牙釉质表面不同状态对自酸蚀体系剪切强度的影响

目的:研究牙釉质表面不同状态对自酸蚀体系剪切强度的影响. 方法:选择新鲜拔除无龋坏,无缺损的牛切牙32个,流水冲洗下.低速金刚砂片平行于牙长轴切取厚约2.0 mm,约3.5～4.0 mm2的牙釉质片,金钢砂车针表面磨切呈平面,依次以200目、400目、600目砂纸打磨牙釉质,形成标准粘结面,超声波清洁, 将标准粘结面常规处理.加压充填树脂,分层固化.同时以全酸蚀粘结系统作对照组. 所得的试件分为4组:即刻测试组(自酸蚀和全酸蚀)和24 h后测试组(自酸蚀和全酸蚀),每组8个试件.即刻测试:将粘结处理完成后的试件直接放置在万能试验机上测试其剪切强度,剪切头速度为0.5 mm/min. 24 h后将粘结处理完成后的试件放置在人工唾液中24 h,在万能试验机上测试其剪切强度,剪切头速度为0.5 mm/min.结果:经One-Way ANOVA统计分析,可知三种不同状态在自酸蚀粘结系统下即可和24 h测试组比较组内及组间均存在显著差异(P<0.01),与对照组比较,自酸蚀即刻测试组存在显著差异(P<0.01),自酸蚀24 h测试组的剪切强度值存在显著差异(P<0.01). 结论:牙釉质表面在半干燥条件下的即刻和24 h测试组的剪切强度值最大.

Evaluation of shear bond strength of self-etching adhesive systems to enamel in different conditions

AIM: To compare immediate and 24 h shear bond strength (SBS) of self-etching adhesive systems to enamel in difference conditions. METHODS: Flat enamel surfaces (n=32, thickness 2.0 mm, area 3.5-4.0 mm2) from 20 freshly exreacted intact bovine incisors were produced by wet grinding on a 200, 400, 600-grit SiC paper and mounted in acrylic. The adhesive was applied in accordance with the manufacturer's instructions. 32 specimens were randomized into 4 groups: immediate (self-etching and total-etching) and 24 h (self-etching and total-etching). Every group contained 8 specimens. Specimens for immediate bond strength testing were placed in a test machine according to the previously reported method within 1 min of light-initiation. Specimens for 24 h bond strength testing were stored in artificial saliva until testing. The crosshead speed was 0.5 mm/min. Total etch systems served as controls. RESULTS: One-way ANOVA revealed that there were significant differences between immediate and 24 h groups(P<0.01); there were also significant differences in comparison with control group(P<0.01). CONCLUSION: The flat enamel surfaces treated in subarid were significantly different from other conditions. The shear of imme- diate and 24 h is the highest in the condition of the flat enamel surfaces treated in subarid.