复合树脂充填体受不同方向力时固位差异分析

摘要

目的:通过对试件复合树脂块施不同角度的力,了解不同施力角度与树脂块的抗力值,指导临床备出较为科学的洞形结构,使复合树脂充填体达到最佳的固位效果.方法:在离体牙上磨出垂直于牙体长轴的平面,在平面牙釉质上堆砌成边长为2.5mm的正方形复合树脂块,以磨制离体牙平面为基准施于不同角度的力,分别记录每个试件树脂块松动时的抗力值.结果:施力角度在0°、30°、45°、60°、90°的各组试件中,抗力值分别为5.95±0.10、8.63±0.82、9.06±1.01、12.55±1.25、19.68±1.74(P＜ 0.05).结论:复合树脂块抗水平J的能力较弱,抗垂直向的能力较强.故临床备洞时,选用把树脂修复体受的水平力转化成垂直向力的洞型,如鸠尾、固位沟、侧翼等传统的固位结构,仍是复合树脂充填牙体时理想的选择.%Objective:To investigate the relationship between shear adhesive strength and force angle of application,showing that good retention results of composite resin are producing from good cavity form for dental restoration with composite resin.Methods:Grinded surfaces vertical to the long axis of the teeth were fabricated from teeth in vitro and then square composite resins with side length 2.5 mm were produced on the surfaces.And force with different angles were applied to the composite resins and then their shear strength were recorded.Results:Shear strength are 5.95±0.42、8.63±0.82、9.06± 1.01、12.55± 1.25 and 19.68± 1.74 corresponding to angle of application of 0°、30°、45°、60°、90°,showing that shear strength of the composite resin is increasing when angle of application variable from lateral to vertical.The analysis method including one-way ANOVA analysis and independent-sample T test.Conclusion:Shear strength of composite is larger in vertical then in lateral.For cavity preparation in clinical practice,cavity forms that can convert lateral force into vertical,such as dovetail,retention groove and flange,are the preferred selection for composite resin.