Shoko Miura1,2, Shinobu Yamauchi3, Shin Kasahara2, Yusuke Katsuda2, Masanori Fujisawa1, Hiroshi Egusa2. 1. Division of Fixed Prosthodontics, Department of Restorative & Biomaterials Sciences, Meikai University School of Dentistry, Sakado. 2. Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai. 3. Department of Biomaterials, Nihon University School of Dentistry at Matsudo.
Abstract
PURPOSE: The primary purpose of this study was to examine the clinical performance of monolithic zirconia single crowns in terms of short-term failure or complications. The secondary purpose was to detect the originating flaws of clinically failed monolithic zirconia crowns to find the causes of failure. METHODS: A short-term prospective cohort study based on record evaluation and clinical examination of patients treated with tooth-supported monolithic zirconia crowns was performed in the Department of Fixed Prosthodontics, Tohoku University Hospital, Japan. The crowns were prepared during the follow-up period from April 2014 to July 2018. The 3.5-year cumulative success and survival rates were set as primary endpoints. Fractures of the crown or fragments were inspected under a scanning electron microscope for descriptive fractography. RESULTS: During the study period, 40 monolithic zirconia crowns were placed. Four crowns experienced clinical complications, including: 1) fracture of the crown (two crowns), 2) abrasion of the crown (one crown), and 3) fracture of the antagonist tooth (one crown). The estimated Kaplan-Meier 3.5-year success and survival rates were 90.5% (95% confi dence interval [CI]: 73.1-97.1) and 92.8% (95% CI: 74.1-98.3), respectively. Fractography revealed that all fractures were initiated from the wear phase on the occlusal surface. CONCLUSIONS: The results of this study suggest that the molar application of monolithic zirconia crowns requires detailed attention to interocclusal clearance and the restoration of the antagonist tooth.
PURPOSE: The primary purpose of this study was to examine the clinical performance of monolithic zirconia single crowns in terms of short-term failure or complications. The secondary purpose was to detect the originating flaws of clinically failed monolithic zirconia crowns to find the causes of failure. METHODS: A short-term prospective cohort study based on record evaluation and clinical examination of patients treated with tooth-supported monolithic zirconia crowns was performed in the Department of Fixed Prosthodontics, Tohoku University Hospital, Japan. The crowns were prepared during the follow-up period from April 2014 to July 2018. The 3.5-year cumulative success and survival rates were set as primary endpoints. Fractures of the crown or fragments were inspected under a scanning electron microscope for descriptive fractography. RESULTS: During the study period, 40 monolithic zirconia crowns were placed. Four crowns experienced clinical complications, including: 1) fracture of the crown (two crowns), 2) abrasion of the crown (one crown), and 3) fracture of the antagonist tooth (one crown). The estimated Kaplan-Meier 3.5-year success and survival rates were 90.5% (95% confi dence interval [CI]: 73.1-97.1) and 92.8% (95% CI: 74.1-98.3), respectively. Fractography revealed that all fractures were initiated from the wear phase on the occlusal surface. CONCLUSIONS: The results of this study suggest that the molar application of monolithic zirconia crowns requires detailed attention to interocclusal clearance and the restoration of the antagonist tooth.
Entities:
Keywords:
CAD/CAM; Digital dentistry; Fractography; Risk factor; Y-TZP