树脂与无机改性牙本质的粘结界面及其微漏研究

Micromorphological structures and microleakage investigation of resin bonding to deproteinized dentin

目的:比较不同牙本质表面处理后树脂-牙本质界面的超微结构和微漏程度。方法:于8颗人离体磨牙颊、舌面牙颈部制备箱型V类洞,根据牙本质表面处理方法随机分为磷酸酸蚀组和无机改性组(n=8)。分别涂布粘结剂,复合树脂充填。染料渗入法检测充填体边缘的微漏程度,并观察粘结界面的微观形貌。结果:不同粘结处理方法对微渗漏程度无显著影响(P>0.05),各组根方渗漏程度显著高于冠方(P<0.05);无机改性处理后界面可见混合层形成,树脂突可见大量侧枝伸出。结论:无机改性对牙本质粘结的边缘微漏无显著影响;微机械嵌合作用是无机改性牙本质粘结的重要机制。

Objective： To compare the micromorphological structures and microleakage scores of resin bonded to differently treated dentin, thus to evaluate the effect of dentin deproteinization on the marginal sealability of resin-dentin interface. Methods： Box-shaped class V cavities were prepared in the buccal and lingual surfaces of eight extracted human molars. The cavities were then randomly divided into 2 equal groups according to the pretreatment adopted （n=8）. Phosphoric acid etched group was treated with 35% phosphoric acid for 15s, deproteinized group was treated with 10% NaOCl for 60s following acid etching. Restorations were built up with composite resin following application of dentin adhesives. Microleakage was assessed by means of dye penetration and the micromorphological structures of resin-dentin interface were further investigated with SEM. Results： No statistical difference was demonstrated between the two groups （P〉0.05）, however, microleakage on the gingival margin was significantly severer than that on the coronal margin in each group （P〈0.05）. Under SEM observation, hybrid layer could be clearly seen in the bonding interfaces of the deproteinized dentin, with numerous lateral branches protruding from the resin tags. Conclusion： No significant influence of deproteinization was shown on the marginal sealability of dentin bonding. The micro-mechanical interlocking formed by hybrid layer and the resin tags together with its numerous lateral branches provides a reliable bonding between resin and the deproteinized dentin.