Metal-ceramic partial fixed dentures: a retrospective study

ABSTRACT Objective Metal-ceramic prosthesis are the treatment of choice in oral rehabilitation because of their high survival rates. However, there are few reports in the scientific literature about factors that lead to fractures of metal-ceramic prostheses. The aim of this study was to evaluate whether prostheses units number, abutment type and number, type of the prostheses, prostheses position in the mouth, bruxism and occlusal plaque influence the incidence of fractures in fixed metal-ceramic prostheses. Methods For this study, 16 patients were selected, totaling 74 metal-ceramic prostheses installed between 2000-2010, with follow up of at least four years. Besides dental history, other information was collected, such as patients’ gender and age, prostheses installation date, and the ceramic system used. In case of prostheses fracture, a questionnaire was applied to identify signs of bruxism. A clinical evaluation was done to evaluate the prostheses integrity and opposing dentition characteristics. Success, failure and survival rates were determined. Results The results showed that the success rate of metal-ceramic prostheses was 87.8% and the survival rate was 89.1%. In addition, the success rate was independent of patient age, prostheses installation time, number of prosthesis, number of prosthesis’ units and abutments. The qualitative variables also did not show significant statistical results between success and failure rates. Conclusion It was concluded that metal-ceramic prostheses have high success and survival rates, what guarantees longevity and indication of this type of prostheses in daily practice.

摘要
研究目的：金属烤瓷修复体（metal-ceramic prosthesis）因其高存活率而成为口腔修复的首选治疗方案。然而，当前科学文献中关于导致金属烤瓷修复体折裂的影响因素的报道较为匮乏。本研究旨在评估修复体单位数量、基牙类型与数量、修复体类型、修复体在口腔中的位置、磨牙症以及咬合菌斑是否会影响固定金属烤瓷修复体（fixed metal-ceramic prosthesis）的折裂发生率。

研究方法：本研究共纳入2000年至2010年间安装的74件金属烤瓷修复体，涉及16名患者，所有病例的随访时长均不少于四年。研究人员除收集患者的牙科病史外，还采集了患者性别、年龄、修复体安装日期以及所使用的陶瓷系统等信息。若出现修复体折裂情况，则通过问卷调查识别磨牙症相关体征。同时开展临床评估以检测修复体完整性及对颌牙列特征，并计算修复体的成功率、失败率与存活率。

研究结果：研究结果显示，金属烤瓷修复体的成功率为87.8%，存活率为89.1%。此外，成功率与患者年龄、修复体安装时间、修复体数量、修复体单位数及基牙数量均无显著相关性。定性变量在成功率与失败率之间也未呈现显著统计学差异。

研究结论：本研究结论表明，金属烤瓷修复体具备较高的成功率与存活率，这一结果证实了该类修复体的长期使用寿命与临床应用价值，可为日常临床诊疗提供可靠依据。