Abstract：
OBJECTIVE: To evaluate clasp-retained removable partial dentures (C-RPDs) with a metal framework for survival, maintenance requirements, and biological implications.
METHODS: C-RPDs were retrospectively analyzed based on patient records. Treatment failure was defined as fracture of a framework component (metal base or connector) or loss of an abutment tooth. Other outcome variables included factors that might conceivably impact C-RPD survival (maxilla vs. mandible, Kennedy classes, opposing dentitions, treatment by students vs. certified dentists), mobility and caries of abutment teeth (in relation to clasp designs), and maintenance requirements (relining, clasp or resin fractures). Differences were evaluated by appropriate statistical tests at the P ≤ .05 level.
RESULTS: A total of 612 patients (339 men, 273 women) 60.0 ± 11.5 years old at delivery were included, covering 842 C-RPDs and a mean observation period of 42.1 ± 33.2 months. Kaplan-Meier C-RPD survival was 76.2% after 5 years and 49.5% after 10 years. Biological complications (i.e. loss of abutment teeth) accounted for the vast majority (95.6%) of C-RPDs failures, and Kaplan-Meier C-RPD survival was significantly better in the mandible (P = .015). Some clasp designs contributed significantly to caries and removal of abutment teeth (both P < .05). No other significant differences were noted.
CONCLUSIONS: Tooth loss both emerges as the main cause of C-RPDs failure and might be amenable to careful selection of clasp designs. Overall, better C-RPD survival should be expected in the mandible. A non-contributory role of Kennedy classes and opposing dentitions is tentatively suggested based on numerically heterogeneous subgroups.
METHODS: C-RPDs were retrospectively analyzed based on patient records. Treatment failure was defined as fracture of a framework component (metal base or connector) or loss of an abutment tooth. Other outcome variables included factors that might conceivably impact C-RPD survival (maxilla vs. mandible, Kennedy classes, opposing dentitions, treatment by students vs. certified dentists), mobility and caries of abutment teeth (in relation to clasp designs), and maintenance requirements (relining, clasp or resin fractures). Differences were evaluated by appropriate statistical tests at the P ≤ .05 level.
RESULTS: A total of 612 patients (339 men, 273 women) 60.0 ± 11.5 years old at delivery were included, covering 842 C-RPDs and a mean observation period of 42.1 ± 33.2 months. Kaplan-Meier C-RPD survival was 76.2% after 5 years and 49.5% after 10 years. Biological complications (i.e. loss of abutment teeth) accounted for the vast majority (95.6%) of C-RPDs failures, and Kaplan-Meier C-RPD survival was significantly better in the mandible (P = .015). Some clasp designs contributed significantly to caries and removal of abutment teeth (both P < .05). No other significant differences were noted.
CONCLUSIONS: Tooth loss both emerges as the main cause of C-RPDs failure and might be amenable to careful selection of clasp designs. Overall, better C-RPD survival should be expected in the mandible. A non-contributory role of Kennedy classes and opposing dentitions is tentatively suggested based on numerically heterogeneous subgroups.
摘要：
目的：为了评估具有金属框架的扣环保留的可摘局部义齿（C-RPDs）的生存，维护要求,和生物学意义。
方法：根据患者记录对C-RPDs进行回顾性分析。治疗失败定义为框架组件（金属底座或连接器）的断裂或基牙的丢失。其他结果变量包括可能影响C-RPD生存率的因素(上颌骨与下颌骨,肯尼迪班，相反的牙列，由学生与治疗认证牙医)，基牙的活动性和龋齿（与搭扣设计有关），和维护要求(重新衬砌，扣环或树脂断裂)。在P≤0.05水平下通过适当的统计检验评估差异。
结果：共有612名患者（339名男性，273名妇女）包括分娩时60.0±11.5岁，涵盖842个C-RPDs，平均观察期为42.1±33.2个月。Kaplan-MeierC-RPD5年生存率为76.2%，10年生存率为49.5%。生物并发症（即基牙脱落）占C-RPDs失败的绝大多数（95.6％），下颌骨的Kaplan-MeierC-RPD生存率明显优于下颌骨（P=0.015）。一些扣环设计显著有助于龋齿和基牙的去除（两者P<0.05）。没有注意到其他显著差异。
结论：牙齿丢失都是C-RPDs失败的主要原因，并且可能需要仔细选择表扣设计。总的来说,下颌骨的C-RPD生存率较高。基于数字异构的子组，初步建议肯尼迪类和相对牙列的非贡献作用。
方法：根据患者记录对C-RPDs进行回顾性分析。治疗失败定义为框架组件（金属底座或连接器）的断裂或基牙的丢失。其他结果变量包括可能影响C-RPD生存率的因素(上颌骨与下颌骨,肯尼迪班，相反的牙列，由学生与治疗认证牙医)，基牙的活动性和龋齿（与搭扣设计有关），和维护要求(重新衬砌，扣环或树脂断裂)。在P≤0.05水平下通过适当的统计检验评估差异。
结果：共有612名患者（339名男性，273名妇女）包括分娩时60.0±11.5岁，涵盖842个C-RPDs，平均观察期为42.1±33.2个月。Kaplan-MeierC-RPD5年生存率为76.2%，10年生存率为49.5%。生物并发症（即基牙脱落）占C-RPDs失败的绝大多数（95.6％），下颌骨的Kaplan-MeierC-RPD生存率明显优于下颌骨（P=0.015）。一些扣环设计显著有助于龋齿和基牙的去除（两者P<0.05）。没有注意到其他显著差异。
结论：牙齿丢失都是C-RPDs失败的主要原因，并且可能需要仔细选择表扣设计。总的来说,下颌骨的C-RPD生存率较高。基于数字异构的子组，初步建议肯尼迪类和相对牙列的非贡献作用。
