Rate to remaking of CAD/CAM Produced Composite Resin Crowns.

Objectives: CAD/CAM produced composite resin crowns (CAD/CAM crown) for premolar and lower first molar are used in daily clinical practice in Japan due to the medical insurance system. Some case indicated remaking of the CAD/CAM crown in a short time after placement. The purpose of this study was to investigate by the questionnaire to the dental technical factory about the rate to remaking of the CAD/CAM crowns.
Methods: Questionnaire to the dental technical factory was carried out to investigate of remaking of CAD/CAM crowns. The contents of the investigation were the number of the setting of CAD/CAM crown from April 2014 to February 2019 and the number of remaking of CAD/CAM crown. Remaking number were analyzed statistically using logistic regression analysis to estimate the odds rates and 95% confidence interval for the association between the premolar crowns and the molar crowns.
Results: Total remaking rate was found to be 2.4%. For premolar CAD/CAM crowns, 190 case of 7930 case were remake. The remaking rate of premolar CAD/CAM crowns was 2.4%. For lower first molar CAD/CAM crowns were 4 case of 196 case were remake. The remaking rate of molar CAD/CAM crowns was 2.0%. The reasons for remaking were damage and poor fit. As results of logistic regression analysis, the premolar CAD/CAM crowns and lower first molar CAD/CAM crowns were not significantly different with regard to rate to remaking.
Conclusions: This study suggests that the crown can be used clinically. Many dental clinic newly started to use CAD/CAM crowns in their daily treatment and diffusion is still on the way.
In the future, it is desired to improve the material strength and color in expanding the application to upper first molars or anterior teeth.