牙本质表面状态对丙酮基粘结剂强度和界面的影响

目的：研究干燥或湿润的牙本质表面状态对丙酮基粘结剂粘结强度和粘结界面微观结构的影响，并探讨粘结强度和粘结界面微观结构之间的内在联系。方法：选用3种含有丙酮的湿粘结系统Gluma One-Bond、Bond-1和One-Step，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，并用扫描电镜观察和比较各组试件粘结界面超微结构的异同。结果：湿粘结时，粘结剂对牙本质表面的渗透较为充分，混合层均匀，厚度约为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；干燥粘结时，形成的混合层变薄，并有不完全渗透的混杂层形成。干燥粘结时，3种粘结系统的微拉伸强度均有显著降低，下降幅度最高为39％，微拉伸破坏的方式主要是粘结界面的破坏。结论：含有丙酮的粘结系统在干燥粘结时，对牙本质表面的渗透性下降，微拉伸强度明显降低；微拉伸强度的测试，可以更客观地反映粘结强度的大小。

Bonding strength and interface effects of different dentin surface on acetone-based adhesives bonding

PURPOSE: To study the influences on microstructure characteristic and bonding strength of acetone-based wet bonding systems when bonding on dry or wet dentin surface. METHODS: Three acetone-based wet bonding systems, Gluma One-Bond, Bond-1 and One-Step, were used to bond Chrisma composite resin to dry or moist dentin surface, and the bonding interface was observed with HITACHI S-2700 scanning electron microscope. Microtensile strengths of different groups were measured with Instro 1195. RESULTS: All three bonding systems can infiltrate well into dentin bonding interface in the wet groups. A hybrid layer of about 5microm could be observed with resin tags traversing from the resin layer above into the undemineralized dentin below and the lateral branch of dentinal tubule. In the dry groups, three zones, a surface and a basal hybrid layer sandwiching a middle hybridoid region, could be observed. The hybrid layer was very thinner. Microtensile strength had significantly decreased while bonding on dry dentin surface with acetone-based wet bonding systems, with the maximum decrease of 39% in Bond-1. CONCLUSION: Incompletely infiltrated adhesive on dentin bonding interface could be observed and microtensile strength had significantly decreased while bonding on dry dentin surface with acetone-based wet bonding systems. Moist dentin surface, which can maintain collagen-rich fibrous network of demineralized dentin, is necessary when bonding with acetone-based wet bonding systems. Microtensile strength approaches to the real dentin bonding strength.