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1 B , Chapter Restorative management 5 of dental implants 5.1 Basic implant terminology Planning dental implants Surgical phases Provisional and definitive restoration of dental implants Maintenance phase 138 Self-assessment: questions 140 Self-assessment: answers 141 Overview Assisting patients to attain a healthy, functional and aesthetic dentition is one of the primary goals of any dental practitioner. Unfortunately, there are many reasons why this goal might not be achieved and there is then a requirement for intervention to repair or replace what is damaged or lost over time. Osseointegrated dental implants have been developed over 40 years and now provide a further option for rehabilitating the compromised dentition. This chapter deals with the restorative aspects of dental implants and provides an intentionally basic overview of the restorative and basic surgical elements of rehabilitating patients using implant retained prostheses. After an introduction to basic terminology, the chapter is organised to follow a patient s pathway through pre-surgical planning, fixture placement, immediate restoration, the definitive restoration and maintenance phases of management. The use of dental implants for both single and multiple tooth restorations will be described. 5.1 Basic implant terminology Learning objectives You should be familiar with the basic elements of a generic implant system understand the basic principles involved in the placement and restoration of dental implants be able to discuss basic dental implant treatment in generic terms. A basic understanding of implant treatment is dependent upon knowledge of the underlying structure of the osseointegrated dental implant system. Dental implant technology is growing rapidly with established systems undergoing continuous development and new systems being introduced to the market on almost a daily basis. It is not the intention here to provide a detailed review of the subtle differences between systems, but to provide an understanding of the underlying principles of dental implants. A basic implant system may be considered structurally as comprising three distinct parts: a part which interfaces with the hard tissues; a part which interfaces with the soft tissues; and a part with interfaces with the oral environment. These different structural parts may take the form of either one, two or three separate components. Figure 74 shows three separate components diagrammatically and how they are associated with one another. The component that is osseointegrated with bone is usually referred to as the implant fixture and provides retention and support for the prosthesis to bone. The abutment is the component that is connected to the fixture and traverses the overlying soft tissue to provide a connection between the fixture and the overlying restoration. The final component of the system is the restoration or superstructure which gains support and retention from the fixture through the abutment. Although this is a basic overview of the generic implant system, it may be applied to many products whether they comprise separate fixtures, abutments and restorations or hybrid components (e.g. a fixture and abutment as a single, joined component). Implant fixtures Osseointegrated implant fixtures are available in a vast array of sizes, shapes, surfaces and linking mechanisms. In all cases, the primary aim of the fixture is to integrate with the host s bone and provide stability and retention for the restoration. Primary stability of the fixture is usually provided by some form of mechanical feature (e.g. a selfthreading mechanical attachment to the bone when the fixture is first placed). The long-term stability and retention of the fixture is then dependent upon establishment of biological osseointegration with the host not rejecting what is, in essence, a foreign body placed within the living tissues. Successful osseointegration is indicated by a stable implant fixture, that gives a bright note when percussed. Failure is apparent when the fixture becomes mobile and may eventually be exfoliated, if infection of the site has not already ensued. Implant abutments The abutments link implant fixtures to restorations in the mouth and maintain a permanent defect through the epithelial barrier of the soft tissues. They provide support and INDD 133 6/3/2008 7:14:10 PM

2 Five: Restorative management of dental implants 134 retention for the overlying restoration through either an unbreakable physical link (e.g. a cemented single crown) or a breakable physical link (e.g. a magnetically retained complete overdenture). Implant supported restorations Implant supported restorations serve to replace the tissues which have been lost and it is convenient to consider these as either dental or supporting tissues. A further way to classify restorations is according to whether they are fixed (i.e. cemented, or screw-retained conventional crowns and bridges, or hybrid metal and acrylic screw-retained bridges) or removable, precision attachment retained partial or complete dentures. 5.2 Planning dental implants Learning objectives Implant supported restoration Single unit crown cement retained Implant abutment with holding screw in position Implant fixture Fig. 74 Diagram to show the basic components of an implant restoration. You should be familiar with the indications and contraindications of using dental implants be aware of and be able to discuss the stages involved in planning for dental implants be aware of the basic terminology of implant-supported restorations. It is essential, as with any episode of treatment planning, that the final outcome is taken into account at the outset of the planning process. That is not to say that a treatment plan once formulated, is inflexible, but an opportunity or contingency plan to manage any potential problems before they occur is likely to be of considerable benefit. Consideration of the final restoration and the expectations of the patient must, therefore, be made at the outset so that the treatment plan can achieve the most desirable outcome. Indications Osseointegrated implants provide the retention and support for the dental prosthesis which may take the form of a single tooth, groups of teeth, the entire dentition or even anchorage for an orthodontic appliance. Implants are primarily indicated therefore when there is partial or total loss of the dentition and/or the supporting tissues. The loss of tissues may be a consequence of extensive dental caries and periodontitis or due to more radical change such as neoplasia or maxillofacial trauma. Contraindications Implant surgery may be considered as an elective oral surgical procedure and therefore any contraindications for surgery will also be a contraindication for the provision of dental implants. In general terms, any local or systemic condition which would impact upon wound healing will have the same effect upon the healing at the implant fixture site and may, therefore, impact on the long-term success of implant management. For example, the use of bisphosphonates to manage osteoporosis and the link with postsurgical osteonecrosis. Relative contraindications for treatment may be considered in relationship to the space available for fixture placement and restoration. Cases may present with insufficient bone quantity (e.g. a highly atrophic anterior mandible or a posterior maxilla with a highly pneumatised maxillary sinus). There may also be insufficient space to place the restoration (e.g. a severely over-erupted tooth opposing the site planned for restoration). Case selection The selection of cases for implant treatment will begin with careful and thorough history and examination. It is important to determine why the patient is seeking implant treatment and to ascertain their understanding of what is involved, as well as finding out their expectations of the likely clinical outcome. It should then be possible to balance the patient s expectations with what is clinically achievable to ensure that both the patient and the clinical team are likely to be satisfied with the outcome. During history taking, it is crucial to discuss problems (e.g. a pronounced gag reflex with a removable prosthesis) that may have been encountered with previous restorations and also to determine whether implants are indeed the appropriate line of management. For a patient with a severe gag reflex, it may be more appropriate to undertake desensitising measures first rather than placing multiple fixtures which may not be used for the support and retention of a prosthesis. Careful discussion of the care pathway should be undertaken with the patient to ensure that (s)he understands INDD 134 6/3/2008 7:14:11 PM

3 Surgical phases what the different stages of treatment will involve. For example, during the healing phase, it is sometimes necessary to ask the patient not to wear an interim prosthesis for a short period in an attempt to aid healing. This may not be acceptable to some patients. The actual methods for placement and restoration of the implants and their long-term management should also be considered carefully. Finally, the cost of delivering this type of treatment must be considered, irrespective of whether it is self or publicly funded delivery of care. The initial outlay is considerably more when comparing complete dentures to implant supported overdentures. However, there is evidence to suggest that the long-term costs of these different methods of management is not so large, and this does not take into consideration the psychosocial aspects of comparing these two treatments. Tooth down planning The final restoration of the implant fixtures should be considered at the outset of treatment planning. The question of whether it is possible to place teeth in their ideal position to restore function should also be considered. A decision should be made as to whether it is important or desirable to conform to the features of the patient s remaining dentition or current prosthesis or whether any modifications to the current situation need to be made. Accurate preoperative study casts, mounted on a semi-adjustable articulator, will support the planning process and enable simulation of the final restoration by using a diagnostic wax-up or try-in prosthesis. There are biometric and subjective measures that may be used to assess dental function. Valuable information may also be gathered during history taking when the patient s ability to chew and potential difficulties with speech and aesthetics may be explored. Particular consideration to facial, dental and gingival aesthetics should be made when restoring the anterior aesthetic zone. For example, it is unacceptable to restore a fixture which may be stable but demonstrates poorly adapted supporting tissues in cases where there is a high upper lip line. Special investigations An estimation of the quantity and position of hard tissues may be measured clinically with callipers that penetrate the overlying soft tissues to estimate bone width along an edentulous space. A detailed clinical examination needs to be supplemented with additional assessments such as plain film radiography, tomography or computed tomography (CT) scanning. There are also software applications which use radiographic data to generate 3D simulations which can be viewed and manipulated to allow further treatment planning. Products exist to allow clinicians to design restorations and determine optimum implant fixture placement before requesting custom surgical guides and pre-fabricated restorations prior to implant surgery. Types of restoration Restorations supported by dental implants may be classified into two broad groups. First, those which replace only the lost dental tissues and are therefore directly comparable to conventional single crowns or bridges with the dental fixtures effectively being the roots of the teeth. Second, the restorations may replace both the dental tissues and the supporting tissues and such prostheses include removable dentures and fixed hybrid bridges. Single tooth and conventional bridge restorations are retained on the implant abutments using either a conventional cement lute or screw retention ( Fig. 75 ). The access hole for the screw is then restored using a directly placed restoration. Removable prostheses achieve greater support and stability than their conventional counterparts because the implants act as overdenture abutments ( Fig. 76 ). Retention may also be increased by the use of precision attachments such as ball attachments ( Fig. 77 ), bar and clip attachments or magnets. The hybrid metal and acrylic bridge restoration incorporates a metal framework that is customised to fit the underlying implant fixtures using screw retention either to the transmucosal abutments or directly to the fixtures themselves. This framework supports not only the teeth, but also the pink acrylic of the supporting soft tissues so that the prosthesis may be considered as either a fixed bridge restoration or as a denture. Timing of procedures Multi-disciplinary treatment planning for implant cases is essential to allow the clinical team to generate the customised care pathway for each patient. The different stages for the management pathway should be identified and any contingency plans that may need to be incorporated into the care pathway should be highlighted. For example, an alternative or options that may be available should a fixture that has failed to osseointegrate be discovered or where modification of the surrounding gingival tissues may be indicated. Figure 78 shows a flow chart of the potential care pathways that a patient may follow during implant management. 5.3 Surgical phases Learning objectives You should be aware of the basic surgical principles surrounding dental implant placement be aware of the restorative/surgical interface associated with the provision of dental implants appreciate the importance of the role of the restorative clinician during the surgical phases of implant placement. The detailed description of the surgical aspects of implant treatment are outwith the remit of this chapter. It is, however, pertinent to provide a brief overview of the principal stages of fixture placement and abutment connection with specific reference to the involvement of the restorative clinician. Pre-fixture placement: site evaluation and preparation The multi-disciplinary treatment plan should determine the optimum position for the implant fixtures and so provide the best possible options for replacing the teeth and the supporting tissues. Customised surgical guides which Five INDD 135 6/3/2008 7:14:11 PM

4 Five: Restorative management of dental implants a b Fig. 75 Screw-retained ceramic abutment and cement-retained implant supported crown. a b Fig. 76 Stud attachments and lower implant supported overdenture. 136 Fig. 77 Screw-retained lower hybrid gold and acrylic bridge. replicate ideal tooth position may be used to determine whether sufficient bone is available for fixture placement. Additional information may be obtained at the chairside. For example, the technique of direct ridge mapping uses callipers whose beaks penetrate the overlying mucosa to help quantify bone width. Alternatively, CT scans and commercially available software packages can produce 3D images to assist in simulating the positioning of fixtures. An informed decision can then be made regarding whether or not there is sufficient remaining bone to support the fixture or fixtures. If there is insufficient bone, consideration should be given as to whether or not bone augmentation procedures are required or, indeed, possible. For example, maxillary sinus floor lift or block grafting surgery to widen the alveolus. Finally, should a tooth or root remnant be present at a potential implant site, the decision needs to be made as to whether the fixture will be placed immediately after tooth extraction or following a short delay of approximately 6 weeks to allow gingival healing. Fixture placement When the potential implant site has been identified, a decision needs to be made on the ideal size, position and angulations of fixtures. Optimum placement may be assisted using a customised surgical stent or guide with carefully positioned orientation holes cut through the acrylic. Matched osteotomy sites can then be prepared to receive each fixture. A decision to attach the transmucosal section of the implant is made with either closure of the mucoperiostial flap around the transmucosal abutment or closure over a buried fixture. If a transmucosal abutment has been attached, then some form of provisional restoration will be indicated incorporating either a fixed or INDD 136 6/3/2008 7:14:12 PM

5 Provisional and definitive restoration of dental implants History and examination and special investigations Insufficient bone to place fixture Bone grafting to planned fixture site Definitive restoration agreed and ideal fixture placement determined Partial failure of osseointegration of implant fixture guided bone generation Complete failure of osseointegration of implant fixture removal of failed fixture Options for modification of definitive restoration in original treatment plan Surgical placement of implant fixture(s) Surgical placement of transmucosal abutment Provisional restoration of transmucosal abutment Simultaneous placement of transmucosal abutment with provisional restorations Simultaneous placement of transmucosal abutment with provisional restorations Five Definitive restoration of transmucosal abutment Long-term maintenance of fixtures and replacement programme of restorations Fig. 78 Flow diagram of the care pathway followed during implant treatment. removal prosthesis. Careful consideration of the loading implications to such restorations needs to be made so that the healing osteotomy sites undergoing osseointegration are not compromised. Immediate or delayed restoration If an implant fixture is covered using a mucoperiostial flap so that it is positioned submucosally for a short period to facilitate osseointegration prior to loading, then a second surgical procedure is required to expose the implant and allow connection of the transmucosal part. This is achieved either by raising a mucoperiostial flap, or in some cases through a localised excision of the overlying mucosa using a custom-sized tissue punch. Again, temporary restoration of the site may be required and involve the use of either a fixed or removable prosthesis. Soft tissue recontouring The position and long-term stability of the gingival tissues surrounding the transmucosal section of an implant is often uncertain and unpredictable. Localised gingival recession may be a consequence of the healing and maturation of the soft tissues or, alternatively, there may be an excess of redundant soft tissue that can also compromise placement of the definitive restoration. In some cases, minor surgical modification of the gingival tissues may be indicated. 5.4 Provisional and definitive restoration of dental implants Learning objectives You should understand how dental implants are provisionally and definitively restored recognise the options available for restoring dental implants be able to discuss the basic principles of dental implant restoration. The numerous dental implant systems that are available all have slight variations in their protocol for restoration in the immediate and long term. This section describes the basic stages during the restorative phase of implant temporisation and restoration. The delayed loading approach and the immediate loading of implant fixtures at the time of their placement will be considered. Restorations prior to fixture placement When a patient presents for implant treatment planning it is likely that they will already be wearing some form of dental prosthesis. This may be a fixed resin bonded or conventional bridge, or a partial or complete removable denture. Some patients may also present with failing teeth INDD 137 6/3/2008 7:14:19 PM

6 Five: Restorative management of dental implants 138 that may need to be extracted prior to fixture placement. Optimising restorations prior to starting implant treatment is essential to ensure that: they remain functional they provide good aesthetics the edentulous spaces and occlusion remain stabilised they do not compromise the healing surgical site following implant fixture placement. Restorations at fixture placement A delayed approach to implant loading is usually adopted when the fixture is covered surgically by a layer of mucoperiostium to allow a closed environment that heals by primary intention. The surgical site should be protected and not compromised by either pressure on, or displacement of the surgical flap. Ideally, any removable prosthesis should be left out for a short period of 1 or 2 weeks. Clearly, this can lead to significant problems if the prosthesis replaces teeth in the aesthetic zone. In those circumstances where it is essential that a removable prosthesis must be worn, then it should be stable and must rely on support from other areas of the mouth other than the healing surgical site. Particular attention should be given to the fitting surface of the removable prosthesis and modifications made to relieve excess pressure or to smooth any fins of denture base material that may protrude into flap margins. If an implant fixture is to be loaded immediately after placement, then the transmucosal section needs to be connected to the implant fixture at the time of surgery. The transmucosal section of the restoration may be: a prefabricated abutment that is designed to carry a conventional provisional or definitive crown or bridge that is cemented in place a custom-made, single piece abutment which is integrated into a provisional or definitive crown or bridge that is screw-retained to the fixture a prefabricated abutment which allows a hybrid metal and acrylic bridge to be screw-retained to multiple fixtures a custom-made, single piece abutment which is integrated into the definitive hybrid metal/acrylic bridge and allows it to be screw-retained to multiple fixtures The prefabricated abutments are available in a number of shapes, angles and sizes so that the clinician is able to select the best available fit at the time of surgery. One drawback, however, is that each component is made to a population average and may not have the optimum features for each specific case. This will not be a problem in cases where aesthetics are not a primary importance, but when there is a high aesthetic challenge, it is prudent to use custom fit solutions to allow for individual variation. Custom-made elements require a level of pre-surgical information to allow their construction. In the case of immediate loading of implants, CT scanning and computer-aided design can accurately plan fixture placement and therefore help with identifying the most appropriate overlying restoration. Surgical guides may help to control for variation that may be inherent during multiple fixture placement and the number of implant systems now incorporate protocols that allow for fixture placement and restoration using custom-made prostheses within a single surgical and restorative clinical session. Restoration immediately after abutment connection Implant fixtures may also be left submerged to allow osseointegration to occur prior to restoration and this delayed loading approach will require a second surgical procedure so that the transmucosal section of the implant may be connected to the fixture. As with the immediate loading protocol, off-the-shelf abutments may be appropriate in combination with provisional or definitive restorations. Alternatively, an impression may be made of the fixture head with an impression coping to accurately transfer to the laboratory the accurate position of the implant fixture(s) in relationship to the remaining dentition and soft tissues. A custom-made abutment with separate restoration or a one piece abutment and restoration can then be fabricated. Recording the fixture impression may also be undertaken at the time of fixture placement and this has the advantage of allowing immediate placement of a restoration at the time of fixture exposure and abutment connection. The decision to immediately restore an implant when the transmucosal section is attached for the first time will depend upon the impact of the gingival tissue implant interface on aesthetics and function. When an implant has minimal or no impact on aesthetics, it is generally accepted that the definitive restoration can be completed as soon as possible. For example, this would be the case for implantsupported removable prosthesis and hybrid metal/acrylic screw-retained bridges. A high proportion of implant-supported restorations are placed in the anterior maxilla and consequently aesthetics are of paramount importance. It is expected that any surgical intervention to replace missing hard or soft tissues in this area will already have been undertaken prior to the provision of the definitive restoration which is then considered as a process to refine the aesthetic result rather than to incorporate gross corrections or modifications. The overall appearance of gingival margins around the teeth and implants should be considered with regard to the colour, height, width, biotype and symmetry of the soft tissues. The emergence profile of the restorations from the fixture head should try, wherever possible, to give an appearance of a natural tooth. The use of gold or ceramic abutments may reduce the grey appearance of titanium which can sometimes be apparent when the gingival tissues have a thin biotype. 5.5 Maintenance phase Learning objectives You should understand the requirement for long-term maintenance and follow-up of dental implants understand the process of reviewing dental implants be familiar with methods of patient and professionally delivered dental implant maintenance be familiar with potential complications associated with dental implants INDD 138 6/3/2008 7:14:20 PM

7 Maintenance phase The long-term follow-up and maintenance of implant work is an essential requirement for long-term stability and success. There is a substantial body of evidence to suggest that implants will remain successfully osseointegrated for decades and, as those initial patients who received their implants in the 1970s and 1980s become older, our knowledge of longer-term complications will be enhanced. Of course, the provision of implants should be considered in relationship to the long-term provision of dental care to the remaining dentition and as a consequence, both the multi-disciplinary specialist team and the general dental practitioner will have interactive roles in the provision of this care. Immediate-term follow-up After completion of the surgical and restorative stages of implant treatment, the responsibilities for the long-term care of both the implants and the restorations must be reinforced to the patient. Oral care should include tooth brushing, interdental and subgingival cleaning with an appropriate aid such as floss, super floss or mini-interdental brushes. Where multi-implant restorations are linked, the design of the restoration gingival and mucosal interface should facilitate easy cleaning by the patient at home. Postoperative radiographs can be used as a base line record of the restoration tissue interface and assist the clinician to check that restorations have been seated correctly onto the implant fixture or abutment with no gaps seen at the interfaces. The base line radiographs can also be used to compare with future radiographs so that an assessment can be made of long-term stability or changes that might occur at the bone fixture interface. Long-term follow-up Implant supported restorations have the potential, similar to tooth and prosthesis surfaces, to attract biofilm and with time, may suffer detrimental effects in so far as the adjacent gingival tissues may become inflamed and the underlying bone susceptible to resorption. It is therefore essential that implant fixtures are reviewed regularly to identify potential problems as early as possible and to instigate appropriate treatment where indicated. The frequency of such review appointments should be determined by a patient s need and the previous history of dental disease. It is also prudent to review patients more frequently during the first few years following the provision of implants and then to extend the time of recall interval when stability of the implant system is assured. Percussion of an implant-retained restoration should give a bright sound as opposed to the dull sound of an implant which is failing or has failed. Gentle probing subgingivally using a plastic probe to avoid scratches on the implant surface will help to detect plaque, bleeding upon probing, changes in probing depth with time and subgingival calculus. Calculus can then be removed using plastic scalers and curettes. Sequential radiographs will provide an assessment of supporting bone levels and, most importantly, any changes in the quantity or quality of bone that may have occurred compared to base line records taken following the completion of treatment. Radiographs may also provide evidence of component failure (e.g. a fractured screw, which may remain undetected in a linked multi-fixture restoration). The regularity of radiographic investigations should be a patient-based decision and should conform to best practice with respect to regulations for the use of ionising radiation. Complications Frequently reported factors which impact upon the longterm success rate of dental implants include the quality and quantity of the bone, the impact of smoking and the history of advanced chronic periodontitis. Long-term, longitudinal clinical studies have reported success rates of nearly 90%, 10 years following placement of fixed, hybrid bridges although this success rate falls to 70% after 15 years. The success for single tooth restorations supported by dental implants is higher, with a reported 10-year survival being in excess of 95%. Once an implant has successfully integrated, the final restoration is subject to the oral environment which places many demands upon the restoration. Porcelain may crack or shatter under excessive occlusal loads, acrylic resin will wear with time just as it would do with any non-implantretained or supported prosthesis. The interface between the soft tissues, the bone and the implant provides another point of ingress for oral microorganisms, and subgingival biofilms which may drive a localised inflammatory reaction and lead ultimately to peri-implant disease. Soft tissue recession around abutments and along fixtures may occur with time and lead to problems with aesthetics. Implantsupported restorations are not immune to the effects of trauma in the maxillofacial region; with the union between the implant and the bone being direct, there may be potentially more risk of bony fractures as compared to avulsion of a natural tooth with its own periodontal ligament. Five INDD 139 6/3/2008 7:14:20 PM

8 Five: Restorative management of dental implants Self-assessment: questions Extended matching items Theme: Components of the implant system The list below (1 10) comprises different components of the generic implant system together with restorations and prostheses that may be implant retained. For each of the statements (a e), which describe an implant component or restoration that is often used in implant-retained units, select from the list the single most appropriate item that applies to that statement. Each item may be used once, more than once or not at all: 1. Implant fixture 2. Implant abutment 3. Screw-retained crown 4. Screw-retained bridge 5. Cement-retained crown 6. Cement-retained bridge 7. Screw-retained metal/acrylic hybrid bridge 8. Overdenture 9. Abutment screw 10. Impression coping a. The section of an implant system that provides retention and stability to a restoration. b. The section of an implant system which traverses the epithelial lining of the oral cavity. c. A restoration which replaces the hard and soft tissues of the oral cavity and cannot be removed by the patient. d. A device which allows the accurate transfer of an implant fixtures position and orientation within the oral cavity to the laboratory. e. A restoration that is retained by stud, magnetic or bar and clip precision attachments and that may be removed by the patient. Short note question Write short notes on the steps taken to plan for a single tooth implant to replace a missing upper central incisor INDD 140 6/3/2008 7:14:20 PM

9 Self-assessment: answers Self-assessment: answers Extended matching items answers a. 1 b. 2 c. 7 d. 10 e. 8 Short note answer A comprehensive list of notes would include: Patient factors willingness to undergo surgery willingness to leave restorations/prostheses out during immediate, postoperative healing periods lip/smile line. Risk factors systemic surgical environmental (further trauma to area; e.g. through contact sports) sufficient funding other options for restoration (removable or fixed prostheses). Site factors sufficient space between adjacent teeth, the need for pre-surgical orthodontics sufficient space/clearance interaction with occlusion Sufficient bone to implant into: ridge mapping computer simulation available site to harvest bone and willingness to undergo grafting procedures if there is insufficient bone relationship of ideal tooth position to the potential underlying fixture placement diagnostic wax-up production of custom surgical guides. Restoration factors relative dimensions of the restoration to the remaining dentition loss of space drifting/tipping/rotation of teeth choice of abutments off-the-shelf ; pre-fabricated bespoke custom type of material use of screw or cement-retained definitive restorations excessive spacing between teeth therefore no support for papilla creation/augmentation emergence of profile of restoration and soft tissue aesthetic consideration thickness of tissue and impact of abutment materials (titanium will show through thin biotype gingival tissue) INDD 141 6/3/2008 7:14:20 PM

10 INDD 142 6/3/2008 7:14:20 PM