三种牙本质粘接系统微拉伸粘接强度的比较

目的　用微拉伸粘接强度检测法评价 3种不同类型的牙本质粘接系统与正常牙本质的粘接强度 ,用扫描电镜分析其断裂类型。方法　选择 15颗正畸治疗拔除的健康前磨牙 ,去除面釉质层 ,随机均分为 3组。选用 3种牙本质粘接系统All Bond 2 (AB2 组 ) ,Fluoro Bond (FB组 )和XenoⅢ (Xeno组 ) ,分别按厂商说明书要求用于暴露的表层牙本质面上 ,再用蓝色复合树脂恢复牙冠至要求高度。用低速锯将牙齿片切为横截面积约 0 81mm2 的长方体状样本 ,用微拉伸测试仪检测其粘接强度 ,加载速度为 1mm/min。用扫描电镜观察样本断端形态 ,对微拉伸粘接强度测试值和断裂类型进行统计学分析。结果　 3种牙本质粘接系统的微拉伸粘接强度分别为AB2 组 :( 2 9 5 6± 5 4 7)MPa ,Xeno组 :( 15 81± 7 6 7)MPa,FB组 :( 14 6 1± 4 5 0 )MPa。AB2 组的微拉伸粘接强度高于Xeno组和FB组 (P <0 0 1) ,后两者的测值间差异无显著性 (P >0 0 5 )。扫描电镜观察结果显示 ,绝大部分样本的断裂类型都是粘接面型断裂。结论　 3种牙本质粘接系统与正常牙本质的粘接强度存在差异 ,All Bond 2的粘接强度最高 ,但临床操作复杂 ,技术要求较高 ;Fluoro Bond和XenoⅢ使用方法较简单 ,对牙髓的影响可能较小。

Microtensile bond strengths of three dentin adhesive systems

OBJECTIVE: To evaluate in vitro the microtensile bond strengths of three dentin adhesive systems and their respective fracture modes. METHODS: A total of 15 intact young human premolars extracted for orthodontic reasons were used. The enamel of occlusal surfaces of these premolar teeth was removed and superficial dentine was exposed, finished with wet 600-grit silicon carbide paper. And then these teeth were randomly divided into three groups. A block of composite resin was bonded respectively with three dentin adhesive systems: All-bond 2 (Group AB(2)), Fluoro-Bond (Group FB) and Xeno III (Group Xeno) according to manufacturers' instructions. The bonded teeth were kept in distilled water for 24 h at 37 degrees C. The roots were removed from the remaining crown approximately 1 - 2 mm below the cemento-enamel junction with a slow-speed diamond saw. The teeth were sectioned to obtain bar-shaped specimens, whose bonded surface areas were about 0.8 mm(2). The specimens were stressed at a crosshead speed of 1 mm/min until rupture of the bond. SEM was used to observe the fracture modes. The mean bond strengths were compared using one-way ANOVA and LSD tests. The frequency of fracture modes was compared using Krukal-Wallis and Mann-Whitney U-test. RESULTS: Mean microtensile bond strengths were (29.56 +/- 5.47) MPa for Group AB(2), (15.81 +/- 7.67) MPa for Group Xeno, and (14.61 +/- 4.50) MPa for Group FB. The bond strength of Group AB(2) was greater than those of the other two groups (P < 0.01). The bond strengths of Group Xeno and Group FB were not significantly different. SEM examination indicated that the adhesive failure was the most mode of fracture. CONCLUSIONS: The microtensil bond strengths of three dentin adhesive systems to normal human dentine were different and the total-etching adhesive All-Bond 2 exhibited the greatest bond strength. It was recommended that dentin adhesive agent should be used according to clinical situation.