An intraindividual clinical comparison of 2 metal-ceramic systems

Purpose: It has been questioned whether the surface and color of the cerami c and the metal-ceramic bond strength of a titanium-ceramic system are comp arable to those of a conventional noble alloy-ceramic system. It was theref ore the aim of this study to carry out an intraindividual clinical comparis on between crowns fabricated according to the Procera system (titanium copi ngs veneered with a low-fusing ceramic) and noble-alloy copings veneered wi th a medium-fusing ceramic. Materials and Methods: Twenty-one crown pairs w ere fabricated for eighteen patients; three of the patients were each provi ded with two crown pairs. After 2 years nineteen crown pairs in sixteen pat ients could be compared. Clinical examinations were performed by two calibr ated dentists who are long experienced in prosthetic dentistry. The crowns were rated according to the California Dental Association system. In additi on, Bleeding Index and Margin Index were evaluated. Results: After 2 years the quality of surface and color of the ceramic material seemed to have det eriorated more in titanium-ceramic crowns than in conventional metal-cerami c crowns, although the difference was not statistically significant. Regard ing anatomic form, margin integrity, Bleeding Index, and Margin Index the d ifferences between the two crown systems were small. Conclusion: The low-fu sing ceramics have been subject to improvements during the last few years. Their bond strength to titanium seems to be comparable to that of conventio nal metal-ceramic systems. However, in the long run one problem may be the surface and color stability of low-fusing ceramics. To make extended long-t erm comparisons between the two metal-ceramic systems possible the present patient material will be followed for a longer period than the current 2 ye ars.