Clinical Performance of Ceramically Veneered Milled Titanium Crowns

Objectives: The alpha-case of cast titanium restorations influences the adhesion of ceramics negatively, but no alpha-case is produced on milled titanium. Therefore, it could be expected that ceramically veneered milled titanium crowns show less defects of the veneers. The aim of this study was to evaluate clinical failure rates of ceramically veneered milled titanium restorations after 12 months. Methods: 34 patients received 162 veneered units (29 incisors and 133 molars) according to a defined protocol. All the restorations were milled from grade 2 titanium (Everest, KaVo, Germany) and completely veneered with titanium ceramics (Vita-Titankeramik, VITA Zahnfabrik, Bad Säckingen, GC Initial Ti, GC Germany). Re-examination of the restorations was carried out using a standardised protocol. The study design comprises a baseline examination on the day of insertion and controls after 6, 12, 24 and 36 months. Results: All the patients returned to the 12 months reinvestigation. Therefore, it was possible to evaluate all the restorations. There were 14 defects (8.7%), one hairline crack (0.6%), 10 chippings inside the ceramics (6.2%) and 3 fractures with denudation of the metal (1.9%). There was no statistically significant difference between the two ceramics. Five restorations had to be redone until now. Conclusions: The failure rates of ceramically veneered titanium crowns are similar to those of pfm-crowns on high noble alloys. Just 3 of the 14 defects are a failure of the titanium-ceramic compound. Reasons for the defects inside the ceramic could be unsuitable size or design of the titanium substructure or insufficient mechanical properties of titanium ceramics.