纳米树脂直接修复离体切牙切角缺损后充填体边缘微渗漏研究

Study on microleakage of incisally fractured incisors restored with nanofilled composite resins

目的研究纳米树脂直接修复离体切牙切角缺损后充填体边缘微渗漏的情况。方法收集12颗完整离体切牙,用磨除法制备离体切牙近中2/3切角缺损模型。将12颗牙齿按大小相近的原则分为A、B两组,每组6颗。两组牙齿皆预备唇侧贴面及舌侧鸠尾,A组额外对切缘进行2 mm磨除。用纳米树脂对两组牙齿进行分层分色直接充填修复,冷热循环试验模拟口腔温度环境变化,染料渗透法检测微渗漏情况,并将两组进行对比。结果12颗牙齿模型中,除1颗未发生微渗漏外,其余11颗皆发生了不同程度的微渗漏,其中1颗出现染料渗入达髓轴壁的现象。两组微渗漏情况差异无统计学意义。结论纳米树脂直接修复离体切牙切角缺损后仍然不能完全避免微渗漏的发生;切端是否磨除对微渗漏无明显影响。

Objective To evaluate microleakage of incisally fractured incisors restored with nanofilled composite resins.Methods Twelve previously extracted incisors were assigned to two groups （A and B） equally according to the size of tooth.The teeth were cut obliquely from the mesial incisal angle to simulate uncomplicated tooth fracture.Labial reduction of 0.5mm and dovetails in the lingual surfaces were prepared.Additional 2mm of the incisal edge were cut horizontally in group A.The teeth in both groups were restored with nanofilled composite resins using a multilayer technique.Thermal and mechanical cycling was used to simulate oral temperature and aging effect.Level of microleakage was assessed.Statistical analyses were conducted between the two groups.Results Eleven of the twelve samples revealed microleakage,and one case had the leakage up to the medullary shaft wall.Difference between the two groups revealed no statistical significance.Conclusion According to the results of this study,microleakage still exists when using nanofilled composite resins to restore incisally fractured incisors.Whether to reduce 2mm of incisal edge or not does not affect level of microleakage.