纤维桩与根管不同处理后剪切粘结强度实验研究及电镜观察

目的比较四种不同粘结系统处理后纤维桩与根管各部剪切粘结强度,探讨其内在机理。方法 25颗完整离体尖牙于釉牙骨质界冠方2mm处截冠。根管治疗后分五组修复：DTlight纤维桩＋3M Unicem组,DTlight纤维桩＋可乐丽DCcore组,DTlight纤维桩＋Dual-link（Bisco）组,DTlight纤维桩＋Lux-acoreZ组（纤维桩表面涂布粘结剂）,DTlight纤维桩＋Luxacore组（纤维桩表面未涂布粘结剂）。包埋后切片对不同根管段行剪切粘结实验,体视显微镜下观察断裂模式,记录数据并统计分析;每组选取2个样本进行扫描电镜观察粘结界面形态。结果剪切粘结强度（MPa）依次为：6.61±1.82,7.72±2.03,5.35±1.42,10.15±0.67,7.25±0.71。体视显微镜观察显示绝大部分样本的断裂方式都是树脂/纤维桩界面断裂。扫描电镜观察显示不同处理后其显微结构各不相同。结论纤维桩修复的剪切粘结强度与粘结部位、粘结材料密切相关。

Study of shear bonding strength on different bonding treatment of fiber post in root canal and scan electrical microscope analysis

Objective To investigate the vitro influence of difference root canal adhesive materials on shear bonding strength of root filling canine restored with fiber-reinforced post and its internal principle. Methods Twenty-five sound canines were root filled after being sectioned transversely 2mm coronal to the labial cemento-enamel junction. Fiber posts were placed with four different root canal adhesive materials（n=5）： （Group A） RelyX Unicem（3M）, （Group B） DC core, DC bond（Kuraray）, （Group C） Dual-link, One step（Bisco）, （Group D） Luxacore Z, Luxabond（fiber post coated with resin adhesives）, （Group E） Luxacore Z, Luxabond（fiber post non-coated with resin adhesives）. Each root specimen was cross sectioned into five samples （＋/-2.0 mm in thickness）, the post sections were pushed-out to determine the bonding strength to dentin, and the fracture mode was observed by stereomicroscope. In each group, two samples were observed under the scan electrical microscope （SEM）. Results Group E（10.15±0.67MPa） was statistically higher than Group A（6.61±1.82MPa）, Group B（7.72±2.03MPa）, Group C（5.35±1.42MPa） and Group D（7.25±0.71MPa）（P〈0.01）. Groups A, B and E showed no statistically significant difference while Group C presented statistically significant difference with Group B （P〈0.05） Generalized Estimating Equations, a=0.05]. The fracture mode observed by using stereomicroscope showed most rupture occurred between the post and the rensin cement .SEM analysis indicats that different treatments lead to different microstructures. Conclusions The shear bonding strength has close connection with the bonding treatment.