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ePaper created 2014-10-07, 09:31:41 | version 1.30.01
I special _ 3-D planning for implants 32 I cone beam3_2014 poromandibular joint is important. The number of teeth necessary for prostheses has not been deter- mined definitively. Within the last few years, recon- structing up to the first molar, and up to the second premolar in cases with an extension, has been usual. Generally, alveolar atrophy progresses most rapidly horizontally in the lateral jaw area, starting buccally, and frequently is later followed by atrophy of the vertical dimension. If one avoids augmentation or performs only mi- nor augmentation, longer prostheses are necessary for short implants, which are situated more lingually than the natural teeth. The use of short implants in the lateral jaw is subject to several restrictions, such as good bone quality, primarily connected crowns or caps, no extension bridges, no lateral excursion contactsandnopara-functionalhabits.Angulationis limited to 20 degrees. Furthermore, angled implants are not recommended for a shortened row of teeth according to the guidelines of the European Associa- tionofDentalImplantologists.5 Ifalignmentiscarried out with respect to antagonists in the natural den- tition, positioning the new implant-borne crowns will not lead to any functional losses, unless the an- tagonistswerenotfunctionallysituatedinthedental arches originally. Space towards the cheeks must be regained, even if patients with a long case history sometimes com- plain about spontaneous cheek biting and bolus re- tention.Onemustchoosecarefullybetweenthemore pleasantapproachofusingshortandangledimplants with long crowns and the more difficult approach of bone augmentation. Three-dimensional planning provides indispensable information in cases like these. With reference to typical defect patterns, Figure 2 demonstrates that restoring bone volume for very different defects can be problematic. A typi- cal reconstruction using a surgical guide for pilot drillings in a shortened row of teeth with good initial conditions is depicted in Figures 3a and b. _Edentulous jaw Three-dimensionalplanningisofvitalimportance for determining the treatment approach for implan- tation in edentulous jaws. For instance, one has to decideuponwhetherandwhichaugmentativemeas- ures are required and whether a removable or fixed prosthesis is suitable. With regard to the last point, it must also be decided whether extensive single- tooth replacement is possible, whether small or large bridges must be used, and whether a greater inter- maxillary distance must be filled prosthetically by longer crowns or by a mucosa substitute. The number of implants for fixed dental pros- theses include the All-on-4 concept (Nobel Biocare), the consensus conference recommendations of six Figs. 5a–f_Two-step technique in a case of advanced atrophy of the alveolar process before prior to fixed prostheses. Horizontal and vertical augmentation Iintra-operatively, fixed bone block (left) and covered with membrane cover (right; a). Healed post-augmentation (b). Post-implantation (c). Radiograph after placement of the bridge (d). Prosthetic result, lip repose (e). Prosthetic result, lip raised (f). Despite augmentation, long crowns are were still required. Figs. 6a & b_Loading of an edentulous mandible with a fixed bridge on inter-foraminal implants: Planning detail (a). Four years post-treatment (b). Fig. 5a Fig. 5b Fig. 5c Fig. 5d Fig. 5e Fig. 5f Fig. 6bFig. 6a CBE0314_29-33_Ehrl 30.09.14 14:16 Seite 4