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cone beam1_2012 case study_fixed partial denture I I 23 Fig. 3_Three-dimensional CBCT based virtual rendering (3DVR) of the mandible revealed a buccal concavity in the alveolar crest. gual aspect of the anterior region of the mandible. These variances were reported in the Journal of Oral Implantology in 2007.3 While no biopsies were per- formed in that study in order to obtain histological data on these anatomic variances, it was assumed that they are most likely developmental rarefactions (regionsofdecreasedparticledensity)andradiopaci- ties (regions of increased particle density). The mere fact that the associated mean bone radiodensitywithintheanatomicvariancemeasured above the mean bone radiodensity observed in adja- cent sites suggested that there were no limitations fromabonequalityandimplantfixationperspective in these regions. Furthermore, while the overall success rate of dental implants is high, accomplishing predict- able reconstruction and esthetic results for single or multiple teeth replacements with dental implants is challenging, and as dental implants become an increasingly viable treatment for replacing missing teeth,wemayencountermorerandommaxillofacial anatomic conditions. Therefore,andasseeninthiscase,withtheuseof CBCT three-dimensional based dental imaging, we capturedavolumeofdataandthroughareconstruc- tion process we constructed images that took the guesswork out of our treatment planning and made us more proficient. Given the unique slim knife-edge shape, meas- uring infinitesimal bucco-lingually in the gingival region of the alveolar crest as seen in the 3-D CBCT- based cross-sectional slice in Figure 2b, and the eminentbuccalconcavityinthealveolarcrestasseen in the 3DVR in Figure 3a, the following alveolar bone surgical approaches were considered in preparation for the implants-supported FPD treatment option: 3a)Avarietyoftechniquesandmaterialsareused toexpandthebuccal-lingualdimensionofthealveo- lar crest support for dental implants. Alveolar crest augmentation techniques include several surgical approaches, such as onlay grafting and ridge split- ting, to name a few. In this particular case, in order to gain an increase in the buccal-lingual dimension ofthealveolarcrest,aboneridgesplittingtechnique was considered.4 3b) A different technique used to achieve the buccal-lingual dimension necessary to support den- tal implants is to flatten the alveolar crest. This technique is also referred to as “tabling” the alveolar crest. However, due to the very slim knife-edge alveolar crest, considerable vertical tabling will be necessitated. Following an interdisciplinary professional con- sult between the restoring dentist and the oral surgeon, a decision was made to consider tabling of the alveolar crest in the middle region where teeth #24 and #25 used to be. This surgical approach would increase the buccal-lingual dimension of the alveolar crest and allow placement of two implants- supported four-unit fixed partial denture. As seen in Figure 4, a computer-generated im- age represents a four-unit fixed partial denture supported by two implants. This surgical approach would prevent the tabling of the alveolar crest in the regions close to teeth #22 and #27, avoiding future supporting bone loss, thus significantly improving their long-term life span. _Conclusions The specific goal of this case report was to review thenotionofremovablepartialdenturevs.fixedpar- Fig. 3