident on Doug Kase the radiograph. The EPT is not diagnostic in symptomatic cases of irreversible pulpitis because the pulp is inflamed and still responds to electrical stimulus. Irreversible pulpitis is the most likely to have referred pain.

MISCONCEPTION 2: When there is no area of rarefaction on the radiograph the teeth are OK.

Areas of rarefaction are evident on a radiograph only when the destruction has eroded the cortical plate. Therefore, a tooth can be nonvital and have bone destruction around the apices but not be evident from radiographic examination. This becomes evident when you obturate a nonvital tooth and there is a significant cement puff on the final film. This is a tooth that had apical bone destruction with no intact PDL, but the condition did not appear on the radiograph because the bone destruction had not broken through the cortical plate.

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MISCONCEPTION 3: Leaving a tooth open is a good option if the tooth has drained and the patient is in pain.

It is common to open an infected tooth and have purulent drainage. In most cases, after cleaning and shaping the canals the drainage will stop. The tooth should be allowed to drain under the rubber dam for up to 20 minutes. If the drainage stops, closing the tooth after treatment is the best procedure, because teeth left open are often involved in mid-treatment flare-ups (Seltzer, 1997). In rare occasions when the tooth will not stop draining, a patient can be placed on antibiotics and a sponge or cotton pellet should be placed in the access. The tooth should be closed the next day. Teeth that are left open show higher levels of secretory IgA than teeth not left open, and this can lead to an increase in periapical cyst formation (Torres, 1994). The possibility of mid-treatment flare-ups and cyst formation illustrate the desirability of closing all teeth under the rubber dam after treatment whenever possible.

MISCONCEPTION 4: A patient who has a fistulous tract should be placed on antibiotics.

If a patient presents with a fistula, the first step is to trace the fistula and obtain a radiograph. After correct diagnosis is confirmed, and root canal therapy is initiated, when possible the tooth should be cleaned and shaped and packed with calcium hydroxide. The patient should be rescheduled for evaluation and completion of treatment in approximately ten days. It is best not to give the patient antibiotics after the first visit because as practitioners we would like to see the fistula resolve through the removal of the etiology of bacteria. If the fistula resolves with no antibiotic coverage, we know we have successfully removed the etiology of the infection. Antibiotic coverage can cause the fistula to disappear although the bacteria in the canal have not been removed, and can give a false sense of healing.

November-December 2005

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Claudia Hoffman, D.D.S. Temporary Fillings and Coronal Leakage

AFTER the non-surgical root canal therapy is A poor seal on completed, a strong temporary cement must be placed top of an in the pulp space to prevent leakage and contamination. As endodontically dentists, we have a variety of cements and filling materials treated tooth can available and we must choose a cement that provides a allow bacteria satisfactory seal. A poor seal on top of an endodontically and fluid products treated tooth can allow bacteria and fluid products from the from the oral oral cavity to re-contaminate the pulp space. The cement cavity to re- Claudia Hoffman must have strength to withstand masticatory forces and contaminate the preserve a good seal at the same time. pulp space. The most common materials used as temporary fillings are IRM reinforced zinc oxide cement; Cavit, a mix of zinc oxide, calcium sulfate, glycol, polyvinyl acetate, polyvinyl chloride, and triethanolamine; and TERM, a filled composite resin. Of these three options, Cavit and TERM provide a better seal than IRM at any thickness. IRM has been shown to have more extensive marginal leakage of fluid than Cavit does. Although IRM has a bacterial barrier due to the eugenol, that does not prevent other fluids from leaking in. If Cavit is used, it must be placed at a thickness of at least 4 mm. If a stronger filling is needed, you can place glass ionomer on top of the Cavit (Pathways of the Pulp, 8th Ed.). So the question arises, when should we retreat a previously endodontically treated tooth if we suspect contamination? Swanson and Madison (1987) demonstrated that it took only three days for coronal leakage of a tracer dye to reach the apex. Khayat and Torbinejad (1993) demonstrated recontamination of obturated root canal systems by bacteria placed in natural saliva within 30 days. Based on these and other studies, you should retreat leaking non-surgical root canal therapy cases if left open for longer than three weeks.

January-March 2006

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and add your The canal does not have to be 100 percent comments about any dry to use EZ-Fill® epoxy root canal sealer. of the articles in Endo-Mail. The epoxy sealer will set even under water!

[ﺩﻡﺡﻡ file:///D|/HEALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/ch11temporary.html[2/21/2011 10:25:43 Leaders in Continuing Education

Dentistry Today Leaders in Continuing Education

Dentistry Today N THEIR DECEMBER 2003 issue, Dentistry Today has acknowledged both Dr. Allan S. Deutsch and Dr. Barry Lee Musikant as Leaders in Continuing Education. Their dynamic speaking style and their ability to direct dentists to the very heart of stress-free techniques set them apart from highly marketed trends that falsely give the appearance of being a standard. Their thirty-plus years of practice experience have crafted them into the top authorities in endodontics. It is often said that they introduce a logic and common sense that is undeniable. The lecture schedules of Dr. Musikant and Dr. Deutsch have taken them to more than 200 domestic and international Dentistry Today locations. The content of their lectures ranges from practice- building to clinical issues to best practices in endodontic treatment. As partners in the largest endodontic practice in Manhattan, New York, they conduct hands-on workshops with EDS products, as well as other products frequently used in dentistry, to teach the innovative techniques that they have developed. Each has co-authored more than 150 articles in dentistry that have appeared in numerous dental journals in the United States and Canada as well as major international journals. A complete list of the articles can be found on the Essential Dental Systems website. Dr. Deutsch and Dr. Musikant are members of the American Dental Association, the American Association of Endodontists, the Academy of General Dentistry, the Dental Society of New York, the First District Dental Society, the Academy of Oral Medicine, Alpha Omega Dental Fraternity, the American Society of Lasers, and Advanced Technologies in Dentistry. Essential Dental Seminars offers a variety of courses that teach techniques for instrumentation, obturation, and restoration. All Essential Dental Seminars are ADA and AGD approved and recognized. Please contact EDS for upcoming seminar dates and times by phone at 201-487-9090. If you are interested in co-sponsoring an event, please contact Dawn Landini at 201-487-9090 x104.

February-March 2004

Remember: when excavating for

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the secondary MB canal (MB2 canal) in an upper molar, angle the excavation towards the MB1 as you deepen the excavation apically to avoid perforation. The root anatomy of the palatal aspect of the MB root can taper quickly towards the buccal. — Doug Kase

FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

[ﺩﻡﺡﻡ file:///D|/HEALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/dentistrytoday.html[2/21/2011 10:25:43 Numbness and Alteration of Sensitivity after RCT

Dr. Gertsberg Numbness and Alteration of Sensitivity after RCT

S TECHNOLOGY ADVANCES in dentistry, new Always study pre- materials and techniques are becoming available to operative x-rays produce better-quality dentistry. Graduation from with concern NYU Dental School changed my way of thinking about about mental various dental procedures. My main problematic procedure foramen. remained root-canal therapy, a technique that produced numerous complications, such as PAP (periapical pathology), broken instruments, and numbness. I had taken many courses and spent a lot of time and money to learn new techniques in endodontics. Nothing worked well for me. Then a friend of mine, Dr. Natapov, recommended that I attend Dr. Musikant’s course. This two-hour meeting changed my life. I am very appreciative of Dr. Musikant for his simple and generous technique. It enabled me to run my practice stress-free and turned my most-feared procedure into my most-loved. Now, I would like to report about one of the most stressful complications from RCT, which I experienced in very few cases. This was numbness and alteration of sensitivity after completion of RCT. Usually, it is very rare that complications arise from mandibular blocks or mental foramen anesthesia, but in my cases, it resulted from RCT itself. A 43-year-old Caucasian female came to my office for a second opinion with complaints of alteration of sensitivity in the LLQ and her lower lip following RCT on #21. The patient stated that the anesthesia did not go away completely and the next day it had worsened. One x-ray showed a canal of #21 overfilled by approximately 0.5 mm. Mental foramen located approximately 1 mm from the apex, and periapical pathology, possibly a cyst, produced lowered tactile sensitivity in the whole area plus a completely numb area of 5 mm on the lower lip. The patient was referred to an oral surgeon. During her consultation, they discussed redoing RCT on #21. The surgeon explained to the patient that the treatment would offer a chance to remedy her situation, but if it didn’t work, she would need to do something else. In other words, the patient was informed about the possible results of the treatment. Using the technique of Dr. Musikant, old gutta percha was removed and the canal was instrumented, irrigated, and refilled with EZ-Fill® cement and new gutta percha to 0.5 mm prior apex. The patient reported feeling

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better the next day, and in the following three days said that she had gone back to normal. At the six-month checkup, x- rays showed that PAP had disappeared. I had two similar cases with teeth #20 and #28 in which the RCT was performed by me. The situation in those cases was stressful, not only because of complications, but because RCT was performed on the teeth so that they could serve as an abutment for future bridges. In those three cases, I used Dr. Musikant’s techniques, which made it possible for me to resolve easily problems that might otherwise have led to malpractice cases. Always study pre-operative x-rays with concern about mental foramen. It’s better to underfill the canals of lower premolars than to overfill them. It seems that filling the canal to radiographic lengths, as required by most insurance companies, is equal to overfilling.

Dr. Gertsberg originally hails from the USSR and has made his home and professional practice in Brooklyn.

January - March 2005

FEEDBACK? When using an apex We welcome your locator, it is important to responses and check that a circuit exists. questions. That means check all Please feel free to visit contact points. By simply the Endo Forum and touching the lip ground to add your comments the instrument probe about any of the articles (particularly on the Endex) in Endo-Mail. a full sweep of the meter indicates good contact and no breaks in the circuit. Failure to get this result can come from a faulty or broken wire or a buildup of residue from continued contact of drying fluids contained in cold sterilization wipes. Now you want to make sure that a circuit exists between canal and lip ground. Make sure you wet the lip ground. As the mucosa that the ground is in contact with dries due to mouth breathing or airflow from the saliva ejector, the

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conduction in the circuit will change and hence affect your measurement control. What was once at the apex will now be long. A dry canal may also do the same thing. So keep things wet.

Doug Kase

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Doug Kase, D.D.S.

Tales from the Chamber: Don’t Bite Off More Than You Can Chew

Doug Kase he purpose of step-back instrumentation during the SET procedure, using both .02 tapered stainless steel as well as NiTi instruments, is to establish the corresponding resistance form of either a fine-medium or medium gutta- percha point with a minimal amount of dentin engagement. The philosophy underlying this technique is to incorporate more instruments and for each instrument to do less work when widening a canal. in comparison with techniques that use fewer instruments with each file doing more work, this Doug Kase system

reduces chair time reduces operator stress decreases the incidence of fractured instruments

The possibility of fractured instruments increases if, as some manufacturers and clinicians advocate, we put the demand on our Ni-Ti files to do more work than they should be doing. This possibility increases even further when increased demand is coupled with high-energy rotary delivery. The following case is one that can evoke butterflies in all our stomachs. After instrumentation of a central incisor, a .08 file of greater taper was fractured near the apex. The operator felt that the canal was wide enough to skip the .06 GT file and jumped right to the .08 file. The result was the fracture illustrated in Figure 1, below. The operator used the surgical microscope to visualize the file. Using a fine ultrasonic Spartan diamond tip, he made a trough around the coronal aspect of the file. Then, using a white hollow trephine bur from a Masserann Kit by Micro Mega, he created a tunnel to the top of the GT file. Since the trephine bur cuts counterclockwise, as does the GT file, he reversed the rotation to clockwise and exerted apical pressure to grip the remaining piece of GT file (Figure 2) and rotate it clockwise, coronally out of the canal (Figure 3). An alternative method for removal is to aspirate a small amount of cyano-acrolate cement (Crazy Glue) into the lumen of a 20 to 23 gauge needle. Insert the needle to the

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exposed instrument and engage the coronal aspect of the file. After the instantaneous set, try to rotate the instrument out of the canal.

Figure 1 Figure 3 Figure 2

FIGURE 1: Fractured instrument in the canal. FIGURE 2: Gripping the remaining piece of GT file FIGURE 3: Rotating the file clockwise with a hollow trephine bur. out of the canal.

FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Doug Kase, D.D.S.

Tales from the Chamber: My Apex Runneth Over

Doug Kase n event you may have encountered at one time or Figure 1 another in your endodontic past or may yet encounter in your endodontic future is an overfill during obturation of the canal either with gutta-percha or sealer. Employing techniques that utilize lateral and or apical pressure with or without thermoplastics increase the possibility of an overfill. FIGURE 1 Over-extended gutta-percha or extruded sealer of various types such as ZOE-based sealers can act as chronic irritants, Doug Kase preventing the healing of periapical pathology or even causing apical breakdown that did not have pathology to Figure 2 begin with. Thus, it is important to choose the correct system of obturation that is consistent with a low probability of overfill. A single-cone technique utilizing AH-26 or its derivatives, such as EZ-Fill cement, will minimize your exposure to an overfill. Placing a single gutta-percha cone to a pre- FIGURE 2 measured length without apical pressure as in the Simplified Endodontic Technique (S.E.T.), will eliminate gutta-percha overfills and decrease the probability of apical sealer extrusion. Since AH-26 and its derivative EZ-Fill cement Figure 3 are biocompatible, the minimum amount of cement that may be extruded is well tolerated. As illustrated by the series of radiographs at the right, which show a maxillary molar obturated with EZ-Fill and a single-cone technique, the body will resorb sealer extrusion. FIGURE 3 The one-month and six-month recall films further indicate that the healing process is unimpeded. 03/20/2000 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

[ﺩﻡﺡﻡ file:///D|/HEALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/dsk02myapex.html[2/21/2011 10:25:45 Cracked Tooth Syndrome

Doug Kase, D.D.S.

Tales from the Chamber: Cracked Tooth Syndrome

Doug Kase t is a sure bet that at one time or another you have wanted to tell a patient in your practice, “You’re cracked!” The incidence of cracks in teeth seems to be on the rise. Whether it is the stressful environment in which we live that is forcing us into crack-producing habits such as bruxism and clenching or just the fact that we keep our teeth to an older age, the cracked tooth and its symptoms are here to stay. The key to saving these teeth is early diagnosis and treatment. The diagnosis of a cracked tooth can be a frustrating and Doug Kase time-consuming experience for dentist and patient. If it is not done correctly, it can result in too little treatment, which can lead to premature tooth loss or unnecessary treatment.

Symptoms “Cracked Tooth Syndrome” symptoms are variable and may not present themselves consistently due to difference in direction, location, and extent of the crack. Teeth with cracks may have erratic pain on mastication, particularly on the release of pressure rather than with the increased biting force. Additionally, pain, especially to cold, is a telltale sign. However, absence of pain does not rule out the presence of a crack. Usually there is no percussive pain and no radiographic pathology. Some patients will note a prolonged history of pain or discomfort that could not be diagnosed or treated. The presence of the crack does not always involve the pulp, but if the crack extends to the root surface, a periodontal pocket may be associated with it. Cracks usually start out small and then grow with time and function. Thus, an early diagnosis will lead to a better prognosis.

Clinical Tests When a patient presents for a cracked tooth diagnosis, a number of clinical tests should be performed. Prior to these tests, a thorough dental history should be taken. Check for a history of trauma, clenching or bruxism habits, other masticatory habits (such as chewing ice), or a history of occlusal adjustments for relief of the symptom or a history of other cracked teeth. A clinical and visual exam comes next. Have the patient

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point you in the right direction, keeping in mind that the patient's perceptions may not be accurate. Examine the teeth with a sharp explorer, check for craze lines in the enamel that are stained darker, palpate and probe the gingiva for pocketing that may be related to a vertical root fracture. Usually these pockets are narrow with little movement of the probe from side to side. Check for cracked restoration and use transillumination with magnification to help visualize the suspected crack. The surgical microscope is a wonderful adjunct and may be all that is necessary to visualize and diagnose the crack. Using a cotton roll, have the patient chew down on it like chewing gum, isolating each tooth in the suspected area. A rubber wheel or bite stick can also be used. A device called a “Tooth Sleuth” can be used to isolate the individual cusp of the tooth that is cracked. A sharp and increased response to a stimulus as compared to adjacent and contralateral teeth may also indicate the presence of a crack. A long sustained response may indicate pulpal involvement. Cracks generally do not show on radiographs unless they are perpendicular to the X-ray film. However, the long-term effects of cracks may eventually appear. Changes in the pulp chamber, PDL, or even the beginning of periapical radiolucency could be signs of the presence of a crack. Look at endodontically treated teeth for sealer expressed out of a fracture line or the position, length, and thickness of a post in relation to the suspected fracture. Restoration removal may be necessary to help visualize the crack and assess its position in regards to pulpal involvement. Cracks versus craze lines can be solved with transillumination. Remember that most adult teeth have craze lines, which are only in the enamel, are painless and only of aesthetic concern. When illuminated, craze lines will allow the light to pass through them and illuminate the whole crown. If there is actually a crack in the tooth, the light will not pass through the crack and will not illuminate the complete tooth. A common crack affecting the dentin but not requiring endodontics is a cuspal fracture. These fractures are easy to diagnose and the easiest to restore.

The Patient’s Needs The diagnosis of a cracked tooth can be difficult, but there is no doubt that it must be done with expediency. Prividing a solution to your patient’s elusive problem, no matter what the prognosis satisfies the patient’s reasons for having sought your expertise and allows the patient to initiate the appropriate treatment plan.

11/02/1999 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your

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comments about any of the articles in Endo-Mail.

[ﺩﻡﺡﻡ file:///D|/...LTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/dsk03crackedtooth.html[2/21/2011 10:25:45 Putting an Old Spin on a New Technique

Doug Kase, D.D.S.

Tales from the Chamber: Putting an Old Spin on a New Instrumentation Technique

Doug Kase hroughout issues of Endo-Mail, we have discussed in great detail the Simplified Endodontic Technique (S.E.T.). As we know, this system utilizes a combination of instruments that includes both .02 stainless steel files, .04 files, and files of greater taper which are both made of nickel titanium. The other important instrument that is used at various times throughout the Simplified Endodontic Techniques is the Peeso or Gates Glidden reamer. It is used to widen the coronal one-third to one-half of the Doug Kase canal, which greatly reduces the stress on the hand file or reamer being used and on the operator using that file. Using this rotary instrument in a canal should not induce fear or hesitation, for we have been taught to use it proficiently for post preparation since we were dental students.

First Use of the Peeso Reamer The number 2-Peeso reamer is used three times during the procedure. It has always been used with a passive pressure in a wet environment allowing the wieght of the hand piece to exert the force. Generally, this rotary instrument is first used after the full length has been negotiated to a number 20 file or reamer. Why should we ask a thicker .02 tapered instrument or even worse, a NiTi instrument that is easier to fracture to continue to enlarge the full length of the canal? Once the Peeso has been used, the dentist will find that instrumentation of the remaining one-half to two-thirds of the canal will proceed with much less resistance. It is important to remember when using these rotary instruments in the canal that one must keep the internal and external anatomy of the tooth in mind. We never want to widen a canal towards an external groove or concavity such as the mesial concavity of maxillary bicuspids. Check your radiographs for root and canal angulations and root diameters. By using a passive pressure and staying in line with the canal you will never create a ledge and never perforate.

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Second Use of the Peeso Reamer The second time we employ the use of the 2-Peeso reamer is after the canal has been fully instrumented with the .02 series of files or reamers which includes the back step to a number 45 instrument. The Peeso is placed back into the coronal aspect and advanced under passive pressure perhaps only 1/2 to 1 more millimeter. In some canals that possess a greater curvature, you may be able to widen the coronal aspect a bit more which actually reduces the curvature for future instrumentation.

Third Use of the Peeso Reamer The third time the 2-Peeso is used is after instrumentation with the .06 File of Greater taper. Again, you may only advance the Peeso or widen the canal minimally, but after using the final Ni-Ti hand instrument, the .08 GT., the perfect resistance form for the insertion of a medium gutta percha point to measurement control has been created.

Using a rotary instrument such as a Peeso reamer to augment hand instrumentation will lessen stress for both dentist and instrument and ultimately lead to a final endodontic obturation that any dentist could point to with pride.

11/02/1999 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Doug Kase, D.D.S.

Tales from the Chamber: Access the Key to Success

Doug Kase HE STATEMENT THAT “you must be able to walk Figure 1 before you can run,” has, believe it or not, a fair amount of endodontic merit. In other words, a fair amount of preliminary work has to be done when performing an endodontic procedure. Diagnosis and treatment planning are perhaps a bit of a given and could, of course, be discussed at length. However, what we all may take for granted and try our hardest to be conservative about is endodontic access. Doug Kase We anesthetize, place our rubber dam, pick our newest bur and proceed to drill a small, conservative hole in a tooth through which we will instrument and obturate this root canal. What goes around and around in our head is to keep the access small so as to preserve as much tooth structure as we can. However preserving tooth structure unnecessarily may interfere with your ability to perform proper endodontics. Without proper straight-line access to the FIGURE 1: After attaining canals, our ability to instrument, clean, shape, and access to the pulp ultimately obturate them is greatly hindered. chamber, remove overhanging tooth Overhanging Tooth Structure structure. Endo Tip WHEN YOU HAVE attained access to the pulp chamber, it is extremely important to remove any overhanging tooth Figure 2 structure (see Figure 1). Any remaining tooth structure diminishes your ability to visualize the chamber and locate Remember: the canals as well as any calcified or extra canals. If calcified canals are an issue, then straight-line access is always use your imperative for exploration and excavation, particularly Peeso reamer to when you are using magnification. In addition, remaining straighten the tooth structure may force you to pre-curve instruments unnecessarily and gain entry to the canal from impossible coronal aspect of angles. Access to the mesiobuccal roots of upper molars, for the canal away example, is difficult enough without the presence of extra from tooth tooth structure. anatomy, such Once the pulp chamber has been penetrated, you can use a large round slow-speed bur in combination with a barrel as the furcation diamond to widen the opening into the chamber so that in molars or straight-line access can be achieved. external grooves FIGURE 2: Overhanging Straight-Line Access tooth structure forces in bicuspids. endodontic instruments to

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ONCE YOU HAVE straight-line access, your negotiate an unnecessary instrumentation and obturation procedures will be made coronal curve, increasing easier. If you do not have straight-line access, you will stress during reaming or subject your endodontic instruments to more stress during filing. reaming or filing because they will be negotiating an unnecessary coronal curve, which becomes even more accentuated as a result of the overhanging tooth structure (see Figure 2). Additionally, if there are any further curves or bends within the canal anatomy, the stress on the instrument is further multiplied. If we are dealing with a nickel-titanium instrument, this could get dangerous very quickly and lead to fracture. When the E. Z. Fill technique is used, having straight-line access further facilitates our ability to use our Peeso reamer to continue to straighten the coronal curvatures, thus making instrumentation less stressful to both the instrument and the dentist. It is nice to preserve tooth structure and be conservative when possible in performing root canal treatment. However, improper access can lead to a plethora of problems for the dentist and ultimately for the patient. Proper endodontic access is the key to a successful outcome and a happy patient.

November-December 2000 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

[ﺩﻡﺡﻡ file:///D|/HEALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/dsk05access.html[2/21/2011 10:25:46 Post Removal Revisited

Doug Kase, D.D.S.

Tales from the Chamber: Post Removal Revisited

Doug Kase ET’S FACE IT: the discovery of a fractured post is Ruddle Remover Kit depressing! It is not only depressing and disappointing to the dentist whose hard work may not have gone the distance for some unforeseen reason, but also to the patient, who is likely to be upset over what feels like a wasted investment of time in the dental chair and dollars out of pocket. The patient may lose confidence in the dentist, especially if the failure occurs just a short time after the FIGURE 1: Components of endodontic procedure. Additionally if this post fracture the Ruddle Post Remover Doug Kase results in the loss of the tooth, the issues could become much Kit. more complicated. All of a sudden the options of fixed bridges, removable dentures, implants, or—even worse—a legal issue may loom overhead.

Explaining the Situation

A REASONABLE explanation to the patient is a good start toward rectifying the situation. The reasons for post fracture can be multifaceted. Recurrent decay, habits of occlusion, or unknown trauma are just a few causes of post fracture. Whatever the cause, informing the patient that all is not lost, especially the tooth, may take a potentially very negative situation and turn it into a positive one with you as the hero of the story. So how do we become the hero or heroine? We remove the fractured post and save the day. Slow-speed bur Removing a Fractured Post Trephine bur

THE REMOVAL of a fractured post can be done in a variety of manners. We can drill them out with very fine high-speed burs under magnification. The endodontic microscope is an invaluable aid during this procedure, especially as we drill deeper into the root. Using a fine diamond ultrasonic tip improves your ability to visualize the apical end of the post and facilitates its removal by vibration. If enough of the post is accessible, an ultrasonic tip can be used to vibrate the post out of the tooth without the use of a drill. We can also use an instrument called the Ruddle Post Remover (Figure 1), which can provide an expeditious end to a tough endeavor. FIGURE 3: The trephine FIGURE 2: The slow- bur is used to shape the speed bur is used to If there is enough of the post showing coronally, the

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head cylindrically. expose the top of the post. Ruddle Post Remover can extract it from the root with very

little effort. The Ruddle Post Remover can be used even if the remaining head of the post is below the existing tooth Ruddle post remover structure, but use of this device becomes harder and perhaps inappropriate the more submerged the head is. Additionally, this instrument can be used only with passive posts, since the post will be pulled out of the root and threads that engage dentin will interfere with its function. FIGURE 5: Ruddle post Using the Ruddle Post Remover remover with tap and cushion in place and ready THE FIRST STEP is to use the included slow-speed bur to to use. tunnel down and expose the top of the post (Figure 2). Once access to the post head is established, an appropriate FIGURE 4: The tap with trephine bur (Figure 3) is used to shape the head into a protective cushion is threaded over the corresponding cylindrical shape. prepared post head. Then a corresponding tap with a protective rubber cushion (Figure 4) is reverse-threaded in a counterclockwise direction over the prepared post head. It is this tap that the post remover (Figure 5) engages, and as it is tightened the remover extracts the post coronally. An additional benefit to the reverse threads of the tap is on a threaded post. By its use in a counterclockwise direction it can facilitate the actual “unscrewing” of a threaded post since it cannot be extracted directly. The end result is a happy patient due to a saved case because we were able to save an abutment and perhaps save our “butts” as well.

January-February 2001

FEEDBACK? Endo Tip Have you ever opened the pulp chamber of a tooth and detected a We welcome fetid odor? I have. Using a syringe to irrigate the pulp canal with your responses mouthwash works to eliminate that odor. Many times I’ll leave the and questions. rinse inside the chamber for a few minutes. Afterwards, I’ll rinse Please feel free to with sodium hypochloride. Then the odor will dissipate. Patients visit the Endo who smelled the initial odor feel terrific for there is no longer an Forum and add odor. Furthermore, they feel that you (as a practitioner) have your comments “really” done something for them. about any of the articles in Endo- — Amy Dukoff Mail.

[ﺩﻡﺡﻡ file:///D|/...ALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/dsk06postremoval.html[2/21/2011 10:25:46 The “Kase” of the Bifurcated Bicuspid

Doug Kase, D.D.S.

Tales from the Chamber: The “Kase” of the Bifurcated Bicuspid

Doug Kase HERE ARE TIMES when I look at an x-ray and discover root anatomy complicated enough to make me exclaim, “Oy Vey!” The case that I’m going to discuss in this column concerns one of those teeth that not only looks complicated, but is also a challenge to our endodontic technique. The tooth shown in Figure 1 is a perfect example of a lower bicuspid that bifurcates in the apical one-third or one- quarter of the root. The fact that coronally there is a common Doug Kase canal within one main root rather than two separate canals within a common root makes every step—negotiation, instrumentation, and finally obturation—a very tough endeavor.

Accessing the Bifurcated Canal Figure 1: A lower bicuspid that bifurcates in the apical WHEN YOU GAIN ACCESS to the pulp chamber, it is one-third or one-quarter of important to open wide enough to attain straight-line access the root. to the canal. If the common section of the canal is wide enough to begin with, then finding the split toward the apex will be easier. Placing two instruments into the tooth at the same time initially may be impossible. If the common section is very thin initially, then—with copious irrigation and RC Prep—the common section can be instrumented to a number 20 file or reamer and then widened with Gates Figure 2: Follow-up Glidden or Peeso reamers or a combination of the two. After radiograph taken to verify the widening is complete, access to the split canals will be which canal the instrument easier. is in A sufficiently wide coronal section will allow you to place a small 45-degree bend in the initial instrument tip and then rotate this tip into each end of the bifurcated canal. After you have established a working length with an apex locator, you should take a follow-up radiograph to verify which canal you are actually in (see Figure 2). It is important to remember how your initial instrument was inserted into the common canal (for example along which wall) so that you can guide it back into each of the splits properly. Instrumentation can be achieved by alternating between the Figure 3: Each canal and canals with the same instrument. In other words, do not the common section of the instrument one side of the split totally for you will surely canal widened sufficiently to allow a smooth

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block the other side with debris. Figure 4: Radiograph of transition into each split. the completed fill (suitable When you are alternating between canals, please keep in for framing). mind the internal and external root anatomy. Your object is to widen each canal and also to widen the common section of the canal to allow a smooth transition into each split (see Figure 3). Widening the common section with a number 2 Peeso reamer will enable you to accomplish this transition, using the EZ Fill technique with the stainless steel series of instruments, and ultimately the nickel-titanium instruments will also pass easily into each split. You are now ready to obturate. Obturation

TRYING TO OBTURATE this anatomical freak of nature may actually undo all the good work you accomplished in the instrumentation phase. By filling one canal perfectly, you may actually block access to the other side of the split. In the situation illustrated here, I was only able to widen the coronal section enough to accommodate one medium gutta-percha point at a time. However, due to the taper of the point and the widening of the mid-root canal area, once the first point was placed to the apex in one canal with EZ-Fill epoxy-resin cement I could remove the coronal section of gutta-percha with a Peeso reamer. Then by using a very thin stainless steel finger spreader as a path-finding instrument, I was able to re-establish access to the other side of the split with ease. Additionally, the thin finger spreader pushed the mid-root mass of gutta-percha against the appropriate wall of the common section of the canal, further facilitating the placement of a second medium gutta-percha point. When you have achieved the final fill of a case as complicated as this one, the radiograph (see Figure 4) would be one to frame as an 8 x 10 glossy and hang on your office wall.

March-April 2001

FEEDBACK? Endo Tip Always use SafeSiders in a wrist-watch-winding tip We welcome your responses movement. This applies to both reamers and files. and questions. Never use them with an up-and-down filing motion. The Please feel free to visit the up-and-down motion will cause ledging and blockage of Endo Forum and add your the canal with dentin debris. comments about any of the articles in Endo-Mail.

[ﺩﻡﺡﻡ file:///D|/HEALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/dsk07bifurcated.html[2/21/2011 10:25:47 The “Kase” of the Blunderbuss

Doug Kase, D.D.S.

Tales from the Chamber: The “Kase” of the Blunderbuss

Doug Kase S JERRY SEINFELD would say, did you ever wonder what’s the deal with the word blunderbuss? Oh, I know that a blunderbuss was a short musket with a wide bore, but how often do you run across one of those nowadays? Now if I were on the corner of 57th Street and 7th Avenue, waiting for the downtown bus, but accidentally boarded the crosstown bus, I might consider that a blunderbuss. However, in the world of endodontics, a canal so wide apically that you may not even have the Doug Kase instrumentation to obturate it would be called a blunderbuss. That kind of canal certainly can evoke feelings of helplessness. You might even turn to immediate unnecessary apical surgery in order to correct any overfill of gutta-percha and sealer that comes spilling out of an uncontrolled apical Endo Tip foramen. Figure 1: The blunderbuss. This is the case of a 28-year-old male patient with a history of trauma to tooth number 8 when he was a child. As Figure 1 clearly shows, there was incomplete root formation Did You Know? including the absence of apical closure. There was also evidence of a periapical radiolucency. The patient came in The surgical with symptoms of abscess, including pain and periapical masks that we swelling. I placed him on antibiotics and analgesics to wear lose their control the acute symptoms and we scheduled another effectiveness in appointment for treatment. Initially, it looked as if it would 30 minutes under be a cut-and-dried case of obturation and immediate apicoectomy. normal use. When he returned in two weeks, the acute symptoms had According to New abated, and I initiated treatment. I opened the access as wide as possible without compromising the crown, achieved York State’s measurement control with an apex locater, confirmed it by mandated radiograph (Figure 2), and accomplished instrumentation guidelines for Figure 2: Verifying with instruments as wide as a #140 reamer. I utilized large- measurement control. infection control, diameter hedstrom files along the canal walls to check for autoclaves should tissue and debris. be tested weekly Now, how in blazes was I going obturate? I was able to with a spore test dry the canal and then pack MTA cement to the apical and a permanent measurement, using the reverse side of a coarse paper point record should be until there was some apical resistance, thus creating a stop. maintained. Using cotton wrapped around a large diameter file, I cleaned the excess cement from the canal walls. I then placed EZ-

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Packaged Fill cement, using the bi-directional spiral, and thus the canal autoclaved was flooded with sealer. instruments I reversed a large gutta-percha cone, dipped it into solvent should be for three seconds, and placed it to measurement control. resterilized every Using a spreader with no apical pressure, I laterally six months and condensed the mass of gutta-percha, then coated a second unwrapped large cone with sealer and placed it into the canal in the normal direction. instruments every Figure 3: The final result. six days. Since research has shown that AH-26 based EZ-Fill sealer alone would be good enough to seal the canal, the gutta- Even one percha core only helps to force the sealer against the MTA complaint from a stop and the canal walls, leading to the final result seen in patient about your Figure 3. Immediate surgery was not necessary, and the patient office can cause walked out very happy. The dentist also felt satisfied with an O.S.H.A. the result, but only time will decide the ultimate success in investigation the case of this blunderbuss. (informal or formal). May-June 2001 You must supply four pieces of personal protective equipment (gloves, eye protection, mask, and garment) to all employees in contact with blood and saliva.

Sodium hypochlorite is a good hard-surface disinfectant? A 1 : 10 ratio of bleach to water will disinfect in three minutes; however, it can eventually cause damage to the item you are disinfecting.

Doug Kase

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FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

[ﺩﻡﺡﻡ file:///D|/...ALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/dsk08blunderbuss.html[2/21/2011 10:25:47 The Zen of Root Canal

Doug Kase, D.D.S.

Tales from the Chamber: The Zen of Root Canal

Doug Kase AITHFUL READERS, I know you are expecting The patient’s another bizarre and twisted tale of endodontic expectations experience that keeps your eyes glued to the page and your stomach on an emotional roller coaster. This time, however, are I am going to wax a bit philosophical! To do endodontics critical to a and enjoy what you do, you must accomplish it with the least positive amount of stress. In order to have less stress, the first thing you must master is to visualize your final product. Once you endodontic can do this, you can create a plan that will lead you to that experience. Doug Kase goal. My philosophy is simply “be one with the tooth.” Now, I am no Obi Won Kanobi; however, being one with the tooth is the most important starting point of stress-free endodontics. We are, of course, making the assumption that the tooth in question has been properly diagnosed and the need for endodontics is apparent. Now it is time to observe and think! Make sure your radiograph is current, and take a new one if necessary. Take any additional radiographs to check for additional roots or canals by varying the angle. Try to use the paralleling technique so that there is a realistic one-to- one relationship between the tooth and the film, thus eliminating foreshortening or elongation. Look at the distance between the occlusal table and the roof of the pulp chamber to avoid drilling too deep and to avoid an unnecessary perforation. Check for mesial and distal angulations of the tooth so that your access will be in line with the coronal and root anatomy. It is also important to check for radiographic calcifications and visibility of the canals in addition to root curvature. A calcified curved canal will change your expectations and thus your final product. Knowing this and accepting it may alter your treatment plan, thus extending a one-visit endodontic procedure to two or more. It may also mean that you require the use of the endodontic microscope to locate the canals, so perhaps this isn’t one of those 45-minute one-visit molar root canals that we have all been speaking of. Make sure you check the clinical root anatomy and compare it with the radiograph. Sometimes it may be beneficial to gain access without the rubber dam so that your perception of actual anatomy is not distorted. You will find that your patient will actually be

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pleased to be informed that you have changed your expectations before the longer procedure begins, and you will find that by informing the patient you reduce your stress astronomically. Sharing your expectations with your patient makes you a better practitioner in your patient’s eyes and your own! You now give the local anesthesia. This is one situation in which it can’t hurt to over-do. Make sure that your patient is numb. To patients who arrive after a rough night of pain and discomfort, give marcaine so that they are anesthetized for a longer post-operative period of time and can go home or to work and enjoy the feeling. You can even give them an additional injection just as they leave your office to extend the anesthetic relief that much longer! Don’t be afraid to use the periodontal ligament injection. If used conservatively, this can be a great adjunct to anesthetize a hot tooth, but tell the patient that using this injection may cause a bit more post-operative discomfort during chewing. The patient’s expectations are critical to a positive endodontic experience.

It’s time for access. Go back to your radiograph and look at the external anatomy of the tooth to verify your plan of action. Once inside the pulp chamber, find the canals and always suspect the bizarre. Look for that extra mesio-buccal canal in maxillary second molars and check for a lingual canal in mandibular first bicuspids. Again remember . . . be one with the tooth. O. K., you found the canals and it’s time to whip out your faithful apex locator. Make sure your reading is repeatable. Watch out for contact with metallic restorations either physically or by conduction with blood or irrigating solution. Use an instrument that fits the canal intimately so that there is adequate contact in the apical regions. A good fit will give you a very accurate reading. Make sure you check your measurement control before you obturate, for the working length will change in curved canals as they are instrumented and straightened coronally. Now you are in the meat-and-potatoes of endodontics, and the E-Z Fill Technique will show you the way. If you follow the technique, you will achieve the end result you visualized. Do not try to shortcut the technique, for the slower you work, the quicker you will achieve your expected result. That sounds like a paradox, but it’s so. If the canals are calcified, start out with a .06 or .08 instrument. To avoid blocking the apex, be careful to use the instrumentation with the correct motion when filing the canal. If you have to reiterate the canal with the same instrument, it’s O.K. to make sure the apex is clear. Do not worry about taking an extra five or ten minutes to achieve the result you want! Close your access with a temporary restoration that will not leak and will not wash out. Nothing can be more frustrating for patient and dentist than to have to retreat a perfectly done root canal because the temporary restoration washed out and leaked. I use ZOP or glass ionomer cement to close my access

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cavities. Your post-operative instructions and a patient’s post- operative expectations can be as important as the procedure itself. Use medications as needed and when needed! Do not be afraid to tell your patients that they will have discomfort. A patient “in the know” is a happy patient. Information is the key to a post-operative night that is smooth and telephone-call free.

July-August 2001

FEEDBACK? Endo Tip We welcome your responses and questions. Please feel free to visit

the Endo Forum and For a free subscription to the Endo-Mail add your comments newsletter, just fill in this form and click the about any of the SUBMIT button. articles in Endo-Mail. Enter my NEW subscription to the Endo-Mail Newsletter. Change my address.

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[ﺩﻡﺡﻡ file:///D|/HEALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/dsk09zen.html[2/21/2011 10:25:48 Never Give Up! Never Surrender!

Doug Kase, D.D.S.

Tales from the Chamber: Never Give Up! Never Surrender!

Doug Kase OMETIMES a patient may present to your office with a Figure 1 problem (related to dentistry, of course) that after a careful clinical and radiographic exam makes you kind of say to yourself . . . why bother? Sometimes taking a shot at treatment might be well worth the result, ultimately saving the patient from a surgical procedure or an extraction and the eventual replacement of that lost tooth. This story starts out more than twenty years ago, when a FIGURE 1: Large patient had endodontic therapy performed on tooth #3. The retrograde filling, shortened Doug Kase tooth was obturated using silver points and ultimately root, and (arrow) fistula restored. Years later, it was found to have developed a traceable to the periapical radiolucency over the distobuccal root, and the distobuccal root. patient was subsequently referred to an oral surgeon for an Figure 2 apicoectomy. The procedure was completed, and our patient was expected to live happily ever after, which he did for a number of years. The Plot Thickens!

THE PATIENT described above became my patient when he developed a fistula traceable to the distobuccal root where the FIGURE 2: Extrusion of apicoectomy was performed. There was quite a large sealer around retrograde filling (arrow), completely retrograde filling, the root had been shortened quite a bit, and sealing the canal and —adding insult to injury—the palatal root also had a closing the fistula. periapical area (Figure 1). There now were treatment alternatives to discuss, such as extraction, another Figure 3 apicoectomy, root amputation or resection, or retreatment. The patient wanted to save the tooth and did not want a bridge or to have to go through an implant procedure. Because the root was so short, any other surgical procedure would have to be very conservative to preserve as much root as possible. Performing an apicoectomy on the palatal root could have been much more complicated and could have FIGURE 3: The core involved the maxillary sinus as well. The alternatives of root rebuilt and the crown amputation and root resection also would not have addressed recemented permanently the problem of the failing palatal root. with Ketac cement. An interesting question is why did the original apico fail? The reasons could be that it did not seal the apex, eventually leaked, or there were lateral canals that eventually reinfected the case from the original silver point obturation. Whatever

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Figure 4

the cause, I decided to retreat the case and try to create a better internal seal on the distobuccal root and the other roots as well. It is always better to remove a crown if possible when attempting to remove silver points. With the crown off, you FIGURE 4: Three-month have much greater access to grab the point rather than recall radiograph. attempting it through a smaller access opening in the crown. The crown was removed with no damage and, using very fine hemostats, the points were lifted out of the canal with little effort. There was evidence of breakdown within the tooth. (You know . . . schmutz!) Measurement control was achieved with an apex locator, and the canals were re-instrumented using the EZ-Fill® technique until clean filings were seen on the instruments. Care was taken on the distobuccal canal not to dislodge the retrograde seal. The canals were obturated with EZ-Fill Cement and single point gutta-percha cones. It is important to note in Figure 2 the extrusion of sealer around the retrograde filling, which completely sealed the canal and ultimately resulted in closure of the fistula. The core was rebuilt, and the crown was recemented permanently with Ketac cement (Figure 3). The patient returned recently for a follow-up radiograph (Figure 4). He remains symptom-free. Sometimes the easy way may not be the best way for our patients. Remember: never give up, never surrender!

September-October 2001

FEEDBACK? Endo Tip We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments Give 600 mg. Motrin along with two about any of the articles in Endo-Mail. Tyenol every eight hours. The Tylenol potentiates the effects of the Motrin. Result: better pain control! Young Bui

[ﺩﻡﺡﻡ file:///D|/...ALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/dsk10nevergiveup.html[2/21/2011 10:25:49 It’s a Dangerous World!

Doug Kase, D.D.S.

Tales from the Chamber: It’s a Dangerous World!

Doug Kase ELL, FAITHFUL READERS, we all have managed Your to get back in gear and resume our everyday lives in psychological and light of September 11th. Learning to live with what physical health happened and what could happen is something we must all are intimately master, and must master rather skillfully. So, if you think the entwined. world has turned into a hazardous place to live, you’re right, Maintaining one but for now let’s concentrate on some of the occupational will help maintain hazards that we encounter every day in our dental practices. the other. Numerous communicable diseases can rear their ugly Doug Kase heads within a dental office environment. Among the most common that are spread by inoculation are the blood-borne pathogens hepatitis viruses B, C, Delta, and G, human immunodeficiency virus (HIV), and herpes. Additionally, a number of respiratory viruses, from the common cold to tuberculosis, can be spread by inhalation. How do we protect ourselves? The answer is simple, for we do so by implementing “universal precautions” and viewing every patient as a potential source of infection. Make sure your patient’s medical history is complete, and don’t be lazy. Put on your mask, gloves, and protective eyewear. Inoculation most commonly occurs through a needlestick or sharps-related injury. Thus it is important to establish routines within your office to minimize exposure to this hazard for you and your staff. Use disposable items when possible and try not to recap a contaminated needle without the correct single-handed technique or a safety device. All sharps should be disposed into a proper container and any instruments should be carried to the sterilization area in a closed container. All clinical waste should also be disposed of properly. Ionizing radiation can also be a dental office hazard. Make sure all x-ray units are well maintained and inspected. Using newer faster film or digital radiography will reduce exposure time. Using the lead apron for your patient and maintaining a proper distance from the x-ray head for the dentist should be common sense. Also, a radiation- monitoring device can provide additional insurance for you and your staff.

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When my father, who was also a dentist, lost his high- pitch hearing, we all blamed it on his handpiece. The evidence that sound hazards in the dental office can create hearing loss is inconclusive. Our high-speed handpiece operates in ranges from 3900 to 12500 Hz and more. Duration and degree of exposure can be the critical factors in hearing loss. A good piece of advice that I could give my readers is “Watch your back!” And while you are doing that, watch your wrist and other parts of your body, too. Musculo- skeletal problems can be induced while practicing dentistry either correctly or incorrectly. Sit correctly and practice good posture. Make sure you have a comfortable operator’s chair that is set to the correct height to avoid pressure on your sciatic nerve. Take breaks, stretch properly, and maintain your physical fitness. To help prevent carpal-tunnel syndrome, try to avoid repetitive movements and overly flexed positions of your wrist. Take rest periods, and don’t grip your instruments too tightly. When it comes to stress there is only one thing I can say —“It stinks.” Let’s face it, our beloved profession can be psychologically stressful. Office problems, staff problems, and patient problems can snowball into an unmanageable mess. Try to practice behaviors that reduce this stress. Manage your time properly and try not to overbook your day. Taking a routine lunch break may help to buffer a busy schedule. Frequent staff meetings and scripted scenarios for dealing with problem patients will certainly also help. Obviously, your psychological and physical health are intimately entwined, so maintaining one will help maintain the other.

November-December 2001

FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

[ﺩﻡﺡﻡ file:///D|/HEALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/dsk11dangerous.html[2/21/2011 10:25:50 Never Assume!

Doug Kase, D.D.S.

Tales from the Chamber: Never Assume!

Doug Kase ell, readers, it’s time for some bizarre stuff. A patient Figure 1 presented to our office with pain to cold stimulus and chewing pressure associated with a mandibular right first molar. A vitality test using the electronic pulp tester and also one using Endo-ice gave a severely hypersensitive and sustained response indicative of acute pulpitis. Nothing strange here, but let’s move on. Using a cusp isolator, such as a Tooth Sleuth, I was able to elicit symptoms when pressure was placed on the lingual Doug Kase cusps. FIGURE 1: Debris in the Transillumination under magnification confirmed a fracture isthmus between the mesiobuccal and line on the mesial and distal aspects of the tooth over the mesiolingual canal. marginal ridges. I was now dealing with cracked tooth

syndrome, and I informed the patient that the prognosis was guarded and that endodontic therapy and full coverage would Figure 2 be needed. Nothing too strange here, either, but wait! Using the EZ-Fill™ SafeSider® technique, I performed endodontic therapy on four canals. After I had gained access, I established under magnification that the fracture did not involve the pulpal floor and stopped short of the cervical area. I measured the canals, instrumented, and dried for obturation, and that was when things started to take a turn FIGURE 2: Note the five toward the unusual. instruments. In the isthmus between the mesiobuccal and mesiolingual

canal (Figure 1) some debris remained; I proceeded to remove it with an explorer only to find some trapped tissue. Figure 3 To my surprise, after one swipe with the explorer this area began to bleed. Excavation with a small round bur was then extremely productive because, lo and behold, I discovered an extra mesial canal (Figure 2). I established measurement control and instrumented the extra canal. I completed obturation, and the prognosis is good (Figure 3). Searching for the presence of extra canals—such as a FIGURE 3: Completed second mesiobuccal canal in a maxillary molar, a second obturation. canal or even double-rooted mandibular canine, or even a fifth canal in a mandibular first molar—should become second nature to the treating dentist. By taking an angled radiograph and using magnification beyond our standard 2 times operating loops, we should make the discovery of these extra canals much easier. Using either 4 times wide field-

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magnifying loops or the endodontic operating microscope further enhances our ability to locate these elusive passages to the apex. Those procedures, coupled with the use of fine- tipped ultrasonic instruments to excavate these areas, makes access possible. Thus, in the end, it is our job to become more suspicious of these teeth and look for the unusual. My motto is “If you see three, look for four. If you see four, look for five. If you see five, it’s probably a third molar!”

January-February 2002

FEEDBACK? Endo Tip We welcome your responses and questions. Please feel free to visit It is important to determine whether two the Endo Forum and add your comments canals join apically to avoid frustration when about any of the articles placing your gutta-percha point. Place two in Endo-Mail. number 30 files in each canal simultaneously after complete instrumentation. If one instrument stops short of the apex, remove the other and retest. If it now reaches the apex then the canals join.

Doug Kase

[ﺩﻡﺡﻡ file:///D|/...LTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/dsk12neverassume.html[2/21/2011 10:25:50 Angulation Is Good for Your Health

Doug Kase, D.D.S.

Tales from the Chamber: Angulation Is Good for Your Health

Doug Kase ery often while doing endodontics, what you see is not Figure 1 what you actually may get. Frequently, root anatomy and canal position will be so closely superimposed that clinical or radiographic identification may be very difficult. If it is difficult to see the problem on your final film, you may shrug your shoulders and walk away with a false sense of satisfaction. This difficulty commonly leads to non- negotiated, unclean, and unfilled canals, resulting in ultimate FIGURE 1: starting failure down the road. Of course this occurs (using Murphy’s radiograph of tooth #19, Doug Kase Law of Dentistry) just after you have permanently cemented showing a mid-root drop- a multi-unit restoration. So it becomes very important to out. identify these anatomical situations before you obturate the obvious canals. First, we must identify the common culprits that give us Figure 2 this pain in our nether region. The mesiobuccal root of the maxillary first molar may be a good candidate. We all know of the existence of either a second canal or even a second root occurring at a varying position on a line between the mesiobuccal canal and the palatal canal. Another candidate is one of the lower bicuspids. Usually, the first bicuspid is the more frequent problem. It is important to look for a lingual FIGURE 2: angled film canal that branches from the main and larger buccal canal showing a distolingual about 1/4 to 1/2 way down its length. This canal can canal. represent the existence of a completely separate root. This condition can also occur in the second bicuspid as well, but is much less frequent. Watch for two canals, usually within one Figure 3 root, when it comes to lower central incisors. An even rarer, but not unheard-of occurrence is the presence of two canals or even two roots in the lower canines. A common mistake is assuming that, in lower first and second molars, a large distal canal, the kind you can drive a Mack truck down, means that there is only one canal! Very often there is another. So how do we fix the problem, or—more importantly— FIGURE 3: confirming the how do we avoid the problem? Taking angled radiographs final result. and observing the position of canal orifices relative to external crown and root anatomy is the way to avoid the pitfalls. A dead-on parallel starting film may be more important than an angled film for diagnostics such as caries proximity to the pulp, depth of existing restorations, marginal integrity, bone height, existence of periapical pathosis and

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approximate root length. It certainly gives a more realistic and one to one relationship of tooth to radiograph. It also may show a large canal that drops out on the radiograph mid- root. This may be an indication that the canal splits into two at this level. However, a second mesially angulated film is equally as important, especially if diverse root and canal anatomy is suspected. If a tooth is rotated, make sure whatever angle you take your radiograph from, the radiograph separates the canals on the film. A mesial angulated x ray on a tooth with a rotation toward the distal will cause superimposition of the canals. Also, it is important to see how an orifice is positioned on the pulpal floor in relation to the others and to the external aspect of the tooth. If a distal canal on a lower molar seems to be oriented too far to one side of the tooth and for the most part not centered then suspect another canal. Trying to ascertain the existence of these canals is obviously more advantageous before obturation, so don’t be shy about taking an extra radiograph before starting and even a working film (not to establish measurement) if you suspect extra canal and root anatomy. Also if you discover this fact on your final film, try to correct it on the same visit if possible. The set sealer may block your ability to access the canal. Figure 1, the starting radiograph of tooth # 19, shows a mid-root drop-out. The canals were instrumented and it appeared that there was only one large distal canal. The tooth was obturated and an angled final film (Figure 2) was taken to make sure that the canals were filled properly. Oops! The angled film showed me that a distolingual canal existed. The gutta-percha was removed quite easily from the distobuccal canal, and, using a #2 slow-speed round bur and a fine Spartan ultrasonic file, the lingual aspect of the existing distal canal was slowly excavated. With a pre-curved number 10 file, I was able to find the mid-root split. The canals were instrumented and obturated and the final result was confirmed (Figure 3).

May-June 2002

FEEDBACK? Endo Tip We welcome your responses and questions. Please feel free to visit When hunting for calcified canals try to the Endo Forum and add your comments rubber-dam clamp the tooth behind it and about any of the articles drag the dam material to the tooth in front, in Endo-Mail. exposing three teeth in the field. Doing this exposes external tooth anatomy, which can be obliterated by the clamp. This exposed

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view may help to orient your excavation for this calcified canal.

Doug Kase

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Doug Kase, D.D.S.

Tales from the Chamber: A Good Foundation Ensures a Solid House

Doug Kase ELIEVE IT OR NOT, this is not a builder’s guide to Many doing endodontics. As a philosophy to help ensure practitioners have dental success and patient satisfaction the idea of had to deal with building a good foundation may help steer us down a path to the discomfort better diagnosis and treatment. The good-foundation that a patient philosophy applies to all phases of dentistry, but the focus of feels from a this Tale is endodontics, both pre-operatively and post- pulpitis after operatively. permanent crown Many practitioners have had to deal with the discomfort cementation. Doug Kase that a patient feels from a pulpitis after permanent crown cementation. The situation is extremely frustrating for the dentist, and it is likely to lead to patient dissatisfaction (and we all know the possible consequences of that). We all tell our patients to wait it out and give it time. “Don’t worry,” we say. “It will go away.” We make numerous occlusal adjustments, grinding away the beautiful porcelain anatomy. Although the tooth is symptomatically better, it is still uncomfortable. The patient looks to us for answers, and sometimes the ultimate answer may be endodontic treatment. We all understand that developing a pulpitis is a risk of any invasive restorative procedure. However, sometimes the “riskee” is not as understanding. The dentist feels bad, and the patient may feel worse. The patient experiences continuing discomfort, a perceived esthetic compromise after the access opening has been filled, and an investment of more time and money. If the crown becomes undermined structurally, then the tooth may require a post and core and new crown, imposing a burden of time and money on the dentist. How can we avoid this pulpitis problem? The unfortunate truth is that we cannot! However, we can try to minimize the conditions that lead to it and the trouble that results from it. What Can Be Done?

FROM A DENTAL-LEGAL point of view, communication is the key word. Because an informed patient is ultimately a happy patient, it is important to inform the patient of the possible risks. Signed consent is great, but some consider it overkill. Tell your patients before you start that there is a

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possibility of a pulpitis after a restorative change to a tooth. Explain that the risk increases as the procedure becomes more invasive (as for an onlay or crown), and that existing deep fillings or fractures or current deep decay can also increase the risk. Let them know that pulpitis may become irreversible and ultimately result in the need for a root-canal procedure. Your patients should be active participants in the decision-making process with you as their guide to proper dental care. So enough with philosophy and on to the clinical nitty- gritty. Although not foolproof, there are some techniques we can turn to so that we may be able to better forecast the pulpal future of a tooth that is in need of dentistry that will be, from the patient’s point of view, time-consuming and costly. First and foremost, it is essential to pulp-test the tooth before beginning your restorative procedure. Even if no radiographic pathology or even clinical pathology is present before a filling or crown change, the tooth may possibly already be non-vital or barely vital. Finding this out before placing a crown would certainly avoid your finding a periapical radiolucency three months after placing it. A minimal positive pulp test as compared to adjacent and contralateral teeth may predict future non-vitality and the need for preventive endodontic therapy. If the pulp test shows that a tooth is extremely hypersensitive compared with adjacent and contralateral teeth, it may have a present pulpitis. Hypersensitivity often forecasts treatment difficulties, such as an increased tendency to pericementitis, difficulty in attaining adequate anesthesia during treatment, and prolonged temperature sensitivity that may come and go. These hyperemic symptoms, which may be present in the temporary crown stage, can disappear; however, after permanent cementation they have a tendency to return and end in the need for a root-canal procedure. Fracture lines are also predictors of the need for preventive endodontics. Again, the presence of a fracture is not a guarantee of ultimate pulpal demise; however, if you are unable to prep away a fracture line in a restorative procedure, that should set off an alarm. Normal pulp tests and lack of symptoms may make you feel that fracture lines alone do not indicate a need for preventive endodontics at present; however, you should still inform the patient of the future risk. If there is microscopic communication to the deeper open dentinal tubules, the permanent cementation procedure may ultimately be irritating to the pulp. If the fracture lines are dark and on transillumination do not transmit the light to other parts of the tooth, then this is a more severe fracture that can influence pulpal longevity. A history of deep fracture close to the pulp should also raise an eyebrow. Calcifying receding canals can be another predictor of the need for preventive endodontics. As the pulpal tissue calcifies, it does so non-uniformly, and the calcifications can choke off the circulation to other parts of the pulp, resulting

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in eventual pulpal death and eventual abscess. This sometimes can be preceded by a severe symptomatic pulpitis. From a practical point of view, it will always be easier to locate calcifying canals before a crown is placed rather than afterwards through a conservative access opening.

It also is important to look for signs of resorptive changes on the radiograph. If asymptomatic internal resorption is suspected, then endodontics is indicated prior to full coverage to insure a better long-term prognosis. Restorative history may also predict the necessity of preventive endodontics. A tooth with a long and large history of deep restorations is more prone to pulpal pathology. Obviously, a small and short clinical crown preparation, which may be more prone to fracture or loss of crown retention, would need endodontics for post placement and core buildup. The Dividend

UNFORTUNATELY, none of us possesses the great dental crystal ball. (If I had it, I would have tuned it to stocks and sold two years ago.) Don’t be afraid or shy about doing the endo if it’s needed or you strongly suspect that it will be needed in the future. With the techniques available, particularly the EZ-Fill® SafeSider™ instrumentation technique, your clinical decision will have a safe and predictable outcome. No dentist can absolutely predict whether a tooth will end up in “endoville” soon after the new crown is cemented or when the patient is given his six-month recall exam. However, the time and effort you invest in determining whether there is a strong likelihood that endodontics will be needed will certainly pay the dividend of alleviating some post-operative pains in your gluteus area.

September-October 2002

FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Doug Kase, D.D.S.

Tales from the Chamber: Have I Got a Hot Tip for You!

Doug Kase WANT TO pass along to you a number of tips that I think you will find especially useful. Test-Bending

“Breaks in your hand, not in the tooth!” It is very important to remember to test-bend nickel-titanium instruments in your hand by bending them 90 degrees before using them. Test- bending will reduce the likelihood that the instrument will Doug Kase separate in the canal.

Rubber Dam

The rubber dam may sometimes obscure tooth anatomy and root angulation, making access difficult, particularly when you are hunting for thin or calcified canals. Thus it is sometimes necessary to place the rubber dam by clamping the tooth behind the one you are working on and then dragging the dam forward over the tooth in front. Doing so allows you to view the tooth in a more open field without losing the protection of the rubber dam. Working Length Changes

Recheck your working length with the apex locator as you instrument and straighten a curved canal. The length will change by .5 to 1.5 mm. Formocreosol

Here’s a new use for an old medicament. Like chicken soup, a little “formo” couldn’t hurt. It couldn’t hurt to place a squeezed dried cotton pellet of “formo” in the chamber and over a post prep after a one-visit root canal. The formocreosol may help to ensure and maintain sterility until the restorative is started. Carbocaine

Carbocaine has a quicker onset than lidocaine, so use carbocaine before lidocaine as a local anesthetic; then follow

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it up with a lidocaine 1:100,000 epinephrine injection to vasoconstrict and augment the carbocaine’s effect. Apex Locator Readings

Using a loose-fitting file to obtain measurement control with an apex locator can lead to an inaccurate reading. A slightly tighter-fitting instrument that contacts the walls of the canal will allow the apex locator to electronically read the canal better. Also a loose instrument may move too easily as you try to obtain a reading while attempting to manipulate the stop, thus giving you a false length. Removing a Post

When you are trying to remove a prefabricated post, use an ultrasonic instrument and vibrate the post in all planes (buccal-lingual and mesio-distal). Remove Core Material

Remember to remove as much core material as possible around a prefabricated post and try to trephine around its base with a fine diamond at the prep orifice before you start to use ultrasonics. Fractured Post

Use a one-half or one-quarter round surgical-length high- speed bur with magnification to drill out a post that is fractured or not removable by ultrasonics. Take an extra check radiograph when necessary to check your progress. Reduce the Core-Tooth Interface

When you are removing a cast post and core, remove as much core as you can to reduce retention caused by the core- and-tooth interface before you attempt ultrasonic removal. If there is a larger area of contact between tooth and core, less of the force of the ultrasonic vibration will reach the post- and-post-prep interface. Tapping a Post Out

Sometimes a small notch can be cut into the core material and the post can be tapped out with a back action crown remover. Do this prudently because the force of the tapping can cause a root fracture. Revealing Old Gutta Percha

If retreatment is the goal, then using a microscope and a fine Spartan ultrasonic diamond tip may be necessary after post removal to cut through any remaining cement at the base of

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the post prep in order to find the old gutta percha. Retreating Canals Without Posts

If only the canal or canals without the post are failing, then you can drill through the crown and core material conservatively and retreat these canals without disturbing the post and crown. (See Figures 1 and 2.)

Figure 1 (before) Figure 1 (after)

FIGURE 1 (before) FIGURE 1 (after) Figure 2 (before) Figure 2 (after)

FIGURE 2 (before) FIGURE 2 (after)

Apicoectomy or Retreatment?

When a patient presents to your office with failing endodontics under a post and core, your first instinct may be to refer the patient for an apicoectomy. This instinct is particularly well founded when the restorative is relatively new. However, we must remember that an apicoectomy on top of a root canal that failed because it was inadequate may result in a failure of the apico as well. The failure of the apico usually occurs because lateral canals coronal to the retrograde filling were not obturated properly. Even in the case of calcified apices or a calcified apical third of the root, it is important to have a solid obturation coronal to that point. Thus retreatment becomes a rational option. Also, if the surgery is risky anatomically, such as apex proximity to the mandibular canal or maxillary sinus in the case of maxillary palatal roots, retreatment may be a better option. We must also take into account the possibility of the patient’s lack of compliance and cooperation regarding the surgery and must consider whether the patient is a poor medical risk for the procedure. If the restorative is in question and is slated for a redo, then without question disassembly is the treatment of choice. The radiographs in Figures 3 through 9 illustrate what can

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be accomplished.

Figure 3 (before) Figure 3 (after)

FIGURE 3 (before) FIGURE 3 (after) Figure 4 (before) Figure 4 (after)

FIGURE 4 (before) FIGURE 4 (after) Figure 5 (before) Figure 5 (after)

FIGURE 5 (before)

FIGURE 5 (after) Figure 6 (before) Figure 6 (after)

FIGURE 6 (before) FIGURE 6 (after) Figure 7 (before) Figure 7 (after)

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FIGURE 7 (before) FIGURE 7 (after) Figure 8 (before) Figure 8 (after)

FIGURE 8 (before) FIGURE 8 (after) Figure 9 (before) Figure 9 (after)

FIGURE 9 (before) FIGURE 9 (after) November-December 2002

FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Doug Kase, D.D.S.

Tales from the Chamber: Looking at the X-ray Is Not Enough

Doug Kase MONG ALL THE endodontic cases that we all do, there is always the one that turns into that horror movie called “Attack of the Killer Root Canal”! It’s POP the one we begin with a good deal of confidence and an internal voice that says, “I can do that—no problem,” but QUIZ we finish wishing that we could call our dental school instructor to bail us out, have him pat us on the shoulder Identify the foreign and tell us it’s OK. With that horror movie in mind, it is object shown in the x- important when beginning treatment of an endodontic case ray below. Is it . . . Doug Kase to make sure that you have looked at the radiograph not only for the diagnosis but also to assess the clinical picture Pop Quiz X-ray of the tooth in question as it appears in the mouth. Restorations, tilts, rotations, and gingival root angulation all become factors when you are gaining access and searching for canals. The radiograph is important, but it is only 50 percent of the road map we use to plan our trip to the pulp chamber and beyond. Looking at root angulation and emergence profiles at the gingival margin is particularly important in cases with calcified pulp chambers and when you are searching for calcified canals. Periodontally probing the tooth while gaining access will give you a visual indicator of the external anatomy and allow you to judge how far you should excavate the area while searching for canals. This 1. a surgical pin knowledge is very important in maxillary molars, where the 2. a dislodged position of the palatal root may be shifted distally, or when silver point and you are looking for the mesio-buccal canals. Also compare retrograde the location of existing canals in the access cavity with the external shape of the tooth. For example, comparing the amalgam external lingual surface of the tooth and the position of the 3. a fragment of wider buccal canal as it appears in the access cavity will endodontic help you detect the presence of a secondary lingual canal in endosseous lower incisors. If there is more tooth structure on the implant lingual side than the buccal side and the canal is oriented to 4. a traumatic the buccal, then suspect an extra canal. Check the position projectile of furcations and measure them not only on the radiograph, fragment but clinically as well to avoid perforations. This 5. every parent’s measurement is especially important if the chamber is nightmare—the calcified or the coronal aspect of the tooth is obscured on dreaded nose the radiograph by a radio-opaque restoration. Trans- stud!

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illumination from the buccal and lingual will help immensely. Look at teeth for rotations and tilts that are likely to throw off your orientation when drilling toward the pulp (Click for the answer.) chamber. Severe mesial tilts of lower molars can move the distal canal into the mesial position. If you’re not aware of the orientation, you may drill farther distally in search of a canal that doesn’t exist and perforate. Rotations obviously also shift the positions of canals, so be aware when gaining access. When we are doing root canal we cannot have blinders on. We can’t let our confidence keep us from looking at the whole picture, both clinically and radiographically. Each component can have great value in determining the ultimate success or failure of the case. “Kase Presentation”

A PATIENT presented to our office with a calcified lateral incisor, tooth #10, which was excavated deeply and widely for the canal (Figure 1). Using the endodontic surgical microscope, I was able to find the canal and also locate a small perforation on the distal aspect of the excavation. I instrumented the canal and fitted a medium-large gutta- percha point to the apex. I mixed MTA cement and, using an apico amalgam carrier and fine pluggers, packed the cement around the gutta-percha point (Figure 2). After twenty minutes, the MTA cement was hard enough to remove the point, and I sealed a damp paper point in its place for 24 hours. When the patient returned, the MTA was fully set and I removed the paper point. I then sealed the canal, using EZ-Fill cement and a single cone of gutta percha (Figure 3), and post-prepped on that visit (Figure 4).

Figure 1 Figure 2

FIGURE 2: MTA cement packed around the gutta- FIGURE 1: Tooth #10, percha point. excavated deeply and widely for the canal.

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Figure 3 Figure 4

FIGURE 3: Canal sealed FIGURE 4: The tooth after with EZ-Fill cement and a post-prepping. single cone of gutta percha.

February-March 2003

Endo-Tip FEEDBACK? We welcome your responses and questions. Please feel free to visit Use the trial fit of your medium gutta-percha point to the Endo Forum and the apex in a canal with an apical curvature as a guide add your comments for the maximum apical extent of the EZ-Fill cement about any of the articles spiral. The gutta percha usually retains the shape on in Endo-Mail. withdrawal, so it is easy to measure to the beginning of the curvature.

Doug Kase

POP QUIZ ANSWER: # 5: the dreaded nose stud!

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Doug Kase, D.D.S.

Tales from the Chamber: A Pair of Kase’s Cases

Doug Kase DENTIFYING, instrumenting, and obturating a bifurcated root can be a very frustrating and difficult procedure. The following cases are examples of endodontic procedures performed on teeth of this kind and may give some insight into how to treat them. In the first case, by taking a radiograph from a mesial angulation I was able to identify the possible existence of a secondary root or canal on tooth number 28 (Figure 1). After some minor excavation under magnification, I found Doug Kase a centrally located orifice and gained access into the buccal canal (Figure 2). I established measurement control with an Endex apex locator and instrumented the canal using SafeSider® reamers according to the EZ-Fill® technique. Opening the coronal aspect of the canal with a number 2 Peeso reamer enabled further investigation for the lingual canal.

Figure 1 Figure 2

FIGURE 1: A radiograph FIGURE 2: Access into the from a mesial angulation buccal canal achieved reveals the possible through a centrally located existence of a secondary orifice. root or canal on tooth number 28.

After additional excavation toward the lingual, I was not able to find an additional orifice for the lingual canal. When excavating for an additional canal it is most important to keep in mind the external anatomy of the root to avoid a perforation. So by placing a 45-degree bend at the tip of a number 10 reamer, I was able to find a catch on the lingual wall of the main canal about 4 mm from the apex. The

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radiograph (Figure 3) confirmed that I was dealing with a bifurcated canal. I instrumented the lingual canal, using plenty of RC Prep and irrigation. An apical bend in all of the instruments helped to re-negotiate the apical anatomy. It is also important to continually check the already instrumented buccal canal to make sure that you do not block it with debris. The case was obturated using the EZ-Fill technique. I placed EZ-Fill cement into the canal with the EZ-Fill cement spiral and inserted a medium gutta-percha point to the apex of the buccal canal. Note on the radiograph (Figure 4) the movement of cement into the lingual canal caused by the lateral force generated by the cement spiral and the lateral pressure occasioned by the placement of the gutta-percha point.

Figure 3 Figure 4

FIGURE 3: Radiograph FIGURE 4: Note the confirms that the canal is movement of cement into bifurcated. the lingual canal.

Due to the widened common coronal two-thirds of the canal, I was able to use a number 25 finger plugger, not for apical condensation, but to move the coronal mass of gutta percha against the buccal wall and to create a passageway for my lingual gutta-percha point. A small curve was placed in the apical end of the plugger to facilitate its passage into the lingual split. I used a plugger rather than a reamer to make sure not to pull out the buccal fill (Figure 5). I did an immediate post prep, and thus the final product (Figure 6).

Figure 5 Figure 6

FIGURE 5: Using a plugger FIGURE 6: The final rather than a reamer left the product. buccal fill undisturbed.

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The next case was also a two-canal bicuspid, but the canals diverged at a more coronal level. With a second angled radiograph, it was easier to see the divergent canal architecture (Figure 7). This case was referred to our office because the referring dentist thought that he had perforated with an instrument out the mesial aspect of the root. This tooth had a centrally located common canal, but it split off into two canals at a higher point than the canal in the first case did. What the dentist had actually done with his instrument was to locate the lingual canal and negotiate it rather than perforate the tooth (Figure 8). The apex locator indicated a short measurement of this lingual canal, which corresponded to the location of the radiolucency on the mesial aspect of the root. I instrumented this canal and then initiated excavation for the buccal canal.

Figure 7 Figure 8

FIGURE 7: The divergent FIGURE 8: Showing that canal architecture of a two- the tooth had not been canal bicuspid. perforated.

By opening the common canal with a number two Peeso reamer, I was able to use a fine Spartan ultrasonic diamond tip to further widen the buccal aspect of the common canal. With a 45-degree bend in a number 10 file I was able to snake it into the buccal canal orifice (Figure 9). I instrumented this canal fully while also making sure that there was continuous access to the already instrumented lingual canal. The canals were filled using the E-Z Fill technique. Note on the final radiograph the puff of cement from the lingual canal toward the mesial-lingual at the same level as the radiolucency (Figure 10).

Figure 9 Figure 10

FIGURE 9: A number 10 FIGURE 10: Note the puff of file snaked into the buccal cement from the lingual canal orifice. canal toward the mesial-

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lingual.

It is extremely important to examine both radiograph and root morphology when dealing with a suspected bifurcated canal in any root. Mandibular first bicuspids commonly have two canals (approximately 21 percent) with quite a bit of variation in the location of the lingual orifice. Please take an extra working radiograph if you have to so that you can confirm its existence. Remember what Doug Kase told you: The canal that forks like a snake’s tongue toward the front of the mouth can be a big pain in the rear.

May-June 2003

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Doug Kase, D.D.S.

Tales from the Chamber: A Variation on the Theme

Doug Kase S THOUGHTS OF SUMMER begin to fade from our minds and visions of falling leaves, colder temperatures, and inches of snow start to permeate our consciousness, there is one thing we all can take comfort in: our patients need root-canal therapy! Now the old saying that says you have to walk before you can run certainly has validity when it comes to the SafeSider® technique and EZ-Fill® obturation. The techniques that we teach you allow dentists to incorporate their own nuances into the system without compromising the Doug Kase fundamentals of ultimately creating the proper taper of the canal (.08 taper) and its single-point obturation using the EZ-Fill armamentarium, which emphasizes the use of .02 stainless SafeSider endodontic instruments and the # 2 Peeso reamer to accomplish 90 percent of our canal instrumentation and hand NiTi SafeSiders to place the finishing touch (taper). As a dental student at NYUCD and a resident at the Manhattan VA hospital, I had the opportunity to perfect the use of the Gates Glidden reamer as aid and shortcut to the core technique that we were all taught way back in dental school. Now you may know that Barry Musikant has taught all of us the equation that Gates Glidden reamers = Peeso lights! However, I do vary the EZ-Fill technique to incorporate the use of Gates Glidden reamers. Please understand that in no way am I saying that this variation is better than the “EZ-Fill core technique” that we have taught in the past, but this variation does help my technique. Remember that the function of the NiTi .04 and .08 SafeSiders is to do the final shaping of the apical canal after the apex has been negotiated with a stainless .02 #30 or #35 SafeSider reamer and appropriately back-stepped. The SafeSiders are not meant to be used to negotiate the apical 5 to 10 mm of the canal, but rather to shape the canal and eliminate the “back step” cross-section it developed due to the use of the Peeso reamer and back-stepped instrumentation. Thus the further the NiTi instruments are seated on initial try in, the less work the instrument and dentist have to do to achieve this final shape. If you already can accomplish this with standard rotary instruments that you are accustomed to using, such as the Peeso reamer, you may find that incorporating Gates Glidden reamers in your procedure may make it easier. “How?” you may ask. The sequence that I have used—and remember that it is only

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a variation on the theme that happens to work in my hands—is the following. I instrument to my measurement control to an .02 #20 instrument. Then I widen the coronal aspect of the canal with “passive pressure,” starting with a Gates #1, then #2, then #3, and then I use a #2 Peeso reamer. I move the instruments apically until I meet resistance and go no further. Wait a second . . . I hear gasps about using a #1 Gates! Won’t it break? If you use “passive pressure” in a wet canal and do not force the instrument, it will never separate. “Passive pressure” means to use only the weight of your handpiece and tactilely feel for resistance because you may meet a curve or constriction in the canal. Initially I do not attempt to move beyond this point. Doing so can separate the Gates or ledge the canal. Obviously, in a straight canal you will be able to sink the Gates and eventually the #2 Peeso to the hub of the handpiece. Remember to straighten the coronal aspect of the canal away from furcations and grooves by applying selective pressure in the proper direction with a pecking motion of the handpiece. Now we have debris to deal with. Reiterate the apex with a #15 and then a #20 SafeSider instrument to break up the debris, and be sure to irrigate and use RC-Prep continually. Now I instrument a #25 and #30 to the apex with very little resistance because the rotary sequence I have used has done quite a bit of coronal instrumentation, perhaps moving more apically than by just using a #2 Peeso initially. Back-stepping with a #35 and a #40 is a piece of cake, and even moving the 35 to apex is not an obstacle. I can’t stress it enough: irrigate, irrigate, irrigate and use lots of RC-Prep. Now I do it again. I use the same sequence of Gates and Peeso reamers and believe it or not with the same passive pressure, the #1 and #2 Gates are apparently flexible enough to negotiate a bit more of the curve in a canal and move further apically. Forcing these instruments into a curve can cause a strip perforation, so be careful. This further rotary instrumentation of the canal facilitates deeper penetration of the NiTi instruments and thus puts less stress on the instrument and dentist. In my experience, the .04 #30 NiTi becomes a debris breaker and remover, and the .08 #25 NiTi usually can be inserted to within 1 to 2 mm of the apex and worked to measurement to create our .08 taper with very little effort and thus prepare us to obturate the canal according to the EZ-Fill technique.

Now here is my “Tale.” The following case is an interesting one. This patient presented with a buccal fistula associated with quite a bit of bone loss in the furcation of a lower molar and what appeared on the radiograph to look like some sort of perforation in the mesial aspect (Figure1).

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Figure 1

FIGURE 1: Showing a possible perforation in the mesial aspect.

I was not sure at the time whether it was resorptive or iatrogenic. Access was gained and from the looks of the pulp chamber it was virgin territory, so we were dealing with something pathologically natural. I extirpated the tissue and was able to isolate the canals. Measurement control was taken by apex locator and confirmed by radiograph (Figures 2 and 3).

Figure 1 Figure 1

FIGURES 2 AND 3: Measurement control taken by apex locator (left) and confirmed by radiograph (right).

The mesiolingual canal gave me a wild and inaccurate reading on the apex locator in comparison to the mesiobuccal; thus I knew that the mesiolingual was the canal with the perforation. I managed to find the apical portion of the canal by hugging the mesial wall of the canal. I widened the mesiolingual canal with my sequence of hand and rotary instruments and was ultimately able to visualize the perforation and canal with the endodontic microscope. I obturated all the canals using the EZ-Fill technique and then removed the coronal gutta percha in the ML canal to the level of the perforation. I packed a plug of Colicote into the communication to the furca and then back-filled the coronal portion of the canal with MTA cement (Figures 3 and 4).

Figure 1 Figure 1

FIGURES 3 AND 4: A plug of Colicote packed into the communication to the furca (left), and the coronal portion of

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the canal back-filled with MTA cement (right).

Two weeks later the fistula remains closed and the patient will be recalled in three months to evaluate healing.

September-October 2003

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Doug Kase, D.D.S.

Tales from the Chamber: Legally Yours!

Doug Kase VER THE PAST YEAR, I have had the opportunity to participate in a few malpractice cases. Wait . . . hold back the gasps! My participation took the form of expert exam and testimony in the defense of my fellow dentists in regard to any endodontic involvement that their case may have had. As such, my assuming this role has given me the chance to observe some common problems and themes of risk management that may infiltrate and perhaps interfere with our ability to defend ourselves in the event of the dreaded malpractice case. Doug Kase To start—and this is usually where we should all start with our patients—consider the issue of informed consent. The question of written versus oral has always been an issue. Obviously, a signed consent form would offer the best protection, but alternatively as long as you inform the patient orally of the risks of endodontic treatment and note in your chart that you have done so, you will have protected yourself as well. Creating a standardized office “script” that you can read from would be very helpful to maintain uniformity from patient to patient. It is important to include, for example, the issue of calcified canals, which may result in the dentist’s either not finding a canal or not negotiating the canal to its full extent. This leads us to the next recurring topic in risk management and endodontics, which is a missed or inadequately filled canal. If you cannot find a canal or you cannot negotiate it to the apex, for heaven’s sake tell your patient and note it in your chart. It is not malpractice to not find a canal, such as the MB2 canal in a maxillary first molar, if you have made the effort to look for it and explained to the patient the possible ramifications. Then, of course, enter it in your chart! Next topic of course is your chart. There are certain things that we all remember from grammar school, particularly our three Rs. Forget for a minute about the reading and the ’rithmatic, and let’s concentrate on the ’riting. For an expert trying to defend his brethren, there is nothing more frustrating than trying to read a chart that is written so illegibly that it might as well be in an intergalactic language. It is one thing not to be able to understand the language, for that is subject to interpretation; however, not to be able to make out any intelligible markings really puts a damper on an effort to defend. What I am getting at is to please write up your charts legibly and express yourself clearly. A good defense is much more

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likely if everyone involved is able to read a legible chart and understand the language. Separated instruments are a real stomach turner! Any endodontists who tell you that they have never broken an instrument must not have done much endo in their lifetimes. Separated instruments are a usual risk of endodontic treatment and should never be considered an act of negligence. Just tell your patient that it happened and then enter it in your chart! S**t happens! Thus far, I have not met any dentists so infallible that they deserved to have Superman’s “S” tattooed on their chests. Don’t be afraid to tell your patient the truth, for silence has a way of biting you on the rear end. Breaking an instrument in a canal is not an intentional act of malpractice, but only represents an effort to do a root canal on a difficult tooth. Remember that it all comes down to expectations. Endodontics is 90 to 92 percent successful. Eight to ten percent of the best cases fail for some unknown reason. Some we can fix, and others we cannot. If your patient is informed and understands the risks involved and we as dental professionals maintain open lines of communication to our patients, this combination may help to minimize our exposure to any malpractice issues in the future. Kase’s Case

I GUESS you have all been waiting for the “Kase” of the month. When I first saw the starting film for this lower second molar (Figure 1), I took one look at those apices and said to myself, “Self, you are never getting to the end of these canals!”

Figure 1

FIGURE 1: The starting film for a lower second molar.

I quickly informed the patient of her bizarre anatomy (her roots) and also informed her of the probability that I would not be able to negotiate the apex due to the tortuous path my instruments would have to follow. Additionally, due to the proximity of the apices to the mandibular canal, there was a possibility of some paresthesia, more than likely temporary, but possibly—though rarely—permanent. This of course was entered into her chart very clearly along with her consent to proceed after understanding all the alternatives. Using an apex locater, I took measurement control, and I achieved negotiation to the apex, starting with .06 (pink) instruments. This was a situation where throwing out overly used instruments was certainly warranted to avoid separation.

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Using a tremendous amount of RC Prep and irrigation helped, but didn’t make matters easy. As I straightened out the coronal aspect of the canal with Gates and Peeso reamers, I continued to recheck my measurement control, for I knew that it would change as the coronal canal curvature was straightened. I continued to instrument according to the SafeSider/EZ-Fill technique and ultimately achieved a result that I can reach around and pat my own back for. P.S., the patient is pretty happy too. (See Figures 2 and 3.)

Figure 2 Figure 3

FIGURES 2 and 3: The ultimate result, after negotiating tortuous paths.

November-December 2003

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Doug Kase, D.D.S.

Tales from the Chamber: Two Cases of Kase’s

Doug Kase s you have all read in past issues, we are staunch believers in the use of the apex locator. It is the only way to get an accurate measurement control to which we can instrument. Accurate apex location results in fewer post- operative complications, such as pain, because it reduces overinstrumentation and resulting overfills. The following case is a perfect example of the importance of using an apex locator when doing endodontics. This patient was first referred to our office for continued Doug Kase discomfort on tooth #12 after the completion of endodontic therapy. Radiographs showed an acceptable root-canal obturation on #12, but also a periapical radiolucency on tooth #13 (Figure 1). Symptoms, however, were specific to #12. I suggested a re-treatment of the endodontics prior to any surgical intervention. The patient returned two months after the retreatment (Figure 2) with continued symptoms, and he also had developed a small pea-sized swelling over the buccal plate approximating the apex of #12. He was placed on a regimen of clindamycin and advised to return for an apicoectomy during which we would also investigate tooth #13.

Figure 1 Figure 2

FIGURE 1: Showing an FIGURE 2: Two months acceptable root-canal obturation after the re-treatment. on #12, but also a periapical radiolucency on tooth #13.

The patient returned for the surgery, whereupon, after a local anesthetic had been given, I created an incision from the mesial of #14 to the mesial of #11 in attached gingival and also made a vertical release incision on the mesial of #11. Upon flapping back the tissue, I was able to visualize the root tip of tooth #12 sticking through the buccal plate with a 3 mm extension of

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gutta-percha through the apex. Additionally there was a bony defect over the apex of tooth #13. I beveled back both the apex of #13 and buccal apex of #12 and curetted any tissue out of the site. A check radiograph was taken to help visualize the location of the palatal root of #12 (Figure 3), and I excavated for that and beveled it back as well (Figure 4). I made retrograde preparations using ultrasonic diamond surgical tips, and placed amalgam seals (Figure 5). I sutured the site, and the patient tolerated the procedure quite well. The patient is now asymptomatic and doing well.

Figure 3 Figure 4

FIGURE 3: Check FIGURE 4: Palatal root of radiograph taken to help #12 beveled back. visualize the location of the palatal root of #12.

Figure 5

FIGURE 5: After placing amalgam seals.

If the original endodontic therapy had included the use of an apex locator, perhaps this overfill would have not occurred and thus the surgical intervention on this tooth would have been avoided. Unfortunately, not all overfills can be avoided. Some may occur due to open apices combined with an obturation technique that utilizes condensation or thermoplastics. But it is apparent that overfills are minimized when accurate electronic apex location is used in conjunction with single-point obturation in an appropriately tapered canal, as in the EZ-Fill® technique. The next case is just an example of practical dentistry. A patient presented to our office with endodontics started on tooth #12 (Figure 6). This tooth was part of a very recent long-span bridge with tooth #13 as a terminal cantilevered pontic. Teeth #10 and #11 were present as abutments. Because there had been some loss of marginal seal on the mesial and a distal angulation of the root, I placed an instrument in the canal to verify and confirm the results from my apex locator (Figure 7). I completed the endodontics using the EZ-Fill technique (Figure 8), and the patient was to return for a post and core.

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Figure 6 Figure 7

FIGURE 6: Showing FIGURE 7: Instrument endodontics begun on placed in the canal to tooth #12. verify and confirm the results from the apex locator.

Figure 8

FIGURE 8: Endodontics completed using the EZ-Fill technique.

Under normal circumstances, one might ask why we are trying to restore an abutment for a cantilevered restoration when there is a definite loss of marginal seal and cantilevers are somewhat unfriendly to the abutments anterior to them. In this case, restoration was the practical solution due to the age of the restoration and the patient’s economic wants and needs. Thus, on the next visit, I prepared the tooth and placed a #1 Flexi- Post® (Figure 9). I packed an internal amalgam core into the marginal opening and sealed the access (Figure 10). The patient is happy, and the referrer is happy as well.

Figure 9 Figure 10

FIGURE 9: Showing a #1 FIGURE 10: With an internal Flexi-Post® in place. amalgam core packed into the marginal opening and the access sealed.

Spring 2004

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FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

[ﺩﻡﺡﻡ file:///D|/HEALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/dsk20twocases.html[2/21/2011 10:25:55 Don’t Bite Off More Than You Can Chew

Doug Kase, D.D.S.

Tales from the Chamber: Don’t Bite Off More Than You Can Chew

Doug Kase HE USE OF SafeSiders instruments in the EZ-Fill technique facilitates a standardization of procedure that leads to a standard superior result. However, certain clinical circumstances may require a slight deviation from the formula that we have taught our loyal readers. As I’m sure you have all seen, the technique over the years has evolved to a point where you can achieve a superior result with minimal stress to the dentist, the dentist’s hand, schedule, and instruments—and, of course, to the dentist’s patient. There are, however, those Doug Kase annoying situations that arise in which, when we try to follow the EZ-Fill technique map, we find that we are not getting to the final destination as easily as we want to. Certain anatomical situations may pop up, such as severely curved canals, that really throw a monkey wrench into the machinery of the finely tuned EZ-Fill assembly line. Sometimes inherently harder dentin, calcifications within the canal, or both, compound an already difficult situation. In such cases, working each instrument to the apex becomes much more difficult, particularly as the instruments increase in diameter. As a result, we must sometimes remind ourselves of our old philosophy that it is OK to work a little slower and longer to ultimately finish a little faster. The issue of not biting off more than you can chew applies both to instrument design and to instrumentation technique. Now, of course, the design aspect is a built-in “no brainer”! The SafeSiders instruments are reamers by design and have a flattened surface to ultimately engage less dentin when negotiating the canal walls. This unique design thus facilitates reaching apical measurement more easily with each increase in diameter of each instrument we use. The issue of technique is an entirely different story. The EZ- Fill “formula” in its present form utilizes a one millimeter back step when progressing from a #35 instrument to a #40. Sometimes, in curved or very tight canals, initially using an incremental one millimeter back step from apical measurement helps us achieve our final .08 tapered resistance form with less stress to instruments and dentist. First take each of the number 6, 8, 10, and 15 instruments to the apex. Then step back one millimeter with a #20 and then two millimeters with a #25. At that point you can use your #2 Peeso reamer to widen and straighten the coronal anatomy of the canal as needed. Return to the apex with a #15 instrument and then try moving apically with

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the #20 and #25. If reaching the apex with the #25 is still difficult, then step back in half-millimeter increments from measurement control with this instrument and then a #30 and then try again. Once the #25 makes it to measurement, follow the same procedure with the numbers 30, 35, and 40, making sure that you reintegrate the use of the #2 Peeso and #2 Gates as described in the EZ-Fill technique to gain a little more coronal canal straightening and depth. From this point, using the NiTi .04 and .08 tapered instruments and moving them to the apex will be a simple process. Remember to use the reamers with a light rather than heavy touch; the light touch is very important. Don’t try to engage the dentin as if the reamers were files. Please keep an eye out for instrument fatigue and remember to test-bend all NiTi instruments before use. Remember that the final result will be the same (.08 taper and fitting a medium gutta-percha point) even though we used a slightly modified formula to achieve our goal. Case Report

THIS CASE is an interesting retreatment. The patient presented with an old silver point RCT having both clinical symptoms and radiographic evidence of breakdown at the apices (Figure 1).

Figure 1

FIGURE 1: Showing evidence of breakdown at the apices.

He was placed on Clindamycin 150 mg three times a day for ten days to reduce the mild symptoms, which began to abate within three days. Retreatment was started on day four, and the crown was removed with out any damage. In this situation, I felt that retreating with the crown off would be easier because of the necessity of removing a post from the palatal root and the silver points from the buccal canals. Was I right! Under the crown was an amalgam core, which I removed with a fine diamond around the remaining tooth structure. I then used an ultrasonic scaler to selectively loosen any remaining amalgam from the post head and silver wires in the pulp chamber. The patient indicated that he had a problem on the contra lateral tooth with an undiscovered fourth canal (MB2), and after the points and post were removed I did find an MB2 canal that had not been treated. The case was instrumented with SafeSiders and obturated using the EZ-Fill technique (Figures 2 and 3). The patient is doing well and is asymptomatic.

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Figure 2 Figure 3

FIGURES 2 and 3: After instrumentation and obturation using the EZ-Fill technique.

Summer 2004

Do not add more EZ-Fill Cement liquid FEEDBACK? to thin the viscosity of a perfectly mixed We welcome your batch of sealer that has begun to responses and thicken. Instead, re-spatulate the mix, questions. using a lightly heated spatula to bring it Please feel free to visit back to a usable viscosity for obturation. the Endo Forum and add Doug Kase your comments about any of the articles in Use a cotton pellet saturated with alcohol Endo-Mail. to remove excess EZ-Fill from the pulpal floor. Young Bui

Always place a little topical anesthetic on the reverse side of the rubber dam. It will let the dam slide over the clamp much more easily. Allan Deutsch

[ﺩﻡﺡﻡ file:///D|/HEALTH/DENTISTRY/L%20E%20C%20T%20U%20R%20E%20S/E%20N%20D%20O/endomail/articles/dsk21dontbite.html[2/21/2011 10:25:55 Reciprocation Innovation

Doug Kase, D.D.S.

Tales from the Chamber: Reciprocation Innovation

Doug Kase ERTAIN INNOVATIONS or techniques in a dentist’s life make a dramatic difference in the way he or she practices. For some it’s a new procedure or technique; for others it’s a new instrument or product. As an endodontist I have been subject to a barrage of all of the above over the years. New techniques and philosophies, such as crown-down instrumentation; new instruments, such as nickel-titanium in various tapers; a slew of constantly changing rotary techniques and a slew of different handpieces; and of course the many Doug Kase different methods of obturation techniques are only a few that have had their impact on the practice of endodontics. For my father, who graduated in 1943, moving from stand-up to sit- down dentistry made a big difference. For me, leaving the stomach-churning world of rotary Ni-Ti for the safer pastures of a more reliable, predictable, and safer system of doing root canal was the ticket! I am sure you all remember our Simplified Endo Technique (S.E.T.), which used .02 tapered standard stainless steel reamers in combination with .04 and .08 tapered NiTi hand instruments to create a greater tapered canal. This was the beginning of a stress-free endodontic evolution in my professional life. When our technique further evolved with the advent of SafeSiders and a further refinement of the system, so came another level of stress reduction and predictability. Using this technique in combination with electronic apex location has allowed me to do one-visit endodontics in a safe and stress-free way with incredibly predictable results. Well, something else has come along! For weeks, Barry Musikant has been asking me whether I have tried adding a reciprocating handpiece to my armamentarium for doing our EZ- Fill SafeSiders technique. Being the stubborn person that I am, I asked myself why I should add a handpiece when the system is so easy the way it is? I was already doing one-visit molars in under an hour with little stress, so I wondered how this handpiece could improve my technique. Well, readers, I gave it a try and needless to say since that day I have used my reciprocating handpiece for all instrumentation over a # 20, including NiTi, in the EZ-Fill SafeSiders technique. The advantages of using a reciprocating handpiece are many besides the obvious one of decreased hand fatigue for the operator. I have been using the NSK reciprocating contra-angle

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on a Star slow speed engine. Its 30-degree reciprocation from center in clockwise and counterclockwise directions provides stress-free instrumentation of the canal without the instrument’s reaching a resistance point. We all know that we try to replicate this movement with our hands; however, the proprioceptive feeling that we get prevents us from moving past this subjective resistance point. Since this can be a subjective boundary, it differs for different operators. Moving beyond this point can distort an instrument or—even worse—eventually cause an instrument to fatigue and fracture. Since the movement of the instrument in the handpiece never meets and moves beyond this point, the risk of fracture becomes incredibly low with stainless steel instruments and, even more importantly, with NiTi instruments. Coupling this low risk of fracture with a pre-bend test for NiTi instruments makes the likelihood of a separation within the canal almost non-existent. When the reciprocating handpiece is used in a pecking motion, its rapid reciprocation works synergistically with SafeSiders reamers to provide a more rapid and efficient instrumentation. Remember that the flat on the SafeSiders reamer not only helps with negotiation to the apex, but also acts as a chisel that allows the instrument to cut in both directions. I have tried using the NSK in both straight and curved canals, and it really works! A note to my “Rotary” colleagues: if you love rotary endodontics because you need a handpiece to reduce hand fatigue during instrumentation, then this is the innovation for you. Using a reciprocating handpiece with the EZ-Fill technique will fulfill all your requirements for performing stress-free endodontics. The following case is an example of the results that can be achieved using this technique in a curved canal with the addition of the NSK handpiece. (See Figures 1 and 2.) The results are the same, but the effort and operator stress required to achieve the results are greatly reduced.

Figure 1 Figure 2

FIGURE 1: The canals FIGURE 2: The final film were instrumented by hand shows the same to a # 20 and then the # 2 predictable results that we Peeso reamer was used to have all become straighten the coronal accustomed to when using architecture of the canal as this technique. much as possible before the NSK reciprocating handpiece was used for the rest of the SafeSiders instrumentation.

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Figure 3 Figure 4

FIGURES 3 AND 4: Different cases, same technique, same results!

Fall 2004

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Doug Kase, D.D.S.

Tales from the Chamber Product Review: Medidenta Handpiece

Doug Kase ELLO AGAIN, my loyal readers. Since my last “Tales” about adding a reciprocating handpiece into the SafeSiders® technique, I have had the opportunity to use a handpiece manufactured by Medidenta and NSK (Figure 1). It is a standard four-hole air motor (Meditorque America “E” type Air Motor) with an “E” attachment to which the NSK sheath (Model E4R) and NSK head (Model TEP-Y) are attached.

Doug Kase Medidenta Handpiece

FIGURE 1: The Medidenta handpiece consists of, left to right, an NSK head, an NSK sheath, and a Meditorque America air motor.

The Medidenta engine has plenty of torque and operates at 20,000 rpm; however with a 4:1 reduction in the sheath, the contra-angle is operating at 5,000 rpm. The instrument latch button is very easy to use and opening it to change SafeSiders endodontic instruments in rapid succession requires little effort. Its smaller head facilitates ease of use in tight posterior areas where limited jaw opening or tooth angulations could create limitations. This flexibility is also particularly useful when in certain circumstances an instrument must be placed into a canal by hand due to dilacerations or extreme apical curvatures. This small-headed handpiece can then be placed easily onto the inserted instrument and activated. The NSK Head will reciprocate through a full arc of 90 degrees, 45 degrees in either direction from neutral center. The SafeSiders technique recommends using the handpiece at about 2,000 rpm; however, I have been using it at full speed (5,000 rpm) and it works great! Instrumentation with instruments from #25 to #40 proceeds with little effort. The use of the NiTi SafeSiders instruments is equally as easy, and the handpiece eliminates any hand fatigue that you may have

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experienced, especially after a long day of dentistry. I have also found that in cases that are difficult to instrument due to calcifications or just harder dentin, the reciprocating motion in combination with small-diameter instruments, such as #08 and #10, works equally as well. In general, when it comes to reciprocation it is almost impossible to distort an instrument. The 45 degree reciprocating arc it travels never allows the instrument to meet severe distortional resistance; thus there is no instrument deformation. This fact is even more important while using the NiTi instruments. So, in closing, I have to give this product a great review, five out of five stars. I advise all practitioners who are using SafeSiders to add this to their technique. And as I said in my last article to all you rotary guys, if the only reason you are staying with rotary is that you want a handpiece to ease hand fatigue, then you don’t have an excuse any more. Try it, you’ll like it! Just a note: EDS will also be selling a version of this reciprocating handpiece in the future, so keep checking in. So with that in mind here are . . . Dr. Kase’s Top 10 Reasons He Loves Reciprocation

# 10 The myths your mother told you are wrong. . . . You don’t really go blind! Ooops, hold on, that’s something else. Let me continue.

# 9 Because it works!

# 8 Less operator hand fatigue.

# 7 Ease of instrumentation in tight anatomical access to posterior teeth or distally angled teeth.

# 6 Because it allows more rapid instrumentation of calcified canals.

# 5 Reciprocation makes it easier to penetrate and remove old gutta percha with less solvent when retreating a case.

# 4 It’s much less expensive than rotary crown down and quicker = less chair time = more productivity.

# 3 Less chair time = a happier patient.

# 2 It will probably prevent an ulcer because it’s safer than rotary, hence less gut-wrenching to use than rotary. It can be used with all SafeSiders instruments, stainless and NiTi, and it doesn’t distort and break instruments as rotary does.

And the # 1 Reason Dr. Kase Loves Reciprocation: Because it really, really, really works fantastically and makes doing endodontics a pleasure.

Winter 2004

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FEEDBACK? Remember to examine the We welcome your responses external anatomy and root and questions. angulations with a perio probe Please feel free to visit the and radiograph when looking for Endo Forum and add your calcified canals to avoid comments about any of the perforations. articles in Endo-Mail.

Doug Kase

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Doug Kase, D.D.S.

Tales from the Chamber Everything Old Is New Again

Doug Kase he topic of the month is: old comfortable shoes! I’m sure we all have a pair. We wear them, and although they look a bit dated and worn, they are just too comfortable to put into retirement. They may go well with our equally tattered and worn comfortable pair of blue jeans, but we may not want to wear them when we’re out on a night on the town. Well, with that in mind we have an announcement. The office of Musikant, Deutsch, Kase, Dukoff, Bui, and Hoffman is upgrading. Yes folks, it’s a total makeover from Doug Kase soup to nuts! Since even before our most recent millennium we have helped the practice of endodontics evolve into the 21st century with our E-Z Fill® technique and SafeSiders® instrumentation, and we now are also bringing our physical plant along as well. The reconstruction of our office has always been more than just a thought over the years, but it was only recently that all the ingredients came together in a recipe whose end result will be a wonderful workplace for us to practice and a pleasant surprise for your patients. Additionally, our remodeled space and new equipment will continue to be a focus of continuing education for our fellow dentists with the addition of an endodontic microscope for every room. We will have the ability to capture and record intra-oral images for you and present them to you in future lectures and newsletters. You will also have the ability to use these microscopes during our hands-on courses to augment your endodontic technique. After months of research, I finally had the opportunity to work closely with Becker-Parkin and DentalEZ to start the planning phase of our makeover. With Becker-Parkin’s recommendation of a general contractor, Fred Marsilisi, we all started to put our heads together to pick our equipment and plan our operatory designs, utilizing our existing physical plant. Designs for sterilization and our front desk reception area were also accomplished. However, throughout all our planning and plotting the most important factor that had to be considered was that we would never close our office during the remodeling. I would like to end this by saying that it’s history in the making, but that would be too simple an ending.

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The plan was to start phase one (remodeling five out of nine operatories) on December 22, 2004, and be up and running by January 5. So, after two weeks of working evenings and weekends we were up and running by the 7th and in the grand scheme of things, considering the holidays, that’s a big winner. For us, this is a group effort, and through successful coordination we have maintained our goal of continuous coverage for our referrers and uninterrupted treatment of your patients. As the remodeling continues through the end of February, we deeply appreciate your patience and your continued confidence in our practice. I look forward to keeping you all updated on our progress and to presenting you with our final product. Take a look at some pictures from our past and some from our present.

In the beginning, circa 1978 . . .

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The first steps . . .

Stages in the installation of updated cabinetry by Dental EZ, equipping the practice for 21st-century endodontics

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January-March 2005

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FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Doug Kase, D.D.S.

Tales from the Chamber Construction Update

Doug Kase HE MONTHS have gone by, and except for our waiting room furniture order I can finally say that our new construction and upgrade is 99.9999999 percent complete. It’s certainly taken awhile, but it’s been well worth the wait. Our DentalEZ chairs, units, and cabinetry are functioning without flaws and serving all our ergonomic needs. The Silhouette Chair we chose for our patients’ comfort is so well designed that it allows for a physically stress-free practice of endodontics with no obstructions to our legs and thighs. Positioning the patient has become a simple matter, using the four Doug Kase programmable preset positions. Also, keeping the chairs and units clean and aseptic has been an easy task, thanks to their flush-mounted controls, which can easily be covered with disposable plastic tape. The DentalEZ New Seiler endodontic microscope. Lumina Light in our operatories is track-mounted and provides two levels of great shadow-free illumination. These lights can be operated in a sensor mode and activated by merely passing your hand under the light, providing contamination-free operation. All our operatory cabinetry was designed and built by DentalEZ and customized to fit the operatory floor plan that was laid out by Becker Parkin. As I mentioned in last issue’s “Tales” article, we have both under-chair and rear-delivery units that eliminated any over-the-patient delivery issues we all had. If any of my readers are left-handed or have partners or associates who are left-handed, these units and chairs can be quickly adapted to either persuasion. The sliding counters behind all our patient chairs have come to replace the old “Alabama” carts we used in our old operatories. They are easily positioned, since they have the DentalEZ Galaxy under-chair ability to move not only left and right but also in and out. delivery unit. Storage is more than adequate in drawers and cabinets and easily accessible to doctor and assistant. Everything has been manufactured to last with heavy-duty sliders and hinges. All our operatories are now equipped with endodontic microscopes, which are now the standard of practice. I must say that Becker Parkin and DentalEZ have made themselves incredibly accessible in the process of final tweaks to our equipment. Collaborating with Becker Parkin has been a great experience. Although we have used them for many years for supplies, repair, and maintenance of our older equipment, their input regarding our new equipment and subsequent installation has been invaluable. The size of the company allows for a large support staff, but it’s not so large that a personal touch Sliding countertop work surface. and individual concern for an ongoing project are ever put on the back

burner. Barry Salzman, the president of the company, has always made himself available and has been in constant contact throughout the project. The same can be said of the DentalEZ Company; they have also participated in and followed our progress closely like a proud parent. When it comes down to the final analysis, both Becker Parkin and DentalEZ are great companies to work with because they are experienced and large enough to do the job right, but not so big that you become just another invoice in a pile of customers. A very special thanks to Carl Bretco, president of DentalEZ, and all his staff who helped to bring our project to a happy ending.

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The front desk of any office has to be a masterpiece. It is not only the welcome mat that you extend to your patients, but also a gateway to the clinical part of their visit. We wanted our front desk to have an open look and invite patients to feel actively able to communicate with the staff, ask questions, and voice concerns. The thought of a root canal can elicit quite a range of emotions, and being able to interact with our staff, not through a “bank teller window,” was very important to us to make DentalEZ Lumina Light. every patient feel at home. With that in mind DentalEZ’s designer came up with a couple of choices, and the final product was built and installed after a detailed preparation of the space by our General Contractor, Fred Marsalisi of D.E.S. Interiors in Danbury, Connecticut. The input of our front desk staff was greatly appreciated when the design parameters were considered. Remember, they are the ones who have to work there. Seating area, computers, telephone, and interoffice communication all have to be taken into account when you plan. There will be more to say about our new office in future issues, but suffice it for now to say please enjoy our new digs; we certainly do. Feel free to stop in for a visit if you are in the neighborhood.

Galaxy rear delivery unit.

Welcome! This is the new front-desk as our patients see it upon arrival. Auxiliary front desk work space.

The front desk from behind the scenes.

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DentalEZ operatory cabinets.

Sterilization area.

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Sterilization area.

New operatory.

Front desk and new files.

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July-September 2005

FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Doug Kase, D.D.S.

Tales from the Chamber If at First You Don’t Succeed . . .

Doug Kase HIS MONTH I will start “Tales” with an Figure 1 interesting case. A patient presented with a fistula associated with tooth # 3. This tooth had quite an active history, which included prior endodontic treatment approximately one and one-half years ago and a subsequent PFM crown. Nine months later the case failed, and the patient had an apicoectomy on the mesiobuccal and distobuccal roots, leaving the palatal root untouched. This now brings us to the present FIGURE 1: An actively draining Doug Kase situation (Figure 1) with an actively draining fistula, fistula associated with tooth # 3. which seemed to be associated with the mesiobuccal root and a periapical radiolucency at the palatal apex. Well, we all like to think of ourselves as heroes, so— Figure 2 being the hero that I am—I initiated an endodontic retreatment of the tooth with the goal of finding an MB2 canal and retreating the palatal endo. Eureka! I found the MB2 and retreated the palatal root as planned (Figure 2). I prescribed clindamycin 150 mg TID and dismissed the patient with the expectation of a closed fistula on the checkup visit in two weeks. To my great dismay the fistula was still present and draining in all FIGURE 2: Following retreatment its glory. of the palatal root. Frustrated but nontheless very determined, I decided to retreat the entire tooth. Using the apex locator, I was able to remove the existing gutta percha and re- Figure 3 instrument the canals with the retrograde amalgam seals without dislodging them. Once again victory was in sight as I re-obturated the canals (Figure 3) and told the patient that all was well. Needless to say, my patient returned, as did the fistula. It was time to take out the big guns! Extraction and replacement was not an option, so an apicoectomy was scheduled. After two carpules of Septocaine, an incision was FIGURE 3: After retreatment of made in attached gingival from the mesial of # 2 to the the entire tooth. mesial of # 4, where a vertical release incision was done to achieve greater access without stressing the tissue on reflection of the flap. It was apparent when the flap was raised that there was a fenestration in the buccal plate over the MB root. Using a # 4 surgical round bur, I opened a window over this area to

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Figure 4

discover that the DB root was involved as well. Using a 557 surgical length bur, I beveled the MB and DB roots back, removing the old retrogrades. On the MB root, I identified both the MB and MB2 canals, which I then prepared for retrograde amalgam seals, using my FIGURE 4: Showing the DB and Newton Ultrasonic unit and retrograde prep tip that is palatal roots sealed—persistence integrated into our DentalEZ chair side units. pays! Now when I beveled back the DB root, that’s when things got a bit interesting. As I beveled, I identified the DB canal, but 3 to 4 mm palatal to that I saw another “vein” of gutta percha in this dumb-bell shaped root. I thought, “Could this possibly be the palatal root?” How could the great God of endodontics be so good to me? Sure enough it was the palatal root, for this was a great example of fusion of the distobuccal and palatal root anatomy and explained why this radiolucency actually involved all three roots. The DB and palatal were prepped and sealed and the surgical site closed (Figure 4). Clindamycin and NSAID analgesics were again prescribed, and the patient returned one week later for suture removal without any post-operative complications. Persistence paid off, the fistula has not returned, and the patient is healing well. A happy ending for all!

July-September 2005

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Doug Kase, D.D.S.

Tales from the Chamber It’s Not What You Say; It’s How You Say It

Doug Kase N AN OFFICE, particularly a large office, it is Figure 1 extremely important to be able to communicate with your staff efficiently and of course equally as important, vice versa. Good intra-office communication results in an efficiently run practice. When your front desk can notify you that your next patient has arrived, the chart is filled out, and the patient is ready to be seated without staff members’ having to leave their posts, and without your having to Doug Kase divert your attention from your present task, practicing in general becomes that much easier. If this communication for the most part is silent, then your patient in the chair will never have the feeling that you FIGURE 1: The Comlite 4000 are rushing a procedure to move to your next series unit. appointment. For some strange reason, screaming down the hallway just doesn’t set the right professional atmosphere. Additionally, a silent communication Figure 2 system becomes much more important with the increased need for confidentiality when communicating information regarding patient treatment. When I talk of silent communication, I am referring to a light signaling system. For years, dating from the time when our office was originally built, we used the Visicom system with a series of indicator lights and private intercom. As the office aged, so did the system, FIGURE 2: “Maybe with a little and eventualy it suffered from old age. When we luck . . .” reconstructed the office, we considered a new Visicom system; however, that system’s higher cost and our history of repairs led us to choose the Comlite 4000 Figure 3 series unit (Figure 1). This very affordable system offered a quiet and discreet way to communicate our intra-office messages, such as “new patient arrival,” “important phone call,” “patient seated,” “come to location,” and “personal message.” The system uses lights and chimes to communicate these messages. Since it was similar to what we had and so easy to customize to our needs, the transfer and learning curve FIGURE 3: Mission for our staff was quick and easy. accomplished! The Comlite 4000 series we chose was the LAS4000, which also includes voice intercom

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communication, which can be routed to any of the 17 Figure 4 individual units we have throughout the office. The units can be placed on a desktop or wall mounted. There is no master unit, and all can send or receive messages. They can be customized to your needs with appropriate included adhesive labeling. This system uses your power grid in your office to link up; hence all that is necessary to get started is to just plug it in. However, in a larger office such as ours with more Figure 4 individual stations, it was suggested to use the option of hardwiring the units together using standard telephone wire to insure that all units would communicate properly, which they did flawlessly. Using a series of dip switches on the back, each unit was designated individually for intercom communication that allows one to one or one to all voice communication. The buttons can be lit in a steady mode by pressing once or be made to blink by FIGURES 4 AND 5: A second pressing twice and each message is followed by a case of a curved canal. pleasant chime which is volume controlled at each unit. The LAS4000 front surfaces are flat membranes that are easily cleaned and also can be protected easily with additional plastic wrap for infection control purposes. These can also be controlled with an optional IR remote up to 35 feet away, which makes placement an easy task. So how do they perform? I have to give them five out of five stars. After working through some wiring issues that had nothing to do with the system itself, they have functioned flawlessly. They were easy to customize for our inter-office communication purposes and continue to help maintain a quieter and less stressful atmosphere. The quality of the voice communication feature is good when we need it and simple to implement and direct. The Comlite LAS4000 is a valuable addition to our office.

A Case From Kase Danger Curves Ahead!

Curved roots are a pain in the ass. There I said it. I am quite sure we all feel the same way. You take a look at your pre-op film (see Figure 2) and say to yourself “Oy veh! Maybe with a little luck and lots of sealer I can squash something around that curve.” With a little persistence and patience, curved roots and curved root apices can be somewhat easily instrumented and obturated. This case was a doozie. The need for endodontic therapy was self-explanatory after taking a glance at the x-ray; however, a successful completion was in question. The mesial canals were a no brainer, so I will confine my technique explanation to the much more complicated distal canal on tooth # 18.

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To attain measurement control with my apex locator I had to pre-bend the tip of a .08 stainless steel file at about 45 degrees, and with very gentle hand reciprocation I was able to negotiate the apex after a few tries. Using plenty of RC Prep and hand placement of my instrument in the canal to apex, I placed my reciprocating handpiece on the head of the .08 while still in the tooth and stepped on the gas. There was very little fear of instrument separation due to the nature of the 45-degree arc of movement from center not creating instrument stress as less accurate hand motion could while in such a curved apex. Once I was able to move the handpiece coronally and back apically with little resistance, I moved on to a # 10 reamer and repeated the process, which I also did for a # 15. I then widened the coronal aspect of the canal with Gates Glidden and # 2 Peeso reamer. I reiterated the apex with a pre-bent # 15 and continuous reciprocation, and I continued the sequence of instrumentation up to a # 25. I then re-widened the coronal portion with a # 2 Peeso. At this point I started to back step with # 30, 35, and 40 one mm per instrument and each time re- negotiating the apex with my # 25. Once this was accomplished, I was able to move my pre-curved #30 and 35 to the apex, still using reciprocation. Then I additionally gave each of my new NiTi instruments a bit of a bend at the tip and under reciprocation they moved readily to the apical measurement. The case was obturated using the standard EZ-Fill® technique, and I patted myself on the back for mission accomplished! (See Figure 3.) In most canals—and especially curved canals— reciprocation is the instrumentation technique of choice. Due to the nature of the circumscribed arc the instrument takes in the reciprocating handpiece, there is much less mechanical stress on the instrument because you never reach and surpass mechanical engagement. Additionally as an instrument increases in diameter it becomes stiffer. Thus pre-programmed reciprocation in a handpiece greatly reduces mechanical distortion or zipping of the curved canal apex because there is no rotation of the instrument, either stainless or NiTi. Here is a second case of a curved canal that was instrumented with SafeSiders® and obturated with the EZ-Fill technique. (See Figures 4 and 5.)

July-September 2005

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Doug Kase, D.D.S.

Tales from the Chamber Looks Can Be Deceiving

Doug Kase IAGNOSIS of an endodontic problem can sometimes be obvious. You take a look at a particular tooth that a patient is complaining about, and you see clinical caries that has created a hole so large you can park a Mack truck inside it. Or if it is not that obvious, usually on a radiograph there is some sign of pathology, either caries or a periapical radiolucency, that points you in the right treatment direction and thus you say to yourself that this is a “no brainer.” Well my loyal readers, not everything is what it seems! The case I am going to present to you was somewhat of an initial “no Doug Kase brainer.” A patient was referred to our office with an obvious need for endodontic treatment on tooth number 3. The X-ray showed a clear radiolucency associated with the apicies of tooth #3 and a relatively large restoration (Figures 1 and 2).

Figure 1 Figure 2

FIGURES 1 AND 2: X-rays showing a clear radiolucency associated with the apicies of tooth #3 and a relatively large restoration.

Upon conducting a clinical exam, I also found a fistula on the buccal gingival, where I placed a gutta percha point to trace its origin (Figures 3 and 4).

Figure 3 Figure 4

FIGURES 3 AND 4: X-rays showing a fistula on the buccal gingival, traced to its origin.

The diagnosis seemed pretty clear-cut in my opinion. Feeling pretty cocky, I informed the patient that this would be a simple root canal, there should be very few post-operative complications due to the fistula, and we would be able to complete it in one visit. I was a hero and everyone was

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happy! I administered buccal infiltration local anesthesia and gave a small palatal injection at the gingival margin also to numb for the rubber dam clamp. Because this was a non-vital case, I felt that there was no need to give a deep palatal injection, which can be uncomfortable for the patient. Actually, due to the non-vitality, I could have done the treatment with very little to no anesthesia. No symptoms + dead nerve + fistula = no pain. I started a conservative access opening through the onlay, and as soon as my bur touched dentin the patient gave me a sign that he was feeling something —he jumped! Impossible, I thought, so I tried again and got the same response from the patient. Now I had to start up the diagnosis machine. I looked back at the radiographs. Perhaps due to internal calcification in the pulp chamber, the palatal root was still vital and walled off and all the pathology was associated with the non-vital buccal roots. Or perhaps was this a bony lesion that was not even associated with an endodontic problem at all. I removed the rubber dam and placed Endo-Ice on the palatal aspect of tooth #3 and got a clear vital response. Using the logic that if there was not enough palatal anesthesia to anesthetize tooth #3, there certainly was not enough to anesthetize #2 as well, I pulp-tested tooth #2 with Endo-Ice, and believe it or not there was no response. How could this be? Everything preoperatively pointed to #3, but there was obvious vitality. Instead of numbing further and proceeding to complete a root canal on #3, which would have looked like a winner on an x-ray, I closed up shop for the day so that I could bring the patient back to retest the area without the presence of local anesthesia. The patient returned the following day, and upon a pulp test of tooth #3, I found that I was able to elicit a vital response from the buccal and palatal surfaces. However, #2 gave no vital response at all. The patient was informed that perhaps tooth #2 was the actual culprit and the radiographic pathology was just presenting mesially. Since this was the only reasonable explanation, endodontic therapy was performed on tooth #2 and the radiographic result on the final films gave me the final answer to this very interesting diagnostic case (Figure 5).

Figure 5

FIGURE 5: Showing the lateral canal off the mesial aspect of the mesiobuccal root and the corresponding puff of sealer into the periapical radiolucency.

Note the lateral canal off the mesial aspect of the mesiobuccal root and the corresponding puff of sealer into the periapical radiolucency. The patient returned one week later without any postoperative symptoms, and the fistula was closed. So remember, don’t always believe what you see. It is OK to do a little second-guessing.

November-December 2005

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FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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In the News

DentalTown HE JANUARY 2005 issue of dentaltown profiles Dentistry Today Essential Dental Systems and its founders Barry Musikant and Allan Deutsch. “In two decades,” the article states, “EDS has gone from being the dream of two of New York City’s most notable endodontists to a pioneering force in the dental universe. Combining their inventiveness and business savvy, EDS has utilized cutting-edge research and state of the art technology and advancement to blaze a path of innovation and creativity in the field. In the process, it has educated practitioners the world over and brought relief to untold multitudes of patients; and its future is still being written.” In the March 2005 issue of Dentistry Today, you will find Allan Deutsch’s “Pulp Chamber Morphology: Basic Research Leads to Clinical Technique,” in which he reports the research that led to the development of the PulpOut™ Bur. This remarkable research has shown that there is a critical depth from the cusp tip to the pulp chamber of teeth with furcations. The “fixed stop” feature of the PulpOut Bur allows you to take advantage of this depth and gain access without the fear and anxiety of furcation perforation.

April-June 2005 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Jay Vuong, D.D.S. In Search of Modern Endodontics

Jay Vuong NCREASED public awaremess of endodontic treatment and increased public demand for it are both realities. This increased demand and the financial rewards for practitioners who use predictable and time-saving strategies to render treatment have helped fuel a so-called “endodontic revolution” in recent years. A variety of endodontic products and techniques have Jay Vuong been in the forefront of this revolution. Terms such as “crown-down rotary instrumentation” and “thermoplastic gutta-percha” are now buzzwords equated with superior endodontic technique, and those techniques are sold by manufacturers as the cure to all woes. How does the average dentist make sense of all of this? What does this mean to the seasoned generalist, the recent graduate, or the dental student who have been taught or still use endodontic techniques and materials deemed “outdated” by the many self-anointed endo gurus? To many, this “endodontic revolution” has raised more questions than it has answered. The standards for treatment outcome have risen—some without justification. Many practitioners now question consciously or subconsciously their own ability to render acceptable endodontic treatment. Some do so to the point of having feelings of inadequacy. Many generalists I have spoken to say that they have no choice but to be defensive. Many others have attended expensive continuing education endo courses. These courses often leave those who attend them with a feeling that something is still missing—that “modern endodontics” is still beyond their grasp. SEARCH FOR If you have those feelings of confusion, or even inadequacy, let me assure you that you are not alone. APPROACHES Ironically, there is still some confusion and debate in the THAT WORK endodontic community regarding the best way to render root FOR YOU. canal treatment. There are several schools of thought on these matters— each of them with an interest in preserving their way of practicing. Academic and clinical arguments in philosophy and practicality have left many endodontists close-minded in their attempt to justify their positions. Dental research deemed good or bad, past or current, can be manipulated or interpreted to support any of these positions. In the midst of all this, my advice has been to do what

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works for you. In light of the fact that there are no conclusive empirical findings regarding many endodontic matters, I have always preferred practicing in a way that is the easiest and most economical for me. Successful patient management and reduction of stress are always major goals when I look to evolve my approach to root canals. I have found that the S.E.T. and EZ-Fill techniques have several strong points regarding practicality; they have worked well for me, and they may work for you. Nevertheless, I urge you to continue your search for approaches that work for you, not just in dentistry, but in your life as a whole. In the upcoming months, I would like to try to answer any questions, or to discuss thoughts concerning endodontic philosophy, technique, materials, and anything else. Comments and questions from readers of this newsletter are not only welcome, but are needed to shed light on what people in our dental community may be thinking about. E- mail us or write to us with your questions or comments. January-February 2001

Endo-Tip

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Jay Vuong, D.D.S. Negotiating Calcified Canals Oscillating Your Way to Success

Jay Vuong E’VE ALL ENCOUNTERED the situation in which a preoperative film shows calcification of the root canal system. Upon seeing the film, you may feel a little hesitant in starting the root canal treatment. Upon starting the procedure and making your access, you may spend countless minutes unsuccessfully trying to introduce very fine instruments in orifice areas where you find a “stick” Jay Vuong in the explorer. Let me reassure you that you are not alone— there’s nothing inadequate about your manual dexterity or skill—but there are alternative techniques to help you negotiate these calcified canals. Maybe I’m clumsy or impatient, and maybe a little of both, but I’ve never had much success using files smaller than a #10 K-file or reamer. When using #6 or #8 files, I would ruin them too easily and would become frustrated just as easily. I would go through an entire box or more and then begin to think about their replacement cost. They tend to be too flexible, requiring exact placement and angulation in order to prevent their bending irreversibly. I find the small files very effective, however, in conjunction with a microscope. Seen through the microscope, a calcified orifice, once explored, shows up as an actual opening in which a #6 or #8 can be inserted carefully at the proper angulation. However, suppose that you are a general dentist who doesn’t have a microscope handy. What can you do when you’re faced with a calcified canal?

The Oscillation Technique

LET ME DESCRIBE one technique that has helped me negotiate a presumably calcified canal once an accurate stick of the explorer is found. I call it the file size oscillation technique. The technique uses larger file sizes to facilitate the movement of smaller files deeper, and then uses a smaller file to facilitate the movement of the previous larger files. The technique assumes that you can make an access to the anticipated level of the orifices, that an accurate feel for a stick is present, and that you can judge and memorize the penetration angle into the orifice. You also have to be patient enough to use light apical pressure in a simple watch- winding, back-and-forth rotational movement of the file or

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reamer. After accessing to the floor of the tooth, I immediately use the double sided endo explorer, usually a sharp Dg16. The explorer helps me feel for the catch of the orifice. More importantly, the explorer, once it is engaged in the orifice, imparts an angulation that one can use to enlarge the access at strategic points. Also, this angulation is the very important angle that you need to place your initial file. In this oscillation technique, I use #10, 15, and 20 files or reamers. I initially begin with a #15, inserting it at the same penetration angle as the explorer. A rule to remember is that you should always allow the file to “go where it wants to go.” Never force a file in a preconceived direction that you want the file to take; forcing the file is a precursor to ledging. An easy way to counteract ALWAYS the tendency to force the direction is to check and allow the file to “flutter” every once in a while. Fluttering involves ALLOW THE engaging your file or reamer into the canal, letting go of the FILE TO “GO instrument, and then flicking the handle and seeing how the WHERE IT file angles. It is at this angle that you want to apply all your forces and motions. WANTS TO GO.” I move the #15 file or reamer apically with a light watch- winding movement, fluttering the handle, checking the angle, and applying my apical force in the direction that the file wants to go, not where I want the file to go. I continue in that manner until I encounter a binding point at which two watch-winding cycles combined with light apical pressure will not advance the file further. When the binding point has been reached for the #15 file or reamer, it is necessary to use the #10 or the #20 file or reamer in the same way. If my initial #15 binds halfway into the canal or deeper, I tend to “oscillate up” in file size, to the #20. Using the #20 in the same way as I used the #15, I will usually encounter resistance at a shorter length than that to which the #15 had penetrated, or, sometimes, at the same length. I then “oscillate down” in file size, using the #15 again with the same watch-winding apical movement. Because of the “crown-downing” effect of the # 20, the #15 will now usually reach the apex. If my initial #15 binds less than half way down the canal, I tend to “oscillate down” in file size, using #10 next. The slimmer #10, used in the same way as the #15, will slide into the canal deeper than the depth created by the #15. Oscillating back and forth between these two instruments, #10 and #15, I can gain enough apical depth to allow the #15 to reach halfway down the canal—that is, past the first curve of the canal. The #20 is then introduced as in the first scenario described above, and the #15 is then used to approach working length. The oscillating approach relies on the use of use of larger instruments to facilitate the apical movement of smaller instruments. Unlike a pure crown-down approach, however, it uses smaller instruments to facilitate the apical movement of larger instruments, then vice versa, until the entire length

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of the canal is negotiated. One is never in a rush to reach the apex, and no one instrument is ever used longer than necessary in the canal. Each instrument is allowed to penetrate at a passive angle, “where it wants to go.” A light touch is essential. Learn to avoid “picking” at the binding point in the canal. Instead, allow the “endodontic game” to come to you. I have found that using three file sizes, #10, #15, and #20, switching among them as I have described, has allowed me to negotiate most fine and otherwise calcified canals. Keep in mind, however, that this oscillating approach is not rigid; you can develop your own sequence, incorporating other tools such as Gates Gliddens or Peesos, to meet your needs more effectively. Personally, I have found that once the canal is negotiated to the apex at a size 20, then incorporating the practical measures that the SafeSider and EZ-Fill techniques allow for becomes very easy. I urge you to try. If you encounter difficulties or want more information, contact us. Better yet, sign up for our free continuation course in which you can explore this and other topics more thoroughly. You’ll find registration information here. May-June 2001 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Jay Vuong, D.D.S. Second Thoughts About NiTi

Jay Vuong N THIS PRESUMABLY modern era of endodontics, With all of the many more dentists are experimenting with the newer positive nickel titanium instruments only to encounter their attributes of limitations. Because of the alloy’s flexibility, nickel titanium nickel titanium, shaping instruments can be sized with larger and varying why do many degrees of taper. These increased tapers and computer-aided endodontists, flute designs have helped impart a more uniform and including me, still Jay Vuong predictable shape to the canal space, especially in the apical rely heavily on half. Depending on the usage, the shape defined or refined the traditional by existing NiTi instruments may be used to enhance the stainless steel effectiveness of cleaning and the ease of obturation through instruments? standardization. With all of the positive attributes of nickel titanium, why do many endodontists, including me, still rely heavily on the traditional stainless steel instruments? Besides the substantial increase in cost, one reason lies in the physical property of the nickel titanium metal itself. Stated plainly, nickel titanium, although flexible, has a tendency to fracture when strained, especially under the torsional strain that occurs when instruments rotate in the confines of tight, curved, and long canals. Predicting the likelihood that an instrument will fracture is difficult. True, using newer instruments can reduce separation rates. However, with such an increase in operational cost, older instruments tend to “appear” usable unless we remind ourselves of their age through the tedious process of marking the instruments according to their number of uses and factoring in the additional wear imparted with prior uses in difficult canals. Even with all these precautions, NiTi instruments can still separate without any prior visual evidence of distortion. Once separated in the canal, NiTi instruments are often difficult to remove or bypass. The flex of the metal makes them difficult to unwind out of the canal, especially around a curve. Their flexibility also allows them to absorb the energy of ultrasonics without dislodging their threads from the dentinal walls. Rather, under ultrasonic vibration, the metal has a tendency to chip away. The silver lining to this difficult situation may be that the NiTi instrument often fractures “at the apex” when binding is usually at its maximum, and that its radiographic opacity matches well, if not inconspicuously, with adjacent gutta- percha. The film may look good, but I still feel a little uneasy, especially in infected cases.

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Another main reason why I still rely on stainless steel instruments is that although NiTi instruments are good for shaping once a pathway in the canal is established, they are not predictable penetrating and gauging instruments. Using NiTi instruments in a rotary fashion will only allow them to stay centered and penetrate the canal by screwing their way into an existing pathway. Although this action should facilitate the apical movement of these instruments in a crown-down fashion, there are times when the existing path in the canal is irregular in anatomy. This irregularity is a precursor to the instrument’s binding and separation. The centering effect of these instrument predisposes them to remove dentin indiscriminately on the furcation or depression side of the root as well as dentin in the root’s thicker and safer zones. Unless a straightening, anticurvature mechanism is used at the coronal level prior to deep NiTi introduction, the situation becomes predisposed to strip perforations, especially in curved, thin, and long canals. An operator’s tendency to abandon the very important endodontic doctrine of straight-line access becomes a compromising habit when one overestimates the abilities of nickel titanium. Through trial and error, especially with rotary instrumentation, most endodontists still feel the need to explore, measure, and establish the canal using traditional stainless steel instruments. This exploration, measurement, and establishment of the main canal space with stainless steel instruments is especially important with cases that present with unusual pulpal anatomy or prior mishaps, such as blockage, ledges, strip perforation, and apical distortions. These are the very cases that require thoughtful manipulation, usually requiring the tactile sensitivity of stainless steel instruments. NiTi instruments can therefore be viewed as “dumb” instruments mainly having the ability to ream the walls of the canal. Their “smartness” is the shape that is imparted into their design, which then can be imparted to the final canal shape. Their flexibility doesn’t allow the operator to have optimal directional sensitivity inside the canal space; rather, sensitivity becomes a measurement of torque or resistance control—the operator becomes more preoccupied with avoiding instrument fracture than exploring the pulpal anatomy. NiTi’s amazing elastic memory, the ability to stay straight no matter how you bend the instrument, is an asset as the instrument threads its way into a cana; however, it becomes a hindrance if you need to prebend the instrument or its tip in order to explore or bypass a ledge or blockage. At larger instrument sizes, this elastic memory translates to a disposition to strip perforations and apical distortion in straightening the canal and is easily underestimated by the overconfident operator. Taking some of these pluses and minuses of the NiTi instruments as applied to endodontics, I have favored the older, yet more reliable stainless stain instruments. Rather than using NiTi instruments as a means to all ends, the

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recognition that NiTis are used most effectively as sizing and shape refining instruments has allowed me to use them more sparingly. July-August 2001 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Jay Vuong, D.D.S. Stressed Tooth, Stressed Dentist

Jay Vuong HEN I FIRST STARTED doing referral-based What is a endodontics, I was surprised by the number of “stressed tooth”? complaints that some patients had about their general On an endodontic dentists. One group of complaints would center on typical level, I see the issues, such as how rough, uncaring, and unavailable their stressed tooth as dentists could sometimes be. The other main group of a tooth (without complaints would center on how the patients had gone to prior root canal Jay Vuong their dentists for routine treatment and then for some treatment) that unknown, unexplained reasons, they now had severe has a significant toothaches or infections. Making matters worse, these two risk of developing types of complaint would often go hand in hand as the an irreversible patients asked whether I could refer them to another dentist. pulpitis or Of course, I wouldn’t and still don’t. After a little persuasion abscess once and encouragement, on my part, the patients would feel better additional about their dentists; that is, they would feel better about their procedures are judgment in choosing their dentists in the first place and then performed on the feel comfortable about giving their dentists “another try.” tooth. Why do patients get upset in the first place? From complaints like the ones described above, it sometimes appears that the patients’ dental experiences fall short of their expectations. With reasonable patient expectations and a little sensitivity and foresight on the dentist’s part, stressful situations like the upset patient with a toothache can often be avoided. One clinical situation that tests the patient/dentist dynamic is the recognition, presentation, and treatment of the “stressed tooth.” Often, the patients who give their dentists compliments when they present in our endodontic practice are patients of dentists who recognize the stressed tooth and present it through their treatment plans. These patients are usually well informed or informed enough to enable them to rationalize the reason for their now needing a root canal, especially after just getting a new restoration. The patients’ dental pain and blame is vented on their own dental situation rather than on the ability of their general dentists. The dentists are seen, by these patients, as the wise caretakers who foresaw the stressful predicament that the patient is now in. These dentists had taken their patients’ expectations into account and, as a result, their patients are not surprised or confused by their current position of needing a root canal. What is a “stressed tooth”? On an endodontic level, I see the stressed tooth as a tooth (without prior root canal treatment) that has a significant risk of developing an

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irreversible pulpitis or abscess once additional procedures are performed on the tooth. Examples of the stressed tooth might include a tooth with a deep amalgam filling, once replaced with a “white filling” or crown that now has a persistent sensitivity to cold, then to heat, with the sensitivity finally turning into a full-blown toothache. Another example is the periodontically compromised tooth, crowned years ago, which with a recent root scaling then develops an acute endodontic abscess. The stressed tooth, as seen in these examples, tends to be recognized once the endodontic problem arises. Wouldn’t it be nice to recognize the stressed tooth before it becomes a problem to you and your patient? One way to increase one’s recognition requires the dentist to view the tooth biologically. It is often practical and productive to see the tooth as an inert solid that the dentist can manipulation in a way that a craftsman or artist manipulates a piece of wood or marble. A problem with this view of the tooth arises, however, when you take the pulp into account. Biologically, dentin can be seen as an extension of the pulp. The dentin, which is not solid at all, but rather porous because of is tubule construct, houses the extensions of pulp odontoblast in a delicate fluid dynamic. Drilling into dentin can then be viewed as cutting into a living tissue. Lacerations in dentin, like lacerations in skin, result in an inflammatory process. In the tooth, if the inflammatory process is significant it leads to permanent changes in the low compliance environment of the pulp. These changes in the pulp can compromise the ability of the pulp to recover from further inflammation resulting from injury. The tooth’s inability to recover translates into clinical symptoms when the patient develops temperature sensitivity then percussion pain that doesn’t go away and only gets worse. Sometimes the pulp or nerve dies, often without symptoms (sometimes in the presence of a temporary sedative) until an abscess develops in the future. To recognize the stressed tooth, one must be able to recognize all the past “injuries” the tooth has undergone and all the suggestive clinical symptoms the tooth has now. Injuries to the pulp are usually revealed by looking at the dentin. Usually, they can be seen in the radiographic and clinical evidence. Carious lesions; extensive restorations in dentin; periodontal defects adjacent to dentin; and clinical evidence of abrasion, attrition, erosion, and recession may be evidence of injury sustained by the pulp. In addition to these factors, you might also be able to recognize changes in the pulp directly. These changes may include thinning or calcification of canals and chamber, pulp stones, thickening of the PDL, or opacity of the bone beneath the root (i.e., condensing osseitis). These pulp changes alone may not present a risk to further restorative insult. However, when they are present in conjunction with other previous dentinal injuries, the situation should be questioned. The patient should also be questioned and listened to. Has the tooth ever bothered the patient in the past? Does the

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tooth bother the patient in any way now? If you see an accumulation of the factors above in an individual tooth, you can define the tooth as a stressed tooth. The stressed tooth has the potential to inflict endodontically related pain when a further significant restorative or periodontal procedure is performed on the tooth. Once a questionable tooth is recognized, the dentist who informs the patient about the situation is one step ahead of the game. The decision to perform or not to perform “prophylactic endodontic treatment,” however, requires a good understanding of treatment planning in conjunction with an accurate assessment of the patient’s risk tolerance . . . and your own. January-February 2002

ENDO TIP Make sure that you clean the FEEDBACK? We welcome your isthmus between the mesiobuccal responses and and mesiolingual canals of a questions. lower molar with a fine diamond Please feel free to visit to remove trapped tissue and look the Endo Forum and for extra canals. add your comments about any of the articles Doug Kase in Endo-Mail.

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Jay Vuong, D.D.S. ABCs of Endodontic Diagnosis, Part 1 The State of the Pulp

Jay Vuong WAS PROMPTED to write this article because it had Statistically, occurred to me that many practitioners, while approaching patients endodontic diagnosis from a practical, hassle-free complaining of standpoint, do not have a complete understanding of pulpal dental pain dynamics. An understanding of pulpal biology and how it significant translates to clinical symptoms would help the dentist utilize enough to appropriate treatment regimens with the hope of maximizing mention to their Jay Vuong the likelihood of a successful outcome. dentist tend to We must agree that when it comes to root-canal treatment, have there is a great deal that we can do to ensure a successful endodontically outcome. However, there are times when the most heroic or related pain. ideal procedural effort does not ensure a predictable outcome or a symptom-free tooth on which to build a restoration. Endodontic outcome, to me, then becomes a question of probability or statistics. To increase the probability of a successful clinical outcome, we must first start with an accurate diagnosis—to begin, we must ask, “what state are the nerve and pulp in?” When patients come in with tooth pain, we as dentists should not dismiss their discomfort. Statistically, patients complaining of dental pain significant enough to mention to their dentist tend to have endodontically related pain. As clinicians, we usually ask a few questions or perform a few tests to see if root canal treatment is appropriate to address the pain. Another way of looking at the situation is that we are presented with an opportunity to match the pulpal condition of a symptomatic tooth to a degenerative timeline that most teeth tend to follow. The biological state of the pulpal tissues tends to give correlating symptoms and radiographic clues. As the pulp initially becomes damaged, it becomes slightly inflamed at the site adjacent to the insult, exemplified by gross decay with resulting inflammation to the underlying pulp horn. This initial inflammation results in a heightened sensitivity to cold, with a sensation of pain, often followed by a heightened sensitivity to heat at a later time. At first, the pain is initiated and sustained only by the stimulus (this is reversible pulpitis). Later, as the pulpal swelling spreads from the initial area of damage or irritation to the rest of the pulpal tissue in the chamber, the pain initiated by the stimulus becomes more prolonged (this is

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irreversible pulpitis). If enough pulpal tissue becomes damaged, the pain may initiate or persist without any stimulus at all. At the same time, the degenerative inflammation of the pulp may reach down the entire length of the root or roots and begin to cause the apical PDL to become inflamed (this is irreversible pulpitis with periapical involvement). Now the patient may have not only a throbbing toothache but also pressure sensitivity (to the pressure of chewing or percussion). This stage marks a later point in the pulpal degenerative timeline when the tooth is the “hottest” and usually the most difficult to get numb. It is at this stage that most people would come in for dental treatment if they hadn’t done so already. Radiographically, we may not be able to see anything unusual periapically since x-rays only show hard-tissue changes and not soft-tissue inflammation. The PDL may look thickened once the lamina dura has resorbed slightly. The Calm Before the Storm

IF THE PATIENT progresses past the period of pulpal inflammation mentioned above without root-canal intervention, the tooth usually enters a calming period. What this really means is that the nerves or pulp have completely degenerated past the stage of total pulpal inflammation to became necrotic. In this state, pain provoked or sustained by temperature would have disappeared. Constant throbbing pain, or the continuous dull radiating ache usually associated with pulpal swelling or degeneration, also subsides. The tooth may still feel sensitive to pressure, since the PDL may still be inflamed due to the presence of the adjacent irritating necrotic debris of the pulp. Some teeth may become asymptomatic, especially with the help of antibiotics and bite adjustment. However, the tooth will not respond to temperature changes or electronic pulp testing. This later stage of pulpal death can be view as the calm before the storm. Because of the bacteria residing in the necrotic pulp, the situation always has the potential to transition toward an endodontic abscess. However, the transition can often take months or even years, depending on a variety of factors. Although many dentists try their best to medicate symptomatic teeth in the hope of avoiding root- canal treatment before restoration, the truth is that many of these teeth tend to feel better because they have slowly arrived at this transitional stage of pulpal death. The sedative dressing or temporary filling usually acts as a nerve blocker (as eugenol does, for example) and is effective as a topical pain medication. Unfortunately, the medication does little to reverse the degenerative inflammatory process that has already begun; pulpal recovery from acute inflammation usually is more dependent on the degree of tissue damage sustained and whether the damage is in conjunction with a bacterial presence. Radiographic evidence may appear within normal limits. However, if teeth stay in

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this stage for a sustained period of time, the bone around the root apex may resorb in the effort to limit the antigenic irritation from the dead pulp. Periapical radiolucency is then seen from a periapical film of the tooth. Sometimes, if the cortical bone adjacent to the radiolucency is lost, a fistula may develop from the area of inflammation or infection that can be seen clinically as a stoma. Its formation is usually a pain-free event, but the situation could become painful if the stoma became clogged or impacted. When a tooth develops an endodontic abscess from the transition period of pulpal death, pressure pain slowly becomes more and more pronounced. The tooth may even become mobile. An infrequent or continuous ache can also arise, not from the swelling of the pulp (which is already dead) but from a swollen periodontal ligament or from a buildup of pressure surrounding the periapical tissues of the tooth. Edema, with a subsequent buildup of pus, usually creates pressure that translates into pain. Swelling or tenderness is usually seen intraorally adjacent to the root apexes. If the infection is not allowed to drain (via a pulpal opening, fistula, or an incision), extraoral swelling and lymph node involvement may develop as the abscess spreads beyond the local confines of the periapical area and into the facial planes. Radiographically, a noticeable radiolucency can usually be seen beneath the abscessed tooth. From this short discussion of pulpal deterioration, you can see that the process is a continuous and dynamic one. As dentists we are usually presented with a “snapshot” of the state of the pulp in time. This basic understanding of the tooth’s pulp has given me more assurance in my endodontic diagnosis. Although there are always some exceptions, the symptoms that a patient presents with usually must fall into the pulpal timeline discussed above if root-canal treatment is to be helpful or meaningful. In the end, the root-canal treatment only accomplishes the removal of the inflamed, degenerative, or dead pulpal tissues from the tooth—and by doing so removes the source of pulpal pain or limits the potential for future ligamental inflammation and periapical bone destruction.

September-October 2002

ENDO TIP Always check to see if there is FEEDBACK? We welcome your more than one canal in a lower responses and bicuspid. See the before and after questions. X-rays below. This tooth has Please feel free to visit three canals. the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Figure 1 Figure 2

BEFORE AFTER

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Jay Vuong, D.D.S. Perforation Revisited

Jay Vuong DENTIST WHO creates a perforation in the process of Ultimately, success performing a root-canal procedure may benefit from depends on the knowing the factors that influence success and failure after a repair of the perforation. amount of bacterial Problems arising from perforations can ultimately be seen contamination still as problems associated with loss of attachment and present beneath destruction of bone in the area adjacent to the defect. Loss the perforation Jay Vuong of structural support as a result of large perforations should also be a consideration. Coronal perforations in unattached repair and the tooth surfaces (that is, coronal to the periodontal attachment) potential of the can be viewed as deep restorative areas, which, once repair material to repaired, have the potential for sulcular irritation unlike deep restorative margins. Considered in this light, perforations of seal against future this type can be repaired with a suitable restoration material bacterial to support the remaining tooth structure and to reduce contamination. irregular margins, paying close attention to the strength of the material and its ease of manipulation. The perforations that require endodontic attention are the ones that occur in areas adjacent to existing periodontal attachment, which often includes the PDL and its associated lamina dura. This type of perforation, if located near the sulcus of the tooth, can be seen as a periodontal threat. If the attachment in this area does not repair and the loss migrates to join into the sulcular space, periodontal pocketing can result. Problems that occur with this periodontal situation then must be alleviated in a periodontal manner. If the perforation occurs more deeply (for example, in strip perforation of a canal), the attachment loss may create a chronic potential for inflammation or infection. Not unlike granulomas at the bottom of chronically inflamed root apexes, the granulation tissue that may form in areas adjacent to failed perforation repairs has a potential to cause pressure discomfort and to progress to abcessing. In this situation, the perforation initially lacks a communication with the sulcus and may progress to eventually become a periodontal problem if the inflammatory process establishes a communication. In light of the above discussion, the aim of perforation repair should focus on repair of the attachment apparatus using the appropriate endodontic or periodontic measure or both. Eliminating (or reducing) bacteria at the site of the perforation during the time of repair and in the future should

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be a priority. In choosing a reparative material, you should consider

Biocompatibility: The chosen material should decrease chronic inflammatory response, promote epithelial or fibrous attachment, or both. Stability: The material should be structurally stable over time. Strength: It should have sufficient tensile and compressive strength if the perforation has substantially weakened tooth support. Sealing ability: It should seal well enough to decrease future bacterial contamination. Handling characteristics: It should be easy to use.

Allowing for a learning curve, the techniques for use of most repair materials can be mastered with practice and an attention to detail. No matter who does a perforation repair (generalist or specialist), success usually depends on timing, size, location, and disinfection. Timing involves repairing the perforation ASAP if possible. Delayed repairs require more difficult disinfection. A perforation that is larger or located near but beneath the cervical attachment has a worse prognosis than a smaller perforation located apically in the canal (away from the sulcus). The larger the area of attachment loss and bony damage, the more difficult disinfecting, sealing, and regenerating will be. Also, the closer the defect is to the sulcus, the less chance there is for a successful repair due to the future ingress of bacteria from the pocket space. A periodontal problem will result. Disinfection of the perforation usually demands good isolation and the use of disinfectants (such as NaOCl). Ultimately, success depends on the amount of bacterial contamination still present beneath the perforation repair and the potential of the repair material to seal against future bacterial contamination. Controlling those circumstances becomes more difficult as perforation size increases. Location plays a role in that the sulcus provides an additional source of bacterial ingression that impedes attachment formation. February -March 2003 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Michelle Verdi, Experdent Consultant Let’s Talk Phones!

would like to discuss the importance of the telephone in making a good first impression on patients. To begin, ask yourself the following questions:

When your phone rings, do you know how it is being answered? Does your staff have the proper training to represent your practice?

When patients (or potential patients) call your office, they make judgments about you and your practice based on what they hear over the phone. They do not see the office decor, they may not have met you, and if they are new patients, they do not know the quality of your care. You are relying on the verbal skills of your receptionist to convey an image of your practice. Why dedicate an article to telephone skills? It is a fact that despite the telephone’s widespread use, it is often a misused communication tool. I am sure that you have had many frustrating business calls because of a poorly trained or ENDO TIP ineffectual person on the other end. I have witnessed telephone communications go hopelessly wrong, and I believe that telephone etiquette is an acquired skill. The proliferation of electronic devices, such as Have you ever opened the answering machines and cell phones, is part of chamber of a pulp and the contemporary style of telecommunications. experienced a fetid odor? I The irony is that the more accessible we have have. Using a mouthwash in become through technology, the more a syringe to irrigate the pulp communication has become a one-way canal works to eliminate that dialogue. The practice of using answering odor. Many times I'll leave machines when an office is closed can be positive or negative. If you use an answering the rinse inside the chamber machine, be sure that your message includes for a few minutes. Afterwards, I'll rinse with sodium practice hours hypochloride. Then the odor emergency contact procedures will dissipate. Patients who when the office will reopen smelled the initial odor feel terrific, for there is no longer

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If you leave a pager number, be sure that it an odor. Furthermore, they works! feel that you, as a practitioner, Never just leave the traditional answering- have "really" done something machine message that says, “No one can take for them. I hope you have as your call at this time. Please leave a message at much success with this the tone.” This is possibly the most irritating technique and patients' form of answering-machine abuse for a potential acceptance of it as I have. patient or an existing patient to hear. If you use an answering machine during lunch Amy Dukoff, D.M.D. breaks or meetings, include that fact in your message, and also let callers know when to call back or when to expect a call back from you. Voice mail can also be an effective means of communicating. Patients can be offered options, such as

scheduling appointments general practice information leave messages for individual doctors

A system that handles overflow can also be used to prevent the caller from hearing “Doctor’s-office-please-hold” as soon as the calll is answered, something that is a common phrase in busy offices. If you use a voice mail system, be sure that to check the messages and respond as soon as possible. I cannot tell you how often I hear complaints from patients who did not get a call back or were lost in the system. 11/02/99

FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Young Bui, D.D.S. Post-Operative Pain Management

Young Bui PRIMARY PURPOSE for performing a root canal procedure is to relieve the patient of dental pain. Unfortunately, certain aspects of the root canal procedure sometimes introduce post-operative pain in the same tooth that we are trying to repair. The most common type of post-operative pain is hyperocclusal pain. Fortunately, this is also the easiest type Young Bui of post-operative pain to prevent. Before initiating the procedure, reduce the occlusion on the suspected tooth at least 2 mm or completely out of occlusion. This reduction of the occlusion is very important if the tooth is a vital one or if the patient has positive percussion pain at the start. If that tooth is not going to be restored by a crown, then perform the root canal procedure and reduce the hyperoccluded area, using space occlusal paper to minimize tooth removal. Another post-operative pain that can be prevented is caused by stripping or perforating the apical constriction upon instrumentation of the canal. By using an apex locator, you can easily detect the anatomic apex and not perforate through it. In a vital tooth, perforating the constriction will cause trauma and inflammation to the periodontal ligament. Unfortunately, In a non-vital tooth, perforating the constriction will make it certain aspects of more likely that you will accidentally push the debris through the root canal the apex and cause post-operative flare-ups. procedure A related type of pain is caused by excreting cement or sometimes gutta-percha through the apex upon filling. If you use the introduce post- SET method along with the SafeSider® files, you can operative pain in develop a greater-taper canal. The taper will prevent the the same tooth gutta-percha from extending past the apex upon lateral that we are trying condensation. If you then use the EZ-Fill method of coating to repair. the wall with cement, you will prevent cement from excreting out of the apex and thus prevent irritation of the apical tissues. No matter how good your technique is, there will always be inflammation of the periodontal ligament from any root canal treatment because the tooth is constantly being disturbed in the socket during instrumentation of the canal. This movement of the tooth puts a lot of tension and stress on the periodontal ligament, causing it to become inflamed. Many of us prescribe analgesic medication for post- operative pain, but we tend to forget about the inflammation. Analgesics will provide comfort to the patient, but they will

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not reduce the inflammation caused by instrumentation. This inflammation can be managed with anti-inflammatory medications, such as ibuprofen. Six hundred mg of ibuprofen together with 1 g of acetaminophen will provide both analgesia and anti-inflammation for up to eight hours. This dosage is both economical and effective. May-June 2001 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Young Bui, D.D.S. Who Should Be Given Antibiotic Prophylaxis?

Young Bui EFORE TREATING patients, we should always take a good medical history. Always go over the questions with the patients to make certain that they understand the technical terms. Be sure to ask whether they have had a disease or medical problem that is not listed on the history form. Investigate further about systemic diseases that they mark and ask what medications they are taking. Certain Young Bui patients will need to be pre-medicated before treatment to prevent systemic bacterial endocarditis (SBE). Endocarditis occurs when bacteria enter the bloodstream and infect damaged endocardium or endothelial tissue located near high-flow shunts. The dentist’s goal is to prevent endocarditis from occurring in susceptible dental patients. Any dental procedure that causes injury to the soft tissue or bone, resulting in bleeding, can produce a transient bacteremia. Below is a list of the frequency of bacteremia associated with various dental procedures and oral manipulations based on Bender in 1984 and Pallasch in 1989.

Periodontal surgery 88 % Extractions 51-85 % Periodontal scaling 8-80 % Chewing 17-51 % Dental prophylaxis 0-40 % Toothbrushing 0-40 % Endodontic therapy (non-vital) 0 %

Consider antibiotic prophylaxis (AP) for dental work to minimize effects of bacteremia. Besides the usual heart conditions that require AP, such as rheumatic fever, heart murmur, mitral valve prolapse with regurgitation, and congenital heart disease, many other conditions that require prophylaxis may be overlooked. One example is HIV. We seldom ask patients if they are HIV+ because we don’t want to embarrass patients or because we take universal precautions against HIV. Not asking may be harmful to the patient. A patient who contracted HIV from sharing needles is very likely to have had SBE previously, due to injecting bacteria directly into the bloodstream. Infective endocarditis must be prevented in these patients. AP is best avoided in

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AIDS patients unless severe neutropenia is present (<500 cells per mm3). Under those conditions, the patient will require antibiotic prophylaxis. Patients who had surgically corrected cardiovascular lesions should be given AP up to six months postoperatively. Six months after surgery, most patients are no longer susceptible unless foreign material was used or if they have artificial heart valves. AP is required in patients with the latter two conditions. In patients with pacemakers, a medical consultation is needed to determine whether AP is necessary. It is not recommended by AHA, but some physicians may suggest it. Patients on hemodialysis should be off the dialysis machine for at least four hours before a dental procedure because of heparin, and AP should be considered. In patients with joint prosthesis, AP is not necessary unless they are in the “high risk” category, such as those with rheumatoid arthritis, diabetes, immuno-suppressed conditions, or previous infection. The following bleeding disorders may cause the patient to have post-operative infection and therefore AP should be considered in surgical cases: thrombocytopenia, systemic lupus erythematosus, vascular wall alterations, hemophilia, von Willebrand’s disease, liver disease, and leukemia.

July-August 2001 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Young Bui, D.D.S. One-Visit Root-Canal Treatment

Young Bui S TECHNOLOGY in dentistry advances, we approach We can reduce our treatment techniques in different manners. We the number of continue to strive for perfection while speeding up chair-time and reducing overhead costs. This methodology visits and still applies to all specialties in dentistry including endodontics. maintain a high The fundamentals of endodontics remain the same. The only rate of success. difference is the process by which we attain our goals. With Young Bui the many different hand files and mechanical systems in the market today, we can reduce the number of visits for our patients and still maintain a high rate of success. Root-canal treatment usually required more than one visit in the past because of the difficulty in cleaning and shaping curved and calcified canals and the low success rate of non-vital or necrotic cases. Most root canal systems are straight and patent enough for a size 15 file to fit down to the apex with ease. However, there are cases where the root is severely curved or dilacerated, and some canals are tight due to calcification. To engage into such canals, we need a file that has great tensile strength to resist deformation, flexibility to negotiate the curves, and is thin enough to fit into such tight space. Upon finding a tight canal, we automatically pull out the size 8 or 10 files either in Hedstrom, K-type, or reamers. The problem with these files is that they have weak tensile strength. They tend to bend or buckle at the tip when a little pressure is applied. They do not have the strength to withstand the force exerted upon them as you try to push them down the tight canal. I love to use Hedstrom files, but what I found to be a great file for a tight or partially calcified canal is the EZ-Fill® SafeSider™ size 10 file. This file can negotiate a tight canal with ease and has the tensile strength to withstand deformation. If you have not tried this type of file in a situation like this, I would recommend it highly. I used to be a strong proponent of Hedstrom files until I tried out the SafeSider files. The success or outcome of a root-canal treatment depends on the ability to remove all infected pulp tissues and then seal the canal completely with gutta-percha and sealers. In order to have a tight, dense fill we must first clean and shape the canals to fit the gutta-percha point. Most of the landmark studies use a .02 tapered file to clean and shape the canals. With a .02 file, you are not able to clean out the infected wall

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of a necrotic canal successfully. Studies show that the cleaning and shaping procedures do not remove all the bacteria from necrotic root canals. Removing all the bacteria requires the use of Ca(OH)2 in the canal as an inter-visit medicament to aid in sterilizing the canal system; thus, the patient is required to make a second visit. However, there is another way. By using the new nickel- titanium greater-tapered files of .06 to .08, you can remove more infected dentinal wall of the root canal system and create a nice tapered canal wall to fit the greater tapered gutta-percha cone. Another instrument you can use is the #2 Peeso reamer. It can reduce your cleaning and shaping time significantly. Once you have cleaned and shaped the canal to a .06 or .08 tapered, use EDTA to remove the smeared layer against the wall. Then irrigate the canal with full strength NaOCl and clean the wall with an ultrasonic tip. The vibration will allow you to kill the bacteria embedded .5 mm into the dentinal tubules. By shaping the wall to a .06 or .08 tapered and then using the ultrasonic tip, you eliminate bacteria that are embedded at least 1 mm into the dentinal wall. This will ensure a clean canal and eliminate the use of Ca(OH)2 in between visits. By the way, Ca(OH)2 does not kill enterococci such as E. feacalis. Potassium-iodine can kill all bacteria in the canal in seconds. That is one alternative irrigating solution you can use. Just be careful not to get it on the patient’s clothing. September-October 2001 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Young Bui, D.D.S. MTA: An Excellent Concrete Material

Young Bui TA, mineral trioxide aggregate, is a new material Figure 1 developed for endodontics use. MTA appears to be a significant improvement over other materials for procedures in bone. Unlike ZOE cement, amalgam, and resin composite, which resulted in the formation of fibrous connective tissue adjacent to the bone, MTA allows osteoblasts to attach and spread on it with little or no tissue inflammation. It is the Young Bui first restorative material that consistently allows for the overgrowth of cementum. Schwartz et al (July 1999) showed that root ends filled with MTA had a complete layer of cementum over the filling. Comparing gap sizes between the root-end filling materials and their surrounding dentin shows that MTA had better adaptation compared with amalgam, Super-EBA, and IRM. This improved adaptation allows

MTA to provide a better seal when used as retrograde filling. FIGURE 1: Radiograph showing a non-vital open Keiser et al (May 2000) compare the cytotoxicity of MTA apex before sealing. to other commonly used retrofilling materials, Super-EBA and amalgam. In the freshly mixed state, the sequence of toxicity was amalgam > Super-EBA > MTA. In the twenty- four-hour set state, the sequence of toxicity at a low extract Figure 2 concentration was Super-EBA > MTA, amalgam, and Super- EBA > amalgam > MTA at a higher extract concentration. Torabinejad et al (July 1998) showed the tissue reaction to implanted MTA, amalgam, IRM, and Super-EBA in the tibias and mandibles of guinea pigs. The tissue reaction to MTA implantation was the most favorable observed at both sites. In the tibia, MTA was the material most often observed with direct bone apposition. There are many uses for MTA in addition to its use as a root-end filling. MTA can be used to seal perforations; it acts as a pulp capping material; it produces apical hard tissue formation in immature teeth; and it acts as an apical barrier in open apex cases. Sealing off the perforation site immediately during the initial visit will give the best prognosis for the tooth. The FIGURE 2: Radiograph showing a non-vital open trick for sealing mid-root strip perforation is to first clean out apex after sealing with the canal completely and then fill it with gutta percha and MTA and gutta percha in a sealer. Next, remove the gutta percha to about 2 mm below one-visit treatment. the perforation and irrigate out the debris. Next, mix the MTA to a putty consistency and pack it down the canal with either a plugger or a medium-size gutta percha. The trick to

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mixing the MTA is not to have it too dry. If it is too dry, it will fall apart on you as you try to pick it up. Use enough water to make it into a putty so that you can pick it up easily.

MTA can be used as a pulp capping material in vital mechanical exposure or in primary tooth pulpotomy. Ford et al (October 1996) found that pulps capped with MTA had no pulpal inflammation after five months in five of six samples and all six pulps in this group had a complete dentin bridge formation. In contrast, all the pulps capped with Ca(OH)2 showed pulpal inflammation, and bridge formation occurred in only two samples. Eidelman, Holan, and Fuks (January 2001) did a study to compare the effect of MTA with that of formocresol as pulp-dressing agents in pulpotomized primary molars with carious pulp exposure. They found that none of the MTA-treated teeth showed any clinical or radiographic pathology at a 17-month recall. Ca(OH)2 has been the material of choice for apexification in vital teeth. Shabahang et al (January 1999) showed that MTA produced apical hard tissue formation with significantly greater consistency than Ca(OH)2 or osteogenic protein-1. For non-vital open apex cases, MTA can be packed down to the apex and the canal can be filled in on the same visit. The MTA will act as an apical barrier and allow for bone to grow around it. The radiograph in Figure 1 shows the before and after of a non-vital open apex sealed with MTA and gutta percha in a one-visit treatment. I’m sure that you are probably saying, “Wow, great stuff! But how much will it cost me?” MTA is being sold in six one-gram packages for $249, manufactured by Tulsa Dentsply. Holland (2001) compared the healing property of MTA and Portland cement as a pulp-capping material and found no difference between the two. MTA has the same chemical properties as Portland cement except that MTA also has bismuth to give it a more opaque look in a radiograph. January-February 2002 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Young Bui, D.D.S. Case Report

ach of the following three cases is interesting and educational in its own way. Each has its own uniqueness and value to our everyday treatment. Case 1

A 39-year-old male was referred to our office for evaluation Young Bui of tooth #2. The x ray (Figure 1) showed the beginning of a lucency at the apex of the mesio-buccal (MB) root. The restoration was shallow, with plenty of dentin separating it from the pulp. There was evidence of perio bone loss on the distal side of the tooth. The patient complained of having episodes of dull aching pain over a two-week period. He had pain to percussion but not palpation. He had no sensitivity to cold on the buccal, only on the palatal side. The first thought that came to my mind was a fracture in the tooth. When you have a partial non-vital tooth with a shallow restoration, more than likely there is a fracture in the tooth somewhere that caused the tooth to die. Upon opening up the access, I did not find any fracture line. There was no decay underneath the restoration. The pulp tissues in the mesio-buccal and disto-buccal (DB) canals were non-vital. The palatal (P) root had the entire pulp tissue still intact and vital. My interesting finding occurred when I was taking the working length measurement with the apex locator. Both the MB and P roots were 22 mm long. The reading for the DB root, however, was at 16 mm. I verified it with an x-ray film. Apparently, the DB root ended just above the level of the bone. Bacteria in the saliva must have contaminated the canal, causing retrograde necrosis of the DB root, which in turn infected the MB root. You can truly appreciate my finding in the final x ray (Figure 2).

Figure 1 Figure 2

FIGURE 1: showing the beginning of FIGURE 2: showing the DB a lucency at the apex of the mesio- root ending just above the buccal (MB) root. level of the bone.

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Case 2

An African-American male in his 30s was referred for RCT on tooth #29. The patient was asymptomatic. The pulp was exposed upon excavation by the general dentist. The x ray (Figure 3) shows two distinct roots on this tooth which in itself is pretty rare. Upon instrumentation of the buccal canal, I was able to locate another canal about 3-4 mm apically from the buccal orifice. This is normally the case with multiple-root bicuspids. I have done three maxillary bicuspids with three roots. In all of the cases, the third canal was located in the buccal root about 2-3 mm apically from the orifice. Filling such a root is a little challenging. First, coat the walls of all the canals with RC cement. The next step is to fill the third canal first. Then sear it off and remove the gutta percha down to the opening of the third canal, exposing the main buccal canal. Now you will have an unobstructive path to fill the main buccal canal and the palatal or lingual canal. You can see the two canals bifurcated almost one-third of the way down the root in Figure 4.

Figure 3 Figure 4

FIGURE 3: showing two FIGURE 4: showing the two canals distinct roots on tooth #29. bifurcated almost one-third of the way down the root.

Case 3

A 38-year-old female presented to the office with constant throbbing pain in her lower left jaw. Tooth #18 had had RCT done a year ago. She had pain to percussion and palpation. The x ray (Figure 5) showed perio breakdown in the furcation and periapical lucency on the MB root. The tooth had a ++ mobility. When I saw the perio breakdown in the furcation, the first thing that came to my mind was a strip perforation. It could also possibly have been a lateral canal, but in this case the gutta percha was situated too close to the furcation, indicating a possible strip perforation. I proceeded to remove the old gutta percha and cleaned both roots. When I went in to dry the MB canal, I noticed some blotches of blood on the paper point, confirming the strip perforation diagnosis. I did not know where the perforation was located along the root so I decided to fill the entire canal with MTA. (See “MTA: An Excellent Concrete Material.”) By plugging and laterally spreading the MTA, I was able to force the MTA against the wall and out of the perforation site. I than

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went down the canal with the brown EZ-Fill® SafeSider™ file (25/.08 taper) to make a canal space for the gutta percha. Finally, I filled the canal up with gutta percha and EZ-Fill® cement. You can see the puff of MTA extruding into the furcation through the perforation site in Figure 6. It will allow bone to grow around it without causing any inflammation. You can see the furcation beginning to heal up in the 3-month follow-up x ray (Figure 7). The tooth is asymptomatic and the mobility has disappeared.

Figure 5 Figure 6

FIGURE 5: showing perio FIGURE 6: showing the puff of breakdown in the furcation and MTA extruding into the furcation periapical lucency on the MB through the perforation site. root.

Figure 7

FIGURE 7: the 3-month follow- up x ray.

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Young Bui, D.D.S. Root Fractures

OOT FRACTURES occur in fewer than 8 percent of Figure 2 traumatic injuries to permanent teeth. When they do occur, hemorrhage from the pulp and periodontal ligament (PDL) flows into the fracture site and clots. The fractured surfaces of dentin and cementum are gradually remodeled by surface resorption and apposition of calcific tissue. Root fractures heal differently depending on the degree of separation of the fragments, the Young Bui severity of injury, and the ability of the pulp to heal. the differences in healing may take any of the following forms. Calcific healing is a form of healing in which a calcific callus is formed at the fracture site on the root surface and inside the canal wall. This type of healing requires a wide canal with the fragments in close apposition with little or no mobility. The pulp will be vital and the tooth will have little or no mobility. Connective tissue healing is a form of healing in which a fibrous attachment similar to PDL develops between the fractured fragments. This results when the fragments are FIGURE 2: Calcific callus separated farther apart or because some mobility is present. The formation of the root in an pulp will be vital and the tooth will have little mobility. The extracted tooth. connective tissue will appear as a fracture line on the radiograph.

Combined bone and connective tissue healing is healing in which new bone may grow between the fractured segments if Figure 3 further separation occurs or there is mobility of the parts. The fractured surfaces are lined with cementum with new PDL growing between the tooth and the new bone. The pulp is vital. Healing with nonunion and granulation tissue formation is a form of healing that occurs when the pulp is injured or infected and becomes necrotic due to narrow root-canal space, contamination of the pulp by oral fluids, or severe dislocation of the fractured root. The pulp tissue in the incisal segment undergoes necrosis and the apical segment will remain vital. The tooth will be loose and sensitive to percussion, and it may turn dark.

FIGURE 3: Endodontic treatment on the coronal segment of a tooth with a horizontal fracture.

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Figure 1

FIGURE 1: Different forms of healing: A, Calcific callus; B, Connective tissue; C, Combination of bone and connective tissue; D, Nonunion and granulation tissue formation

With most root fracture maintaining vitality of the pulp, the main goal of treatment is to enhance this healing process. The clinician should try to reunite the fractured segments by calcific callus formation because the tooth will be stronger than one without the union of broken parts. The fracture should be reduced as soon as possible and the broken tooth firmly immobilized by splinting or bonding to adjacent teeth. There are two types of root fracture:

fracture without communication with the oral cavity fracture with oral communication

The noncommunicating fracture occurs in the apical or middle third of the root. Perform a vitality test, check for color change in the crown, and record the degree of mobility of each traumatized tooth. If the pulp is vital, then immobilize the tooth by splinting it to the adjacent teeth. A radiograph should be taken after repositioning to confirm realignment. The length of time to leave the splint on ranges from one week to three months or more, depending on the degree of mobility and the location of the fracture. There is no need to splint the tooth if the fracture is in the apical third with little displacement or mobility. If the fracture is at the crest of the alveolar bone with modest displacement and mobility, the splint will have to stay for three months or more. When the splint is removed, the clinical status of the tooth must be determined. The degree of mobility, color of the crown, and vitality of the pulp should be recorded. If the periodontal attachment has failed to heal, the prognosis for healing decreases drastically. If the tooth responds as normal to a pulp test with little or no mobility and the patient is comfortable, then there is nothing more to do but follow up in six months and a year after that. If mobility is present, the splint must be reapplied and the occlusion adjusted. The tooth should be splinted permanently to the adjacent teeth if mobility is present after six months. If the fracture of any part of the root is coronal to the periodontal attachment, the prognosis for healing is poor. There is periodontal breakdown along the fracture line with pulpal necrosis from the bacterial contamination through the fracture. The most common type of fracture is seen in the maxillary

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incisor with the fracture on the labial surface 2-3 mm supragingival but tapering obliquely to 2-5 mm subgingivally on the lingual. This type of fracture can occur with premolar and molar cusps. The fractured part should be removed during the emergency visit, and endodontic treatment should be done in one visit. Once the emergency has been taken care of, plans must be made for restoring the tooth.

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Young Bui, D.D.S. Endodontic-Periodontal Relations

HE HEALTH of the periodontium is important to the Figure 1 proper function of a tooth. The periodontium includes the gingiva, cementum, periodontal ligament (PDL), and alveolar bone. Disease that affects the periodontium usually is a result of the direct extension of pulpal disease or due to apical progression of periodontal disease. When the pulp becomes infected, the disease can progress Young Bui beyond the apical foramen and inflame the PDL. The FIGURE 1: Endodontic inflammatory process results in replacement of the and periodontal diseases periodontal ligament by inflammatory tissue. Without proper are occurring treatment, the inflammatory response can cause resorption of independently of each the alveolar bone, cementum, and dentin. other. Besides going through the apical foramen, pulpal disease can progress through lateral canals. Lateral canals are seen mostly in the apical third of the root and in the furcation area Figure 2 of molars. Pulp disease may cause an inflammatory response of the PDL at the opening of lateral canals, resulting in a lateral radiolucency on the root. The inflammatory response at the lateral canals may extend crestally along the lateral aspects of the root and ultimately involve the furcation or crestal area of the attachment apparatus. The effect of periodontal disease on the pulp is not as FIGURE 2: Endodontic clear-cut as the effect of pulpal disease on the periodontium. disease is occurring Periodontal inflammation may exert a direct effect on the secondarily to a pulp through the same lateral canal or apical foramen periodontal condition due to bacterial retrograde from pathways. The effect of gingival wounds on the pulp is distal root. shown in irregular dentin formation in the pulp opposite the

wound site. This might be transmitted through irritation of

the odontoblastic process. This irregular dentin formation Figure 3 may be aided by cemental resorption in periodontal inflammation. There are five types of endo-perio lesion that may occur at any given time. We have to be able to diagnose the lesion properly in order to provide the proper treatment. Primary Endodontic Lesions

A sinus tract originating from the apex or a lateral canal may FIGURE 3: Periodontal disease at the furcation is form along the root surface and exit through the gingival occurring secondarily to a sulcus. This is a fistula that drains along the PDL into the pinpoint perforation at the sulcus instead of exiting through the buccal or lingual furcation floor. mucosa. This is not a true periodontal pocket. You may see

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drainage in the sulcus area or swelling simulating a periodontal abscess. The tract can be traced to the source of the infection, usually the apex or lateral canal. This tract is more tubular and thinner than an infra-bony periodontal pocket. Because this lesion is an endodontic problem, complete resolution usually occurs after routine endodontic treatment. Primary Endodontic Lesions with Secondary Periodontal Involvement

If the primary lesion is left untreated, it may progress to involve periodontal disease. An example would be plaque formation appearing at the tract opening that was followed by calculus formation resulting in gingivitis and periodontitis. Once this result has occurred, both endodontic and periodontic therapy will be needed. Primary Periodontal Lesions

Periodontal disease may progress and spread along the lateral aspects of roots and in the furcation areas. In periodontal disease, vitality testing will reveal a normal pulpal response. Periodontal examination will reveal pocket depths and accumulation of plaque and calculus. The bony lesion is usually more widespread and generalized than are lesions of endodontic origin. Periodontal therapy is needed for this situation. Primary Periodontal Lesions with Secondary Endodontic Involvement

Periodontal disease may have an effect on the pulp through dentinal tubules, lateral canals, or retrograde from the apex. If the tooth does not respond to periodontal treatment, a necrotic pulp may be the cause. Once the pulp becomes secondarily inflamed, it can in turn affect the primary periodontal lesion. Scaling, curettage, and flap procedures may open lateral canals or dentinal tubules to the oral environment resulting in pulpal inflammation leading to necrosis. This is likely to be the case when a patient complains of tooth sensitivity or inflammation after a routine scaling and root planing. If a root is exposed as a result of severe periodontal disease, the exposure may allow bacteria to enter through the apex and cause a retrograde necrosis. In a situation such as that, both endodontic and periodontal therapy are required. True Combined Lesions

Some teeth have both pulpal and periodontal disease occurring independently. Each of these diseases may progress until the lesions unite to produce a radiographic and

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clinical picture similar to that of other lesions with secondary involvement. Once the endodontic and periodontal lesions join, they may be indistinguishable from endodontic and periodontal lesions that are secondarily involved.

WITH ALL THIS IN MIND, always do a complete exam and vitality test on a tooth. Together with a good radiograph, these are the diagnostic essentials you’ll need before performing endodontic treatment. An abscess can be of endodontic or periodontal origin. A root-canal treatment on a periodontally abscessed tooth will not resolve the problem.

November-December 2002 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Young Bui, D.D.S. Anatomy of Multiple Canals and Roots

E WERE TAUGHT in dental school the very basic Figure 1 knowledge of root anatomy and the average number of canals in certain teeth. This knowledge gives us the basis to perform root-canal treatment. However, there are times when we stumble upon a unique case with an extra root or extra disto-buccal (DB) or extra palatal (P) canal. These cases may not be too confusing if the canal is wide open and Young Bui is easily engaged with a file. Unfortunately, in some cases FIGURE 1: Upper left first the extra canal is located far from the other opening and is molar with files showing partially calcified. We may not try to gain access into the three individual mesial extra canal because we may think that it is just a dimple in canals. the floor of the tooth or because it is not at a “normal” location for a canal. The number one reason for failure of upper first and Figure 2 second molars is not cleaning the second mesio-buccal (MB2) canal. You should always check to see if there is a little dimple or catch in the isthmus running from the MB canal to the P canal. Dental textbooks say that MB2 occurs in half of all upper molars. In my years of practice, I have encountered MB2s in 75 to 80 percent. I tend to get nervous when I can only find one canal in the MB root. Always FIGURE 2: Upper right assume that there are two canals until careful examination second bicuspid with three proves otherwise. If the two orifices are close to each other, roots. the two canals are more than likely to join at the apex. If you have a second canal midway between the MB and P canal, then you will probably have two separate apexes. Figure 3 Figure 1 shows an upper first molar with three individual MB canals and two palatals. There are also two DB canals, but there was no more room to place in another file. The three MB and P canals have separate apexes and the DB canal joins together at the apex. An upper first premolar usually has two canals with two separate apexes, and an upper second premolar has one or FIGURE 3: Upper left two openings ending in one apex. There are unique cases in second bicuspid with three which you will find three canals or three individual roots in roots. an upper premolar. Sometimes the third canal is located right next to the buccal canal. At other times, the third canal is located a couple of millimeters below the buccal orifice. If an inserted file is angulated toward either the mesial or distal direction, that is a good indication of a third canal. You will see this angulation when the two orifices are situated really close together. If you have a large buccal orifice, but the file

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Figure 3

feels tight as it is being inserted, there is probably a third canal situated a couple of millimeters below the orifice to the side. Widen the orifice with a slow speed #2 round bur and FIGURE 4: Lower right examine for a second buccal canal. second bicuspid with three Figure 2 shows an upper right second bicuspid with three roots. individual roots and canals. The two buccal canals are situated side-by-side close to each other. Figure 3 shows an Figure 3 upper left second bicuspid with three individual roots and canals. The second buccal canal is located a couple of millimeters below the buccal orifice. The frequency of occurrence of two canals in a lower first bicuspid is about 24 percent, and it is 2.5 percent for the second bicuspid, depending on the studies or textbooks you read. The percentage for three canals or roots is given as about 1 percent or less. I have been very fortunate, or maybe FIGURE 5: Lower right first bicuspid with three unfortunate at the same time, to have performed root canals individual canals. on these two rare anatomies. When you see on an x-ray that the tooth does not have a clear, straight canal, start searching for extra canals. Figure 4 shows a lower right second premolar with three individual roots. The third canal is located about 3 mm deep into the buccal orifice. Figure 5 shows a lower right first premolar with three individual canals. When a patient has a tooth with a great-looking root canal that does not seem to heal, there is probably another canal somewhere that is causing the problem. Try to angle the x- ray and see if you can locate another canal.

February-March 2003 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Young Bui, D.D.S. Osteomyelitis of the Jaws

34-YEAR-OLD African-American female presented to our office on a Sunday morning with severe tooth pain that had been keeping her up all night. She had no significant illness. However, she was allergic to penicillin, aspirin, and codeine. She had undergone root-canal treatment before with no adverse reaction.

Young Bui Dental History

She had gone to see a general dentist regarding pain in response to heat and cold on tooth #19, which had an existing composite restoration. The composite was removed and the tooth was temporized to see whether the symptom would subside. She came back with acute pain on #19 and her dentist initiated root-canal treatment. She had one or two days of comfort after the RCT and then pain began again. Her dentist re-instrumented the canals, but the pain began to return a day or so later. She said that her dentist had gone in and instrumented the canals again on four or five other occasions, but the pain had never gone away. The pain was sharp and severe at times with no alleviation from painkillers. Her dentist decided to refer her to me for evaluation and treatment of this tooth. Oral Examination

The tooth was very tender to percussion and finger pressure. The buccal gingival was very tender from #18 to #21, with most tenderness at the base of #19. It felt as though an abscess was ready to break through the cortical plate. Radiograph

The X-ray showed no periapical radiolucency (PAR) or thickened PDL. Number 18 had had RCT done with no PAR. The jawbone had normal trabeculation with no significant pathology. Treatment

I gave two carpules of 2 percent lidocaine with 1:100K epi as an inferior alveolar block. I isolated #19 under a rubber dam and gained access. The canals had already been instrumented

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to at least a .04 taper. I completed RCT in a single visit using the EZ-Fill® SafeSider® technique. There was no drainage through the tooth. I temporized the access with cotton and zinc phosphate cement and gave the patient Bextra 10 mg as an anti-inflammatory and Clindamycin 150 mg as an antibiotic. She came back the next day with severe pain and swelling. I made an incision to relieve some pressure and prescribed Demerol 50 mg for pain. She continued to have pain for the next couple of days, with painkillers giving only a couple of hours of relief. She came back four days later, and I made another incision, which drained out at least 20 cc of purulent exudate. I referred her to an oral surgeon for apical surgery. The surgeon didn’t want to perform the surgery until the swelling had subsided. She was in so much pain that she had the tooth extracted against the surgeon’s advice. After the extraction, she felt better for about a week, but then the same severe pain started up again. She was admitted to the hospital by the same oral surgeon for examination. A CAT scan, MRI, and blood work revealed the patient to have osteomyelitis of the jaw. Surgery was done to remove the entire buccal plate of necrotic bone tissue, which had spread from #18 to #22. She was managed post-operatively with IV antibiotic consisting of Clindamycin 600 mg and Levofloxacin 500 mg. The pain has since subsided, and she is feeling a lot better. Osteomyelitis

The cause of osteomyelitis is associated with Staphylococcus aureus, a skin surface bacterium. The organism is iatrogenically introduced into the deeper tissue planes by surgery or trauma, resulting in an infectious process that is either localized or hematogenously metastatic or both. However, the idea of S aureus as the primary pathogen of tooth-bearing bone does not hold true. Acute osteomyelitis of the jaw is usually a polymicrobial disease, with streptococci, Bacteroides, peptostreptococci, and other organisms involved. Hudson (1993) wrote that “Acute osteomyelitis of the jaws may manifest itself with fever, malaise, facial cellulitis, trismus, and significant leukocytosis. Osteomyelitis of the jaws of a chronic nature has findings consistent with swelling, pain, purulence, intraoral or extraoral draining fistulae, and nonhealing bony and overlying soft tissue wounds.” Computerized tomography gives a more definitive picture of the calcified tissue involvement, especially with regard to disruption of the cortical plates. Diagnosis is based on the presence of painful sequestra and suppurative areas of tooth-bearing jaw bone unresponsive to debridement and conservative therapy. The goal of definitive therapy is to attenuate and eradicate the proliferating pathogenic microorganisms and to support healing. Pathogenic supportive debris should be removed

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and vascular permeability to the infected area must be reestablished. This will aid the host immune response in coming into contact with the offending organisms. A typical treatment regimen for osteomyelitis of the jaws is presented in the table below.

Treatment Guideline for Acute or Chronic Osteomyelitis

1. Disrupt the infectious foci. 2. Debride any foreign bodies necrotic tissue, or sequestra. 3. Culture and identify specific pathogens for eventual definitive antibiotic treatment. 4. Drain and irrigate the region. 5. Begin empiric antibiotics based on Gram stain. 6. Stabilize calcified tissue regionally. 7. Consider adjunctive treatments to enhance microvascular reperfusion (usually reserved for refractory forms only). Trephination Decortication Vascular flaps Hyperbaric oxygen therapy 8. Reconstruction as necessary following resolution of the infection.

Adapted from Osteomyelitis of the Jaws: A 50-year Perspective, J. W. Hudson, D. D. S.

May-June 2003 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Young Bui, D.D.S. Mineral Trioxide Aggregate

T HAS BEEN almost two years since I first wrote about Here is a list the many uses of MTA (Endo-Mail, January-February of clinical 2002). Since then, there have been many articles published in dental journals praising the success of the situations that material. For those of you who did not get a chance to read benefit from the that article when it was first published, here it is again, use of MTA and expanded, and in greater depth. the proper Young Bui MTA was developed by Dr. Torabinejad at Loma Linda University in 1993. It is a compound mixture of hydrophilic treatment for tricalcium silicate, tricalcium oxide, and tricalcium aluminate each case. with some other oxides. An independent analysis reveals that MTA is identical to Portland cement with the addition of bismuthoxide. Because MTA has a pH of 12.5, some of its biological and histological properties can be compared to those of Ca(OH)2. The material sets in a moist environment and has low solubility. The compressive strength of MTA is equal to that of IRM and Super EBA but less than that of amalgam (Nahmias and Bery). There are clinical situations in root canal therapy that would require the use of a product that would provide a reliable clinical outcome and long-term prognosis. Pulp capping, lateral root or furcation perforation, apexification, apicoectomy, and internal and external resorption are some of the cases that would rely on the use of such a product. An ideal root repair material should be non-toxic, bacteriostatic, and non-resorbable. It should also promote healing and provide a good apical seal. Compared to other materials, MTA shows less microleakage, less toxicity, and better bacteriostatic effect. Histologic examination has revealed that it has actually induced cementogenesis, and bone deposition with minimal or absent inflammatory response. Below is the list of clinical situations that benefit from the use of MTA and the proper treatment for each case. Pulp Capping

If you happened to cause a mechanical perforation, immediately place a rubber dam over the tooth for proper isolation. Rinse the cavity with sodium hypochlorite to disinfect the area. You do not have to dry the area since MTA sets in a moist environment. Mix the MTA powder with enough sterile water to give it a putty consistency.

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Apply it over the exposed pulp and remove the excess. Blot the area dry with a cotton pellet and restore the cavity with an amalgam or composite filling material. MTA provides a higher incidence and faster rate of reparative dentin formation without the pulpal inflammation that is seen when Dycal is used. Internal and External Root Resorption

In the case of internal root resorption, isolate the tooth and perform RCT in the usual manner. Once the canal has been cleaned and shaped, prepare a putty mixture of MTA and fill the canal with it, using a plugger or gutta-percha cone. Next insert a SafeSiders 25/.08 down the canal to spread the cement laterally and create a new canal. Flood the canal with EZ-Fill cement and obturate it with a single gutta-percha cone. The MTA will provide structure and strength to the tooth by replacing the resorbed tooth structure. In the case of external resorption, complete the root canal therapy for that tooth. Next raise a flap and remove the defect on the root surface with a round bur. Mix the MTA in the same manner as above and apply it to the root surface. Remove the excess cement and condition the surface with tetracycline. Graft the defect with decalcified freeze-dried bone allograft and a calcium sulfate barrier. Lateral Perforation and Strip Perforation

If you happened to cause a strip or lateral perforation during instrumentation, first finish cleaning and shaping that canal. Irrigate the canal really well with sodium hypochlorite and dry it with a paper point. The paper point will allow you to see where the perforation is located. If the perforation is down at the mid to apical third, then follow the directions for treating an internal resorption, above. The MTA will seal off the perforation as it is spread laterally by the SafeSiders 25/.08 file and the gutta-percha cone. If the perforation is closer to the coronal third, then fill the canal up with EZ-Fill cement and gutta percha as usual. Next, remove the gutta percha about 23 mm below the perforation using the Peeso reamer. (Be careful not to perforate again!) Now mix the MTA and fill the rest of the canal up with a plugger. Furcation Perforation

If you create a furcal perforation while accessing the tooth, there are two ways to repair it. If you can finish the root canal in one visit, then do that first. Next remove the excess gutta percha in the chamber and soak it for 5 minutes with sodium hypochlorite. Now mix the MTA and fill the chamber with it. Using a moist cotton pellet, plug the MTA down into the perforation site and remove the excess cement from the chamber. Place a moist cotton pellet in the chamber to help with the setting of

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the MTA and close the tooth up with a temporary cement of your choice. If you cannot do a one-visit root canal, then first seal the perforation with the MTA mixture. Make sure that you can locate the canal while the MTA has not set and remove the excess material from the area. Close the tooth as above and do the root canal the next visit. Apexification

Vital pulp: Isolate the tooth with a rubber dam and perform a pulpotomy procedure. Place the MTA over the pulp stump and close the tooth with a strong temporary cement until the apex of the tooth closes up. Non-vital pulp: Isolate the tooth with a rubber dam and perform root canal treatment. Once the canal has been cleaned and shaped, irrigate it and dry it with a paper point. Mix the MTA and plug it down to the apex of the tooth, creating a 2 mm thickness of plug. Wait for it to set; then fill in the canal with cement and gutta percha.

November-December 2003 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Young Bui, D.D.S. The EZ-Fill® Technique Using SafeSiders®

’M SURE THAT many of you have tried using the EZ- Fill technique in doing your endodontic procedures. With every new technique there is always a learning curve. Dr. Musikant has explained the steps in using the SafeSiders reamers more than once in recent newsletters (and you can download his full explanation). Do not be disheartened if you are not able to create the perfect-looking canal. It is Young Bui okay to go back on certain size reamers to open up the canal wide enough to get the Peeso reamer down the canal. The SafeSiders reamers are great instruments, but their results are only great if the dentists using them are able to adapt to certain situations. In this article, I will explain the different approaches to certain root anatomy and complicated situations as they occur. I hope that it will help you to understand the methodology behind the technique. This understanding will in turn make root canal treatment easier and more enjoyable. I tend to deviate a little from the method that Dr. Musikant teaches. You have to find a pattern that is comfortable for you to work with. I follow the same initial sequences for every case I encounter. I will then determine the next step upon analyzing the situation I’m in at that time. You cannot expect the technique to work out the same way in every case. The only thing you can expect is the end result, which is a continuous tapered root canal filling using a single gutta- percha cone. I do mostly molars, so I will explain the steps I use in performing the root canals. I would start out with a #6 reamer to get to the apex. I continue to instrument the canal with a #8 and a #10 reamer until the canal feels loose. I will then get the working length with a #15 reamer, because the apex locator gives a better reading with a snugly fit reamer in the canal. Once I have the proper working length, I then proceed to instrument the canal up to #25 to the apex. The chamber is filled with sodium hypochlorite the entire time to aid in the cleaning process and to prevent debris impaction. Now I will open up the canal using a #2 Gates Glidden (GG). The GG should have no problem following the curve of the canal because the shank is a little flexible. The width of a #25 reamer is wide enough to allow the GG to follow. Do not use force to push the GG into the canal. Just use a gentle pecking motion to drive the instrument down the

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canal. This pecking technique will prevent debris impaction. The reason I do not go to the #2 Peeso reamer is that the canal is not wide enough at this point to allow a smooth cutting. You may have encountered this problem once or twice. After I have widened the canal with the GG, I irrigate the canal to remove the debris. I then go back with a #10 reamer to break up the debris created by the GG. Next I use the #2 Peeso reamer (PR) to widen the canal. The PR should cut smoothly down the canal by following the path of the GG. Remember to lean the PR toward the wall away from the furcation. Do not force the PR, but use a light pecking motion. It is okay if the PR does not go far into the canal. It is not important at this point. Remember to irrigate the canal to remove the debris. I then re-instrument the canal starting with the #10 reamer to #30 to the apex. The reason I go back to #10 is to make sure the apical foramen is patent. This is the general sequence of steps I go through with every case. Now during these steps, certain situations arise in which you have to deviate a little from the general sequence. Let’s say that you used the GG with a little too much force to go down the canal and found out that you can’t get back into the canal again. You have probably caused debris impaction in the canal. What you want to do is to make sure the chamber is filled with sodium hypochlorite. Next, go back in with a #10 Hedstrom and gently turn clockwise one revolution and pull out. This procedure will help you to remove the debris and renegotiate the canal. Do not rush and push too hard or you will make your own canal instead. If you used too much force with the PR and can’t get back into the canal, you have probably caused a little ledge at the curve of the root. In that case, you would take a #15 SafeSiders reamer and bend the tip a little bit. Insert it into the canal and gently twist it back and forth slowly until it renegotiates the canal. Continue in the same manner up to a #30 reamer. If the ledge is too tight for you to get the NiTi files to engage the canal, you will have to go back in with a Hedstrom and strip the curvature a little bit to allow the NiTi file to engage. This procedure will take a little time, but don’t rush. If you are working on a molar with a sharp curve like the one in Figure 1, do not use the GG or PR until you have Figure 1 opened up the canal to at least a #30 reamer. The reamers do not have to reach the apex at this point as long as they go past the curvature. Now go in with the GG slowly with a gentle pecking motion. Don’t worry if the GG doesn’t go in too far. It’s not supposed to because of the sharp bend in the root. Now irrigate the debris and make sure that the chamber is filled with sodium hypochlorite. At this point, I make another deviation from the general steps. Take a #10 Hedstrom and instrument to the apex using the technique of FIGURE 1: Upper molar making one clockwise revolution and pulling out. This with a very curved mesial buccal root. technique will allow you to widen the canal and reduce the sharp curvature at the same time. Follow this with a #15 SafeSiders reamer to open up the canal for the #15 Hedstrom

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Figure 2 to engage. Continue with this SafeSiders-Hedstrom routine until you get the #30 Hedstrom to the apex or close to it. Remember to irrigate well after each SafeSiders-Hedstrom set to prevent debris impaction. Now use the #2 GG, and it should be able to go a little farther down the canal. After that, go in with the #2 PR with a light pecking motion. Do FIGURE 2: Upper first not push when you feel resistance. After all these steps are premolar with a lateral completed, take the orange NiTi 30/.04 and instrument the canal filled with EZ-Fill canal to the apex with a watch-winding motion. You do not cement. have to get the brown NiTi 25/.08 down to the apex. You just need to get it past the curvature to give a continuous- Figure 3 taper shape to the canal. The most important part of the instrumentation process is the constant contact of the sodium hypochlorite with the canal wall. It will assist in debris removal and also in removing pulp tissue in lateral canals and apical fenestration as seen in Figures 2 and 3. What I normally do is to flood the FIGURE 3: Lower second chamber with the solution and leave it there while I molar with a distal root instrument the canal. The bi-directional spiral will coat the apical fenestration filled in wall very well and force the EZ-Fill cement to fill in the with EZ-Fill cement. lateral canal and apical fenestration. I hope that this article will help you in the future if you happen to encounter such problems.

February-March 2004 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Young Bui, D.D.S. Using Concrete to Seal the Crack

OW MANY TIMES have you crowned a root canal tooth with a history of a vertical fracture and had the patient return within a few months or a year complaining of pain when chewing? The patient becomes upset because he or she wasn’t informed of the fracture and because the crown and root canal were costly investments. I have encountered many cases in which root canal therapy Young Bui was needed due to vertical fractures. The prognosis for a vertically fractured tooth ranges from good to poor depending on the extent of the fracture. The prognosis also depends on the symptoms that a patient is experiencing when he or she presents to the office for treatment. If the fracture is down one wall but does not enter the canal, the prognosis is good. This is just a coronal fracture that will hold up well with a PFM crown. If the fracture extends down the canal, then the prognosis is guarded to poor, depending on other factors. A thick, dark fracture line indicates that the fracture has been there for a long time. The pulp in these canals tends to be necrotic, and the patient has no pain when chewing. The only reason such patients need root canal therapy is either a radiographic finding like PAR from the infected pulp or swelling from the infection. This type of fracture has a guarded prognosis as long as the root canal therapy was done well and the tooth was restored right after with a PFM crown. The tooth may hold up for as little as six months or longer than five years. A tooth with a lighter fracture line indicates a recent fracture. The pulp will still be vital, and the patient tends to have pain when chewing. This type of fracture would have a poor prognosis because the pressure from mastication is spreading the fractured parts, causing the pain. Another type of fracture with a poor prognosis is a vertical fracture that goes down the canal, crosses the floor of the tooth, and extends down the other canal. This through and through fracture is always a failure. With any type of fracture, patients should be informed of the situation so that they can participate knowledgeably in the decision making. Let the patient know the prognosis and see what he or she would like to do. Some patients are willing to try to save the tooth even if it is for one extra year. Some prefer an extraction and an implant. If the patient wants to

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try to save the tooth, then the tooth should be crowned as soon as possible after the root canal therapy to help hold the tooth together. Sometimes even when the crown is placed the tooth can still fail if there is leakage through the fracture. In a case like that, MTA would be needed to seal the fractured root. The reason for the success of MTA is not really known. I know that MTA provides a great seal in apicoectomy and also allows for periodontal ligament (PDL) to grow on it. This would allow for complete sealing of the fractured root and Figure 1 allow new PDL to grow along the fracture line. You are probably asking why I don’t just seal the canal with MTA to begin with and avoid having to go back in there a second time. Well, there is no study out there that shows the success of MTA in sealing a fractured root. Gutta percha and EZ-Fill cement have been successful so far for me in many cases. There is also the potential of legal exposure resulting from FIGURE 1: Showing the fact that it is nearly impossible to go back and retreat a thickened PDL at the canal filled with MTA. If this case fails, the patient would apexes of tooth #30. ask why you didn’t use gutta percha and cement first. The following case illustrates a failure of conventional root Figure 2 canal therapy and a successful use of MTA to seal a vertical fracture in the distal root of tooth #30. The patient presented to the office complaining of pain in the presence of heat and cold. The tooth was tender to percussion. She had no pain when chewing. The x-ray showed thickened PDL at the apexes. The tooth was a virgin tooth with a fracture line in the distal margin of the crown. In Figure 1 you can see FIGURE 2: Showing root thickened PDL at the apices of #30. The patient was canal therapy completed and no perio destruction informed of the fracture, and she wanted to try to save the along the root. tooth. Root canal therapy was done in one visit. After instrumentation, the canals were filled with gutta Figure 3 percha and EZ-Fill cement. (See Figure 2.) She went back to her dentist soon after and had the tooth crowned with a PFM crown. She came back a year and eight months later with symptoms on #30. The x-ray (Figure 3) showed periodontal breakdown along the distal root on the furcation side. Apparently there was a vertical fracture along the furcation wall that I had not noticed during the first visit. I FIGURE 3: Showing told the patient of the problem and informed her that the periodontal breakdown prognosis for the tooth was poor. I gave her a choice of along the distal root. either having the tooth extracted or letting me try an experimental procedure on it using a new material. The distal Figure 4 canals were cleaned completely of old gutta percha and the canals were dried with paper points. I mixed the MTA with lidocaine into a putty consistency and then packed it down the two canals with gutta percha points and x-coarse paper points. A seven-month follow-up x-ray (Figure 4) shows complete healing of the periodontal defect along the distal FIGURE 4: Healing of root. If this case holds up well at one-year and two-year tooth #30 with MTA in the follow-ups, I think we will have found a new way to save distal root. vertically fractured roots.

Summer 2004

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FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Young Bui, D.D.S. Ways to Improve the End Result of Root Canal Therapy

HE RUBBER DAM is one of the most important pieces of equipment in the endodontics armamentarium. One should never perform root canal therapy without first isolating the infected tooth with a rubber dam. The rubber dam protects both you and the patient. Imagine the patient’s accidentally swallowing a reamer. The resulting lawsuit is one that you do not want to endure. The rubber Young Bui dam provides unobstructed access to the tooth. It prevents saliva contamination and sodium hypochlorite spillage. Remember to place a rubber dam over the tooth when you are placing in a post. Many dentists do not use a rubber dam in that procedure; without a dam, the saliva can enter and contaminate the post space. This contamination will result in failure of the root canal in the future. Once you have achieved proper isolation, the next step is to create the access opening. The best bur to use for this is the PulpOut bur by Essential Dental Systems. This bur allows you to create an access opening in less then two minutes without the fear of perforating the chamber floor. The first bur is a #4 round bur with a side of it cut flat and a stopper 7 mm away from the tip. The flat side creates a sharper cutting edge that goes through metal with ease. The stopper prevents you from going down too deep; thus there is no danger of perforation. Once you get into the chamber, use the barrel diamond with the non-cutting tip to create the straight-line access. Having straight-line access allows you to find the canals more easily because of better lighting in the chamber. If the tooth has advanced caries, use a #8 slow-speed round bur and remove the decay completely before you instrument the canal. Leaving decay along the chamber wall will prevent proper lighting and make locating the canals difficult. If a wall has been destroyed by caries, remove the decay and restore the wall temporarily with Ketac Cement. You need to have the walls intact to hold the sodium hypochlorite during instrumentation. You can instrument the canals with any of several techniques. The SafeSiders reamers have a flat side that creates a sharp cutting edge. The flat side also makes these reamers more flexible and less likely to bind. These qualities allow the reamers to engage tightly curved canals better than

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Figure 1

any other reamers in the market. If you like rotary because of the reduction in hand fatigue, then use the NSK oscillating handpiece with the SafeSiders reamers. Remember to flood the chamber with sodium hypochlorite during the instrumentation process. The sodium hypochlorite will provide lubrication, prevent debris impaction, and disinfect the canal walls all at the same time. Leave the solution in the canal long enough to kill the bacteria embedded in the canal wall and to remove tissues in the lateral canal. The most important part of the root canal process is to remove all the tissues in the canal. Open the canal wide enough to get FIGURE 1: A premolar adequate cleaning of the apical few millimeters. The number with a lateral defect at the one reason for root canal failure is not short or long fill but coronal third of the root not adequately removing all the tissues impacted down at the sealed with EZ-Fill apex. You would be amazed at how much debris is left at the cement. apex of the root after a complete cleaning. The SafeSiders 30/.04 NiTi file is a great instrument to remove impacted Figure 2 tissues. Even if you do not use SafeSiders reamers to do your root canal treatment, invest in the 30/.04 NiTi and try it out for tissue removal. You will be surprised at what you see. Once instrumentation is complete, dry the canals completely with paper points. Use the bidirectional spiral to coat the canal wall with EZ-Fill cement. The spiral will force the cement laterally so that it will enter any lateral canal present. Use a single gutta-percha cone to fill the canal. Use alcohol-soaked cotton pellets to remove excess cement from FIGURE 2: Complete the chamber. Figure 1 shows a premolar with a lateral defect healing of the defect in a at the coronal third of the root sealed with EZ-Fill cement. six-month recall. Figure 2 shows complete healing of the defect in a six-month recall.

Fall 2004 FEEDBACK? We welcome your responses and questions. Please feel free to visit the Endo Forum and add your comments about any of the articles in Endo-Mail.

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Young Bui, D.D.S. MTAD: A New Intracanal Irrigant

HE SUCCESS OR FAILURE of root canal therapy MTAD seems to depends upon the ability to remove all or most of the be an excellent debris in the canal during instrumentation. Sodium intracanal irrigant hypochlorite (NaOCl) is the solution most commonly used to if used according irrigate the canal. NaOCl used in dentistry has a 5.25 percent to clinical concentration, which can be diluted to 2.60 percent, 1.3 protocol. percent, or .66 percent concentration. As pulp solubilizers, Young Bui the 5.25 percent and 2.60 percent concentrations of NaOCl were equally effective (greater than 90 percent), and 5.25 percent NaOCl was capable of dissolving virtually the entire organic component of dentin (Beltz et al 2003). NaOCl alone, however, does not remove the smear layer left behind from the instrumentation process. Ethylene diamine tetra- acetic acid (EDTA) is commonly used to remove this smear layer. Studies have shown the effectiveness of EDTA in removing up to 70 percent of the inorganic material in dentin. Recently, a new intracanal irrigant has come on the market to compete with EDTA. MTAD is a mixture of tetracycline isomer (doxycycline), an acid (citric acid), and a detergent (Tween 80). The protocol for clinical use of MTAD is 20 minutes with 1.3 percent NaOCl followed by 5 minutes of MTAD. The solubilizing effects of MTAD on pulp and dentin are somewhat similar to those of EDTA. The major difference between the actions of these solutions is a high binding affinity of the doxycycline present in MTAD for the dentin. (Beltz et al J Endod 2003) The benefit of the doxycycline in MTAD can be seen in the study by Torabinejad et al comparing it to NaOCl and EDTA in the ability to kill E. faecalis. MTAD is found to be as effective as 5.25 percent NaOCl and significantly more effective than EDTA. Furthermore, MTAD is significantly more effective in killing E. faecalis than NaOCl when the solutions are diluted. MTAD is still effective in killing E. faecalis at 200x dilution, but NaOCl ceases to be effective at 32x dilution. EDTA did not exhibit any antibacterial activity. Shabahang et al conducted a study to compare the abilities of MTAD and NaOCl in disinfecting human root canals that had been contaminated with whole saliva. Twenty-three of sixty teeth treated with NaOCl remained infected. Only one of sixty teeth treated with MTAD remained infected. With every new product we are always concerned about

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the cytotoxicity to the underlying tissue and the effect it may have on the strength of dentin. MTAD was compared with commonly used irrigants and medications in a study by Zhang et al in 2003. The results showed MTAD to be less cytotoxic than eugenol, 3 percent H2O2, Ca(OH)2 paste, 5.25 percent NaOCl, Peridex, and EDTA. It is more cytotoxic than NaOCl at 2.63 percent, 1.31 percent, and 0.66 percent concentrations. Machnick et al conducted a study to evaluate the effect of MTAD on the flexural strength and modulus of elasticity of dentin. The result showed no significant difference in flexural strength and modulus of elasticity between the dentin bars exposed to saline or MTAD when applied according to clinical protocol as stated above. According to all these studies, MTAD seems to be an excellent intracanal irrigant if used according to clinical protocol. It is better than EDTA in killing bacteria and less cytotoxic than most irrigants. This new irrigant may help increase the success rate of root canal therapy in infected root canals.

Winter 2004 FEEDBACK? If you are using liquid EDTA as an We welcome your end irrigation during final responses and instrumentation to clean out the questions. smear layer in the canal, be sure to Please feel free to visit wash it out thoroughly. This can be the Endo Forum and accomplished with chlorhexidine in a add your comments syringe with a 30 gauge irrigating about any of the articles needle. Fill the canals with in Endo-Mail. chlorhexidine and agitate with an instrument in the reciprocating handpiece and then re-irrigate with the same.

Do not irrigate the canal with Chlorhexidine without rinsing the canal of NaOCl first. The mixture of NaOCl and Chlorhexidine will cause a rust color precipitation and result in a stain of the internal tooth structure.

Doug Kase

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Young Bui, D.D.S. Three Interesting Cases

OLLOWING are three interesting cases that I would like to share with all of you. The first case was a strip perforation of the distal root of tooth #19 on the furcation side that occurred when the post space was prepared (Figure 1). Normally, with a perforation this big, the tooth would be deemed hopeless. However, with the invention of the miracle cement MTA, this tooth still had Young Bui a chance of success. The first step was to remove the long Flexi-Post® without damaging the root further. I created an access opening wide enough to expose the head of the post. Then I used a CPR1 ultrasonic tip to vibrate the post loose from the cement. Once loosened, the post could easily be unwound using the wrench that comes in the post kit. After the post was removed, I went in and instrumented the canal, removing any gutta percha left in the canal. You should not try to seal the perforation until the canal has been cleaned and shaped. The reason is that, once mixed, MTA is a wet putty. You cannot irrigate and clean the canal after the MTA has been applied because the material will be dissolved by the irrigant. Instead, you should apply the MTA when the canal is ready to be filled. Mix the MTA into a putty consistency on the dry side then place it into the chamber. Take a large gutta-percha point or x-coarse paper point and use it as a plugger to push the MTA down the canal. Next use the SafeSiders® 25/.08 NiTi file to spread the the MTA along the wall that has the perforation. Spreading the MTA in this way will help seal the perforation and create a tapered canal space to place the gutta percha in. Figure 2 shows the completed case with MTA extruded out along the length of the furcation wall. Figure 3 shows healing of the furcation and periapical area eight months later. Figure 1 Figure 2

FIGURE 1: Strip perforation of the FIGURE 2: The completed distal root of tooth #19. case with MTA extruded out along the length of the furcation wall.

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Figure 3

FIGURE 3: Healing of the furcation and periapical area eight months later. The cause of failure in the next case was missed canals. The patient presented to the office with pain and swelling over #14. The pre-op x-ray showed thinly filled buccal canals with a large area in the furcation (Figure 4). Access was made and the post was removed as in the case above. Next I used a #8 slow-speed round bur to clean the floor of decay and stain. This procedure allows you to have better lighting so that you can locate canals better. Most upper molar failure is caused by missing MB2. That—and more— was the case with this tooth. After I had cleaned and shaped all the old canals, I found not only the MB2 but also a second palatal canal. You can see five separate filled canals in Figure 5. The key to locating extra canals is to take a #2 round slow-speed and sweep along any groove you find in the floor of the tooth. This will expose any ditch along the groove. MB2 is there at least 70 percent of the time in first and second upper molars. Figure 4 Figure 5

FIGURE 4: Pre-op x-ray FIGURE 5: Showing five showed thinly filled buccal separate filled canals. canals with a large area in the furcation. The last case is pretty much a straightforward root-canal case. The only interesting part of this case is the curvature of the mesial root and the lateral canal near the apex of the distal root (Figures 6 and 7). Upon encountering a curve like this one, the first thing that should come to your mind is to reduce the amount of curvature. By using a #2 Peeso reamer and leaning it against the outer wall, you will turn a C- curvature into a J-curvature. This will reduce the stress on your file or reamer. My suggestion is to use the SafeSiders reamers with the reciprocating handpiece. The SafeSiders reamer is flexible and less binding due to the flat side. This will allow you to instrument the canal without causing any distortion. The bi-directional spiral is a great instrument to apply cement with. The flutes on the spiral force the cement to converge on itself, creating a force that spreads the cement

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against the wall. This will disperse the cement into the lateral canal. Figure 6 Figure 7

FIGURES 6 AND 7: Showing curvature of the mesial root and the lateral canal near the apex of the distal root. January-March 2005

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Young Bui, D.D.S. Three Interesting Cases

’M SURE that most of you have stumbled upon difficulties while doing root canals. Some of the problems are easy to fix; others are not. I will bring up several difficult situations and then explain how to resolve them.

Diagnosis Young Bui A patient presents with generalized pain and cannot pinpoint a specific tooth. There is no pain to percussion, chewing, or palpation. The x-ray shows no indication of pathology on any of the teeth in the quadrant. Rinsing with hot water increases the pain, but the patient still cannot point to a specific tooth. In a case like this, you need to isolate each individual tooth with a rubber dam and run hot water from an irrigating syringe over the buccal side of the tooth. Do this for all the teeth in the upper and lower quadrant to make sure that the pain is not radiating. The culprit tooth will show itself as hot water is poured over it. A patient experiencing acute pulpitis enters your office and has to constantly drink cold water to calm down the pain. Apply Endo Ice on a piece of cotton pellet. Wait for the pain to come back and apply the pellet to each of the teeth in the quadrant until the pain calms down. Wait for the pain to reappear and apply the cold pellet to that tooth again to make sure that it is the cause of the pain.

Proper Isolation

There are times when the coronal tooth structure has decayed out and there is not enough tooth structure above the gingiva to properly place the clamp on. The first step is to use a #8 slow-speed round bur to remove all the remaining decay. Then prepare a mixture of Ti-Core and inject it onto the tooth using a Centrix needle to rebuild the coronal structure. Wait for it to set and then clamp it like a normal tooth. You can also do this using Ketac cement. The only drawback with Ketac is that it is weaker than Ti-Core so it can crack under the force of a clamp over time. If the tooth has decayed out underneath a crown, make sure you remove all the decayed materials. Never start the root canal process until all the decay has been removed. If

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there is a leakage in the margin between the crown and the tooth, seal it up by injecting Ketac cement into the crown. The Ketac cement will flow into the margin area and seal it up temporarily so that you can do the root canal without saliva contamination. Access Preparation

Creating an access opening can be difficult in certain situations. If you go down too deep in calcified cases on molars, you can perforate the floor. By using the PulpOut™ bur you can prevent this from happening. The stopper on the bur will prevent you from hitting the chamber floor. The diamond shaping bur will help you create a perfect straight- line access without scratching the floor. Some pre-molars have large crowns and thin roots. Others are angulated due to spacing. Do not place the rubber dam on these teeth before access preparation. The dam can obstruct your view or give you a false angulation of the root. You can perforate out to the side if you are not careful. Locating Canals

The first thing you want is to create an access opening large enough to allow light to get in. Next, make sure that the chamber is clean of all decay and calcified pulp stone. This will illuminate the chamber, allowing you to better locate the canals. Remember to smooth out the groove along the floor of the upper molars to locate the MB2. Weeping Canal

I’m sure that every one of you has encountered an infected canal that refused to be dried. You cleaned it out well and medicated it with Ca(OH)2 and hoped that it would dry up by the next visit. When you opened it back up, the canal was as wet as on the previous visit. You continued this process of cleaning and closing for a few visits without results. The reason for this is that the apex has been widened due to resorption from the infection. What you want to do is clean out the canal really well to the anatomic apex by using the apex locator. After that, mix a little MTA and plug it down the canal to the apex using an extra coarse paper point. This will absorb the moisture and create a tight plug at the apex. Now you have a dry canal to fill. Removing Excess EZ-Fill® Cement

After the canals have been filled, you find the chamber filled with EZ-Fill cement. Removing this cement is easy by using cotton pellet soaked with alcohol. The alcohol seems to remove the cement very well and leave a clean chamber to be restored with composite or amalgam.

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Do not use force when creating a post space with a flexi drill. Always use a gentle pecking motion so that you can feel the resistance of the gutta percha. If you feel the drill against hard surface, do not push any further. Move the drill in different angles until you feel the gutta percha being removed. When using a Flexi-Flange® countersink drill, run it with water. It will cut a lot smoother than it will when running dry.

I hope that these suggestions will be of help to you when you encounter such problems. Feel free to visit the Endo Forum if you have any other problems pertaining to endo that you need answered.

April-June 2005

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Young Bui, D.D.S. The Effect of Aesthetics in Endodontics

OTARY NiTi and the endodontic microscope have revolutionized the way we do root canal therapy. We are able to find MB2 in upper molars and third canals in the mesial of lower molars much more easily than before due to the introduction of the dental microscope. The NiTi files have helped us to create the almost perfect taper in canals in a shorter time. The end result is a nice, densely filled root canal that is aesthetically pleasing to the eye. However, in our zeal to create a beautiful root canal Young Bui treatment, we tend to forget the most basic fundamental rule in endodontics, and that is cleaning the canal down to the anatomical apex. Most of us clean and fill our root canal to the radiographic apex. We tend to doubt ourselves when the gutta-percha point is short of the radiographic apex. We are letting aesthetics influence our judgment. When we see a failed root canal case with the filling 1 mm short of the radiographic apex, we attribute the failure to the short-filled canal. How do we know whether the filling is short or not? What are the anatomical and radiographic apexes? The radiographic apex is the tip of the root as seen on any given x-ray. However, the anatomical apex is different from one tooth to another. It can be located at the tip of the root on one tooth and a couple of millimeters away from the tip on another. The only way to know for sure where the anatomical apex is located is to measure the length of the root using an apex locator. The two good apex locators are Endex by Osada (which has a needle gauge) or Root ZX by J Morita (which is digital). When you start using the apex locator, you will notice a number of cases in which the anatomical apex is about .5 mm to 1 mm away from the radiographic apex. The reason for this difference is that the canal tends to take a curve at the apical end of the root before it exits the root, as seen in Figure 1. Figure 2 shows the radiographic apex and the anatomical apex as seen from the path of the radiation hitting the tooth at a right angle. If you fill the canal to the radiographic apex of this root, it will be 1 mm overfilled even though it is aesthetically pleasing.

FIGURE 1 FIGURE 2

Figure 3 shows an x-ray taken from the buccal view of a premolar with a file in the canal to the radiographic apex. Figure 4 shows the same tooth in a mesio-distal view with the file overextending the anatomical apex of the

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premolar.

FIGURE 3 FIGURE 4

A good example of a misunderstanding of the difference between a tooth’s anatomical apex and radiographic apex can be found in a bulletin board thread on the Dentaltown website at www.dentaltown.com, entitled by the endodontist who started the thread “Pretendodontist vs. Endodontist.” This endodontist from Colorado took a couple of radiographs from our website and criticized the RCT on the grounds that the fillings are short on the two radiographs. One of the cases (the bicuspid), which was done by Dr. Deutsch (pre-op, see Figure 5), has the final filling 2?3 mm short of the radiographic apex (see Figure 6.)

FIGURE 5 FIGURE 6

However, the apex locator indicates that the length is correct. The follow-up x-ray, Figure 6, shows healing of the large radiolucency, which the endodontist from Colorado failed to disclose. He also criticized my filling on a lower molar because the fill is 1 mm short of the radiographic apex. He seems to be more concerned with the aesthetic look of the root canal than the result. Maybe he is a cosmetic dentist who is a pretendodontist.

July-September 2005

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Young Bui, D.D.S. Pain Management in Endodontics

AIN MANAGEMENT is the key to success in root Make sure that canal therapy. Every patient who walks through the the patient is door with a toothache expects the pain to go away once he or she leaves the office. This expectation puts a lot of really stress on the dentist as he or she tries to relieve the patient of anaesthetized the tooth pain. Patients should be informed prior to any and treatment that they will feel some discomfort to mild pain comfortable Young Bui after the procedure for two to three days on average due to the trauma exerted on the tooth during the procedure. In before starting certain instances, the pain can be moderate to severe, any treatment. depending on the condition of the tooth prior to treatment. They should also be aware that flare-ups may occur, especially in cases with multiple appointments, retreatment cases, periradicular pain prior to treatment, and the presence of a radiolucent lesion. By informing patients, you will take away their worries and anxieties that something may have gone wrong or the treatment was not successful when they experience some pain that night. Make sure that the patient is really anaesthetized and comfortable before starting any treatment. It is better to over- anaesthetize patients than to have them jump while you are instrumenting the canals. Pain will place them in a tension state and make them feel nervous with every sensation they may experience afterward. When giving a local injection to the upper molars, remember to also give a palatal injection. First molars and sometimes the second molars tend to have innervation from the palatal nerve to the palatal root. You will realize this when drilling into the molar and the patient starts to experience pain or when you place the reamer into the palatal canal and the patient jumps. The palatal nerve exits at the level of the 2nd molar about 56 mm from the midline. Inferior and mental blocks tend to be a lot more difficult to achieve than local infiltrations. It can be frustrating for both the dentist and the patient when the entire side of the patient’s face is completely numb but the tooth is still sensitive. There are three secondary methods to achieve anaesthesia in these teeth. The first is interligamentary injection by which a pressure gun is used to administer the solution into the ligament. This quick and forceful injection can sometimes cause PDL necrosis and a lot of postoperative pain for the patient. By using the regular syringe and

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applying gentle force for a couple of minutes, you will achieve the same result but with less damage to the PDL. You will see the tissue blanch as the anaesthetic solution is working its way down to the apex. The second method is intraosseous by which a small hole is drilled into the cortical plate and the solution is administered directly into the jaw bone. This is done by using the Stabident system. The third is pulpal injection—and the most painful injection. You have to get access to the pulp and then inject directly into it with back pressure. The trick is getting access to the pulp with the least amount of pain. Look for the area with the highest pulp horn and do a quick pecking motion with the high speed drill with water to minimize the pain. Sometimes using the slow speed round drill can be helpful because the heat generated from the slow speed is not much and is more comfortable for the patient. The worst time to give an injection is when a patient presents with severe pain from an indurated swelling. Do not inject directly into the area. Start with a shallow injection at the outer edge of the swelling and then go deeper as the area is starting to get numb. Once you are able to touch bone with little pain, then start moving inward toward the center of the swelling. Again start with a shallow injection and continue to go deeper as the area is getting anaesthetized. The entire injection will take about 1015 minutes to accomplish. By using the apex locator, we are able to determine the apical constriction to prevent over-instrumenting the apex. If the apex is violated in a vital tooth, the PDL will be traumatized and the patient will experience post-operative pain. Over-instrumenting the canal will lead to overfilling of the canal. The extruded gutta percha point will irritate the periapical ligament, resulting in chronic inflammation. The patient will experience tenderness in the tooth for a long time. The other reason not to violate the apical constriction is that debris can be pushed beyond the opened apex resulting in flare-ups. We can control and manage the pre-operative pain with local anaesthesia. However, post-operative pain is more difficult to manage. Each patient reacts differently due to different pain thresholds and different pre-operative symptoms. One way to help prevent post-operative pain is to reduce the occlusion so that there is no contact with the opposing teeth. Use an articulating paper to minimize tooth removal. This is the most important step in preventing post- operative pain. I like to prescribe a combination of pain killer and anti-inflammatory and have them alternate between the two every four to five hours as needed for pain. Patients who are allergic to codeine can take a combination of 600 mg of ibuprofen and 1000 mg of acetaminophen together every six hours for pain control. Studies show that this combination is more effective than ibuprofen alone. For teeth with active infection or with PAR, I prescribe Augmentin 875 mg BID and for Pen-allergic patients, Clindamycin 150 mg QID. These are the two best antibiotics for necrotic cases or

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retreating failed RCT because they kill E. faecalis bacteria which are the toughest bugs to get rid of. Dr. Deutsch found that a cardiac dose of antibiotic right after the procedure reduces the number of flare-ups in his patients. Remember to inform the patient not to chew on the treated tooth for at least a week to allow it to heal properly.

September October 2005

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Young Bui, D.D.S. Three Cases to Share

T WAS TAUGHT in school that a necrotic tooth with Today, canals periapical lesions should be cleaned out and medicated are cleaned out with Ca(OH)2 for at least a week before filling it. Some still believe in that teaching while others believe in the one- using greater visit root canal treatment. The reason for the teaching of a tapered files, two-visit treatment is because the technology back then was thus allowing not as advanced as today. Most of the root canals in the study the removal of Young Bui done by Bender and Seltzer were performed using a .02 taper file to do the cleaning. This method does not allow proper more infected cleaning of the canal’s wall. Today, canals are cleaned out dentinal wall of using greater tapered files, thus allowing the removal of more the root canal infected dentinal wall of the root canal system. I do most of my cases in one visit using the SafeSiders® technique. This system. technique allows you to clean and shape the canals to a .06 or .08 taper as in any rotary NiTi system. The canals are constantly flooded with NaOCl during the instrumentation process. Once the canals have been cleaned and shaped, rinse them thoroughly with liquid EDTA to remove the smear layer. Next soak the canals with a 2 percent chlorhexidine solution and let it sit for about two minutes. By shaping the wall to a .06 or .08 taper and then using the EDTA and 2 percent chlorhexidine, you eliminate bacteria that are embedded in the dentinal wall. This will ensure a clean canal and eliminate the use of Ca(OH)2 between visits. By the way, Ca(OH)2 does not kill enterococci such as E. feacalis; 2 percent chlorhexidine does. The molar in Figures 1 and 2 was done in one visit. As you can see in the six-month recall, the root canal was a success.

Figure 1 Figure 2

FIGURE 1: Molar x-ray showing FIGURE 2: The same tooth as in finished root canal and periapical Figure 1, six months later, with area at the apices. the apices healed.

I’m sure everyone reading our newsletter has read about the SafeSiders reamers. The reason for the flat side on these

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instruments is threefold. First, the flat side reduces the amount of binding along the length of the canal. This allows the SafeSiders reamer to negotiate even tight and curved canals with ease. Second, due to the flat side, the reamer is more flexible than regular reamers thus preventing distortion in sharply curved canals. Lastly, the flat side acts as a failsafe system. If you happen to separate a SafeSiders reamer, you can bypass the reamer along the flat side because it is not binding to the canal’s wall. I used rotary NiTi in my early years, and I was constantly worried about separating the file. Rotary NiTi can shape straight canals easily, but when it comes to curved ones, that is where the stomach wrenching begins. I find the SafeSiders technique to be better due to the fact that I’m not worried at all when it comes to negotiating tight and curved canals as seen in Figures 3 and 4. The mesial and distal roots in this molar have sharp curves that end up touching each other. I call this the “kiss of death.” I had to use the SafeSiders reamers with the reciprocating handpiece to instrument these canals. The #2 Peeso widens the upper portion of the canal to reduce the amount of stress on the reamer at the curve. The reciprocating motion also aids in the instrumentation with no distortion at the curve. I was able to instrument to a 30/.02 stainless steel SafeSiders reamer and end with a 30/.04 SafeSiders NiTi file. The canals were filled using a single cone with EZ-Fill® cement.

Figure 3 Figure 4

FIGURE 3: Molar with curved FIGURE 4: Finished root canal roots. on the molar in Figure 3.

When we perform root canal treatment on lower premolars, we assume that the tooth has only one canal unless we see that there are two roots on the x-ray. Sometimes, there is an extra canal midway down the main canal. I’m never satisfied with the cleaning of a lower bicuspid with one canal unless I have run up and down the length of the wall with a bent #10 reamer. The reamer will get a catch along the wall if there is another canal present. Figure 5 shows the pre-op x-ray of a lower bicuspid with two roots. The case was referred to me after the general dentist had a difficult time filling the canal. After I cleaned and irrigated the two canals, I ran a #10 reamer up and down the canal and found another canal along the wall. The other two canals are straightforward, but in the case of the third, the instrument must be pre-bent in order to engage the canal. I cleaned and shaped it using the SafeSiders technique and filled it using a single cone with EZ-Fill cement (Figure

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6).

Figure 5 Figure 6

FIGURE 5: Pre-op x-ray of a FIGURE 6: The bicuspid from lower bicuspid with, apparently, Figure 5 with three roots filled. two roots.

November-December 2005

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