牙齿表面不同状态对自酸蚀体系剪切强度影响的实验研究

Evaluate of shear bonding strength of a self-etching.adhesive to enamel and dentine in different conditions

目的:研究牙釉质、牙本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,低速金刚砂片切取厚约2.0mm,面积大小3.5～4.0mm的牙釉质、牙本质片各32个,依次以200目、400目、600目砂纸打磨,按如下处理:①在湿润条件(人工唾液)下;②在半干燥(棉球沾干表面)下;③干燥条件(气枪吹干)下,采用自酸蚀粘结系统固定内径为4mm、高为2mm的铜环。加压充填树脂,分层固化,同时以全酸蚀粘结系统作对照组。所得的试件分别分为4组:即刻测试组(自酸蚀和全酸蚀)和24h后测试组(自酸蚀和全酸蚀),每组8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0.5mm/min。24h后测试:将粘结处理完成后的试件放置在人工唾液中24h,在万能试验机上测试其剪切强度,剪切头速度为0.5mm/min。结果:经统计分析,可知3种不同状态在自酸蚀粘结系统下即刻和24h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24h测试组的剪切强度值存在显著差异(P<0.01)。结论:①牙釉质、牙本质表面在半干燥条件下的即刻和24h测试组的剪切强度值最大,与其他两组存在显著差异(P<0.01);②3种条件下的24h测试组的剪切强度值较即刻测试组的剪切强度值大,存在显著差异(P<0.01);③与全酸蚀为对照组的比较,即刻组的剪切强度值均小于对照组的剪切强度值,存在显著差异(P<0.01),24h测试组的剪切强度值大于对照组的剪切强度值,存在显著差异(P<0.01)。

Objective The aim of this study was to compare immediate and 24-hour of shear bond strength （SBS） of self-etching systems on difference conditions. Methods 32 freshly extracted bovine flat enamel and,dentine surfaces, were produced by wet grinding on a 200,400,600,800-grit SiC paper, and mounted in acrylic. The flat enamel surfaces were treated by three conditions： overdrying, overwetting and middlewetting.The samples were clamped in a stand under a split copper mould with a hole in the centre （4 mm diameter,2 mm high）.The mould was then filled in increment with a composite resin （Z100） The adhesive was applied in accordance with the manufacturer＇s instructions. Specimens for immediate bond strength testing were placed in a test machine according to the previously reported method within 1 minute of light-initiation.Specimens for 24-hour bond strength testing were stored in distilled water until testing.The crosshead speed was 0.5mm/min. Total etch system group as control Results were analyzed using one way ANOVA. Results There were significant differences between immediate and 24-hour groups （P〈0.01） there were also significant differences compare with control group（P〈0.01）. Conclusion The flat enamel surfaces treated in middlewetting were significant differences compare to others conditions. There were also significant differences between immediate and 24- hour groups.