Fitting accuracy and fracture resistance of crowns using a hybrid zirconia frame made of both porous and dense zirconia.
The purpose of this study is to evaluate the fitting accuracy and fracture resistance of crowns using a hybrid zirconia frame made of both porous and dense zirconia. Commercial semi-sintered zirconia, sintered dense zirconia and sintered hybrid zirconia were used. Sintered zirconia was milled using the CAD/CAM system, and semi-sintered zirconia was milled and sintered to fabricate molar crown frames. Completed frames were veneered with tooth-colored porcelain. The marginal and internal gaps between frames/crowns and abutments were measured. Each crown specimen was subjected to a fracture test. There were no significant differences in marginal and internal gap among all the frames and crowns. The crown with the hybrid zirconia frame had a 31-35% greater fracture load than that with the commercial or dense zirconia frame (p<0.01). This suggests that the all-ceramic crowns with a hybrid zirconia frame have a high fracture resistance.
Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry.
Takashi
T
Nakamura
Tsuyoshi
T
Sugano
Hirofumi
H
Usami
Kazumichi
K
Wakabayashi
Hiroshi
H
Ohnishi
Tohru
T
Sekino
Hirofumi
H
Yatani
D017076:Computer-Aided Design; D003442:Crowns; D003764:Dental Materials / Q000737:chemistry*; D017268:Dental Prosthesis Retention / Q000592:standards*; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D006801:Humans; D015040:Zirconium / Q000737:chemistry*
D003764:Dental Materials; D015040:Zirconium; C028541:zirconium oxide