Department of Prosthodontics and Periodontics, Piracicaba Dental School, State University of Campinas (UNICAMP), Piracicaba, SP, Brazil.
J Biomech. 2013 Apr 26;46(7):1358-62. doi: 10.1016/j.jbiomech.2013.01.023. Epub 2013 Mar 7.
The aim of this study was to evaluate the effect of the prosthesis material (metal-acrylic resin or metal-ceramic) on loosening torque of the prosthetic screws in an implant-supported mandibular denture under two levels of vertical misfit. Ten frameworks were fabricated with commercially pure titanium, and five of them received acrylic resin and acrylic artificial teeth as veneering material and the other five were veneered with porcelain. Two levels of vertical fit were also created by fabricating 20 cast models to obtain four experimental groups according to the prosthesis material and misfit: Group 1 (metal-acrylic resin prosthesis with a passive fit); Group 2 (metal-acrylic resin prosthesis with a non-passive fit); Group 3 (metal-ceramic prosthesis with a passive fit); and Group 4 (metal-ceramic prosthesis with a non-passive fit). Two hundred prosthetic titanium-alloy screws were divided in 40 sets (five screws per set, n=10). After 24h, the loosening torque of the screws was evaluated using a digital torque meter. The results were submitted to two-way ANOVA analysis of variance followed by a Tukey's test (α=0.05). The mean values and standard deviations for each group were G1=7.05 (1.64), G2=5.52 (0.90), G3=6.46 (1.34), and G4=4.35 (0.99). Overall, the prosthesis material and misfit factors showed a statistically significant influence on the loosening torque (p<0.05). Metal-ceramic prosthesis and misfits decreased the loosening of the torque of the prosthetic screws.
本研究旨在评估在两种不同的垂直不匹配程度下，义齿基托下种植体支持式下颌总义齿中修复体材料（金属-丙烯酸树脂或金属-陶瓷）对修复体螺丝松动扭矩的影响。制作了 10 个商业纯钛框架，其中 5 个用丙烯酸树脂和丙烯酸人工牙作为贴面材料，另外 5 个用瓷贴面。通过制作 20 个铸造模型来制造两种不同的垂直拟合程度，从而根据修复体材料和不匹配程度创建了四个实验组：第 1 组（具有被动拟合的金属-丙烯酸树脂修复体）；第 2 组（具有非被动拟合的金属-丙烯酸树脂修复体）；第 3 组（具有被动拟合的金属-陶瓷修复体）；第 4 组（具有非被动拟合的金属-陶瓷修复体）。200 个钛合金修复体螺丝被分为 40 组（每组 5 个螺丝，n=10）。24 小时后，使用数字扭矩计评估螺丝的松动扭矩。结果采用双向方差分析（ANOVA），随后进行 Tukey 检验（α=0.05）。每个组的平均值和标准差分别为 G1=7.05（1.64）、G2=5.52（0.90）、G3=6.46（1.34）和 G4=4.35（0.99）。总体而言，修复体材料和不匹配因素对螺丝松动扭矩有统计学显著影响（p<0.05）。金属-陶瓷修复体和不匹配程度降低了修复体螺丝松动的扭矩。
