Compendium of Continuing Education in Dentistry

This article will discuss and evaluate the potential conditions that can present in patients who require or already have had multiple anterior tooth extractions; the proper considerations for the use of ovate pontics in the treatment plan also will be discussed. While the ultimate treatment decisions must be determined on a case-by-case basis, it is important to recognize in advance the various potential outcomes to ensure that realistic decisions are made about the best treatment options for each patient. Accordingly, the four most common presentations a clinician is likely to encounter will be examined, as well as how they may be managed and the most likely compromises that might exist in the final result. Learning Objectives: After reading this article, the reader should be able to: evaluate the potential conditions that may present in patients who need or have had multiple anterior tooth extractions. consider when the use of ovate pontics is warranted. recognize each patient’s various potential outcome possibilities to make informed and realistic decisions about treatment options. The loss of a single anterior tooth can be difficult for almost any patient, but replacing it with an implant or a fixed partial denture results in a predictable esthetic outcome unless significant bone and soft tissue were lost with the tooth. Even then, in the hands of a skilled team of clinicians, the result is generally acceptable. The loss of multiple anterior teeth, especially if they are adjacent to each other, is a much more difficult esthetic challenge and often requires the combination of implants and ovate pontics to achieve an acceptable esthetic result. HEIGHT CONSIDERATIONS INFLUENCING TREATMENT OUTCOME Accounting for this difference are the biology of the periodontium and the response of the bone and soft tissues when one tooth is lost rather than multiple teeth. In the case of a single-tooth loss, if a single-tooth implant is placed, the interproximal papilla levels will be determined by the height of the interproximal bone on the adjacent natural teeth, not the interproximal bone on the implant.1-3 In the average patient, the papilla height will be 4 mm to 4.5 mm above the interproximal bone on the adjacent natural teeth (Figure 1). Therefore, if the natural teeth have no bone loss, the papilla height after tooth loss will be similar to what it was before tooth removal because the average SIGN IN OR REGISTER NOW Email Password Forgot Password? SUBMIT View Active CE Courses List by Specialty List by Title List by Date Compendium of Continuing Education in Dentistry http://ce.compendiumlive.com/loadarticle.asp?quizid=134 2 of 11 7/22/2008 2:11 AM papilla height above bone between natural teeth is also 4.5 mm.4,5 The facial gingival margin around the implant, however, is not related to the bone on the adjacent natural teeth, but rather to the facial bone levels on the implant, as well as the thickness and position of the free gingival margin before tooth removal.6,7 For a single anterior implant, the least predictable soft-tissue outcome results when the adjacent natural teeth have interproximal bone loss because managing the papilla heights can be difficult. These same rules closely apply to the replacement of a single anterior tooth with a pontic (ie, the final papilla location will be influenced by the bone on the adjacent natural teeth, and the free gingival margin location dictated by the location of the bone and tissue thickness on the facial of the pontic). However, when comparing pontics with implants, the one significant difference concerns the height of interproximal tissue above the bone. While this height averages 4.5 mm between natural teeth, or between a natural tooth and an implant, it has been shown that after soft-tissue grafting, the amount of tissue above the bone interproximally between a pontic and a natural tooth, or between a pontic and an implant, averages 6.5 mm and, in fact, in some patients can be as high as 9 mm.8 If the adjacent natural teeth in a single-tooth replacement situation have bone loss, soft-tissue ridge augmentation, followed by placement of a pontic, can achieve greater coronal height of the papilla than a single-tooth implant could in the same situation. BIOLOGIC RESPONSES OF TISSUE IN DIFFERENT LOCATIONS POSTEXTRACTION The challenge of multiple tooth replacement occurs when adjacent teeth are already missing or need to be removed. Consider the loss of two maxillary central incisors. It is helpful to separate the biological response to evaluate how the soft tissue responds in several locations following tooth removal. First, consider the response of the papilla between the centrals that were removed and the adjacent remaining lateral incisor. The same scenario exists as if the situation involved a single-tooth replacement (ie, the interproximal bone on the remaining lateral incisor will determine the papilla height between the centrals and laterals). The facial free gingival margin height on each central also will be similar in response to a single missing tooth (ie, the facial bone level and tissue thickness will determine the final facial gingival margin). In addition, just as in the single-tooth situation, if the final facial gingival margin is less than ideal, it is much easier to augment in height and thickness on both centrals with a soft-tissue procedure than it is to improve the papilla’s height. The real challenge when removing the two centrals is to evaluate what happens to the papilla between them after extraction.9,10 Before extraction, the osseous crest around both centrals, assuming no periodontal disease exists, roughly follows the scalloped nature of the cementoenamel junctions (CEJs) as they flow from the facial into the interproximal, resulting in an average osseous scallop of 3 mm; the average interproximal bone height is 3 mm coronal to the facial crest of bone. Because the soft tissue typically follows the scallop of the bone, the osseous scallop results in a gingival scallop of 3 mm. However, when teeth are present, an interesting phenomenon occurs. The gingiva on the facial of the tooth is positioned so that, on average, the free gingival margin is 3 mm coronal to the crest of bone. However, the interproximal papilla between teeth is positioned, on average, 4.5 mm coronal to the interproximal crest of bone, 1.5 mm, on average, more coronal to the crest of bone than is the facial tissue. This additional 1.5 mm, along with the 3 mm average osseous scallop, results in the tip of the papilla being an average 4.5 mm to 5 mm coronal to the facial free gingival margin (Figure 2). Compendium of Continuing Education in Dentistry http://ce.compendiumlive.com/loadarticle.asp?quizid=134 3 of 11 7/22/2008 2:11 AM Figure 1—The relationship of the interproximal papilla height to the interproximal bone of the adjacent tooth is 4.5 mm. Figure 2—Between natural teeth, the average osseous scallop is 3 mm from the facial to the interproximal, and the average gingival scallop is 4.5 mm from the facial to the interproximal. Figure 3—When adjacent implants are placed 3 mm or more apart and the interproximal crest of bone is retained (ie, red line), the papilla between the implants may be within 1 mm to 1.5 mm of the original papilla height (ie, yellow line). Figure 4—If the interproximal crest of bone is between adjacent implants, the average papilla height above the bone is 3.5 mm (ie, red line), which results in a significant difference in papilla height when compared to the pre-extraction papillary height (ie, yellow line). REPLACEMENT METHODS AND THEIR IMPACT ON BONE AND TISSUE It is necessary to understand what happens to the osseous scallop and papillary soft-tissue height above bone following tooth removal. To a certain extent, the answer to this dilemma is determined by how the central incisors will be replaced and how the replacement method affects the underlying bone and the soft tissue. Use of Adjacent Single Implants Traditionally, implants have been made that are nonscalloped or flat coronally; during placement, the implant is placed apically until the platform of the implant is level with the facial crest of bone. However, because the bone is scalloped, the interproximal platform of the implant may be apical to the interproximal crest of bone by as much as 3 mm. Classically, a certain amount of bone adjacent to the implant has been expected to resorb over time, usually to the first thread of the implant.11,12 As these bony changes occur, the interproximal crest of bone that was present at the time of tooth removal might resorb, resulting in a flattening of the osseous crest and a corresponding flattening of the gingival architecture because of the papilla’s height loss as the interproximal bone is lost. Several different approaches are currently being researched to resolve this loss of the interproximal crest of bone between implants. They include scalloped implants, platform switching, altered coronal implant surface design, and microgap location. A discussion of these approaches is beyond the scope of this article, but it bears noting that the maintenance of the interproximal crest of bone is critical to maintaining the height of the papilla between adjacent implants. In addition, there is wide concurrence that it is vital to the maintenance of the crest of bone to maintain 3 mm of space between the Compendium of Continuing Education in Dentistry http://ce.compendiumlive.com/loadarticle.asp?quizid=134 4 of 11 7/22/2008 2:11 AM platforms of the adjacent implants.13 It is also necessary to understand what happens to the height of the interproximal soft tissue above the bone. While the research points to the papilla height being 4.5 mm above the bone between adjacent teeth and bone, or 4.5 mm above the bone on the natural teeth and an adjacent implant, it appears that when adjacent implants are placed, the papilla height above the bone reduces from 4.5 mm to between 3 mm and 3.5 mm.13 When adjacent implants are placed, even if they maintain the interproximal crest of bone perfectly, the papilla between the implants will end up 1 mm to 1.5 mm apical to where it was between the teeth, simply from the change in soft-tissue levels (Figure 3). If this 1-mm to 1.5-mm difference is added to any alterations in interproximal crestal bone height, it is easy to comprehend why the maintenance of the papilla height between adjacent implants is difficult (Figure 4).