牙本质表面状态对酒精-水基粘接剂强度和界面影响的微拉伸及TEM研究

目的　研究干燥或湿润的牙本质表面状态对酒精 -水基粘接剂粘接强度和粘接界面微观结构的影响 ,并探讨粘接强度和粘接界面微观结构之间的内在联系。方法　选用两种含有酒精和水的湿粘接系统OptiBondSolo和SingleBond ,将Chrisma树脂分别粘结在干燥或湿润的人牙本质表面 ,测试各组试件的微拉伸强度 ,并在透射电镜下观察和比较各组试件粘接界面超微结构的异同。结果　湿粘接时粘接剂对牙本质表面的渗透较为充分 ,混合层均匀 ,厚度约为 4～ 5μm ,并可观察到牙本质小管和侧支小管中有明显的树脂突形成 ,粘接界面中有明显的过度湿润的现象 ;干燥粘结时形成的混合层没有明显变化 ,没有观察到过度湿润的现象。干燥粘接时 ,两种粘接系统的微拉伸强度均有显著降低 ,下降幅度最高为 2 3 % ,微拉伸破坏的方式主要是粘接界面的破坏。结论　含有酒精和水的粘接系统在干燥或湿润粘接时粘接界面的超微结构变化不明显 ,其中的水分对干燥的牙本质表面有再湿润效果 ;干燥粘结时微拉伸强度则有明显的降低 ;微拉伸强度的测试可以更客观的反映粘接强度的大小。

Bonding strength and interface study with microtensile and TEM methords of alcohol- water- based adhesives bondingon different dentin surface

Objective To study the microstructure characteristic of alcohol-water-based adhesives bonding on dry or wet dentin surface. Methods Two alcohol-water-based wet bonding systems, OptiBond Solo and Single Bond, were used to bond Chrisma B20 resin to dry or moist dentin surface. The bonding interface were observed with TEM 2000EX transmission electron microscope and microtensile bonding strengths of different groups were measured with Instro 1195. Results Both bonding systems can infiltrate well into dentin bonding interface. Banded collagen and interfibrillar space could be observed at the surface of the acid-conditioned dentin. Hybrid layer formed in demineralized dentin and around the lateral branch of dentinal tubule. A hybrid layer was clearly distinguishable from underlying dentin. No major differences in hybrid layer ultrastructure were observed when the two adhesive systems were bonded to either dry or wet dentin. Isolated blister-like spaces of variable dimensions, which contained adhesive globules, were observed within the adhesive layer in wet bonding groups, indicating the overweting phenomena. In dry bonding groups, no ultrastructure evidence of collapsed demineralized collagen, incomplete or innfiltration by adhesive could be detected, while blister-like spaces were not observed. Microtensile strength significantly decreased while bonding on dry dentin surface with alcohol-water-based wet bonding systems, with the maximum decrease of 23% in single bond. Most of fractures occurred at the bonding interface. Conclusion Alcohol-water-based adhesive can infiltrate well into dentin when bonded to either dry or wet dentin. Water in adhesive can re-expand the air-dried and collapsed collagen network, which can be called self-rewetting effect. Microtensile strength apporachs to the real dentin bonding strength.