Hofmann E, Behr M, Handel G
Dental Clinic, Department of Prosthetic Dentistry, University of Regensburg, Germany.
Clin Oral Investig. 2002 Jun;6(2):104-8. doi: 10.1007/s00784-002-0160-9.
The aim of this study was to evaluate the frequency of technical failure rates and the maintenance costs of clasp- or double crown-retained removable partial dentures (RPDs) (parallel-sided and conical double crowns).
According to three different retainer systems used between January 1992 to December 1998, three subgroups were randomly assigned from a group of 181 patients consisting of forty cases each. The average observation time was 4.2+/-1.7 years, with a minimum of 1.0 years and a maximum of 6.9 years. Technical complications such as fractures of the artificial teeth, loss of cementation, loss of facings as well as fractures of the metal framework and the soldering were recorded due to the medical reports.
Twenty percent of all clasp-retained dentures showed technical complications during the observation period, whereas 50% of conical crown-retained (CC) and 32.5% of the parallel-sided retained dentures (PS) required repair. Most often reported was loss of cementation for double crowns (n=13, 32.5% PS; n=8, 20% CC) and fractures of the clasps (n=5). Although clasp-retained dentures had a markedly lower frequency of failures (n=8) than double crown systems (n=31), the calculated repair costs per event during the observation time were more than twice as high for clasp-retained dentures (172.5 Euro) than for double crown systems (8-78 Euro). The hypothesis that the maintenance costs of the more sophisticated double crown system are higher must be rejected.
本研究旨在评估卡环或双冠固位可摘局部义齿（RPDs）（平行边双冠和锥形双冠）的技术失败率及维护成本。
根据1992年1月至1998年12月间使用的三种不同固位系统，从181例患者中随机分为三个亚组，每组40例。平均观察时间为4.2±1.7年，最短1.0年，最长6.9年。根据医疗报告记录人工牙折断、粘结剂脱落、饰面丢失以及金属支架和焊接处骨折等技术并发症。
在观察期内，所有卡环固位义齿中有20%出现技术并发症，而50%的锥形冠固位（CC）义齿和32.5%的平行边固位义齿（PS）需要修复。双冠最常报告的是粘结剂脱落（n = 13，32.5%PS；n = 8，20%CC）和卡环折断（n = 5）。尽管卡环固位义齿的失败频率（n = 8）明显低于双冠系统（n = 31），但在观察期内，卡环固位义齿每次事件的计算修复成本（172.5欧元）是双冠系统（8 - 78欧元）的两倍多。更复杂的双冠系统维护成本更高这一假设必须被否定。
