三种分层充填方法对牙本质黏结强度的影响

Effect of layering technique of resin composite restorations on microtensile bond strength to dentin

目的:对比研究3种分层充填方法对牙本质黏结的微拉伸强度的影响。方法:选取因正畸需要拔除的前磨牙15个,随机分为3组。去除面釉质,暴露平的牙本质表面,在其中央制备3.5mm×3.5mm×3mm的盒形洞。使用Single Bond黏结剂,按使用说明进行牙本质黏结,用Z100复合树脂充填窝洞:A组:分3层水平充填;B组:分3层斜向充填(第一层水平充填,第二、三层近远中向斜向充填);C组:分3层斜向充填(第一、二层近远中向斜向充填,;第三层水平充填)。用硬组织切片机将实验牙切成黏结面积约0.9mm×0.9mm的正方形小条作为试件,用以测试牙本质微拉伸黏结强度。在体视显微镜和扫描电镜下观察样本的断裂界面。结果:C组的微拉伸黏结强度测试值(31.99±5.27)高于A组(24.56±4.90)和B组(31.19±3.90),3种分层充填方法对牙本质微拉伸黏结强度的影响有统计学意义(P<0.05)。体视显微镜和扫描电镜下观察测试样本的断裂多数为黏结界面破坏。结论:3种分层充填方法对牙本质黏结的微拉伸强度存在影响,其中C组的分层充填方法略优于另外两组。因此,在修复较深的牙体缺损时,采用合适的分层充填方法有利于获得良好的黏结效果。

AIM： To investigate the effect of layering technique of resin composite restorations on microtensile bond strength to dentin in Class I cavities. METHODS：The occlusal enamel was removed to expose a fiat superficial dentin surface on human extracted premolars that were divided into three groups at random. Cavities with 3.5 mm long × 3.5 mm wide were prepared to a depth 3 mm below the dentin surfaces. The adhesive Single Bond was applied according to the manufacturer＇s instructions. The teeth were restored with Z100 composite resin as the following： Group A, filled with three horizontal increments： Group B, filled with three oblique increments, the first resin composite increment was horizontal incremental filling, the second and the third were applied obliquely; Group C, filled with three oblique increments, the first and the second resin composite increments were applied obliquely, the third was horizontal incremental filling. After 24 hours＇storage in water, all the teeth were sectioned to obtain bar - shaped specimens with bonded surface area about 0.9mm × 0.9mm. Dentin microtensile bond strengths were measured. All the fractures were observed under stereo - microscope and scanning electron microscope （SEM）. RESULTS：The microtensile bond strength in Group C was higher than that in Group A and Group B. The results showed that there was significant among three layering restorative techniques on microtensile bond strength to dentin in Class I cavities （ P 〈 0.05 ）. Stereo -microscope and SEM observations of failure patterns showed that most of them exhibited interfacial cohesive failure. CONCLUSION：Three layering techniques of resin composite restorations can affect microtensile bond strength to dentin. And layering technique of resin composite restorations of Group C is better than Group A and Group B. High bond strengths to deep cavity floors can be achieved by using an appropriate layering technique.