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IM0410

I research _ implant fracture Figs. 1a & b_Implants #6 and #7 (Lifecore Biomedical, 3.3 mm x 15 mm) before (A) and after the fracture (B). Figs. 2a & b_Retrospective analysis of the site planned for the implants #6 and #7 (A) revealed an extended overbite, requiring long crowns (B) to meet esthetic needs, and at the same time, the opposing occlusion pre- sented extensive occlusal wear. _The etiology and physical mechanism of frac- tured dental implants phenomenon have been re- viewed and studied at length in recent years.1–8 For the most part, the studies concluded that the crown-to- root ratio guidelines associated with natural teeth should not be applied to a crown-to-implant restora- tions ratio. According to these studies, the crown-to- implant ratios of those implants that were considered successfulatthetimethereviewstookplaceweresim- ilartothoseimplantsthatfailed.Apparently,according tosomeofthesestudies,theguidelinesthatareusedby someclinicianstoestablishthefutureprognosisofim- plant supported restorations are usually empirical and lackscientificvalidationasfarasthepossiblecausesfor implant fractures. However, as oral implantology has beenthefastestgrowingsegmentindentistry,thegain- ingofinsightintothesefailureprocesses,includingthe accurateunderstandingofcriticalanatomical,restora- tive and mechanical information, might stimulate the clinicians’ implementation of preventive action that mayavoidthefuturefracturesoutcomewithdentalim- plants. _Case report A72-year-oldCaucasianmalerecentlypresentedto ourclinic.Consistentwiththepatient’schiefcomplaint, a comprehensive oral and maxillofacial examination, including full-mouth X-rays, revealed, among other things, two fractured endosseous implants #6 and #7 (Fig.1). These 3.3 mm x 15 mm implants (Lifecore Biomed- ical, Chaska, Minn.) were placed and restored in 2003. Theimplantswereplacedasperprotocol,utilizingasur- gical template consisting of two guiding sleeves (De- Plaque,Victor,N.Y.).Theimplantswereallowedtointe- grate for six months. No surgical complications were noted during this time. At the conclusion of the six- month waiting period, the implants were uncovered in thenormalmannerandhealingabutmentsplaced. The implants were subsequently restored with im- plant-supported crowns that were functional for ap- proximatelysixyearsuntiltheimplantsfractured.While thistreatmentoptionwasdevelopedwithanapprecia- tion of the patient’s occlusal and mechanical circum- stances and habits, following the implants’ fracture, a retrospective analysis of the site planned for the im- plantsrevealedextendedinter-occlusalspaceonthear- ticulated models and widespread occlusal wear of the opposingdentition(Fig.2). Implant fracture: A look at the physical mechanisms for failure Authors_Dr Dov M. Almog, Dr Odalys Hector, Dr Samuel Melcer, Dr Kenneth Cheng, USA 12 I implants4_2010 Fig. 2a Fig. 2bFig. 1a Fig. 1b