缩醛树脂卡环固位力与基牙倒凹深度的关系

Relationship between retentive force of acetal resin clasp and depth of abutment undercut

目的:观察缩醛树脂卡环在反复脱位循环过程中固位力的变化趋势,探讨最佳临床固位效果时缩醛树脂卡环的适宜倒凹深度和横截面直径。方法:使用电子万能材料试验机,测试临床常用缩醛树酯-钻铬合金联合三臂卡,检测前磨牙0.50、0.75和1.00mm 3个倒凹深度和1.20和2.00mm 2个横截面直径的缩醛树脂卡环在2 880次脱位循环中固位力的变化。结果:倒凹深度越大,缩醛树脂卡环固位力也越大;横截面直径越大,缩醛树脂卡环固位力亦越大;缩醛树脂卡环固位力随脱戴次数增加而减小,且不同倒凹深度的固位力衰减率之间差异有统计学意义(P<0.05)。结论:缩醛树脂前磨牙卡环放置以横截面直径2.00mm、进入倒凹深度0.75mm为宜。

Objective To study the changes of retentive force during the circulation of the acetal resin clasp dislodging and inserting and discuss the proper depth of the abutment undercut and cross-section diameter of the acetal resin clasp.Methods The instron force measuring instrument was used to record the variation of the retentive force of acetal resin and Co-Cr alloy casting akers clasp when they were dislodging 2 880 times from abutment undercuts of different depths（0.50,0.75,and 1.00 mm） and different diameters of the acetal resin clasp（1.20 and 2.00 mm） on bicuspid.Results The variations of the retention in the measurement were aceording to different undercut depths and different diameters.The value of acetal resin clasp’s retentive force became larger with the increasing of the diameter of cross-section of the clasp and the depth of abutment undercut（P〈0.05）.Conclusion The acetal resin clasp of 2.00 mm diameter and the abutment undercut with 0.75 mm are suitable for bicuspid.