Treatment Standards

180 N. Stetson Ave. Suite 1500 Chicago, IL 60601 aae.org Introduction disparities exist in the levels of knowledge, Endodontics is the branch of dentistry that is competencyDespite similar and predoctoral skill, and clinical educational experiences curricula, of concerned with the morphology, physiology general dentists. Over the past two decades there and pathology of the human dental pulp and periradicular tissues. Its study and practice materials and endodontic treatment procedures. encompass the basic clinical sciences including Thesehave been include significant but are advancesnot limited in totechnology, microscopy, biology of the normal pulp, and etiology, diagnosis, prevention and treatment of diseases and injuries solutions and technologies, digital radiography, of the pulp and associated periradicular tissues as CBCTrotary three Ni-Ti dimensionalfiles, ultrasonics, imaging, enhanced bioceramics, irrigation etc. These changes have created a disparity in the American Association of Endodontists. quality of care provided by specialists versus defined by The American Dental Association and general dentists on teeth with complicated The American Association of Endodontists serves anatomy and morphology. as a trusted and credible source for information on diagnosis of pulp and periapical pathosis, treatment The effect of these developments on the Standard planning, urgent/emergent treatment, vital pulp of Care remains unknown. Currently general therapy, nonsurgical root canal treatment, surgical dentists perform approximately 75% of all endodontics, regenerative endodontic procedures, nonsurgical endodontic procedures. While and outcome assessment. endodontists perform only 25% of the total root canal procedures, they treat 62% of the molars. Treatment by the general dentist is expected to With generalists performing the majority of meet minimum standards as set out in guidelines. the uncomplicated anteriors and premolars it The American Association of Endodontists appears that the predoctoral educational process has developed and published as “Standards of and procedures in general practice should be Practice”. These guidelines were developed to assist concentrated on uncomplicated permanent teeth educational institutions and organized dentistry with specialists treating the more complicated in developing minimum educational requirements molars. and practice standards in endodontic treatment. Treatment is based on a thorough understanding The primary objective of endodontic treatment is to and interpretation of all diagnostic information prevent and intercept pulpal/periradicular pathosis including patient history, clinical and radiographic and to preserve the natural dentition when affected examination. Following the establishment of a by pathosis. The practice model in the United States diagnosis, treatment planning should consider is predicated on general dentists having the basic knowledge and experience regarding endodontic importance of the tooth/teeth being treated, treatment to perform the majority of nonsurgical the periodontalfollowing patient status, modifiers: structural the integrity strategic and root canal procedures on uncomplicated restorability of the tooth, the long term prognosis permanent teeth. for success, and patient factors such as the medical status, attitude and desires, motivation, anxiety, jaw

resources. opening, the gag reflex, disease state, and financial

Access additional resources at aae.org The scope of endodontics in general dentistry Methods of traditional education and the emphasis on facts are changing. Information technology • has transformed the dental profession and placed includes: or swelling of pulpal and/or periradicular origin emphasis on the evidence based practice model. Differential diagnosis and treatment of pain and/ Contemporary methods of education emphasizing • Urgent/emergent treatment of pain and/or problem solving and critical thinking skills employ swelling to include the pharmacologic use of and stress professional interactions and the

drugs and incision for drainage of localized care. abscessesantibiotics, anti-inflammatory agents, analgesic benefits of multidiscipline and interdisciplinary • Urgent/emergent management of traumatic injuries to the dentoalveolar structures AAE Case Difficulty • Vital pulp treatment to include step-wise caries Assessment Form excavation, indirect and direct pulp capping, and pulpotomy procedure Following examination and testing, a diagnosis is • Non-surgical root canal treatment for the established, a treatment plan is formulated, and permanent dentition the prognosis determined. The general dentist • Bleaching of discolored dentin and enamel of teeth Assessmentthen must determine Form provides the degree a national of difficulty protocol for • Treatment procedures such as post and/or cores accomplishingand associated thisrisks. assessment. The AAE Case Difficulty involving the root canal space

Standard of Practice RecognitionThere are many of these factors factors that influenceprior to the degrees initiation General dentists should provide endodontic of treatmentdifficulty and helps risk practitioners of endodontic to treatment.understand the treatment consistent with contemporary complexities that may be involved in individual endodontic standards, their knowledge and clinical cases and prevents adverse outcomes due to experience, and technical skills. The standards of avoidable procedural errors. practice are constantly changing based on new evidence and technology. It is the responsibility of all practitioners to be life-long learners, in order to dentist should not undertake treatment of a In determining the degree of difficulty, a general meet contemporary standards. case unless he/she is prepared to also manage complications that may arise in treatment. Self-evaluation is a critical component of life-long learning. The generalist should be able to critically evaluate their own competency as diagnosticians and clinicians and identify areas that require additional educational experiences. Based on this evaluation each practitioner must be able to determine their own skill and learning in order to determine when the patient should be referred to the appropriate specialist for consultation/treatment.

Treatment Standards | Page 3 AAE Endodontic Case Difficulty Assessment Form and Guidelines

Patient Information Disposition

Treat in Office: Yes No Full Name

Refer Patient to: Street Address Suite/Apt

City State/Country Zip

Phone Date

Email

Guidelines for Using the AAE Endodontic Case Difficulty Assessment Form

andThe recordAAE designed keeping. the Endodontic Case Difficulty Assessment Form for use in endodontic curricula. The Assessment Form makes case selection more efficient, more consistent and easier to document. Dentists may also choose to use the Assessment Form to help with referral decision making Conditions listed in this form should be considered potential risk factors that may complicate treatment and adversely affect the outcome. Levels predictable level and impact the appropriate provision of care and quality assurance. of difficulty are sets of conditions that may not be controllable by the dentist. Risk factors can influence the ability to provide care at a consistently

LevelsThe Assessment of Difficulty Form enables a practitioner to assign a level of difficulty to a particular case. MINIMAL DIFFICULTY Preoperative condition indicates routine complexity (uncomplicated). These types of cases would exhibit only those factors listed in the MINIMAL

MODERATE DIFFICULTY DIFFICULTY category. Achieving a predictable treatment outcome should be attainable by a competent practitioner with limited experience.

Achieving a predictable treatment outcome will be challenging for a competent, experienced practitioner. Preoperative condition is complicated, exhibiting one or more patient or treatment factors listed in the MODERATE DIFFICULTY category. HIGH DIFFICULTY extensivePreoperative history condition of favorable is exceptionally outcomes. complicated, exhibiting several factors listed in the MODERATE DIFFICULTY category or at least one in the HIGH DIFFICULTY category. Achieving a predictable treatment outcome will be challenging for even the most experienced practitioner with an consider referral to an endodontist. Review your assessment of each case to determine the level of difficulty. If the level of difficulty exceeds your experience and comfort, you might Criteria and Subcriteria MINIMAL DIFFICULTY MODERATE DIFFICULTY HIGH DIFFICULTY

A. PATIENT CONSIDERATIONS

No medical problem (ASA Class 1*) One or more medical problem Complex medical history/serious (ASA Class 2*) MEDICAL HISTORY ANESTHESIA No history of anesthesia problems Vasoconstrictor intolerance illness/disability (ASA Classes 3-5*)

Cooperative and compliant Anxious but cooperative UncooperativeDifficulty achieving anesthesia

PATIENT DISPOSITION No limitation Slight limitation in opening

GAGABILITY REFLEX TO OPEN MOUTH None Gags occasionally with radiographs/ Significant limitation in opening treatment compromised past dental care Extreme gag reflex which has Minimum pain or swelling Moderate pain or swelling Severe pain or swelling

EMERGENCY CONDITION in determining appropriate case disposition. The American Association of Endodontists neither expressly nor implicitly warrants any positive results associated with the use of this form. This form may be reproduced but The contribution of the Canadian Academy of Endodontics and others to the development of this form is gratefully acknowledged. The AAE Endodontic Case Difficulty Assessment Form is designed to aid the practitioner [email protected] aae.org may not be amended or altered in any way. © American Association of Endodontists, 180 N. Stetson Ave., Suite 1500, Chicago, IL 60601; Phone: 800-872-3636 or 312-266-7255; Fax: 866-451-9020 or 312-266-9867; E-mail: ; Website: Access additional resources at aae.org Criteria and Subcriteria MINIMAL DIFFICULTY MODERATE DIFFICULTY HIGH DIFFICULTY

B. DIAGNOSTIC AND TREATMENT CONSIDERATIONS

Signs and symptoms consistent with Extensive differential diagnosis of Confusing and complex signs and recognized pulpal and periapical usual signs and symptoms required DIAGNOSIS conditions History of chronic oral/facial pain symptoms: difficult diagnosis

interpreting radiographs interpreting radiographs (e.g., high interpreting radiographs (e.g., RADIOGRAPHIC DIFFICULTIES Minimal difficulty obtaining/ Moderate difficulty obtaining/ Extremesuperimposed difficulty anatomical obtaining/ structures) vault, presence of tori) floor of mouth, narrow or low palatal POSITION IN THE ARCH Anterior/premolar 1st molar Slight inclination (<10°) Slight rotation (<10°) 2nd or 3rd molar Moderate inclination (10-30°) Extreme inclination (>30°) TOOTH ISOLATION Routine rubber dam placement Moderate rotation (10-30°) Extreme rotation (>30°) required for rubber dam isolation required for rubber dam isolation Simple pretreatment modification Extensive pretreatment modification Normal original crown morphology Full coverage restoration Porcelain restoration anatomy/alignment CROWN MORPHOLOGY Bridge abutment Restoration does not reflect original Moderate deviation from normal tooth/root form (e.g., fusion dens in tooth/root form (e.g., taurodontism Significantdente) deviation from normal microdens) Teeth with extensive coronal destruction

Slight or no curvature (<10°) Closed apex (<1 mm in diameter) Crown axis differs moderatel from curve CANAL AND ROOT rootModerate axis. Apicalcurvature opening (10-30°) 1-1.5 mm in MandibularExtreme curvature premolar (>30°) or anterior or S-shaped with MORPHOLOGY diameter 2 roots

Canal divides in the middle or apical Maxillarythird premolar with 3 roots Very long tooth (>25 mm) Open apex (>1.5 mm in diameter)

Canal(s) visible and not reduced Canal(s) and chamber visible but Indistinct canal path OF CANAL(S) in size reduced in size Canal(s) not visible RADIOGRAPHIC APPEARANCE Pulp stones

RESORPTION No resorption evident Minimal apical resorption Extensive apical resorption Internal resorption External resorption

C. ADDITIONAL CONSIDERATIONS

Uncomplicated crown fracture of Complicated crown fracture of mature Complicated crown fracture of mature or immature teeth teeth immature teeth TRAUMA HISTORY Subluxation Horizontal root fracture Alveolar fracture Intrusive, extrusive or lateral luxation Avulsion

No previous treatment Previous access without complications Previous access with complications (e.g., perforation, non-negotiated ENDODONTIC TREATMENT canal, ledge, separated instrument) HISTORY Previous surgical or nonsurgical endodontic treatment completed

None or mild periodontal disease Concurrent moderate periodontal Concurrent severe periodontal disease disease PERIODONTAL-ENDODONTIC Cracked teeth with periodontal CONDITION complications Combined endodontic/periodontic lesion Root amputation prior to endodontic treatment

Class 1: No systemic illness. Patient healthy. Class 2: Patient with mild degree of systemic illness, but without functional restrictions, e.g., well-controlled hypertension. Class 3: Patient with severe degree of systemic illness which limits activities, but does not immobilize the patient. Class 4: Patient with severe systemic illness that immobilizes and is sometimes life threatening.*American Society Class 5:of Anesthesiologists (ASA) Classification System www.asahq.org/clinical/physicalstatus.htm

Patient will not survive more than 24 hours whether or not surgical intervention takes place. Treatment Standards | Page 5 Treatment Procedures Non-Surgical Endodontics A variety of endodontic techniques, materials and treatment philosophies present a challenge to dental practitioners, patients, governing bodies and Uncomplicated Mature Permanent Teeth other interested parties making decisions about the Nonsurgical root canal treatment is indicated appropriateness and/or quality of endodontic care. primarily in cases of irreversible pulpitis and when pulp necrosis with and without periapical pathosis Endodontic treatment procedures should be of occurs. However, elective root canal treatment may such quality that predictable and favorable results be considered for restorative treatment planning will occur with the understanding that, in a biologic and for overdentures or where teeth need to be system, treatment procedures that are appropriate preserved over extraction in patients who are may not always result in a successful outcome. receiving systemic treatments including head Success is dependent on many variables that may and neck radiation treatment, bisphosphonates, preclude a successful outcome. These factors chemotherapy, and/or corticosteroids. include but are not limited to the patient’s medical and dental condition, patient compliance, variations Endodontic treatment involves chemo-mechanical in anatomy and morphology, and complications preparation of the root canal system to eliminate during the procedures. organic, inorganic and bacterial products and When practitioners are presented with sealing of the radicular space with a biocompatible challenges during treatment that risk material (obturation). Root canal sealers are used procedural errors and poor outcomes, consultation and referral are always valid establish an adequate three dimensional seal and in conjunction with the core filling material to options. induce hard tissue formation in healing outcomes.

Considerations Root Canal Disinfection INTENT STATEMENT: A practicing dentist should General dentists must recognize that pulp and be able to safely and effectively utilize standard periradicular pathosis is primarily a microbial disinfection protocols in the irrigation and disease. Strict adherence to aseptic procedures to medication of root canal spaces. include the use of the rubber dam is required. The primary etiologic agents of apical periodontitis Nonsurgical root canal treatment must employ are microorganisms and their by-products that materials proven to be biocompatible. For have invaded the pulpal space and established example, the use of paraformaldehyde containing sealer/pastes are below the standard of care for endodontic treatment. canalmultispecies infection biofilm and can communities be found on in root the canalroot canal walls,system. in Biofilms dentinal are tubules, involved and in on all extraradicular stages of root surfaces. The clinical management of infected root canals undergoing non-surgical root canal treatment involves instrumentation and disinfection.

infected soft and hard tissues and provides access forInstrumentation irrigation and disrupts exposure biofilms to antimicrobial which colonize solutions for disinfection of the root canal

Access additional resources at aae.org Irrigants currently used for endodontic treatment both antimicrobial agents and the mechanical system. Disinfection is achieved by the use of 1. Antimicrobial agents [e.g. sodium may be categorized as: the disruption, displacement and removal of pulpal hypochlorite (NaOCl), chlorhexidine (CHX)] remnants,flushing action microorganisms, of irrigation, metabolicwith the goal byproducts, being debris and the smear layer created during The most commonly used antimicrobial instrumentation. When treatment is provided irrigant is NaOCl, an oxidizing agent that over multiple appointments, inter-appointment releases chlorine in the form of hypochlorous intracanal medicaments provide additional acid (HOCl). NaOCl has a dose-dependent opportunities for disinfection. effect on polymicrobial biofilms, with higher concentrations being more effective. NaOCl The development of irrigation and disinfection is an excellent organic tissue solvent and can clinical protocols in current use has been based be used to remove the organic component of the smear layer. Continuous exchange of that used methods of aerobic and anaerobic fresh solution and agitation enhances the primarily on the findings reported in classic studies culturing of viable microorganisms. More recent tissue dissolution capability of NaOCl. A studies using molecular and advanced imaging major disadvantage of NaOCl is its toxicity, particularly in the event of extrusion into the periradicular tissues. techniques have shown the endodontic microflora canto be remain significantly in inaccessible more complex areas ofthan the can root be canal shown Chlorhexidine is a cationic bisbiguanide with system,by culture regardless methods, of and clinical that techniquesbiofilms and used debris concentration-dependent antibacterial and during treatment. Taken together, these studies substantivity properties. It is available in both have established that disinfection, rather than liquid and gel form. While CHX has a broad sterilization, of infected root canals is a reasonable, spectrum of antimicrobial activity, it lacks and achievable, expectation. The overall goal is to tissue solvent properties, and is less effective provide an environment that will enable healing. against biofilms than NaOCl. 2. Irrigants and Medicaments Demineralizing agents [e.g. The “ideal” irrigant should be an effective ethylenediaminetetraacetic acid (EDTA)] antimicrobial agent and organic tissue solvent, demineralization can be facilitated by the non-irritating, stable and easily stored. It should During instrumentation, dentin be active in the presence of blood and serum, which are capable of forming soluble non- non-staining, non-antigenic, non-toxic, have low ionicaction chelates of chelating with agentsmetallic such ions, as such EDTA as surface tension, and be non-destructive to dentin, calcium found in hydroxyapatite crystals. apical tissues and endodontic instruments. Ideally, Chelating agents assist in the negotiation it should remove the smear layer and disinfect and enlargement of severely constricted or dentinal tubules. Substantivity (persistence of obstructed root canals, as well as the removal effect) may be desirable as long as residue is not of the inorganic component of the smear layer left that could interfere with root canal obturation. immediately prior to root canal obturation. Irrigants ideally should be convenient and inexpensive. There is no single solution currently with or without a surfactant or antiseptic. available that possesses all of the aforementioned EDTA is typically used as a buffered solution, desirable qualities.

Treatment Standards | Page 7 3. Combinations of agents, with or without It should be noted that no particular antimicrobial detergents, antibiotics, antiseptics and future irrigant or medicament can claim to result in directions superior healing outcomes. As such, decisions The flow of antimicrobial agents can be on which irrigant(s) to employ may be based enhanced by the addition of surfactants that decrease surface tension thereby potentially treatment, case selection and costs incurred. on factors such as clinicians’ skill, efficiency of enabling better penetration and access to narrower, confined portions of the root canal Irrigation Delivery system. Solutions with low antimicrobial The aim of irrigation is to physically disrupt activity may be combined with antiseptics and debride the root canal. Intracanal irrigation to enhance their usefulness. In the near provides a stream of chemicals to induce future, advanced research with nanoparticles antimicrobial activity, demineralization, tissue and energy activation of solutions will bear dissolution, lubrication, bleaching and hemorrhage witness to endodontic inquiry addressing control. The current or force created by irrigation future challenges in biofilm tenacity and the complexity of root canal systems. carries away debris towards the orifice; the Medicaments should be placed as inter- such as access to surfaces, volume of solution and efficacy of this process is influenced by factors appointment intracanal dressings if treatment solution exchange. Irrigation should be employed is completed over multiple visits. Medicaments at each instrument change with the total volume of can reduce the microbial count of species irrigating solution dependent on the size, shape and remaining in the root canal system, prevent regrowth and detoxify endotoxin. Even for the the root canal space. number of canals. Irrigants should be confined to vital tooth undergoing NSRCT over multiple visits, Current irrigation delivery techniques can be the placement of intracanal medicaments can help mitigate the consequences of inadvertent 1. Needle and syringe (“conventional”, categorized as follows: contamination or unanticipated leakage of the “positive pressure”) interim restoration. When used, the medicament The most common irrigation technique utilizes needle and syringe delivery. should entirely fill the canal to allow for optimal Effectiveness is dependent on the depth Currently, calcium hydroxide is the primary efficacy. of insertion of the needle and is improved choice of intracanal medicament. In addition to with increased apical size and taper of the its antimicrobial action, the alkaline pH of calcium root canal. Needle gauge should be based on hydroxide facilitates dissolution of organic tissues case selection and canal size. Canals need and bacterial products such as endotoxin. Calcium to be enlarged sufficiently for the needle to hydroxide can be placed as a slurry (powder mixed be placed loosely in the canal to the desired with a liquid such as saline or sterile water) or as depth. This will depend on factors including a proprietary paste via syringe, lentulo, or paper root length, curvature and apical anatomy. point delivery. It should be noted that CaOH can be Clinicians must avoid placing excessive highly toxic if expressed into the neurovasculature pressure on the syringe during irrigation and tissues so choice of a delivery method should be ensure that the needle is not bound in the based on the clinical parameters of each case. canal nor inserted too deeply into the canal of a tooth with a wide-open apex.

Access additional resources at aae.org Slow injection using side-venting needles If clinicians prefer to use lower and constant movement in small, vertical concentrations, antimicrobial activity can amplitudes can help prevent hydrostatic be facilitated by using higher volumes and buildup. increasing the frequency of irrigation. 2. Negative pressure 3. The majority of information on the clinical The rationale behind negative pressure usage of NaOCl has been obtained on irrigation delivery is to reverse the direction concentrations of between 0.5% to ~6%; the of irrigant flow away from the apex thereby efficacy and toxicity associated with higher minimizing the risk of apical extrusion of concentrations is not known. irrigant compared to other approaches. Final considerations in root canal disinfection 3. Energy activated devices used alone or as 1. The use of rubber dam is mandatory to avoid supplementary methods microbial contamination of the root canal Activation systems (sonic and ultrasonic) aim system during treatment, to retract tissues to enhance the movement of irrigant solutions and protect the patient, prevent aspiration or within the confines of the root canal space swallowing of instruments, and limit aerosols. in order to disrupt biofilms and debris, and 2. While many current concepts about root canal facilitate their removal. irrigation and irrigants evolved in earlier No particular irrigation delivery technique times, the fundamental goals of disinfection, can claim to induce superior healing success. tissue-debridement, lavage and lubrication remain unchanged. be based on factors such as clinicians’ skill, 3. The majority of clinical studies have efficiencyDecisions ofon treatment, which system case to selection employ mayand used NaOCl as an irrigant delivered via costs incurred. conventional irrigation techniques that Essential considerations with the usage of flushed the canal without the application of NaOCl as an irrigant energy; these studies have formed the basis for treatment outcome estimations. 1. In the event that NaOCl is extruded into the periradicular tissues, the patient may 4. The best approach to controlling microbes experience immediate severe pain, bleeding, during endodontic treatment is the use of ecchymosis and, potentially, long-term aseptic technique, effective debridement, local paresthesia. If a predisposing risk for irrigant antimicrobials, systemic antibiotics only if extrusion into the periradicular tissues indicated, and optimal apical and coronal seal. is suspected, such as open apices, root perforation or vertical root fracture, clinicians should proceed with caution, or consider using another irrigant solution. 2. The higher the concentration of NaOCl, the greater its antimicrobial activity, but also the greater its toxicity and potential adverse effect on biomechanical properties of dentin.

Treatment Standards | Page 9 Competence in Access well-angulated preoperative radiographic images Preparation and access; negotiation of the root canal system; and Instrumentation of toare minimize mandatory the to risk facilitate of procedural a safe and errors efficient that may result from unexpected anatomical complexity or Root Canal Systems bite-wings (for posterior teeth) provide an initial an inappropriate orientation. Periapical films and Access Cavity Preparation direction and alignment of pulp chamber and root canal position. Although two radiographs with INTENT STATEMENT: A practicing dentist should be able to predictably access the pulp chamber for the purpose of performing root canal treatment by computeddifferent angulations tomography are (CBCT) often sufficientimages may to developbe locating all main canal orifices. a 3D image of the tooth to be treated, cone beam INTENT STATEMENT: A practicing dentist when of extra canals, complex morphologies, curvatures accessing a pulp chamber should be able to minimize and/orjustified dental and necessary developmental to evaluate anomalies. the existence excessive removal of tooth structure, structural Images should be studied carefully, and coronal damage to the treated tooth, including prevention of perforations. lighting in complicated cases is warranted and appropriate.access aided Currently,by enhanced the magnification use of the dental and Purpose of Accessing the Pulp Chamber operating microscope is the highest achievable All intracanal procedures require a preparation through the coronal structure in a prescribed when pulpal complexity and natural deposition location and opening of the pulp space. The oflevel mineral of lighting reduces and prognosis magnification and affect and is a justified ultimate goal of this step is to expose the pulp successful outcome. Cases with anatomical and chamber and radicular space for subsequent morphologic complexity and potential clinical instrumentation, irrigation, debridement and challenges beyond a practitioner’s skill level antimicrobial treatment. Therefore, it is essential should be referred to a colleague with specialty skills in endodontics. accessible. that all canal orifices are identified and rendered Following treatment, all root canal-treated teeth Performing the Access Preparation For optimal aseptic conditions, a rubber dam remaining tooth structure and promote longevity must be in place before commencing access must receive a definitive restoration to protect the cavity preparation. There are rare but occasional that the coronal access opening be provided with clinical situations in tooth alignment or rotation, theand least function. damage To fulfill to dental this objective,structures. it is essential particularly where treatment is undertaken by inexperienced clinicians, when accessing before Information Gathering Prior to Access rubber dam isolation for cleaning and disinfection In order to prepare an access cavity appropriately, that is in the correct orientation and location, must be applied prior to introducing endodontic may have benefits; however, the rubber dam preoperative knowledge of the tooth anatomy and instruments and canal preparation. Standardized morphology must be considered by the clinician access cavity outlines for each tooth help to mitigate some of the risks involved. These risks include perforation as well as inappropriate and variationsregarding thewithin number any given and location tooth. Towards of canal this orifices, goal, excessive tissue loss. and the incidence and configuration of anatomical

Access additional resources at aae.org Appropriate access provides a convenience form, Detrimental Outcomes During Access in which the smallest possible dimensions of an A perforation on access, either towards the access cavity are dictated by the precise location of furcation in multi-rooted teeth, or towards the periodontal ligament in other locations, canal entrances on the pulpal floor. The concept of further to the primary curvature of the root canal treatment. However, subtler structure loss is also a so-called straight-line approach to an orifice and is relevant to minimize procedural errors during associatedsignificantly with reduces reduced the prognosisoutcome of for the long-term overall subsequent treatment procedures. A large access retention of root canal treated teeth. Endodontically with divergent walls is not required for the use of treated teeth are more frequently extracted because of fracture than because of persistent apical canal instruments. pathosis and efforts to maintain tooth structure are contemporary flexible and fatigue-resistant root Access preparation is more readily achieved with These contemporary concepts in access cavity beneficial. instruments. Many teeth have suffered considerable design change the current focus from coronally magnification, enhanced lighting, and appropriate tissue loss prior to endodontic intervention, and it divergent preparations to the selective preservation may be even more important in such cases to adopt of dentin, prioritizing the removal of caries and a thoughtful, deliberate, and conservative approach restorative material ahead of tooth structure. to access in order to avoid further unnecessary However, the focus on dentin preservation tissue loss and structural weakening. should not mean that treatment goals must be In most generalist practices, practitioners compromised, and access preparation should not are encouraged to work as conservatively as be so restrictive as to impede the location and entry reasonable. Clinical steps include establishing the appropriate coronal outline form with a high speed handpiece under water cooling and cutof instruments within restorative into all materials canal orifices such for as safecomposite and penetration into the pulp chamber towards the orefficient amalgam cleaning can often and shapingbe slightly procedures. larger. Complete Cavities removal of existing restorative materials in their entirety provides a better coronal seal and allows endlargest cutting pulp bur horn. which The isoutline unlikely is then to damage refined, the a more complete understanding of the remaining including unroofing the chamber with a non- tooth structure and restorability of the tooth handpiece. When the dental operating microscope following treatment. ischamber available, floor conventional or walls or high-by using and a low-speed slow speed burs may be less desirable, and practitioners may prefer to selectively unroof the chamber with specially designed ultrasonically energized tips that improve visual access, while providing micro-instrumentshigh cutting efficiency, are combinedavailable to with facilitate safety such and control. Specifically designed endodontic burs and illumination. procedures under microscopic magnification and

Treatment Standards | Page 11 Measuring Competence Purpose of the Preparation of Root Canals Competence in accessing root canal systems is Clinical procedures for root canal instrumentation

• Appropriate preoperative evaluation of anatomy natural dentition for the lifetime of the patient demonstrated by the following skills: have two fundamental goals: to preserve the and morphology and the analysis of the skill level (“retention”) and to treat or prevent apical periodontitis (“healing”). These are not mutually exclusive goals, and both are important. There is necessary to predictably find and reveal all canal solid evidence that debriding all canals to working • Understanding structural parameters and the orifices length demonstrates competence in treating apical prognosis for adequate ferrule related to dentin periodontitis while committing over-preparation height and width at the restoration interface • reduceserrors or prognosis filling beyond for retention. the confines of the root Designing and creating access cavities with canal system impedes success and significantly orientation in the oral cavity of the patient The purpose of shaping is to facilitate debridement, respect to specific internal anatomy and • Preparing coronal access preparations that disinfection and to provide space for the placement preserve tooth structure, are centered in the of obturation materials. The main technical coronal position, are measured for depth and objectives of shaping are to maintain the apical long axis orientation, permit location and foramen in its original position, allowing it to instrumentation of all canals, and prevent remain as small as possible; and to develop a perforations (lateral and furcal) continuously tapering funneled preparation from

Root Canal Preparation shape to provide apical resistance form during INTENT STATEMENT: A practicing dentist obturation.the canal orifice to the apex allowing the tapered performing root canal preparation should be able to determine and maintain an appropriate working Metrics of Canal Preparation: length. Apical Width and Length INTENT STATEMENT: A practicing dentist Based on studies of apical anatomy, the ideal apical performing root canal preparation should be able to point of termination, also known as working length, prepare a canal to width conducive to debridement, has been established empirically to be 0.5 to 1.0mm subsequent antimicrobial treatment, and obturation. from the radiographic apex. Contemporary clinical INTENT STATEMENT: A practicing dentist performing root canal preparation should be able perforation,evidence lists preoperative significant adverse periradicular factors disease, that and to avoid procedural mishaps, including but not incorrectinfluence lengthsuccess of such the rootas the canal creation preparation of a ledge and or limited to, damage to major vascular and/or neural structures, canal transportation, ledge formation, radiographic apex or obturation materials extruded canal blockage, file fracture, and perforation. subsequent filling more than 2.0 mm short of the Traditionally the working length has been and not confined to the canal space. determined with periapical radiographs; however, it is recommended that an electronic apex locator is used in conjunction with verifying radiographs to approximate the location of the apical constriction and terminate canal preparation accordingly.

Access additional resources at aae.org The decision of where to terminate the preparation The development of nickel-titanium instruments has dramatically changed the techniques of apical anatomy, tactile sensation, radiographic cleaning and shaping; these instruments have interpretation,in a specific case information will be based from on apex knowledge locators, of the been rapidly adopted by clinicians around the presence of apical bleeding, and occasionally the world. The primary advantage to using these patient’s response. incidence of preparation errors. Degree of Apical Enlargement flexible instruments is a significant reduction in the Generalizations may be made regarding tooth been shown to completely debride the canal anatomy and morphology, although each tooth system.Neither Mechanicalhand instruments enlargement nor rotary of the files canal have is unique. Because morphology is variable, there space dramatically decreases the presence of can be no standardized apical canal size. Rather, microorganisms present in the canal but cannot the degree of enlargement is dictated by the render the canal sterile. Therefore, the use of initial canal size, the irrigation regimen and the antimicrobial irrigants is essential in addition to mechanical preparation techniques. These irrigants canal size is currently required for mechanical are delivered by a needle-and-syringe system and debridementobturation technique and to place employed. antimicrobial A sufficient solutions may effectively extend within the main canal space. into contact with the root canal system. However, the presence of dentin debris in accessory However, as dentin is removed from the canal canal spaces and the complexity of most root canal walls, the root becomes less resistant to fracture systems remain impediments to effective irrigation. and the risk of preparation errors increases. For example, narrow thin roots, such as in mandibular Detrimental Outcomes of Canal Preparation incisors, may not be enlarged to the same degree as bulkier roots, such as maxillary central incisors or overextended and directly impact the periodontal canines. Likewise, many canals in multirooted teeth ligamentWith ineffective and strategic length structurescontrol, files such may as be the such as mesial canals in mandibular molars and mental and inferior alveolar nerves, and maxillary buccal canals in maxillary molars are delicate and sinus. Likewise, errors in canal preparation, curved, limiting canal preparation size. Apical canal resulting in canal perforations either at midroot or enlargement must not be done at the expense of in the apical canal third, can lead to the extrusion coronal dentin, where in molars the radicular wall thickness towards the furcation is in some sections, secondarily damage structures. Other preparation 1.0 mm or less. errors,of irrigation such assolutions instrument or filling fracture, material as well and as canal transportation, ledge and blockage formation, Elimination of Etiology are impediments to complete debridement. In cases of root canal treatment of teeth with Instrumentation must only be performed after vital pulp tissue (irreversible pulpitis and elective proper understanding of canal complexities and treatment procedures), complete removal of the are used. with consideration of the specific instruments that materials is the objective. With pulpal necrosis, roottissue canal and wallscreating are sufficient typically coveredspace for with obturation a accessorypolymicrobial canals. bacterial A variety biofilm, of microbial extending species into can alsosecondary penetrate anatomy deep suchinto dentinal as fins, isthmuses tubules. and

Treatment Standards | Page 13 Measuring Competence INTENT STATEMENT: A practicing dentist must be able utilize obturation techniques and materials that protect the patient from untoward outcomes and Demonstrating competence in shaping of root maximize the potential for healing and well-being. • Ability to predictably enlarge canal spaces to canals is demonstrated by the following skills: mechanically remove vital or necrotic tissues INTENT STATEMENT: A practicing dentist must and microorganisms; provide effective space demonstrate well prepared and filled root canals for antimicrobial solutions and intracanal that display a homogenous radiopaque appearance, medicaments; and the insertion and free of voids and filled to working length. condensation of obturation materials. INTENT STATEMENT: A practicing dentist must • Conscious determination and maintenance of protect the patient by avoiding overfill in the an exact apical end point and restricting canal presence of vulnerable structures or neurovascular anatomy. • Selecting instruments and treatment sequences preparation to the confines of the root canal that minimize damage to radicular structures than root canal treatment for central maxillary incisorsMolar endodontics for several isreasons, inherently notably more the difficult more • In-depth understanding of the development of complex anatomy and the location of the teeth in procedural errors and ways to avoid these the patient’s mouth, among other factors, such • Patient-oriented decision making when as anesthesia. Any anatomical complexity, no recognizing procedural errors matter its position in the arch or the tooth where it is found requires that the successful clinician

Endodontic Obturation competent to manage the unusual or untoward occurrence.will consider the specific patient’s needs and be Shaping any root canal system promotes disinfection and obturation and is the cornerstone Essential Considerations in Effective of non-surgical endodontics. All healing outcomes, Obturation both long and short term, center on the technical Only a well prepared canal system can provide quality and attention to detail invested in these ideal conditions for appropriate obturation. A steps. well-shaped and well-debrided canal system Most importantly, clinicians should continually will potentially create the conditions for healing periapical tissues. Because a root canal system clinical evidence supporting the treatment for its is inaccessible to the body’s immune system, impactevaluate on any overall treatment outcomes, step, clinicaland the healing, scientific as and best practice therefore dictates that root canals well as the outcome of long-term retention of the natural dentition over the course of the patient’s dimensions, in order to prevent ingress of nutrients lifetime. orshould oral microorganisms.be filled as completely None asof possiblethe established in all There is solid evidence that debriding all canals periodontitis, while committing preparation errors reason,techniques a permanent for root canal coronal filling restoration provides shoulda to working length is efficient in treating apical bedefinitive placed coronal,as soon aslateral, feasible and after apical the seal. endodontic For this system is detrimental to this healing process. treatment. or filling beyond the confines of the root canal

Access additional resources at aae.org containing pastes is a great concern. leading to the periodontium; be without voids; be Several of these techniques have shown comparable adaptedIdeally, a to root the canal instrumented filling should canal seal walls, all foraminaand end at the apical terminus. The following considerations periradicular lesions, so that a clinician may choose fromsuccess a variety rates regarding of techniques apical and bone approaches fill or healing that of cleaned and prepared root canal system in order will help to provide a fluid-tight seal of the to protect periradicular tissues from bacterial All of these recommended techniques utilize a solid recontamination. corework material best for aseach well specific as sealer. case The and/or following clinician. lists There are many clinically acceptable materials and 1. Choosing a technique for obturation the main steps in root canal obturation: techniques for root canal filling; the spectrum of 2. Selection of master cones and/or sealer 1. Sealer (cement/paste/resin) only root canal fillings includes: strategy 2. Sealer and a single cone of a stiff or flexible 3. Canal drying and sealer application core material 4. Adapting the cone to the canal and verifying 3. Sealer coating combined with three the position and fit dimensional lateral compaction of core materials 5. Obturating the apical portion (lateral and vertical compaction) 4. Sealer coating combined with three dimensional warm compaction of core 6. Completing the obturation process materials 7. Assessing the quality of the overall obturation 5. Sealer coating combined with carrier-based No particular technique can claim superior healing core materials It is important to recognize that many States in may be based on such factors as clinicians’ skill, success. Decisions on which system to employ the USA adhere to the RESPECTABLE MINORITY RULE: Just because a treating dentist uses different procedures involved and costs incurred. efficiency of treatment, case selection, simplicity of materials or performs a procedure differently, it does not make the dentist’s treatment below the before choosing a technique. In the presence of standard of care. However, paraformaldehyde openAll root apices canals or toprocedural be filled should errors besuch assessed as apical pastes and holistic dentistry that advocates transportation from the original canal position, and and recommends wholesale extraction of also in teeth with apices in close proximity to the endodontically treated teeth or removal of all mandibular canal or the sinus, there is the potential unacceptable and disrespected minority views. metallic fillings, claiming systemic harm, are for overfills and serious injury. In general, canals Studies have shown paste-only techniques are should only be filled when the canal can be dried. subject to volume shrinkage during their set. As placement. Root fillings should be sterile or disinfected prior to such, the material pulls away from the walls as it Most sealers are toxic in the freshly mixed state, sets and the resultant loss of interface adhesion but this toxicity is reduced after setting. When in leaves gaps and/or channel formations between the dentin wall and the set sealer. Controlling length eugenol-based sealers are absorbable while resin basedcontact materials with tissues typically and tissue are slow fluids, to absorb zinc oxide or With the increased risk of extrusion, the toxicity are not readily absorbed. Some by-products of ofand certain density sealers is difficult such andas paraformaldehyde- extrusion is a major risk. sealers may adversely affect and delay healing.

Treatment Standards | Page 15 Therefore, sealers should not be routinely extruded Additional Important Obturation into the periradicular tissues. Recent development Considerations of bioceramic sealers holds promise of being Thermoplastic obturation using heat-softened biocompatible and tolerant of residual moisture in the canal. communications, promoting movement of softened Cones are available in several tapers with the goal gutta-percha intocan filllateral accessory canals, canals and isthmuses. and length, as indicated by the sensation of tug-back, or volume of core material. On the other hand, it can resistanceto fit cones to to pulling the best the wall cone contact out. If at a workingcone is too alsoThis resultallows in for material the filling extrusion of canals into with the a periapical higher tapered for the preparation, it will make contact especially in cases where the apical foramen has short of length. If it is not tapered enough, it will be area because of the enhanced flow characteristics, loose,with the and canal will wallappear coronally crimped with at the the tip. fit being A good showninadvertently higher beensuccess over rates. instrumented. The responsibility Confining tothe avoid root filling overfills to the in canalthe presence space has of predictably vulnerable ofprimary the preparation. fit with apical This tug-back is critical of to a promotemaster cone a good is structures or neurovascular anatomy is the obturation.one adjusted to fit both the apical size and the taper responsibility of the clinician. There is no acceptable defense for any operator when a homogenous radiopaque appearance, free of voids patient’s health and well-being is harmed by a Prepared and filled canals should demonstrate a lack of clinician diligence. should approximate canal walls and extend as muchand importantly as possible filled into canalto working irregularities length. Thesuch fill as Cautions In Obturation Safety an isthmus, ribbon-shaped spaces or a C-shaped An “injection only” technique is not recommended in medication placement or predictable and not a prerequisite for success. canal system. The fill of accessory canals is not obturation because of the danger of overfill; if the inIn theorder mandibular to avoid overextension canal or maxillary of root sinus, filling it is foroperator placement chooses and this density option, before the apicalproceeding fill of with3-4 recommendedmaterial into the to periapicalaccurately tissue, determine and specificallyworking millimeters should always be verified by radiograph length to prevent destruction of the apical Carrier based systems create an apically directed the rest of the fill. constriction. hydraulic pressure during application to the canal. For infected root canal systems, the best healing results are achieved when the working length is While these systems create a dense filling, care between 0.5 to 1.0 mm from the tip of the root as 1. Not use large amounts of sealer. visible on a radiograph. In posterior endodontics, must be taken to: determination of apical canal anatomy is often 2. Insert the carrier slowly. 3. Verify working length to avoid overfilling. second mandibular molars that are in close Avoid Overfilling: Gross overextension of difficult. It may be appropriate when treating proximity to the mandibular canal to de-emphasize obturation materials usually indicates faulty patency and even block apical foramina to technique. impediment to healing and in the worst case may 1. When selecting a filling technique it is beavoid associated large overfills. with nerve Large damage overfills and may permanent be an important to consider adjacent anatomical patient injury (paresthesia and dysesthesia). structures and the patency (level) of the root

Access additional resources at aae.org canal. There are considerable differences in paraformaldehyde or other mutagenic or viscosity of obturation materials between carcinogenic substances must be avoided. lateral compaction and warm filling 3. Though a little sealer extrusion may be well techniques and one must be confident in his/ tolerated and absorbed by the periapical her approach. tissues over time, prevention is in order. 2. Maintaining apical patency is advocated Toxicity will be destructive if compacted into by many clinicians, but if the passage of periradicular tissues, the maxillary sinus or instruments to patency length is not restricted the mandibular canal. to small instruments (#10 or #15) one will 4. Working length should be confirmed destroy (widen) the apical constriction. electronically and radiographically and 3. Because thermoplastic gutta-percha filling maintained throughout instrumentation. The techniques are so effective in filling unusual apical constriction (cementodentinal junction canal aberrations, they have become the technique of choice for endodontists. apically narrowing over several millimeters, or CDJ) may involve multiple constrictions, be 4. The thermoplastic method emphasizes or not exist. heating the gutta-percha to increase its 5. Tactile readings alone are not dependable. flow characteristics, but when that flow is A negotiating file may bind anywhere along not controlled one is apt to extrude large the canal length and be misinterpreted as the amounts of filling material into the periapical constriction. tissues. This potential for overfilling can be 6. The object of instrumentation is to provide a particularly dangerous when the mandibular glide path and a prepared apical constriction nerve, the maxillary sinus, or the opened for the insertion and compaction of gutta apical foramen is at risk. percha. Poor length control leads to over- instrumentation and overfilling. Final Considerations in Obturation Prior to treatment one must closely inspect and Preventing Obturation Mishaps evaluate the tooth/root’s internal anatomy as well 1. It is essential to image and clearly identify as their root-tip relationship with maxillary and radiographically the roots and surrounding mandibular structures. jaw structures in order to understand the 1. third dimension and risks of overfill. development and apical resorption)? Other 2. It is critical to use obturation materials that Does this tooth have an open apex (immature factors include root length, root width, canal are well tolerated by the body after therapy, size, mineralization, internal resorption, etc. rather than unsafe formulations such as paraformaldehyde pastes that should not or approximate the mandibular canal? Is the be used in the good and safe practice of Do the roots extend into the maxillary sinus endodontics.

morphology?degree of canal These curvature questions greater can than identify 30 3. The clinician must practice careful and teethdegrees? where Does routine the root endodontic exhibit an techniques “S” shaped judicious shaping strategies that use multiple may not meet the demands of a case and confirmations of working length (electronic, referral is in order. radiographic, tactile and paper points), in order to take serious precaution against 2. Are the materials biocompatible? Certain overinstrumentation. sealers are neurotoxic. Sealers that contain

Treatment Standards | Page 17 4. It is important to use “resistance form” in as posts and cores and obturation materials controlling overfills. This “resistance form” in addition to remaining necrotic tissues and can be imparted during canal preparation by microbes. To accomplish these tasks, varied producing funnel-form, tapered preparations specialized instruments and armamentaria and by selecting gutta-percha cones to match are required. The procedures are precise, and those canal shapes which will resist the microscopy is often necessary. In addition, obturation forces which promote extrusion. they are time consuming, and have a slightly 5. When using thermoplastic techniques, it is decreased prognosis compared to initial root important to respect the flow characteristics canal treatment. However, in general, referral of the materials and the heat energy used. to an endodontic specialist is preferred over extraction and will provide the best long result 6. The use of paste-fillers and syringes for for the patient. applying endodontic sealers should not be used when there is close proximity to neural The general dentist must be able to ascertain structures and control is compromised. the success and failure of endodontic treatment procedures and recommend appropriate corrective 7. In cases of extreme proximity to the treatment options or consult with a specialist. neurovascular anatomy, the importance of creating a clean dentin plug or bioceramic barrier at the patent apical terminus should Restoration of the be carefully planned when the risk of extrusion is considerable. Endodontically Treated Tooth

Endodontic Retreatment Endodontic treatment is considered complete following obturation of the root canal. However, Periapical pathosis and/or persistent symptoms failure is inevitable in an improperly restored tooth. associated with a previously endodontically treated Coronal leakage and fracture can occur with any tooth or development of periradicular pathosis incompletely restored tooth. It is suggested that in cases where a lesion was not present indicates persistent disease. Persistent disease following access opening or placement of the core buildup initial root canal treatment does not necessitate bewhen performed possible, upon the definitive completion restoration of the root of canal the nor obligate tooth extraction. Clinical assessment therapy and under the rubber dam. The additional and or enhanced imaging often reveals the etiology barrier following obturation has been proposed corrective action can be taken. procedure of the placement of an intraorifice of failure. Once the cause for pathosis is identified, to minimize these risks in case of unforeseen Incomplete treatment, missed canals, poor obturation, and coronal leakage are common causes that can be corrected with retreatment intracoronaldelays in obtaining cracks ato definitive minimize coronal the chances restoration. procedures. Procedural errors such as perforation, ofAdditionally, propagation intraorifice into root structurebarriers may before reinforce a full apical transportation, ledging, loss of length, and coverage restoration can be placed. The procedure separated instruments may not be correctable with a non-surgical retreatment approach and are best treated with surgery by an endodontic specialist. cementfor the intraorifice or bioceramic barrier restorative involves material the placement directly of Retreatment cases vary in complexity; require overa flowable the canal composite, obturation resin-modified material within glass the ionomer canal enhanced knowledge and technical skills to remove coronal restorative materials such allow for a bonded seal when placement of a core orifice followed by a temporary restoration, to

Access additional resources at aae.org space, stagnate, break down, and re-enter the cannot be placed immediately. buildup or definitive access opening restoration It is a popular belief that endodontically treated is now known that treatment failure is not due to tissues causing apical inflammation and disease. It teeth are more brittle due to loss of moisture in the “apical percolation” but coronal bacterial leakage. only slightly affect the collagen of dentin and that must be considered when treatment planning Placement of a definitive coronal restoration andentin. endodontically Yet research treated shows tooth’s that moisture susceptibility loss may to non-surgical endodontic therapy to eliminate fracture is primarily caused by a loss of structure recontamination. due to caries, prior restorations, fractured cusps Root-canal treatment cannot be successful and the access cavity and not the loss of moisture. without timely and adequate definitive Aging of dentin additionally promotes the restoration. It is clear from the literature that any replacement of collagen by hydroxyapatite mineral delay between endodontic treatment and tooth which makes a tooth more susceptible to fracture restoration should be as brief as possible, since by decreasing the dentin’s elasticity. Therefore, the numerous studies report that there is notably strongest tooth with the best restorative prognosis reduced survival after endodontic treatment is one that retains maximum structural integrity of for teeth restored with temporary restorations, dentin and enamel with minimal preparation and a compared to those receiving a permanent “protective” restoration. restoration. Consequently, when restorative care INTENT STATEMENT: A practicing dentist must cannot be completed immediately following be able to recognize that a final restoration of completion of root-canal treatment with the rubber an endodontically treated tooth is considered an integral part of the endodontic treatment. The placed to prevent coronal leakage. dam still in place, an intraorifice barrier should be treatment plan for an endodontically-treated tooth is considered incomplete until the tooth is definitively leakage, and protecting the remaining tooth restored in a timely and adequate fashion. structureProviding willa fluid-tight provide long-termseal, preventing stability bacterial following INTENT STATEMENT: A practicing dentist must be the root-canal treatment. While only one of able to decide the appropriate restorative strategy many factors that the restorative dentist needs for an endodontically treated tooth by evaluating tooth type, the extent and distribution of tissue loss, unacceptable. In general dental practice, patient to fulfill, failure to restore the tooth adequately is as well as type and material of the final restoration. expectations are related to the restoration of masticatory function, esthetics, the longevity of In determining prognosis, restoration of the restoration, or to more practical factors such endodontically treated teeth must be considered as as chairside time or the cost of the restorative an integral part of the endodontic treatment since procedure. it plays a major role in the long-term success of the procedure as well as in tooth longevity. In order to While cuspal coverage is typically recommended maximize the chances of success, the distinctive in the posterior dentition following root canal characteristics of endodontically treated teeth need procedures, this may not be necessary in some to be carefully considered, as well as the recent instances, since such a decision should depend on advances in adhesion, digital technologies, and the amount of remaining coronal tissue. In teeth biomaterials. From the founding of the specialty with minimal structural tissue loss, intact marginal ridges, a conservative access preparation, and no dependent on the apical seal. Should leakage occur, preexisting cracks, the clinician may consider a until the mid-1980’s success was thought to be direct intracoronal bonded restoration as a valid it was thought fluids would enter the apical canal Treatment Standards | Page 19 option. It is less expensive for the patient, conserves intensity. Since root canal treatment weakens teeth due to loss of structure, there is a particular leaves the practice with a permanent restoration in need to adequately protect endodontically treated atooth single structure, appointment. is faster, efficient, and the patient posterior teeth against tooth fracture. The major cause for increased susceptibility to fracture of greatly over the last decades. In particular, resin- endodontically treated teeth appears to be the basedDental composites, materials and which techniques can be micromechanicallyhave evolved loss of hard tissue. Endodontically treated teeth and chemically bonded to the dental tissues, have undeniably often undergo additional dentin become more and more reliable. By tradition, removal in the process of the restoration in creating some dentists continue to use metal posts to a post space as well as preparation for full crowns retain bonded composite restorations while they and occlusal reduction of thin dentin walls. In this regard, it is quite telling that a major cause of resin-based posts which are more protective of further tissue damage is dentistogenic. In light of remainingaccordingly structure; should be or replaced possibly by by fiber-reinforced no posts at all. this paradox, it is important to weigh the necessity This is supported by the fact that a ferrule should be obtained on all endodontically treated teeth. If The ultimate goal of dentistry is to retain a healthy or rationale of additional tissue sacrifice. a 2 mm ferrule can be obtained for any protective complement of teeth for a lifetime; therefore, restoration, a post is not needed to retain a bonded appropriate strategies should be “preservative”, buildup. A ferrule is generally considered to be with existing tissues conserved as much as extremely important to prevent dislodging forces that will lead to coronal leakage. Cusps should be certain advances and evolutions made over the past covered if structural loss has damaged marginal fewpossible. decades In this that regard, are of primeit is significant importance to consider when ridges or undermined coronal walls. considering the best way to restore endodontically Root-canal treatment itself does not seem to and biomaterials that are “protective” of remaining treated teeth: adhesive dentistry, digital technology, susceptibility to fracture appears to be due, in the structure. Generally, goals of the restoration of teeth majority,significantly to coronal weaken and dental pericervical structures; hard increased tissue after endodontic treatment can be summarized in removal. Three major technological developments are challenging the way endodontically treated prevent infection or reinfection of the root canal three main objectives: to restore tooth function, to the remaining tooth structure against further tissue 1. Adhesive dentistry and the development teeth have been restored: damage.space by providing a fluid-tight seal and to protect of increasingly more dependable dental adhesives The dental ferrule refers to a circumferential band of dentin of at least 1–2 mm coronal to the 2. The rise of digital technology, enabling the margin of the preparation for a full crown. It has rapid and reliable design and manufacture of been suggested that the presence of a ferrule may cuspal-coverage restorations in practice reinforce and stabilize endodontically treated 3. The development of biomaterials, with characteristics more compatible to replaced observed that an adequate ferrule lowers the tissues impactteeth, defined of the other by a “ferrule factors sucheffect”. as Research post and hascore systems, luting agents, or crown material on the tooth type, since each is submitted to very survival of endodontically restored teeth. The differentRestorative challenges concepts during should function. be specific Molar to each teeth research clearly states that restorative failure is are mostly challenged by axial forces of high not seen when sufficient coronal dentin is available Access additional resources at aae.org because the restoration does not rely heavily on of dentin remain, a post is not necessary. All metal the bonding of restorative materials to the root posts, regardless of design or type of cement used, dentin. Considering clinical data, on the subject of transmit forces developed during mastication to the root of the tooth, and thus, can promote fracture over time if the root is structurally compromised. survivalpost utilization, after endodontic evidence findstreatment. that the use of post Nonmetal posts offer a more compatible material to retention had no significant influence on tooth be placed adjacent to dentin to prevent the fracture Restoration of Anterior Teeth problem associated with metal posts. These posts are bonded in the canal and have some degree of an anterior tooth after endodontic therapy is determinedThe type of finalby the restoration amount of recommended remaining tooth for dentin). flexibility (similar to the modulus of elasticity of structure. If the only loss of tooth structure results from a conservative access preparation, a bonded Biomimetic restoration composite is adequate. If the tooth is weakened The research and study of interdisciplinary by a large or misdirected access preparation or materials-science is termed “biomimetics”. Inherent proximal caries and/or restoration, a crown should the recovery or mimicking of the biomechanics necessary when the remaining tooth structure ofin the originaldefinition tooth of biomimetics by the restorative in dentistry material. is (afterbe considered crown preparation) as the final restoration.will not retain A post the core.is A Traditional restorative techniques have post should be avoided whenever possible in order incorporated corono-radicular materials that were to reduce the possibility of root fracture. more diverse in their behavior when compared to dentin. Since many endodontically treated teeth are Restoration of Posterior Teeth restored with numerous material components (e.g., The average person can exert enormous forces on gold/stainless steel/ceramic/composite, alloy) the posterior teeth, or about nine times the amount potential for these materials to behave differently of force that is exerted on anterior teeth during than dentin under dynamic function or thermal closure. This force can result in over 200 pounds expansion may affect the resultant modulus of per square inch of stress applied to posterior elasticity, tensile and compressive strength of restorations. Therefore, cusps of posterior teeth each tooth and its remaining structure. Choosing must be protected against vertical fracture. Proper restoratives with similar material traits to dentin is a strong trend in dentistry and in the rehabilitation core placement and crown placement. of endodontically treated teeth. restoration of posterior teeth involves two phases: In summary, a full crown is not universally required Contemporary Post Philosophy after root canal treatment. Evidence indicates The function of a post is to retain a core restoration. that placement of a crown following nonsurgical The function of a core restoration is to retain a root canal treatment enhances the restorative crown. If core retention is not necessary, a post is prognosis primarily by providing cuspal protection. not indicated. To reduce the potential of vertical Factors such as tooth type, extent and distribution root fracture a post should be placed only when of tissue loss, as well as type and material of necessary for core retention. The most important decide the appropriate restorative strategy for the final restoration need to be considered to is the amount of supporting tooth structure an endodontically treated tooth to last a lifetime. remainingfactor influencing after crown whether preparation a post will and be the necessary Universal crown placement after root canal development of a ferrule. If three supporting walls treatment is probably overtreatment.

Treatment Standards | Page 21 Suggested Reading Ricucci D, Siqueira JF, Jr. Biofilms and apicalJ Endod. Disinfection periodontitis: study of prevalence and association with clinical and histopathologic findings. Chow TW. Mechanical effectiveness of root canal Sathorn C, Parashos P, Messer H. Antibacterial irrigation. J Endod. 2010;36:1277-88. Clegg MS, Vertucci FJ, Walker C, Belanger M, Britto a systematic review and meta-analysis. Int Endod J. 1983;9:475-9. LR. The effect of exposure to irrigant solutions efficacy of calcium hydroxide intracanal dressing: in vitro. J Endod. 2007;40:2-10. on apical dentin biofilms Goncalves LS, Rodrigues RC, Andrade Junior theSjogren outcome U, Figdor of endodontic D, Persson treatment S, Sundqvist of teeth G. with 2006;32:434-7. CV, Soares RG, Vettore MV. The effect of sodium apicalInfluence periodontitis. of infection Int at Endodthe time J. of root filling on hypochlorite and chlorhexidine as irrigant solutions Access Preparation and Instrumentation1997;30:297-306. clinical trials. J Endod. Outcomes: long term retention in function, for root canal disinfection: a systematic review of which includes treatment of apical periodontitis 2016;42:527-32. ofGu sodium LS, Huang hypochlorite XQ, Griffin on B, dentinBergeron as usedBR, Pashley in endodontics.DH, Niu LN, et Acta al. Primum Biomater. non nocere - The effects systematicNg YL, Mann review V, Gulabivala of the literature. K. Tooth survivalInt Endod J. Guivarc’h M, Ordioni U, Ahmed HM, Cohen S, following non-surgical root canal treatment: a 2017;61:144-56. Catherine JH, Bukiet F. Sodium hypochlorite Song M, Kim HC, Lee W, Kim E. Analysis of the cause 2010;43:171-189. J Endod. 2017; of failure in nonsurgical endodontic treatment by microscopic inspection during endodontic accident: a systematic review. Kakehashi S, Stanley HR, Fitzgerald RJ. The effects microsurgery. J Endod. 43:16-24. of surgical exposures of dental pulps in germ-free 2011;37:1516-1519. and conventional laboratory rats. Oral surgery, oral survival of endodontically treated teeth at a public medicine, and oral pathology. dentalLandys specialist Boren D, clinic.Jonasson J Endod. P, Kvist T. Long-term Konstantinidi E, Psimma Z, Chavez de Paz LE, 1965;20:340-9. Boutsioukis C. Apical negative pressure irrigation Access Cavity Preparation2015;41:176-181. Identify and Reveal all Major Canal Orifices cleaning and disinfection of the root canal system. Using Appropriate Technology Intversus Endod syringe J. irrigation: a systematic review of Karabucak B, Bunes A, Chehoud C, Kohli MR, 2017;50:1034-54. Setzer F. Prevalence of apical periodontitis in FC, et al. Radiographic healing after a root canal endodontically treated premolars and molars treatmentLiang YH, Jiang performed LM, Jiang in single-rooted L, Chen XB, Liu teeth YY, Tian with and without ultrasonic activation of the tomography study. J Endod. J Endod. with untreated canal: a cone-beam computed Khalighinejad N, Aminoshariae A, Kulild JC, 2016;42:538-541. irrigant: a randomized controlled trial. Williams KA, Wang J, Mickel A. The effect of the Moorer WR, Wesselink PR. Factors promoting the 2013;39:1218-25. dental operating microscope on the outcome of tissue dissolving capability of sodium hypochlorite. Int Endod J. case-control study. J Endod. nonsurgical root canal treatment: a retrospective 1982;15:187-96. 2017;43:728-732.

Access additional resources at aae.org Retain Structure and Avoid Iatrogenic Errors BJ. Increased apical enlargement contributes to Elayouti A, Dima E, Judenhofer MS, Lost C, Pichler the foundation for less invasive alternatives in the managementBoveda C, Kishen of apical A. Contracted periodontitis. endodontic Endodontic cavities: a stepwise microcomputed tomography study. J excessive dentin removal in curved root canals: Topics. Endod. 2 Rodrigues RCV, Zandi H, Kristoffersen AK, Enersen 2015;33:169-186. 011;37:1580-1584. in tooth stiffness as a result of endodontic and restorativeReeh ES, Messer procedures. HH, Douglas J Endod. WH. Reduction preparation size and the irrigant type on bacterial reductionM, Mdala I, in Orstavik root canal-treated D, et al. Influence teeth with of the apical apical 1989;15:512-516. periodontitis. J Endod. and treatment choices based on prognostic factors. Iatrogenic Errors and their Prevention EndodFuss Z, Dent Trope Traumatol. M. Root perforations: classification 2017;43:1058-1063. Clinical Procedures Lambrianidis T. Ledging and blockage of root canals 1996;12:255-264. Buhrley LJ, Barrows MJ, BeGole EA, Wenckus CS. prevention, management, and outcomes. Endodonticduring canal Topics. preparation: causes, recognition, maxillary molars. J Endod. Effect of magnification on locating the MB2 canal in Gorni FG, Gagliani MM. The outcome of endodontic Johnson BR. Endodontic access. Gen Dent. 2009;15:56-74. 2002;28:324-327. J Endod. Schafer E, Schulz-Bongert U, Tulus G. Comparison Canal Preparation: Appropriate Access for retreatment: a 2-yr follow-up. 2004;30:1-4. 2009;57:570-577; quiz 578-579, 595, 679. of hand stainless steel and nickel titanium Antimicrobials to the Root Canal System J Endod.

rotary instrumentation: a clinical study. Clinical Quality reduction.Aminoshariae Int Endod A, Kulild J. J. Master apical file size - 2004;30:432-435. smaller or larger: a systematic review of microbial Burry JC, Stover S, Eichmiller F, Bhagavatula P. Nair PN, Henry S, Cano V, Vera J. Microbial status 2015;48:1007-1022. Outcomes of primary endodontic therapy provided of apical root canal system of human mandibular by endodontic specialists compared with other providers. J Endod. “one-visit” endodontic treatment. Oral Surg Oral Siqueira Jr JF, Perez AR, Marceliano-Alves MF, Medfirst molarsOral Pathol with Oral primary Radiol apical Endod. periodontitis after 2016;42:702-705. Provenzano JC, Silva SG, Pires FR, et al. What 2005;99: Siqueira JF, Jr., Araujo MC, Garcia PF, Fraga 231-252. correlative analysis using micro-computed tomographyhappens to unprepared and histology/scanning root canal walls: electron a microscopy. Int Endod J. 2017. forRC, cleaningDantas CJ. the Histological apical third evaluation of root canals. of the J Endod. effectiveness of five instrumentation techniques Paredes-Vieyra J, Enriquez FJ. Success rate of single- versus two-visit root canal treatment of teeth with Requirements in Length and Size 1997;23:499-502. J Endod. canal instrumentation and obturation, part 2. A apical periodontitis: a randomized controlled trial. histologicalRicucci D, Langeland study. Int K. Endod Apical J. limit of root 2012;38:1164-1169.

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Treatment Standards | Page 23 Obturation Principles and practices. Endod Topics. 2005; Whitworth J. Methods of filling root canals: the factors affecting outcomes of nonsurgical root Ng YL, Mann V, Gulabivala K. A prospectiveInt study Endod of 12:2-24. J comparison of calcium hydroxide plugs and dentin canal treatment: part 1: periapical health. plugsPitts DL, used Jones for theJE, Oswaldcontrol RJ.of gutta-perchaA histological root . 2011;44:583–609. the factors affecting outcomes of non-surgical root J Endod. Ng YL, Mann V, Gulabivala K. A prospectiveInt Endod study ofJ. Restorationcanal filling material. 1984;10:283–293. canal treatment: part 2: tooth survival. Sjögren U, Hagglund B, Sundqvist G, Wing K. Factors 2011;44:610–25. affecting the long-term results of endodontic G. Clinical evaluation of bacterial leakage of Beach C, Calhoun J, Bramwell D, Hutter J, Miller treatment. J Endod. J Endod. Vera J, Hernàndez EM, Romero M, Arias A, van der endodontic temporary filling materials. 1990;16:498–504. Chailertvanitkul P, Saunders WP, Saunders EM, Sluis LWM. Effect of maintaining apical patency on 1996;22:459-62. irrigant penetration into the apical two millimeters in vivo study. J Endod. leakage in the restored pulp chamber of root-canal treatedMacKenzie multirooted D. An evaluation teeth. Int of Endod microbial J. coronal of large root canals: an 2012;38:1340–3. 1997;30: 318-22. literature.Schaeffer MA, J Endod. White RR, Walton RE. Determining the optimal obturation length: a meta-analysis of createGalvan an RR, intracoronal West LA, Liewehr seal in FR,endodontically Pashley DH. Siqueira JF. Aetiology of root canal treatment 2005;31:271–4. treatedCoronal teeth. microleakage J Endod. of five materials used to Int Endod J. 2002;28:59-61. failure: why well-treated teeth can fail. 2001;34:1–10. John AD, Webb TD, Imamura G, Goodell GG. Fluid Consequences of and strategies to deal with barriers.flow evaluation J Endod. of Fuji Triage and gray and white residualWu MK, Dummerpost-treatment PMH, Wesselink root canal PR.infection. Int ProRoot mineral trioxide aggregate intraorifice Juloski J, Radovic I, Goracci C, Vulicevic ZR, Ferrari Endod J. 2008;34:830-2. J Endod. 2006;39:343–56. M. Ferrule effect: a literature review. Khayat A, Lee SJ, Torabinejad M. Human saliva treatmentRicucci D, Rocasoutcome. IN, AlvesJ Endod. FR, Loghin S, Siqueira Jr 2012;38:11–9. JF. Apically extruded sealers: fate and influence on penetration of coronally unsealed obturated root 2016;42:243–9. canals. J Endod. the process. Endodontic Topics. Kishen A. Mechanisms and risk factors for fracture Gluskin AH, Anatomy of an Overfill: a reflection on 1993;19:458-61. 2009; vol.16, predilection in endodontically treated teeth. Endod pgs. 64-81. Topics. theSjögren outcome U, Figdor of endodontic D, Persson treatment S, Sundqist of G.teeth with 2006;13:57–83. apicalInfluence periodontitis. of infection Int at Endodthe time J. of root filling on impact of post space preparation with Gates- GliddenKuttler S, drills McLean on residual A, Dorn dentinS, Fischzang thickness A. The in 1997;30:297–306. distal roots of mandibular molars. J Am Den Assoc.

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Access additional resources at aae.org Magura ME, Kafrawy AH, Brown CE, Newton CW. Human saliva coronal microleakage in obturated like Endodontic Posts—Clinical testing of a root canals. J Endod. Sterzenbach G. et al. Rigid versus Flexible Dentine- a Randomized Controlled Clinical Pilot Trial on 1991;17:324-31. Biomechanical Concept: Seven-year Results of Blundell RE. Effects of an intracanal glass ionomer Endodontically Treated Abutment Teeth with barrierMavec JC, on McClanahan coronal microleakage SB, Minah inGE, teeth Johnson with JD,post Severe Hard Tissue Loss. J Endod. space. J Endod. Swanson K, Madison S. An evaluation of coronal 2012;38:1557-63 microleakage in endodontically treated teeth. Part I. 2006;32:120-2. the factors affecting outcomes of non-surgical root time periods. J Endod. Ng YL, Mann V, Gulabivala K. A prospectiveInt Endod study ofJ. In vitro bacterial 1987;13:56-9. penetration of coronally unsealed endodontically canal treatment: part 2: tooth survival. treatedTorabinejad teeth. M, J Endod.Ung B, Kettering JD. 2011;44:610–25. Webber RT, del Rio CE, Brady JM, Segall RO. Sealing 1990;16:566-9. systematicNg YL, Mann review V, Gulabivala of the literature. K. Tooth survivalInt Endod J. Oral Surg following non-surgical root canal treatment: a Oral Med Oral Pathol. quality of a temporary filling material. Ray HA, Trope M. Periapical status of Wolcott JF, Hicks ML, Himel VT. Evaluation of 2010;43:171–89. 1978;46:123-30. endodontically treated teeth in relation to the treated teeth. J Endod. restoration. Int Endod J. pigmented intraorifice barriers in endodontically technical quality of the root filling and the coronal 1999;25:589-92. 1995;28:12–18. in tooth stiffness as a result of endodontic and restorativeReeh ES, Messer procedures. HH, Douglas J Endod. WH. Reduction Sedgley CM, Messer HH. Are endodontically treated 1989;15:512–516. teeth more brittle? J Endod. Schwartz RS, Robbins JW. Post placement and 1992;18:332–335. literature review. J Endod. restoration of endodontically treated teeth: a Schwartz RS, Fransman R. Adhesive dentistry and 2004;30:289–301. aendodontics: review. J Endod. materials, clinical strategies and procedures for restoration of access cavities: 2005; 31:151–165. endodontically treated cracked teeth with radicular Shariff SS, Davis MC. Success and survival of J Endod. extensions: a 2- to 4-year prospective cohort. 2019;45:848-855.

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