Strength of Porcelain Fused to Titanium Crown Made by CAD/CAM

Objectives: This study investigated the bond strength between porcelain and machined pure titanium, and fracture strength of porcelain fuse to metal crown with machined pure titanium frame. Methods: The crowns were made assuming a maxillary left central tooth. As controls, same type samples made by cast pure titanium were also examined. Machined samples were made by a CAD/CAM system (GN-1, GC, Japan) and casting samples were made using a dental argon arc casting unit (Castmatic, Iwatani, Japan). Commercial porcelain for titanium (VITA-Titankeramik, VITA, Germany) was applied to the specimens. The bond strengths were evaluated using a three-point bend test according to ISO9693 standard. The fracture strengths of porcelain fused to pure titanium crowns were evaluated by applying a static load at the incisal edge of the crowns. Results were analyzed using a paired t-test (a=0.05). Results: The mean bond strength for the machined samples was 36.1(± 3.4) MPa, and those for the cast samples was 36.2(± 2.3) MPa. The mean fracture strength for the machined samples was 1554(± 296) MPa, and those for the cast samples was 1667(± 204) MPa.There were no significant difference between the machined samples and the cast samples in the bond strength and in the fracture strength. The bond strengths for the both methods were above the minimum value specified in ISO9693 (25MPa). The fracture strength for the both methods exhibited almost same values compared to those for the porcelain fuse to gold alloy crowns determined in our previous study. Conclusion: It can be concluded that the both methods for pure titanium have acceptable bond strength to the porcelain and fracture strength of porcelain fuse to metal crown.