Fracture strength of zirconia ceramic crowns according to tooth position / 대한치과보철학회지

ABSTRACT

PURPOSE: The purpose of this study was to compare the fracture strength of the zirconia ceramic crowns according to tooth position. MATERIAL AND METHODS: After 10 metal dies were made for each group, the zirconia ceramic crowns were fabricated using CAD/CAM system (Lava(TM) All-Ceramic System) and each crown was cemented on each metal die with resin cement (Rely X(TM) Unicem). The cemented zirconia ceramic crowns mounted on the testing jig were inclined with 30 degrees to the long axis of the tooth and the universal testing machine was used to measure the fracture strength. RESULTS: 1. The fracture strength of the zirconia ceramic crown in the lower 1st molar (2963 N) had the highest and that in the lower central incisor (1035 N) had the lowest. 2. The fracture strength of zirconia ceramic crown was higher than that of the IPS Empress crowns in all tooth position. 3. The fracture mode of the crowns was similar. Most of fracture lines began at the loading area and extended through proximal surface perpendicular to the long axis of the crowns. 4. There were no significant differences on the fracture strength of the zirconia ceramic crowns according to tooth position except in premolar group. CONCLUSION: Within the limitations of this study, the results suggested that strength of zirconia ceramic crown is satisfactory for clinical use.