季铵盐单体改性粘接剂对牙本质粘接界面耐酶解能力的影响

Effect of quaternary ammonium methacrylates incorporation into a dental adhesive on the resistanceof enzymatic degradation of resin-dentine interfaces

目的研究季铵盐单体改性粘接剂对牙本质粘接界面耐酶解性能的影响，探索提高牙本质粘接耐久性的新方法。方法30颗无龋人第三磨牙通过随机数字表法随机分为3组（每组10颗）：季铵盐单体[2-甲基丙烯酰氧乙基-正十二烷基-甲基溴化铵（ 2-methacryloxylethyl dodecylmethyl ammonium bromide, MAE-DB）]改性的粘接剂（Adper^TM Single Bond2）组（简称MAE-DB组）、氯己定组和阴性对照组（Adper^TM Single Bond2粘接剂）。全酸蚀粘接技术制作标准牙本质粘接试件，37℃水浴浸泡24h后，制成微拉伸试件，浸泡于酶解液中0、24和120h（每组每个时间点30个试件）。检测各组试件粘接强度、断裂模式和纳米渗漏情况。结果未经酶解处理的各组试件粘接强度差异无统计学意义（P〉0．05）。酶解处理24和120h后，MAE-DB组的粘接强度分别为（31．13±8．77）和（24．14±6．64）MPa，分别显著高于阴性对照组相应时间点[（25．63±6．90）和（15．22±6．57）MPa]（P〈0．05）。酶解处理后阴性对照组的断裂多发生于混合层底部，而氯己定组和MAE-DB组断裂多发生于混合层顶部。酶解处理前各组均可见少量的银离子沉积于混合层底部。酶解处理120h后，扫描电镜显示，氯己定组和MAE-DB组混合层底部的纳米渗漏银离子比阴性对照组少，纳米渗漏分级计数差异有统计学意义（P〈O．05）。结论MAE-DB改性牙本质粘接剂可有效提高牙本质粘接界面的耐酶解能力。

Objective To evaluate the effect of quaternary ammonium methacrylates incorporation into a dental adhesive on the resistance of enzymatic degradation of resin-dentine interfaces. Methods Thirty caries-free extracted human third molars were randomly divided into three groups （n = 10）： 2-methacryloxylethyl dodecylmethyl ammonium bromide （MAE-DB） incorporated adhesive served as the experimental group, pre-treatment with chlorhexidine （CHX） served as a positive control, AdperTM Single Bond 2 served as a negative control. The resin-dentin interfaces were prepared using total etch bond systen~ After storage in distilled water at 37 ℃ for 24 h, the bonded teeth were vertically sectioned into beams. Beams were respectively immersed in artificial saliva containing 2 g/L MMP-8 at 37 ℃ for 0 h, 24 h and 120 h （n =30）. Micro-tensile bond strength, failure modes and nanoleakage were examined. Results There were no significantly differences of micro-tensile bond strength between groups before hydrolysis （P 〉 0. 05 ）. After the enzynmtic hydrolysis of 24 h and 120 h, the micro-tensile bond strength of MAE,DB groups[ （31.13±8. 77） MPa, （24. 14 ±6. 64） MPa] were significantly higher than that of the negative control groups [ （25.63 ±6. 90） MPa, （ 15. 22±6. 57） MPa] （P 〈 0. 05）. Most of the failures were found in the base part of the hybrid layer in the negative control group, while failures occurred through the top of the hybrid layer in CHX and MAE-DB groups after the enzymatic hydrolysis. Specimens from each immediate group showed minor silver deposits in hybrid layer. After beams being enzymatic hydrolyzed for 120 h, it was shown that the silver nitrate uptake in the negative control group were significantly different from those in the CHX and MAE-DB groups （P 〈 0. 05）. Conclusions Dental adhesive incorporation of MAE-DB could improve the anti-degrade ability of resin-dentin interfaces.