CAD/CAM international magazine of digital dentistry

case report _ restoration of edentulous maxilla I I 21CAD/CAM 3_2012 from tilting. Which of these two connection types is to be preferred, however, seems unclear. Implants supporting telescopic crowns exhibit a reduced sul- cusfluidrate,whichisinterpretedasasignofaslight inflammation of the periimplant tissues. This, how- ever, as Eitner and his colleagues showed, does not lead to a reduced rate of implant loss in comparison with implant-supported bars, even over a longer pe- riod. Bar-retained, implant-supported superstruc- tures, on the other hand, are significantly less prone torepair,withtheresultthat,accordingtothework- ingpartyunderEitner,noalternativerestorationcan be identified as to be preferred. In each case, follow- ingextensivetreatment,thepatienttreatedexpects— forhim,fromafinancialand,aboveall,anemotional point of view—a substantially uncomplicated, me- chanically “maintenance-free” rehabilitation. In this respect, restoration using a bar-retained, removable superstructureresemblingabridgeis,forus,thefirst choice.Asamatterofprinciple,weincludetwointer- locking mechanisms to improve the wearing com- fort. This prevents a reduction in the retention of theremovableunitcausedbyabrasion.Furthermore, theinterlockinggivesthepatienttheimportantfeel- ing of confidence, since unwanted loosening of the restoration is precluded. _Materials Individually milled bars are usually cast in a chrome-cobalt or gold alloy. A recent option is the central CAD/CAM fabrication of virtually designed bar constructions in accordance to a model scan. This fabrication variant has numerous advantages: on the one hand, the tension-free fit of the bar on the implants is not affected by the shrinkage of the metalcausedbycooling.Ontheotherhand,itispos- sible to manufacture the bar from titanium, which may result in a reduction in gingival inflammation (Abd El-Dayem et al., 2009), since there is a better attachmentofthetissueshere.TheteamunderAbd El-Dayem further concludes that both advantages together, the absolutely tension-free fit of the bar and the material itself, could lead to even less peri- implant bone resorption, which further improves the long-term prognosis. _Case presentation A 73-year-old woman, a non-smoker with an unremarkable medical history, was given six im- plants with two milled bars as anchoring elements. Five XiVE S plus implants were inserted during a si- multaneous sinus floor elevation and were allowed to heal submerged over six months. When the im- plant was uncovered, a vestibular graft was per- formedwithanapicaltranspositionflap.Duetothe less favorable bone volume in region 16, an addi- tional XiVE TG plus implant was inserted subse- quently for the purposes of the procedure and was immediately loaded (Fig. 1). The impression for the fabrication of the CAD/CAM bars was made four weeks later on the MP abutments inserted during this consultation (Figs. 2 and 3). Fig. 5_Working model with bars, bar slides, tertiary structure and inserted slides. Fig. 6_Titanium bars in situ. Fig. 7_The metal base was cemented intraorally. Fig. 8_The finished tertiary structure with open slides. Fig. 4c Fig. 4d Fig. 5 Fig. 7 Fig. 8Fig. 6