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目的观察3种通用混合型复合树脂充填后,不同洞深和固化后不同时间对界面微渗漏的影响。方法取离体前磨牙和磨牙各75个,分别在颌面中央制备直径2 mm,洞深2 mm(前磨牙)和直径2 mm,洞深3 mm(磨牙)的Ⅰ类洞,用随机数字法将两种洞深的样本各分别分为3组,分别用Chalisma复合树脂、Spectrum TPH光固化树脂、Esthet-X复合树脂充填,于光照固化后10 min、30 min、1 h、24 h和48 h,各时间点分别随机抽取各组5个样本,通过充填体矢状方向切开,50%避光氨化硝酸银液浸泡显影,体视显微镜下用测微软件测量粘结界面微裂隙。结果3种通用型复合树脂充填不同洞深均出现微裂隙,固化30 min～24 h裂隙最大,随着洞深深度增加,微裂隙减小;不同时间微裂隙变化速度不同。结论固化30 min～24 h充填物脱落的可能性最大,建议固化后10 min内隔湿,24 h患侧保护性忌咀嚼;分层添加技术适用于较深的窝洞。
Objective To observe the effect of three kinds of universal mixed composite resin on the microleakage of interface after filling at different depths and different time after curing. Methods Seventy-five premolar and molars were excised, respectively. A class I hole with a diameter of 2 mm, a depth of 2 mm (premolar) and a diameter of 2 mm and a depth of 3 mm (molar) was prepared at the center of the maxillofacial region. The samples were divided into three groups by the method of Chalisma composite resin, Spectrum TPH light-cured resin and Esthet-X composite resin, respectively. After curing for 10 min, 30 min, 1 h, 24 h and 48 hours. Five samples of each group were randomly selected at each time point. The samples were cut in the sagittal direction of the filling body and immersed in 50% dark silver nitrate solution for visualization. The micro-cracks . Results The microcracks appeared in different depths of the three kinds of general-purpose composite resins, and the fractures were the largest at 30 min-24 h after solidification. The microcracks decreased with the increase of the depth of the cavities. The velocity of microcracks changed at different times. CONCLUSION: It is most likely that the filling material will fall off within 30 min to 24 h after solidification. It is suggested that moisture should be separated within 10 min after curing and should not be chewed at 24 h. Stratified application is suitable for deeper cavities.