漂白处理对树脂充填体边缘微渗漏的影响

目的:评价35%过氧化氢凝胶对树脂充填体边缘微渗漏的影响。方法:选择离体上颌第三磨牙40颗,在颊面制备Ⅴ类洞复合树脂分层充填,光照固化抛光后按处理时间随机分为4组(n=10):A(对照组)、B(10 min)、C(20 min)、D(30min)。将凝胶涂布于充填体表面进行漂白处理后冷热循环500次,再用2%亚甲蓝溶液染色24 h,沿颊舌纵向剖开,体式显微镜观察并记录染料渗入深度。用Kruskal-Wallis法进行数据分析;Mann-Whitney法组间两两比较,检验水准均为α=0.05。结果:不同漂白处理时间对树脂充填体边缘微渗漏的影响有统计学意义(P<0.05);组间比较显示A与C、A与D、B与D、C与D间差异有统计学意义。结论:35%过氧化氢凝胶漂白处理使复合树脂充填体的边缘微渗漏程度增加。

The effect of bleaching on microleakage of composite resin

Objective: To study the effect of the 35% hydrogen peroxide gel on the marginal microleakage of composite resin.Methods: Class V cavity on the buccal surface were prepared on 40 extracted maxillary third molars and restored with composite resin.According to bleaching time all the samples were divided into 4 groups at random(n=10): A(control group),B(10 min),C(20 min) and D(30 min).Bleaching gel was smeared on the surface of the resin in the teeth.The bleaching was continued for predetermined times in the groups.After that,all the samples were thermo-cycled at 5 ℃ and 55 ℃ for 500 times.Then the teeth were immersed in 2% methylene blue solution for 24 hours,specimens were prepared and observed under stereomicroscopy.The data were analyzed by Kruskal-Wallis test(α=0.05).Results: Higher grade of microleakage was observed in the groups with longer bleaching time.Two-by-two comparison of the groups demonstrated significant differences between A and D,B and D,C and D.Conclusion: Bleaching by 35% hydrogen peroxide may increase the marginal microleakage of the composite resin.