Xu Liya, Hu Jun, Chen Xinmin, Ma Yannan, Yang Yan
Department of Prosthodontics, School of Stomatology, Sichuan University, Chengdu 610041, China.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2006 Apr;23(2):329-33.
Fifty-four simulated tooth roots made of polymethacrylate (PMMA) were divided into six groups according to the root canal convergence angles of 0 degrees, 3.93 degrees, 5.71 degrees, 7.48 degrees, 11.31 degrees, 14.71 degrees. Cast post and cores were manufactured and cemented with Zinc phosphate cement (ZP). The retention capacities of the posts were tested. The bonding strength of ZP at different convergence angles were tested with some casted wafers, and linear regression was made. So the effect of interlocking and the proportion could be calculated. With these results, we made some curvilinear regressions. The results showed that the retention of cast post declined and the bonding strength of ZP fell with the increase of convergence angles. There were significant differences in the bonding strength and retention among groups, P<0.05. The experiment indicates that the dentists should reduce the convergence angles of posts as much as possible to obtain greater retention.
将54个由聚甲基丙烯酸甲酯（PMMA）制成的模拟牙根根据根管汇聚角度分为六组，角度分别为0度、3.93度、5.71度、7.48度、11.31度、14.71度。制作铸造桩核并用磷酸锌水门汀（ZP）粘结。测试桩的固位能力。用一些铸造薄片测试不同汇聚角度下ZP的粘结强度，并进行线性回归。这样就可以计算出嵌合效果和比例。根据这些结果，我们进行了一些曲线回归。结果表明，随着汇聚角度的增加，铸造桩的固位力下降，ZP的粘结强度降低。各组之间的粘结强度和固位力存在显著差异，P<0.05。该实验表明，牙医应尽可能减小桩的汇聚角度以获得更大的固位力。
