Prospective study of fixed CAD/CAM-titanium-ceramic restorations: 2-year results

Objectives: Cast-Titanium-Ceramic-Restorations (C-TCR) are a biocompatible and competitive alternative to fixed metal-ceramic-restorations from high-noble-alloys. In the past problems with defects of the porcelain veneers were reported. The aim of this prospective study was to evaluate the clinical performance of a new system for fixed CAD/CAM-Titanium-Ceramic-Restorations (CADCAM-TCR) after 24-months. Methods: 34 patients without parafunctions were treated with 159 units of CADCAM-TCR (EVEREST-system, KaVo, Leutkirch and VITA-Ti-Ceramic, VITA, Bad Säckingen, Germany) in various areas of the mouth. Patients were seen after delivering (baseline), 12 and 24 months. Quality of ceramic veneers, marginal fit, occlusion, periodontal parameters and patients' habits were recorded by two calibrated examiners. Ceramic-Defects (CD) were classified in 4 groups: I-scratch, II-crack, III-cohesive chipping, IV-adhesive chipping. Friedman- and Wilcoxon-signed-rank-tests were used for statistical analyses (p<0.05). Results: After 12 months all patients (159 units) were seen for follow-up. 14 CDs were recorded: I-1 (0.6%), III-10 (6.3%), IV-3 (1.9%). After 24 months 15 CDs were seen in 30 patients (135 units): I-2 (1.2%), III-10 (6.3%), IV-3 (1.9%). No group-III CD was found. Overall success-rate was 90.6%. Probing depth (1mm), plaque- (0.39) and bleeding index (0.43) decreased significantly. This is in accordance to other findings in fixed C-TCR. No restoration needed replacement. No decementation, loss of occlusal contact integrity, caries, tooth-fractures or endodontic complications occurred. Conclusion: After 2-years all followed-up restorations were in function. The success-rate of the tested CADCAM-TCR correlated with findings in C-TCR. 20% of the defects were caused by failings of the metal-ceramic-bonding-system. 80% of the fractures were cohesive fractures inside the porcelain veneer. Further studies should investigate whether the porcelain-system or the framework shape is responsible for the failures of ceramic veneers on milled Titanium-Ceramic-Restorations.