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ePaper created 2016-03-11, 23:13:06 | version 1.38.0
issue 2016 — 23 Advanced Implant Esthetics Article Figs. 1a–e Schematic view of the five-key protocol. Tissue optimization (a). Gingival remodeling (b). Handling reduction (c). Effective component design (d). Abutment surface cleanliness (e). of the abutment has been associated with detrimental effects on the periimplant bone.12 It creates a soft-tissue wound and triggers subsequent bone resorption as a properbiologic dimension of the mucosal barrier attachment to the stable implant surface is re-established. In orderto avoid disturbing the mucosal periimplant seal that preserves the crestal bone level, a customized abutment for a cement- retained prosthesis should be placed with the objective of avoiding repeated im- plant-level impressions and try-ins.13 An abutment-level impression should be taken. When impressions are taken at the time of implant placement and further abutment manipulation can be avoided, less bone resorption has been shown to result.13 — 4. Effective component design (Fig. 1d) The implant macrodesign and, in particu- lar, the design of the implant–abutment junction(IAJ)arecriticalinpreventingthe loss of crestal bone. Numerous publica- tions have demonstrated that some alve- olar bone resorption occurs around the IAJ of platform-matched implants when they are exposed to the oral environ- ment.14, 15 It has been postulated that the first bone-to-implant contact begins around 1.5–2 mm apical to the IAJ or to the first implant thread. About 1.4 mm of horizontal resorption occurs. A different bone response has been documented when platform-switched implants are used. A recent systematic review and meta-analysis showed that significantly less bone resorption occurred when this IAJ design was employed.16 Use ofthe 4/3 3i T3 Tapered Implant (BIOMET 3i) facili- tates following several of these keys to achieve more predictable esthetic restoration of anterior implants. The de- signincorporatesplatformswitching,with a 3.4 mm platform dimension in ordernot to impinge on the interdental space. Histological investigation17 has found that platform switching appears to affect Fig.1a Fig.1d Fig.1e Fig.1b Fig.1c the location ofthe circularlyoriented col- lagen fibers that surround implant abut- ments and apparently stabilize the con- nective tissue and underlying alveolar crest. While these fibers have been found at the level of the first thread of nonplat- form-switched implants, theyhave devel- oped at the IAJ of platform-switched im- plants. The horizontal platform of the platform-switched implants appeared to provide mechanical retention for the cir- cular fibers, allowing them to develop more coronally than in standard implants. The abutment design too can help to sta- bilize the connective tissue above the IAJ andpreservealveolarboneattheplatform level. One concave design has been pro- posed18 that features a circumferential macrogroove that creates space for soft tissue. It arguably creates a ringlike seal that,aftertissuematuration,maystabilize the connective tissue adhesion. Connec- tive tissue stabilization has also been demonstrated when using a narrow laser microgrooved cylindrical abutment.19, 20 The implant–abutment connection too appears to have a significant impact on periimplant crestal bone levels. Internal connections have been demonstrated to better maintain bone.21 Finally, the design of the prosthetic crown and its relation- shiptothe implant abutment are essential factors for restoring tooth anatomy and function.The crown should provide space forfiberstabilizationbetweenthecervical contours and the implant platform. — 5. Abutment surface cleanliness (Fig. 1e) Implant abutments are transgingival de- vices that interact in their most cervical region withthe surroundingtissue, mainly connectivetissueunderneaththegingiva. Abutmentsallowforthere-establishment of the biologic width: as cells attach, the Article_Vela_00-00.qxp_Layout 1 02.03.16 20:54 Seite 2 Article_Vela_00-00.qxp_Layout 102.03.1620:54 Seite 2