Department of Prosthetic Dentistry, University Medical Center Regensburg, Regensburg, Germany.
Gerodontology. 2012 Jun;29(2):e1125-8. doi: 10.1111/j.1741-2358.2010.00394.x. Epub 2010 Nov 5.
This retrospective study aimed to analyse the failure rate of the facings of double crown-retained dentures.
The clinical reports of 575 patients, who received double crown-retained removable dentures with a total of 1807 double crowns between 1984 and 2007, were included in the study. The 575 prostheses were attached to telescopic crowns using a friction fit (FF; n = 1999), conical crowns (CC; n = 61), or parallel-sided telescopic crowns with a clearance fit (CF; n = 315). Survival probabilities for the veneers were investigated using the Kaplan-Meier method; Cox regression analysis was carried out to determine the influence of the double crown used for retention, type of antagonist, and localisation.
Veneer failure occurred in 7.0% of FF, 27.9% of CC, and 4.4% of CF. The risk of veneer failure was 2.3 times higher for CC than for FF (p = 0.042); no significant differences were found between CF and FF (p = 0.363). No significant influences on the localisation of the denture (p = 0.534) or the type of antagonist (p = 0.341) were found.
CC-based double crowns have a higher risk of veneer failure than FF and CF, which may be due to high tensile stresses occurring in the cervical area of their outer copings.
本回顾性研究旨在分析双重冠修复可摘局部义齿饰面的失败率。
本研究纳入了 1984 年至 2007 年间接受双重冠修复可摘局部义齿的 575 名患者的临床报告，共涉及 1807 个双重冠。575 个义齿通过摩擦配合（FF；n=1999）、锥形冠（CC；n=61）或带间隙配合的平行侧伸缩冠（CF；n=315）与伸缩冠连接。采用 Kaplan-Meier 法研究饰面的存活率；采用 Cox 回归分析确定用于保留的双重冠、对颌牙类型和定位的影响。
FF、CC 和 CF 的饰面失败发生率分别为 7.0%、27.9%和 4.4%。CC 的饰面失败风险是 FF 的 2.3 倍（p=0.042）；CF 与 FF 之间无显著差异（p=0.363）。义齿定位（p=0.534）或对颌牙类型（p=0.341）对饰面失败无显著影响。
CC 基双重冠的饰面失败风险高于 FF 和 CF，这可能是由于其外冠颈缘区域出现高拉伸应力所致。
