ABSTRACT
PURPOSE: The purpose of this study was to compare the fracture behavior of Zironia, glass infiltrated Alumina and PFM full crown system. MATERIALS AND METHODS: Fifteen crowns for each of 3 experimental groups (Zironia, glass infiltrated Alumina and PFM full crown) were made by the conventional method. The crowns mounted on the testing jig were inclined in 30 degrees to the long axis of the tooth and the universal testing machine was used to measure the fracture strength. RESULTS: 1. The mean fracture strengths were 588.3 +/- 49.6 MPa for zirconia system, 569.1 +/- 61.8 MPa for PFM system and 551.0 +/- 76.5 MPa for glass-infiltrated alumina system (P>.05). 2. The mean shear bond strengths were 25.5 +/- 5.6 MPa for zirconia system, 38.9 +/- 5.0 MPa for Ni-Cr alloy system and 39.4 +/- 5.1 MPa for glass-infiltrated alumina system. 3. The chemical bonding was observed at interfaces between PFM or glass-infiltrated alumina and veneering porcelain, however, no chemical bonding was observed at interface between zirconia and veneering porcelain. CONCLUSION: With the study, the fracture strengths of PFM crown system had a higher fracture strength than conventional zirconia system crown and glass-infiltrated alumina crowns. and than the shear bond strengths glass-infiltrated alumina system had a higher shear bond strength than conventional PFM system and zirconia system.