On CAD/CAM generated fixed dental prostheses, fit and effect of ceramic veneering

Abstract

The general aims of this thesis were to study CAD/CAM production processes, material aspects on cobalt-chromium (CoCr), clinical performance, and fit of tooth-, and implant-supported fixed dental prostheses (FDPs). A retrospective study of ceramic veneered CoCr FDPs was conducted to evaluate the performance of restorations made with the lost wax technique. One hundred forty-nine patients with 201 FDPs were followed for five years by data collection from patient records. To study CAD/CAM techniques, the fit of tooth-supported CNC-milled CoCr three-unit FDPs, made using conventional or digital impression techniques, was compared. Also, the fit of implant-supported CNC-milled and additively manufactured CoCr and titanium FDPs was evaluated before and after ceramic veneering. CoCr FDPs are a promising alternative to other dental alloys, presenting a low level of ceramic fractures, cement failure, caries, and other complications during the first five years in function. To evaluate their longer-term success and possible biologic adverse effects, further long-term randomized controlled studies are necessary. The digital impression technique produced FDPs with a significantly more accurate fit than conventional impressions using VPS impression material. Implant-supported frameworks can be produced in either titanium or CoCr using either CNC-milling or additive manufacturing with a fit well within the range of what is regarded as clinically acceptable. The fit of frameworks of both materials and production techniques are affected by the ceramic veneering procedure to a small extent, most likely of no clinical significance.