A Multidisciplinary Approach to Single-Tooth Replacement

Home , Osseointegration, Rochette bridge

Sergio Rubinstein, DDS* Alan J. Nidetz, DDS* Masayuki Hoshi, RDT**

ver the last several decades, dentistry treatment, or pathology is, for some patients and O has focused on more conservative treat- dentists, a very aggressive treatment option. In- ment modalities and preventive tech- fection in any of these situations creates an envi- niques. This has been possible not only because ronment in the hard and soft tissues that makes of improved techniques and materials, but also regeneration procedures more difficult, thereby because of the understanding that tooth prepara- complicating the ability to create a natural ap- tion, regardless of how conservative it may be, is pearance in the definitive restoration. an irreversible procedure. While a conventional three-unit fixed partial den- A missing tooth in the anterior region is not ture is a predictable technique to replace a missing only a physical loss, but also may be an emotional tooth, the invasive nature of the treatment can lead experience for the patient as well. To remove to other complications throughout the life of the healthy tooth structure of adjacent teeth to re- restoration. Complications may include mechanical place a congenitally missing tooth or a tooth lost overload of the abutment teeth with weakening or to decay, trauma, root fracture, failed root canal fracture, risk of endodontic treatment, periodontal problems, decay, and cement failure. If any of these complications occurs on one of the abutment *Oral Rehabilitation Center, Skokie, Illinois, USA. teeth, the entire prosthesis will fail. Splinting teeth **Oral Rehabilitation Institute, Skokie, Illinois, USA. can overload the supporting structures because Correspondence to: Dr Sergio Rubinstein, Oral Rehabilitation Center, 64 Old Orchard, Suite 420, Skokie, IL 60077, USA. teeth function individually, and oral hygiene tech- E-mail: [email protected] niques become more cumbersome.

QDT 2004 1 RUBINSTEIN ET AL

HISTORY OF SINGLE-TOOTH structure that could be as thin as 0.2 mm. Use of a RESTORATIONS non-noble metal alloy significantly increases the mechanical retention of the etched framework and For more than 50 years, dentistry has sought a more easily prevents degradation of the luting more conservative approach to replacing a single resin in the oral cavity. Care must be exercised so missing tooth with a conventional fixed prosthesis, the framework does not involve the incisal third of which involves the cutting of sound tooth struc- the abutment teeth, since this could block translu- ture. Treatment possibilities have evolved from cency and result in a graying effect (Figs 2a to 2h). bonding a natural extracted tooth or composite While use of a resin-bonded retainer involves a resin restoration to the adjacent teeth,1–3 to the very conservative technique and preparation of Rochette bridge,4,5 to the Maryland bridge,6–8 and the enamel is minimal, the mechanical retentive currently to the single-implant–supported crown. properties of the prosthesis, by design, have a It is debatable which technique is the most con- wraparound effect of 180 degrees. Still, care must servative, and in many instances the patient’s pref- be exercised to prevent occlusal overload during erence dictates the restoration of choice. The clin- function. ician must also evaluate the advantages and Presently, the single-implant–supported crown disadvantages of such techniques in order to pro- is a predictable method of tooth replacement, vide the patient with the best clinical result since and it has several improvements over resin- not all patients should be treated with the same bonded prostheses: preparation of adjacent teeth restoration type or design. is not needed; the tooth replacement will function While the Rochette bridge replaced the miss- individually; a conventional oral hygiene tech- ing tooth without any tooth preparation, it was, at nique can be used; preservation and stimulation best, considered a temporary solution, and its of existing bone and soft tissues occur, including framework was designed with a gold substructure recreation of the interproximal papillae; and sta- and hence resulted in a thick metal framework. bility and function are improved because of the Such restorations were designed with macrome- implant supporting the crown. chanical retentions (Figs 1a to 1c) to lock the com- While osseointegration around implants is a posite into the gold and through the bonded lin- well-documented phenomenon, the implant de- gual surface. This technique met the patient’s signs will continue to undergo structural modifica- conservative requirements of replacing the miss- tions to fulfill the prosthetic requirements one ing tooth, even though it required the patient’s faces as the practice of dentistry evolves. Such compliance not to overload the prosthesis during changes include the transitions from the standard- masticatory function and necessitated a modified diameter implant to wider-diameter implants; flossing technique because of the splinted pros- from the external-hexagon, antirotational device thesis (Fig 1d). to the internal morse taper connections; and from Proven over the years through the achievement the two-stage surgical approach to the now more of acceptable clinical results, such resin-bonded frequently used one-stage techniques that include prostheses continued to improve, and their evolu- immediate loading. These are just a few of the tion led to the development of the Maryland factors that complicate the analysis of implant de- bridge.6,7 For this technique, the tooth required a signs with respect to failure or success. The area conservative preparation in the enamel only8 with a often considered the most critical is the implant- gingival rest to create a definite seat. The prepara- abutment interface, and because of evolving de- tion design included an interproximal wraparound signs, this is where dentistry may see some signifi- to help prevent lingual displacement and to in- cant changes to obtain the best possible fit and crease stability on a bondable surface area improved tissue response. (enamel) with a solid, nonperforated, metal sub-

2 QDT 2004 A Multidisciplinary Approach to Single-Tooth Replacement

Rochette Bridge

1a 1b 1c

Fig 1a Lingual view of the waxup for the Rochette bridge.

Fig 1b Cast framework on the stone model.

Fig 1c Framework showing mechanical undercuts to lock the bonded prosthesis.

Fig 1d Buccal view of the bonded Rochette bridge. (Prosthetics and laboratory work by Alexander H. Chan, DDS.) 1d

Maryland Bridge

Figs 2a and 2b The maxillary right central incisor and supporting bone Fig 2c A connective tissue graft was have been lost as a result of trauma. The rotation of the left central incisor placed to correct the soft tissue de- and the vertical bone loss required a multidisciplinary treatment approach. fect, and orthodontics corrected the rotation of the left central incisor. (Orthodontics by Sergio Rubinstein, DDS; surgery by Sergio Rubinstein and Patrick J. Pierre, DDS; 1981.)

2d 2e 2f

Fig 2d Lingual view of the Mary- land bridge. The incisal extension required slight trimming to avoid blocking translucency.

Figs 2e and 2f Views of the Mary- land bridge replacing the maxillary right central incisor.

Figs 2g and 2h Views of the patient’s smile. 2g 2h

QDT 2004 3 RUBINSTEIN ET AL

IMPLANT PROSTHODONTICS tion of the missing tooth (Fig 3e). Several clinical concerns need to be addressed: measurement of Since the endosseous implant was introduced in interproximal space and adjacent teeth, the oc- the United States, the prosthetic indications have clusal relationships, anterior and canine guidance, grown from the mandibular, fixed, bone-anchored and esthetic demands. The esthetic demands in- prosthesis to the single-tooth replacement.9–16 clude the lip profile, alveolar height and buccolin- While many clinicians still resist the application of gual dimensions, and the quality of the overlying endosseous implants, preferring the more tradi- gingiva.9 tional restorations, one could argue the relative There must also be enough mesiodistal clear- morbidity of preparing the adjacent teeth for fixed ance for the implant in order to avoid risk to adja- partial dentures compared with the two-stage, cent structures such as the nasopalatine or one-stage, or immediate-loading implant surgical mandibular nerve, nasal cavity, neighboring teeth, and prosthetic protocol. Clearly not only can im- or the maxillary sinus. In most cases, the implant plant prosthodontics offer excellent cosmetic out- and prosthetic components will require a mini- comes, but it also allows for bone preservation mum of 6 to 8 mm of mesiodistal clearance de- and stimulation, and the restoration most closely pending on the location in the dental arch.15–18 A resembles an actual tooth during function. congenitally missing tooth will most likely have a normal osseous ridge, both in height and width, whereas alveolar atrophy always follows the ex- DIAGNOSIS traction of teeth. Its severity depends on several factors, including (1) quantity and quality of bone, When a patient needs replacement of a missing (2) existing or previous pathology, (3) length of tooth (Figs 3a to 3c), the clinician must perform a time following tooth loss, and (4) trauma incurred series of clinical and radiographic evaluations (Fig during the extraction and the loading of the tis- 3d) to visualize and offer the available treatment sues. The collapse of the facial plate and alveolar options. The patient must be made aware of these height subsequent to tooth loss19 can impact the options, which generally include some form of re- position and angulation of an implant. The ideal movable partial denture, resin-bonded retainers, implant placement and how alternative positions fixed partial prosthesis, or an implant-supported affect prosthetic design and morphology has restoration. If a single-tooth implant restoration is been described at length; however, this will vary considered, the clinician must first determine from case to case and depending on the implant whether an adequate recipient bed, or site, for the system selected. implant exists. Once this has been determined Occlusal relationships will influence the design clinically and radiographically, the function, esthet- of the crown. A minimum of 7 to 8 mm is required ics, and contours of the final prosthesis, as well as from the coronal aspect of the implant to the op- peri-implant health, should be considered. Treat- posing occlusion.15,16 When determining the ment should proceed only if all prerequisites are occlusal clearance for an implant, it is important to fulfilled. It is important that the site to be treated remember that implants are often intentionally be evaluated along with the complete dentition to placed below the crest of the ridge about 2 to 4 formulate a comprehensive treatment plan. mm apical to the cementoenamel junction of adjacent teeth to provide a sufficient emergence profile for the crown.20 Incisal relationships that subject CLINICAL EXAMINATION teeth to heavy occlusal loads must be carefully evaluated, because an esthetic result must be Definitive tooth replacement must follow active achieved while the teeth and implant are protected disease control and some type of provisionaliza- from undesirable forces.21,22 While parafunctional

4 QDT 2004 A Multidisciplinary Approach to Single-Tooth Replacement

Restoration of Lateral Incisors

Figs 3a to 3c Pretreatment views of Maryland bridges. The lateral incisor prostheses are improperly contoured because of the malpositioned maxillary central incisors and canines. Fig 3d Initial radiograph showing inadequate space to place implants in the position of the congenitally missing lateral incisors.

Fig 3e Orthodontic treatment in progress with provisional prostheses bonded only to the mesial of the canines while the root position of the central incisors is being adjusted. Once the centrals are in the correct position, the provisionals are bonded to them while the position of the canines is adjusted. Treatment can then proceed to implant surgery. (Orthodontics by Howard Spector, DDS.)

Fig 3f Incisal view of premachined, 15-degree angulated abutments. Note that the implants have been placed slightly palatal to the incisal edge so the abument screws can be placed in the cingulum area. (Surgery by Douglas V. Gorin, DDS.)

Fig 3g Acrylic resin, implant-supported, provisional restorations 4 months after insertion. Soft tissue contouring and tooth bleaching have been accom- plished at this stage. 3d

3e 3f 3g

Fig 3h Final crowns in solid stone model with soft tissue duplication.

Fig 3i Horizontal lingual screws allow for improved lingual contours and ease of retrievability.

Fig 3j Final implant-supported crowns on the maxillary left and right lateral incisors. (Prosthetics by Sergio Rubinstein, DDS; laboratory work by Masayuki Hoshi, RDT.) 3h

3i 3j

QDT 2004 5 RUBINSTEIN ET AL

Soft Tissue Management with a Fixed Provisional Restoration

Fig 4a The patient was unhappy with the esthetics of Fig 4b Healing site showing gingival height discrep- the maxillary right central incisor crown. Supereruption ancy between the central incisors 7 days after tooth ex- of the tooth could have predictably corrected the gingi- traction. (Surgery by Leslie B. Heffez, DDS.) val recession, but the patient declined the treatment. The prognosis was hopeless, and the tooth was extracted.

Fig 4c Composite resin provisional restoration bonded Fig 4d Incisal view of the fixed bonded provisional. in place. Even though the soft tissue discrepancy will (Prosthetics by Sergio Rubinstein, DDS; laboratory work have to be corrected during second-stage surgery, note by Orly Farahmandpour.) the interproximal papillae preservation with the fixed provisional.

activities are not a contraindication for implants, placement, soft tissue management (Figs 4a to they do influence treatment planning.23 It is 4d), and design of the final prosthesis. Loss of cre- paramount to have a passive fit between the im- stal bone requires a longer clinical crown usually plant, component(s), and crown.24–28 with larger gingival embrasure spaces. A narrow Because esthetic demands have an enormous implant diameter placed into a site with minimal impact on the treatment planning of implant-sup- alveolar bone loss can lead to unesthetic results ported prostheses, a high lip position that exposes with improper contours, such as a bulky implant- the gingiva will affect the requirements of implant prosthetic connection with a cantilever effect.

6 QDT 2004 A Multidisciplinary Approach to Single-Tooth Replacement

Soft Tissue Management with Supereruption

Fig 5a Preoperative photograph showing a 3- Fig 5b Orthodontic brackets positioned to mm apical migration of the gingiva at the right achieve 6 mm of supereruption. (Orthodontics, central incisor compared with that at the left restorative dentistry, and laboratory work by central incisor. Alan J. Nidetz, DDS; surgery by David Barack, DDS.)

Fig 5c The labial root is torqued to bring the Fig 5d Supereruption is complete. Note the palatal bone labially. overcorrection of the gingival height.

SOFT TISSUE CONSIDERATIONS rected by adding the amount of the defect in mil- limeters to the “3-mm rule.” For instance, a 3-mm It is well-documented that soft tissue architecture defect would require 6 mm of supereruption (Figs is influenced by the underlying bony architec- 5b to 5d). After supereruption is complete, the ture.29–31 It is further documented that tooth loss clinician should wait 3 months before proceeding results in a loss of alveolar bone height and loss of with extraction and implant placement. This al- soft tissue architecture in both the facial and api- lows for complete maturation of both the bone cal directions.32 When a tooth must be extracted, and the soft tissue. Once the tooth is extracted changes in bone loss and soft tissue architecture and the implant is placed, an ovate pontic is used can be controlled by using orthodontic supererup- to provide scaffolding for the soft tissue during tion prior to extraction.3 This technique can pro- the healing process34,35 (Figs 5e to 5l). The implant vide solutions to very difficult situations (Fig 5a). is uncovered, and an immediate provisional On average, anterior tooth loss will result in a 3- restoration engaging the implant is placed to mm apical migration of the soft tissue. Supererup- allow for tissue maturation36 (Figs 5m to 5p). The tion of 3 mm prior to extraction will compensate final prosthetic restoration is fabricated and deliv- for this loss.33 When a defect in soft tissue archi- ered after the hard and soft tissues have healed tecture already exists, it can be predictably cor- (Fig 5q).

QDT 2004 7 RUBINSTEIN ET AL

Soft Tissue Management with Supereruption (continued)

Fig 5e Radiograph taken immediately after implant placement.

Figs 5f to 5h Fabrication of a fixed provisional Mary- land bridge.

Figs 5i and 5j The provisional Maryland bridge is placed immediately following implant placement.

Figs 5k and 5l Clinical and radiographic views after 4 months of healing. 5e

5f 5g 5h

5i 5j

8 QDT 2004 A Multidisciplinary Approach to Single-Tooth Replacement

Fig 5m Appearance of the soft tissue immediately Fig 5n Tissue appearance immediately after implant upon removal of the fixed provisional. uncovering and placement of the second provisional.

Figs 5o and 5p Tissue appearance 4 weeks after implant uncovering.

Fig 5q Final restoration. (Figs 5a to 5q: Orthodontics, restorative dentistry, and laboratory work by Alan J. Nidetz, DDS; surgery by David Barack, DDS.)

QDT 2004 9 RUBINSTEIN ET AL

Radiographic Stents

Figs 6a and 6b Radiographic and surgical stent with barium sulfate to delineate buccal contours. Gutta-percha markers are placed on the occlusal surface to suggest the ideal implant inclination.

RADIOGRAPHIC EXAMINATION Radiographic stents with radiopaque markers such as gutta-percha or barium sulfate can be Radiographs will provide information regarding helpful (Figs 6a and 6b). These will produce a the bone available for implant placement and the cross-sectional image indicating the desired incli- position of vital structures, as previously de- nation of the implant with its possible correspond- scribed, in order to help prevent disappointing ing contours. This position can then be evaluated postoperative results. Determining the need for in terms of available bone to determine whether specific radiographs depends to some degree on the desired position is surgically realistic. Clearly, the patient’s clinical presentation as well as the the osseous architecture will not always allow for dental team’s philosophy. ideal implant position. The information provided Periapical radiographs will provide a fairly accu- by cross-sectional images will enable the clinician rate assessment of interdental clearance (see Fig to anticipate any limitations and determine how to 3d); however, maxillary anterior radiographs are correct defects surgically or identify acceptable al- subject to frequent elongation as a result of film ternative implant positions. With careful planning, angulation. Panoramic radiographs are also sub- the surgeon and restorative dentist can eliminate ject to significant distortion both horizontally and what otherwise might be an unpleasant surprise vertically.37,38 As much as radiographic markers, and then communicate to the patient possible such as metal balls of known dimensions, can help prosthetic designs as a function of the ultimate to calibrate the films for improved accuracy, the implant position. lack of dimensional reliability combined with the Once all the diagnostic data have been ob- two-dimensional quality of traditional radiographs tained, the surgeon and restorative dentist must underscores the value of digital reformatted com- anticipate the design of the final restoration to puterized tomography. These diagnostic films pro- achieve an optimum functional and esthetic clini- vide a three-dimensional cross-sectional view cal result. The final position of the implant de- through the maxilla or mandible with a 1.1:1 or pends not only on the hard and soft tissue topog- 1:1 magnification ratio.38–40 Linear tomograms can raphy, but also on the implant diameter, the be useful for isolated areas while minimizing radi- desired emergence profile, and the contours of ation and expense to the patient.41,42 This type of the neighboring teeth. The simplest restorative tomogram will clearly demonstrate the quality of design to date places the abutment screw cortical and trabecular bone as well as the bound- through the cingulum in anterior teeth and aries of the facial or linguopalatal plate, the maxil- through the central groove in posterior teeth. To lary sinus, nasal cavity, and mandibular nerve. achieve this result, the surgeon must position the

10 QDT 2004 A Multidisciplinary Approach to Single-Tooth Replacement

implant slightly palatal to the incisal edge for an- positions or angulations that may be clinically ac- terior teeth and close to the central groove for ceptable. Alternatively, the stent should be en- posterior teeth. If the surgeon and restorative tirely open in its lingual aspect to facilitate the sur- dentist determine that a facial angulation is re- geon with additional options. quired, then some form of substructure, such as a When stents are created, the radiographic stent premachined angled abutment (see Fig 3f) or cus- can be designed first, and if necessary it can be tom abutment, will be necessary to maintain an modified to correspond to the computerized to- esthetic result. mogram. Such computerized tomogram–assisted stents will help to place the implant not only in its planned buccolingual and mesiodistal positions, STENT CONSTRUCTION but also at the desired depth.

Once the initial clinical and radiographic findings have been established, a clear acrylic resin or PROVISIONALIZATION plastic stent with radiographic markers should be fabricated. Such a stent should demonstrate the The patient will want to wear some form of provi- ideal prosthetic position and indicate the pre- sional tooth replacement during the primary heal- ferred implant placement as well as acceptable al- ing period, especially in an esthetic area. Primary ternatives that will facilitate an optimum final pros- healing can range from 2 to 8 months depending thesis. on the clinical situation. The type of provisional Clinicians may be tempted to place implants selected can be a removable appliance; a resin- for single-tooth replacements without a stent, be- bonded fixed provisional, if adjacent teeth allow lieving that the neighboring teeth will serve as a for bonding; or a passive acrylic resin provisional reference for implant inclination and position. using the implant, with the restoration being out However, once the flap has been raised, the sur- of occlusion. The advantages of the resin-bonded geon will focus on the osseous architecture to de- provisional are that it is cosmetic, noninvasive, termine optimum implant support. The stent can and fixed; it maintains occlusion and adjacent serve to prevent prosthetic failures resulting from teeth positions; and it allows for tissue contouring overangulation, especially to the facial. Generally, and papillae preservation. the stent used for preoperative radiographs can It is important that the appliance does not also be used during surgery to guide implant transmit any load to the healing implant site and placement and to help in uncovering the implant thus increase the risk of failure. The provisional after the primary healing period. restoration must maintain a passive fit and provide Stents used for single-tooth replacement are for soft tissue support. simple in design and easy to fabricate. A stent that replicates the buccal profile with the palatal portion cut out will prevent screw access to the fa- SURGICAL PLACEMENT OF IMPLANTS cial and will aid in centering the implant mesiodis- tally.43 Some clinicians prefer stents that restrict While placing the implant, the surgeon will focus the implant placement to a specific position (using on avoiding injury to vital structures or adjacent a 2- to 3-mm hole in the stent), as this will clearly teeth, maximizing bony support for the implant, indicate the desired position for the primary drill. engaging cortical bone for implant stability (for Once the surgeon increases the bur size, this stent certain systems), and placing the implant in the is no longer usable. It is possible for the surgeon ideal prosthetic position. These considerations to slightly redirect bur angulation (especially in must be factored into planning the direction of softer bone), but it does not allow for alternative the implant placement, the chosen length and di-

QDT 2004 11 RUBINSTEIN ET AL

ameter of implant to be used, the depth of im- employed for several years,38 the predictability of plant placement (including whether the implant crestal augmentation in the coronal direction is must be countersunk, for some systems), the questionable.46 height relative to the osseous crest and adjacent teeth, and whether or not bone grafting is to be implemented. OSTEODISTRACTION AND BONE GRAFTING A position that is centered between the neighboring teeth, with note to the anatomic struc- According to Samchukov et al,47 “Most significant tures, usually best fulfills these considerations. new ideas, concepts, or products go through a The buccolingual orientation depends on the four-stage evolution in their infancy. They are ini- presence of intact bone and the ability to engage tially rejected by almost all potential users who the palatal or buccal plate, while keeping in mind claim that it cannot be done or it is too much trou- the desired prosthetic position of the implant. If ble. Shortly thereafter, it is accepted by a few; the there is a conflict between the most stable posi- vast majority, however, contend that it is just not tion of the implant and the desired prosthetic po- there yet or maybe later. After a period of time, sition, then the surgeon must refer to the range most people adopt the new technique, and begin of alternative acceptable positions. Some sur- to question why their colleagues are not using it. geons will intentionally engage the floor of the Finally, after years of clinical and experimental maxillary sinus or nasal cavity, but care must be documentation, it becomes the standard of taken not to perforate these vital structures be- care—the technique by which all others are com- cause the predictability of osseointegration will pared.” be diminished.44 The vertical position of the im- Osteodistraction has many clinical applications plant will depend on the desired emergence pro- and facilitates different treatment modalities in a file of the final crown. It has been recommended more conservative and predictable manner. As that the implant be placed 3 to 4 mm apical to distractors become smaller and more efficient, the neighboring cementoenamel junction.9,20 If distraction osteogenesis is becoming a viable minimal resorption of the osseous crest has oc- technique to build up bone in a vertical direction. curred, the crest may require some resection to However, guided tissue regeneration techniques create the required space for countersinking the have improved the predictability for increasing the implant to the suggested depth. Any resection ridge thickness, especially in smaller areas48–53 (Figs should be postponed until the implant is uncov- 7a to 7d). Sinus lift procedures are currently being ered to prevent excessive resorption of the crest performed with a high degree of predictability and subsequent exposure of the implant surface. and are enabling treatment options that once A wider implant diameter or narrower diameter of were not imaginable. It is important to remember the tooth to be replaced can reduce the amount that smoking has been shown to increase the rate of countersinking needed to account for proper of dental implant failure.54 emergence profile.20,45 Presently, the choice of osseous grafting mate- The indications for osseous grafting include rials includes autologous bone, freeze-dried bone augmentation of the ridge for implant stability or allograft, demineralized freeze-dried bone allo- esthetic concerns. Bone grafting may be per- graft, resorbable bone substitutes, and nonre- formed, in some instances, 3 to 6 months before sorbable bone alloplast. Allografts can be placed implant placement. In selective cases, osseous into fresh extraction sites and then covered with grafting can be performed at the time of implant membranes for guided tissue regeneration to pre- placement. If minor bone modification is needed, serve ridge height prior to the implant the osteotome can help stretch the existing bone. placement.48 Researchers do not agree on the While ridge augmentation procedures have been ideal grafting material to be used around en-

12 QDT 2004 A Multidisciplinary Approach to Single-Tooth Replacement

Bone Grafting

Fig 7a The patient was unhappy with the Fig 7b The maxillary lateral incisor was con- Maryland bridge because of the need to floss genitally missing. Note the loss of the buccal laterally with a threader. The patient was not plate, complicating ideal implant placement. A interested in correcting the malposition of the bone graft was required. canine with orthodontics.

Fig 7c Final implant-supported crown. Fig 7d Lingual view of the final crown with a horizontal screw, which improves the lingual contour and ease of retrievability. (Prosthetics by Sergio Rubinstein, DDS; laboratory work by Masayuki Hoshi, RDT.)

dosseous implants.55–60 Many clinicians prefer de- fibrous connective tissue around grafted hydrox- mineralized freeze-dried bone allografts in the yapatite has also been documented.55 If grafted treatment of infrabony periodontal defects. How- sites are infected, there may be a chance for the ever, this grafting material appears to be subject infection to disseminate.61 Autogenous bone is to rapid resorption when used in sites not rich in widely used, but volume may be limited by avail- mesenchymal cells58; therefore, the use of rich able donor sites. A variety of materials have been plasma cells mixed with autogenous bone is in- used with implant placement, but they appear to creasing in popularity. In time researchers will be be most predictable when used with membranes able to evaluate its long-term stability. While bone for guided tissue regeneration.48,49,51,52 growth into grafted sites has been reported,59,61 a

QDT 2004 13 RUBINSTEIN ET AL

TOOTH EXTRACTION WITH IMMEDIATE guided tissue regeneration also support the over- IMPLANT PLACEMENT lying flap and thereby preserve the space to be occupied by bone.62,64,66–68,70 Implants can be placed into fresh extraction sites when adequate bone exists to immobilize the im- One- and Two-Stage Surgery plant62–67; this generally requires that about 40% of the implant be embedded in firm bone tissue. In selective cases, second-stage surgery is not Some benefits are improved preservation of alve- needed when a taller healing cap is placed, thus olar bone and decreased treatment time. Implants preventing the soft tissue from covering the im- should not be placed into sites where there is in- plant. Such cases will depend on ease of the surgi- adequate bone to stabilize the implant; to do so cal technique, occlusion, oral hygiene, and the pa- will risk micromovement of the implant and inter- tient’s ability to follow postoperative instructions. fere with the tissue’s ability to integrate around For other cases second-stage surgery is re- the implant.16 Implants should also not be placed quired. The time allotted for the primary healing into sites with a remaining infection associated period depends on the site of implant placement, with a diseased tooth. This would interfere with the quality of bone, whether bone grafting has tissue healing, risking dissemination of the infec- been performed, or whether the implant has been tion as well as implant failure.68 placed into a fresh extraction site. Generally, this For placement of an implant into a fresh ex- ranges from 2 months71 to 8 months. At the time of traction site, the implant site should be prepared implant uncovering osseointegration must be veri- beyond the apex of the extraction site and quite fied by radiographic and clinical means. often along an axis not parallel to the long axis of the extracted tooth (Figs 8a to 8f). The coronal Implant Uncovery aspect of the implant will be either partially or completely exposed without direct contact to the The desired esthetic result will influence soft tis- socket walls. Therefore, the cells of the bone tissue management during all surgical phases as sue must travel a significant distance to reach the well as during implant uncovering72 (see Figs 3g to implant surface and mature into a supporting tis- 3j). Posterior implants are frequently uncovered by sue. This is in contrast to the surgical principles use of linear incisions or a circular tissue punch. described in which a tight bone fit was consid- Anterior procedures should focus on the preserva- ered critical for osseointegration to occur.69 To en- tion of keratinized tissue, color match of the gin- courage bone fill of the remaining socket space, giva, and the ultimate height of the soft tissue fa- steps must be taken to prevent the gingival flap cial and interproximal to the implant. The need for from contributing to the healing of this potential a wide zone of keratinized tissue around implants space. has been argued for some time. While many One way to reduce the distance the bone cells agree that minimal to no attached tissue is neces- must travel is to place an implant that resembles sary to maintain peri-implant health,73 esthetics the anatomy of the extraction site, either conical demands a healthy, wide zone of gingival tissue or cylindrical in shape. The implant will thus fill around natural teeth and implants. If an inade- more of the socket or be slighter larger to engage quate zone of tissue exists prior to implant place- healthy bone for its stability. ment, soft tissue grafting can be performed prior A bone graft will act as scaffolding for the to placement of the implant. However, either bone-forming cells to travel and reach the implant pedical flaps or connective tissue grafts are pre- surface. Graft materials also support the flap and ferred because these procedures tend to provide may act as a barrier to the soft tissue. Expanded the best color match of grafts to the recipient tis- polytetrafluoroethylene membranes used for sues.

14 QDT 2004 A Multidisciplinary Approach to Single-Tooth Replacement

Immediate Implant Placement

Fig 8a Healing cap over the implant. The tooth was lost Fig 8b Tissue healing around the implant. (Surgery by as a result of vertical fracture, and a fixed provisional Kenneth H. Peskin, DDS.) was not used. Note the loss of the papillae.

Fig 8c Radiograph showing impression post–implant transition. Note the bone loss around the neck of the implant subsequent to a previous infection.

Fig 8d Angled, screw-retained abutment with perfora- tion to accept a lingual screw.

8c 8d

Fig 8e Buccal view of the final crown. Fig 8f Lingual view of the final crown with the lingual screw parallel to the axis of the implant. (Prosthetics by Sergio Rubinstein, DDS; laboratory work by Masayuki Hoshi, RDT.)

Follow-up care should include suture removal if gins when the healing cap is exposed into the oral a flap was raised, plaque control, and evaluation of cavity and will continue throughout treatment until healing prior to initiation of prosthetic procedures. after the implant-supported crown is in place. Oral Oral hygiene with a soft brushing technique be- rinses for plaque control have been shown to pro-

QDT 2004 15 RUBINSTEIN ET AL

Implant-Supported, Cemented Crown

9a 9b 9c

Fig 9a Incisal view of a screw-retained abutment.

Fig 9b Buccal view of an implant-supported, permanently cemented crown on the maxillary right lateral incisor.

Fig 9c Lingual view of an implant-supported, permanently cemented crown.

Fig 9d The maxillary right lateral incisor crown looks natural in the patient’s smile. (Prosthetics by Sergio Rubinstein, DDS; surgery by Robert A. Bress- man, DDS; laboratory work by Masayuki Hoshi, RDT.) 9d

mote healing in the early postoperative period; in- allow for better lingual anatomy on its lingual sur- definite use of chlorhexidine is typically prescribed face along with the improved esthetics (see Fig 7d). as part of the oral hygiene regimen for implants. A Another option is to have the abutment screw 3-month maintenance program has been shown to retained on the implant with the final restoration effectively maintain peri-implant health.74 The sur- temporarily cemented to the abutment to allow geon’s responsibility for the health of the implant for some retrievability. However, in some cases re- does not end with second-stage surgery, but joins trievability of a temporarily cemented crown can with the patient’s and the restorative dentist’s ef- be a challenge. An additional problem can occur forts for a long-term successful result. when the crown is permanently cemented and there is uncertainty of whether the cement has been removed entirely. Two of the most favorable PROSTHODONTIC ALTERNATIVES advantages of the cementable crown are its simi- larity to conventional prosthodontics and the elim- For many clinicians, fabrication of an implant-sup- ination of the screw through the crown, hence ported crown as either a screw-retained or ce- better contours and esthetics (Figs 9a to 9d). mented restoration is a personal preference. Each Designs of implant restorations have evolved to technique has its advantages and disadvantages. accommodate the width of the different teeth The screw-retained restoration allows more simple they can replace, not only wider anterior teeth but retrieval if any modifications, repairs, or alterations also posterior teeth (Figs 10a to 10f). With the ex- to the existing tooth contours or adjacent teeth are isting variations of teeth and the mesiodistal needed. While traditionally the screw will be in a space between teeth in direct correlation to the vertical direction along the axis of the implant, a available supporting bone, it is necessary to have horizontal or transversal placement of the screw in implants of different diameters to solve the chal- the lingual surface of an anterior restoration will lenges faced in implant dentistry.

16 QDT 2004 A Multidisciplinary Approach to Single-Tooth Replacement

Posterior Single-Tooth Restoration

10a 10b 10c

10d 10e 10f

Fig 10a Occlusal view of a customized abutment, with interproximal grooves, milled at 2 degrees of convergence.

Fig 10b Lingual view of the abutment with mesiolingual tapping to allow for a screw-retained crown.

Fig 10c Porcelain-fused-to-metal crown retained with a lingual screw. Note the narrow buccolingual contours to minimize undesirable occlusal loads.

Fig 10d Lingual view of final crown.

Fig 10e Buccal view of final crown.

Fig 10f Radiograph of final crown. While a mesial cantilever is present, it is diminished by the use of the widest available implant. (Prosthetics by Sergio Rubinstein, DDS; surgery by Jeffrey K. Bressman, DDS; laboratory work by Toshiyuki Fujiki, RDT.)

CONCLUSION ACKNOWLEDGMENTS

The ultimate goal of the single-tooth implant We would like to thank Dr Tatiana Quintiliano for her tireless effort in helping us prepare this article for publication. restoration is to restore the lost tooth with both optimum function and esthetics. The definitive restoration should ideally resemble the original REFERENCES tooth in contour and shade while both restoring and preserving the bone and soft tissues. Long- 1. Ibsen RL. One-appointment technic using an adhesive term health will only be possible if treatment is composite. Dent Surv 1973;49:30–32. followed by a proper maintenance program. 2. Ibsen RL. Fixed prosthetics with a natural crown pontic using an adhesive composite: Case history. J South Cal Dent Assoc 1973;41:100–102.

QDT 2004 17 RUBINSTEIN ET AL

3. Jordan RE, Suzuki M, Sills PS, Gratton DR, Gwinnett JA. 25. Zarb GA, Symington JM. Osseointegrated dental im- Temporary fixed partial dentures fabricated by means of the plants: Preliminary report on a replication study. J Pros- acid-etch resin technique: A report of 86 cases followed for thet Dent 1983;50:271– 276. up to three years. J Am Dent Assoc 1978;96:994–1001. 26. Laney WR, Tolman DE, Keller EE, Desjardins RP, Van 4. Rochette AL. Attachment of a splint to enamel of lower Roekel NB, Brånemark P-I. Dental Implants: Tissue-Inte- anterior teeth. J Prosthet Dent 1973;30:418–423. grated Prosthesis Utilizing the Osseointegration Concept. 5. Howe DF, Denehy GE. Anterior fixed partial dentures uti- Mayo Clin Proc 1986;61:91–97. lizing the acid-etch technique and a cast metal frame- 27. Worthington P, Bolender CL, Taylor TD. The Swedish sys- work. J Prosthet Dent 1977;37:28–31. tem of osseointegrated implants: Problems and complica- 6. Livaditis GJ, Thompson VP. Etched castings: An improved tions encountered during a 4-year trial period. Int J Oral retentive mechanism for resin-bonded retainers. J Pros- Maxillofac Implants 1987;2:77–84. thet Dent 1982;47:52–58. 28. Sones AD. Complications with osseointegrated implants. 7. Simonsen R, Thompson V, Barrack G. Etched Cast Restora- J Prosthet Dent 1989;62:581–585. tions: Clinical and Laboratory Techniques. Chicago: 29. Gargiulo AW, Wentz FM, Orban B. Dimensions and rela- Quintessence, 1983. tions of the dentogingival junction in humans. J Periodon- 8. Rubinstein S, Jekkals V. Preparation for anterior resin-bonded tol 1961;31:6261–6267. retainers. Compend Cont Educ Dent 1986;7:631–632. 30. Vacek JS, Gher ME, Assad DA, Richardson AC, Giambar- 9. Parel SM, Sullivan DY. Esthetics and Osseointegration. resi LI. The dimensions of human dentogingival junction. Dallas: Osseointegration Seminars, 1989. Int J Periodontics Restorative Dent 1994;14:154–165. 10. Ohrnell L-O, Hirsch J, Ericsson I, Brånemark P-I. Single- 31. Becker W, Ochsenbein C, Tibbetts L, Becker BE. Alveolar tooth rehabilitation using osseointegration. A modified bone anatomic profiles as measured from dry skulls. Clini- surgical and prosthodontic approach. Quintessence Int cal ramifications. J Clin Periodontol 1997;24:727–731. 1988;19:871–876. 32. Kois JC. Esthetic extraction site development: The geologic 11. Lewis SG, Beumer J III, Perri GR, Hornburg WP. Single- tooth implant restorations. Int J Oral Maxillofac Implants variables. Contemp Esthet Restorative Pract 1998;2:10–18. 1988;3:25–30. 33. Salama H, Salama M. The role of orthodontic extrusive re- 12. Jemt T, Lekholm U, Grondahl K. A 3-year follow-up study modeling in the enhancement of soft and hard tissue pro- of early single implant restoration ad modum Brånemark. files prior to implant placement: A systematic approach to Int J Oral Maxillofac Implants 1990;5:341–349. the management of extraction site defects. Int J Peri- odontics Restorative Dent 1993;13:312–333. 13. Andersson B, Odman P, Carlsson L, Brånemark P-I. A new Brånemark single-tooth abutment: Handling and early 34. Kan JY, Rungcharassaeng K. Site development for ante- clinical experiences. Int J Oral Maxillofac Implants rior single implant esthetics: The dentulous site. Com- 1992;7:105–111. pend Contin Educ Dent 2001;22:221–232. 14. Weiner RE. A comparison of the UCLA abutment to the 35. Spear FM. Maintenance of the interdental papilla follow- Cera-One technique [abstract from the 7th annual meeting ing anterior tooth removal. Pract Periodontics Aesthet of the Academy of Osseointegration, February 1992]. Int Dent 1999;11:21–28. J Oral Maxillofac Implants 1992;7:126. 36. Jemt T. Restoring the gingival contour by means of provi- 15. Interpore IMZ Technique Manual, Revision 3. Irvine, CA: sional resin crowns after single-implant treatment. Int J Interpore International, 1987. Periodontics Restorative Dent 1999;19:21–29. 16. Hobo S, Ichida E, Garcia LT. Osseointegration and Occlusal 37. Klinge B, Petersson A, Maly P. Location of the mandibular Rehabilitation. Chicago: Quintessence, 1990:105–132. canal: Comparison of macroscopic findings, conventional 17. Priest GF. Single-tooth implants and their role in preserv- radiography, and computed tomography. Int J Oral Max- ing remaining teeth: A 10-year survival study. Int J Oral illofac Implants 1989;4:327–332. Maxillofac Implants 1999;14:181–188. 38. McGivney GP, Houghton V, Strandt JA, Eichholz JE, Lubar 18. Priest GF. Failure rates of restorations for single-tooth re- DM. A comparison of computer-assisted and data-gather- placement. Int J Prosthodont 1996;9:38–45. ing modalities in prosthodontics. Int J Oral Maxillofac Im- 19. Atwood DA. Bone loss of edentulous alveolar ridges. J plants 1986;1:55–68. Periodontol 1979;50(4 special no):11–21. 39. Schwarz MS, Rothman SLG, Rhodes ML, Chafetz N. Com- 20. Saadoun AP, Le Gall MG. Periodontal implications in im- puted tomography, Part I: Preoperative assessment of the plant treatment planning for aesthetic results. Pract Peri- mandible for endosseous implant surgery. Int J Oral Max- odontics Aesthet Dent 1998;10:655–666. illofac Implants 1987;2:137–141. 21. Graf H. Bruxism. Dent Clin North Am 1969;13:659–665. 40. Schwarz MS, Rothman SLG, Rhodes ML, Chafetz N. Com- 22. Hobo S, Ichida E, Garcia LT. Osseointegration and Occlusal puted tomography, Part II: Preoperative assessment of Rehabilitation. Chicago: Quintessence, 1990:257–259. the maxilla for endosseous implant surgery. Int J Oral 23. Ramfjord SP, Ash MM. Occlusion, ed 2. Philadelphia: Maxillofac Implants 1987;2:143–148. Saunders, 1971:99–140. 41. Lindh C, Petersson A. Radiologic examination for location 24. Brånemark P-I, Zarb GA, Albrektsson T. Tissue-Integrated of the mandibular canal: A comparison between panoramic Prostheses. Osseointegration in Clinical Dentistry. radiography and conventional tomography. Int J Oral Max- Chicago: Quintessence, 1985. illofac Implants 1989;4:249–253.

18 QDT 2004 A Multidisciplinary Approach to Single-Tooth Replacement

42. Clark DE, Danforth RA, Barnes RW, Burtch ML. Radiation 59. Hjorting-Hansen E, Worsaa N, Lemons JE. Histologic re- absorbed from dental implant radiography: A comparison sponse after implantation of porous hydroxyapatite ceramic of linear tomography, CT scan, and panoramic and intra- in humans. Int J Oral Maxillofac Implants 1990;5:255–263. oral techniques. J Oral Implantol 1990;16:156–164. 60. Holden CM, Bernard G. Ultrastructure in vitro characteri- 43. Parel SM, Funk JJ. The use and fabrication of a self-retain- zation of a porous hydroxyapatite/bone cell interface. J ing surgical guide for controlled implant placement: A tech- Oral Implantol 1990;16:86–95. nical note. Int J Oral Maxillofac Implants 1991;6:207–210. 61. Marshall SG. The combined use of endosseous dental im- 44. Brånemark P-I, Adell R, Albrektsson T, Lekholm U, Lindstrom plants and collagen/hydroxyapatite augmentation proce- J, Rockler B. An experimental and clinical study of osseoin- dures for reconstruction/augmentation of the edentulous tegrated implants penetrating the nasal cavity and the max- and atrophic mandible. A preliminary report. Oral Surg illary sinus. J Oral Maxillofac Surg 1984;42:497–505. Oral Med Oral Pathol 1989;68:517–526. 45. Jensen OT, Brownd C, DeLorimier J. Esthetic maxillary 62. Lazzara RJ. Immediate implant placement into extraction arch vertical location for the osseointegrated cylinder im- sites. Int J Periodontics Restorative Dent 1989;9:333–342. plant. J Am Dent Assoc 1989;119:735–736. 63. Ashman A. An immediate tooth root replacement. An im- 46. Santoro F, Maiorana C, Rabagliati MI. Long-term results plant cylinder and synthetic bone combination. J Oral Im- with autogenous onlay grafts in maxillary and mandibular plantol 1990;16:28–38. atrophy. J Long-Term Eff Med Implants 1999;9:215–222. 64. Becker W, Becker BE. Guided tissue regeneration for im- 47. Samchukov ML, Cope JB, Cherkashin AM. Craniofacial plants placed into extraction sockets and for implant de- Distraction Osteogenesis. St Louis: Mosby, 2001. hiscences: Surgical techniques and case reports. Int J Pe- 48. Seibert J, Nyman S. Localized ridge augmentation in riodontics Restorative Dent 1990;10:377–391. dogs: A pilot study using membranes and hydroxyapatite. 65. Barzilay I, Graser GN, Iranpour B, Natiella JR. Immediate J Periodontol 1990;61:157–165. implantation of a pure titanium implant into an extraction 49. Becker W, Becker BE, Handlesman M, et al. Bone forma- socket: Report of a pilot procedure. Int J Oral Maxillofac tion at dehisced dental implant sites treated with implant Implants 1991;6:277–284. augmentation material: A pilot study in dogs. Int J Peri- 66. Caudill RF, Meffert RM. Histologic analysis of the osseointe- odontics Restorative Dent 1990;10:93–101. gration of endosseous implants in simulated extraction sock- 50. Nyman S, Lang NP, Buser D, Bragger U. Bone regenera- ets with and without E-PTFE barriers. Part I. Preliminary find- tion adjacent to titanium dental implants using guided tis- ings. Int J Periodontics Restorative Dent 1991;11:207–215. sue regeneration: Report of two cases. Int J Oral Maxillo- 67. Becker W, Becker BE, Handelsman M, Ochsenbein C, Al- fac Implants 1990;5:9–14. brektsson T. Guided tissue regeneration for implants 51. Wachtel HC, Langford A, Bernimoulin JP, Reichert P. Guided placed into extraction sockets: A study in dogs. J Peri- bone regeneration next to osseointegrated implants in hu- odontol 1991;62:703–709. mans. Int J Oral Maxillofac Implants 1991;6:127–135. 68. Simion M, Baldoni M, Polcan M. Effectiveness of GTAM 52. Zablotsky M, Meffert RM, Caudill R, Evans G. Histological membranes with and without early exposure: A compara- and clinical comparisons of guided tissue regeneration on tive study [abstract from the 7th annual meeting of the dehisced hydroxyapatite-coated and titanium endosseous Academy of Osseointegration, February 1992]. Int J Oral implant surfaces: A pilot study. Int J Oral Maxillofac Im- Maxillofac Implants 1992;7:121. plants 1991;6:294–303. 69. Carlsson L, Rostkund T, Albrektsson B, Albrektsson T. Im- 53. Mentag PJ, Kosinski T. Hydroxyapatite-augmented sites as receptors for replacement implants. J Oral Implantol plant fixation improved by close fit. Acta Orthop Scand 1989;15:114–123. 1988;59:272–275. 54. Bain CA. Effects of smoking on failure rates of dental im- 70. Hurzeler MB, Quinones CR. Installation of endosseous plants [abstract from the 7th annual meeting of the oral implants with guided tissue regeneration. Pract Peri- Academy of Osseointegration, February 1992]. Int J Oral odontics Aesthet Dent 1991;3:21–29. Maxillofac Implants 1992;7:123. 71. Lazzara RJ, Porter SS, Testori T, Galante J, Zetterqvist L. A 55. Kramer G, Mattout P, Mattout C, Mellonig JT. Clinical and prospective multicenter study evaluating loading of Os- histological responses to a mixed bone/hydroxyapatite seotite implants two months after placement: One-year graft: Report of a case. Int J Periodontics Restorative results. J Esthet Dent 1998;10:280–289. Dent 1989;9:9–21. 72. Palacci P. Optimal Implant Positioning and Soft Tissue Man- 56. Aspenberg P, Kalebo P, Albrektsson T. Rapid bone healing agement for the Brånemark System. Chicago: Quintessence, delayed by bone matrix implantation. Int J Oral Maxillo- 1995. fac Implants 1988;3:123–127. 73. Krekeler G, Schilli W, Diemer J. Should the exit of the arti- 57. Hoen MM, Strittmatter EJ, LaBounty GL, Keller DI, Ne- ficial abutment tooth be positioned in the region of the speca JA. Preserving the maxillary alveolar ridge contour attached gingiva? Int J Oral Surg 1985;14:504–508. using hydroxyapatite. J Am Dent Assoc 1989;118:739–741. 74. Flemming TF, Berwick RHF, Newman MG, et al. Effect of a 58. Toriumi DM, Larrabee WF, Walike JW, Millay DJ, Eisele 3-month maintenance program on osseointegrated im- DW. Demineralized bone. Arch Otolaryngol Head Neck plants. Microbiological observations. Z Zahnarztl Implan- Surg 1990;116:676–680. tol 1990;6:45–51.

QDT 2004 19