【作者】 戈旌；

【导师】 林军；

【作者基本信息】 浙江大学 ， 口腔临床医学， 2010， 硕士

【摘要】 研究背景：牙本质树脂间的粘结力一直是近年来研究的热点。自酸蚀树脂水门汀因操作简便、不易引起术后敏感而得到广泛应用。但其粘结力不如全酸蚀系统,且长期粘结力下降较快,限制了自酸蚀粘结剂的应用。而微渗漏和牙本质胶原纤维降解是引起长期粘结力下降的主要因素。目的：为了研究氯已定预处理对保存牙本质-树脂长期粘结力的作用和釉质边缘对粘接力的影响,本研究采用两步法自酸蚀粘结剂Panavia F2.0 (PF, Kuraray Medical Inc., Tokyo, Japan)和一步法单组分自酸蚀粘结剂RelyX Unicem Aplicap (UC,3M ESPE)进行研究,通过微拉伸实验,比较不同浓度(2%和0.2%)CHX预处理和是否存在釉质边缘,对牙本质-树脂长期粘结力的影响。方法：1、样本制备：1.1、牙体预备：将56颗磨牙的牙合面釉质和牙根尖1／2去除,自凝塑料包埋牙根,用600目砂纸,200r/min带水打磨牙体牙合面60秒,获得粘接平面。将56颗牙随机分为7组,每组8颗。其中3组用金刚砂车针去除外层釉质。1.2、树脂块制备：用3M Z250光固化树脂制作56颗直径10mm,厚度为5mm的圆柱形树脂块。2、实验分组和牙本质粘结A组：对照组,不使用CHX预处理,不去除外层釉质,按粘结剂操作说明完成牙本质-树脂粘结后,将样本储存3天。B组：不使用CHX预处理。其中B2组去除外层釉质。按粘结剂操作说明完成牙本质-树脂粘结后,将样本储存6个月。C组：使用2%CHX预处理。其中C2组去除外层釉质。按粘结剂操作说明完成牙本质-树脂粘结后,将样本储存6个月。D组：使用0.2%CHX预处理。其中D2组去除外层釉质。按粘结剂操作说明完成牙本质-树脂粘结后,将样本储存6个月。3、微拉伸实验：用低速切片机(Buehler.USA)沿垂直于粘接面方向将样本切割为横截面积0.9x0.9mm的长条状,使用微拉伸测力仪(BIS-CO.USA)检测各组的抗拉伸力。4、扫描电镜观察：选取每组样本中10根被拉断的牙本质部分样本其中使用PF和UR的样本各5根,干燥后喷金,进行扫描电镜观察。5、统计学分析：用SPSS软件将各组的微拉伸力制作箱形图,并对结果进行正态分布检测、方差分析和t-检验。结果：1、微拉伸试验：测试结果使用SPSS16.0软件包进行正态检验和单因素方差分析(one-way ANOVA)。结果显示实验数据基本符合正态分布,其平均水平用均值±标准差(X±S)表示。单因素方差分析显示Panavia F对牙本质的粘结强度显著高于Relyx Unicem粘结剂组p<0.05)；釉质边缘的保存能明显延缓牙本质-树脂粘结强度的下降(p<0.05)；使用CHX对保存微拉伸力有显著的作用(p<0.05),但2%和0.2%的CHX对微拉伸力没有显著影响(p>0.05)。2、扫描电镜观察：2.1、Panavia F粘结剂：3天组的样本牙本质面有完整的混合层覆盖,无法看见牙本质小管和胶原纤维。B1组：(储存6个月／有釉质边缘保护／无CHX预处理)的样本的牙本质面有大量粘结剂,无法看见牙本质小管和胶原纤维。B2组：(储存6个月／没有釉质边缘保护／无CHX预处理)的样本的牙本质面无混合层或粘结剂,牙本质胶原纤维网暴露断裂,牙本质小管内无树脂突。C1和D1组：(储存6个月／有釉质边缘保护／2%或0.2%CHX预处理)的样本牙本质面混合层保存完好,无法看见牙本质小管和胶原纤维。C2和D2组：(储存6个月／无釉质边缘保护／2%或0.2%CHX预处理)的样本牙本质面残留少量粘结剂,可见牙本质小管中有部分树脂突。2.2、Relyx Unicem粘结剂3天组的样本断裂面大部分为树脂。B1组：(储存6个月／有釉质边缘保护／无CHX预处理)样本的牙本质面有薄层粘结剂覆盖,少量牙本质面暴露。B2组：(储存6个月／没有釉质边缘保护／无CHX预处理)的样本的牙本质面暴露,无粘结剂残留,牙本质小管空虚,牙本质脱矿不明显。C1和D1组：(储存6个月／有釉质边缘保护／2%或0.2%CHX预处理)的样本牙本质面有大量粘结剂覆盖,牙本质面无暴露。C2和D2组：(储存6个月／无釉质边缘保护／2%或0.2%CHX预处理)的样本牙本质面大部分暴露,少量粘结剂残留,牙本质小管中有树脂突栓塞。结论：1、二步法的Panavia F粘结剂比一步法Relyx Unicem粘结剂对牙本质的粘结力大。2、有釉质边缘保护,能减缓牙本质-树脂粘结力的下降。3、氯己定处理能抑制牙本质胶原纤维的降解,保存长期粘结力。高浓度氯己定比低浓度氯己定对Panavia F粘结剂更有效,但对于Relyx Unicem粘结剂则无明显区别。更多还原

【Abstract】 Background:The longevity of resin restorations is currently an hotspot in adhesive dentistry. Microleakage and the dentine collagen fibrils breakdown has been referred as factors determining the long-term success of composite resin restoration. Ideal marginal seal of resin restorations can be obtained if the margin is on sound enamel. Chlorhexidine (CHX) has an inhibitory effect of the endogenous collagenolytic activity in dentine. It is reported that applying CHX to acid-etched dentin prior to the etch-and-rinse adhesives may prevent the degradation of collagen fibrils and preserve the integrity of hybrid layer.Objectives:To evaluate the influence of enamel border and chlorhexidine pretreatment on resin-dentin microtensile bond strength (μTBS) over time. Methods:Fifty-six extracted non-carious human third molars had a flat dentine surface exposed. Two adhesive systems (Panavia F 2.0, PF; RelyX Unicem Aplicap, UR) were applied and composite resin crowns (Filtek Z250) were constructed. Teeth were divided into 7 groups. Group A, specimens were stored for 3 days. Group B1, specimens were stored for 6 month. Group B2, specimens were stored for 6 month without outer enamel. Group C1, specimens were pre-treated by 2% chlorhexidine then stored for 6 month. Group C2, specimens were pre-treated by 2% chlorhexidine then stored for 6 month without outer enamel. Group D1, specimens were pre-treated by 0.2% chlorhexidine then stored for 6 month. Group D2, specimens were pre-treated by 0.2% chlorhexidine then stored for 6 month without outer enamel. The bonded teeth were sectioned into beams with a cross-sectional area of 0.9mmx0.9mm and further stressed to failure in tension (1mm/min). The data for each adhesive were subjected to a Explore and Univariate Analysis of Variance. The fractured surfaces were examined by scanning electron microscopy (SEM).Results:1、Tensile strength test:the resin cements and margin and chlorhexidine pretreatment had significant effects onμTBS (p<0.05). For PF, lower concentration of CHX digluconate (0.2%) was not able to diminish the loss of bond strength. For UR, lower concentration of CHX digluconate (0.2%) was not able to diminish the loss of bond strength.2、SEM observation:2.1、Panavia FGroup A(3 days):Total cohesive in resin cement and/or in low-viscosity composite layer. Most of the resin tags remained firmly embedded in the tubules. Group B1(6 month&with enamel&no CHX pretreatment):cohesive failure in resin cement.Group B2(6 month&without enamel&no CHX pretreatment):Showing complete removal of the smear plugs, exposed outer peritubular collagen fibers and small traces of the smear layer.Group C1(6 month&with enamel&2% CHX pretreatment):failure at hybrid layer, no dentin surface can be seen.Group C2(6 month&without enamel&2% CHX pretreatment):showing residual smear layer and smear plug partially obliterating the dentinal tubules orifices. The dentine surface with collagen fibrils partially covered by the adhesive resin.Group D1(6 month&with enamel&0.2% CHX pretreatment):failure at hybrid layer, no dentin surface can been seen.Group D2(6 month&without enamel&0.2% CHX pretreatment):Adhesive resin plugs are less than the group C2.2.2、Relyx Unicem:Group A(3 days):A debonded deep dentin specimen that cohesively failed, and luting resin remaining on the dentin surface.Group B1(6 month&with enamel&no CHX pretreatment):Showing failure along the dentin interface.Group B2(6 month&without enamel&no CHX pretreatment):Showing complete removal of the smear plugs.Group C1(6 month&with enamel&2% CHX pretreatment):Demonstrating cohesive failure at the cement-adhesive interface.no dentin surface can been seen.Group C2(6 month&without enamel&2% CHX pretreatment):Failure can be observed to be partially adhesive, where remnants of the resin cement remained on the tooth surface.Group D1(6 month&with enamel&0.2% CHX pretreatment):cohesive failure at the cement-adhesive interface, no dentin surface can been seen.Group D2(6 month&without enamel&0.2% CHX pretreatment):failure along the dentin surface, partial removal of the smear plugs in dentinal tubules.Conclusions:enamel border and chlorhexidine pretreatment are capable of preventing the loss ofμTBS in both PF and UR. Lower concentration of CHX is effective for UR while not useful for PF.更多还原