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[A 5-year retrospective study of computer aided design and computer aided manufacturing ceramic endocrowns in endodontically treated posterior teeth].

Objective: To evaluate the clinical outcomes of computer aided design and computer aided manufacturing (CAD/CAM) ceramic endocrowns in endodontically treated posterior teeth after five years by a retrospective study. Methods: Patients who received CAD/CAM ceramic endocrowns after endodontically treatment in Department of Endodontics, School of Stomatology, The Fourth Military Medical University between January 2016 and June 2017 were invited for this clinical study. Clinical performance was evaluated in the aspect of color match, anatomic form,marginal adaptation, restoration integrity and secondary caries. Survival rate of the restorations was calculated by the use of Kaplan-Meier method. Log-rank test was applied as well for the sake of analyzing the effect of tooth position, sex and materials to the survival rate of the restorations. Results: Seventy-four patients, 25 men and 49 women with age of (38.8±10.2) years, participated in this study for a total of 101 CAD/CAM ceramic endocrowns after observation period of (62.8±12.0) months. There were 8 failed cases among 101 restorations, 5 were loss of retention, 2 were ceramic fracture and 1 was secondary caries respectively. In particular, 93% (89/96) restorations got score A on anatomic form and 95% (91/96) restorations got score A on marginal adaptation, while 38% (36/96) restorations showed the good color match compared with the abutment teeth. The estimated cumulative survival rate of CAD/CAM ceramic endocrowns in endodontically treated posterior teeth after 5 years was 93.0% (95%CI: 87.9%-98.1%). The single-factor Log-rank analysis demonstrated that there was no statistically significant difference in the survival rate of CAD/CAM ceramic endocrowns among men and women, premolars and molars, position in the dental arch, or different materials (χ²<0.01, P=0.957; χ²=0.64, P=0.422; χ²=0.69, P=0.407; χ²=0.88, P=0.349). Conclusions: Based on this clinical study, the clinical performance of CAD/CAM ceramic endocrowns in endodontically treated posterior teeth after five years is reliable, which could be a general option to restore nonvital teeth.