过氧化脲漂白剂对釉质粘结强度的影响

摘要

目的:评价不同载体、不同浓度过氧化脲(carbamide Peroxide,CP)漂白剂对粘结釉质强度的影响.方法:60颗离体磨牙随机分为7组.1～6组颊舌面分别用以卡波姆(carbopol)、聚乙烯吡咯烷酮(PVP),泊洛沙姆(Poloxamer)为增稠载体的含100g/L CP、200g/L CP的漂白剂在37℃、100%湿度条件下每天漂白8h,其中部分样本再浸入10%的抗坏血酸钠凝胶中3h,持续2周后即刻粘结树脂或延迟2周粘结.7组为对照组.准备界面为1mm×1mm的条形试件.通过微拉伸法测试釉质粘结强度,对不同类型的断面进行扫描电镜(scanning election microscope,SEM)观察.利用Spss11.0软件通过双因素方差分析(Two-Way analysis of variance)和SNg-q检验对其微拉伸粘结强度(Microtensile bond strength,MTBS)进行统计分析.结果:各实验组2周漂白后即刻粘结,釉质粘结强度明显低于对照组(P＜0.05);10%CP漂白同时抗氧化治疗或延迟粘结,釉质的粘结强度和对照组没有明显差异(P＞0.05);20%CP漂白同时抗氧化治疗或延迟粘结,可明显提高釉质的粘结强度(P＜0.05),但和对照组仍有显著差异(P＜0.05).同种载体下,经10%CP漂白后的釉质粘结强度高于20%CP漂白组(P＜0.05).同种浓度下,不同增稠载体组间的粘结强度没有显著差异(P＞0.05).结论:漂白后即刻粘结,釉质的粘结强度随CP浓度的增高而下降;延迟2周粘结或抗氧化治疗可从一定程度上提高釉质的粘结强度,缩短漂白后粘结的时间;增稠载体对釉质的粘结强度没有显著影响.%Objective To evaluate the effect of carbamide peroxide (CP) bleaching agents of different concentration and carrier on the enamel-composite resin bonding strength.Methods Sixty teeth were randomly separated into seven groups.Using Carbopol, PVP and Poloxamer as thickening carriers respectively, bleaching gels containing 10％,20％ of CP were applied on the buccal and lingual surface for two weeks from 1 to 6 groups (6～8h/d,37℃ ,100％ relative humidity).Some of them were immersed in sodium ascorbate gel for three hours during bleaching.Bonding immediately after bleaching or two weeks delayed.The seventh group without bleaching as control group.All teeth were sectioned to obtain bar-shaped specimens with bonded surface area about 1.0mm ×1.0mm.Microtensile bond strength was measured and the values were statistically analyzed.Failure mode analysis was performed by SEM.Results Bonding immediately after bleaching, bond strength of enamel was significantly reduced.The bond strength of enamel treated with 20％CP and antioxidant or two weeks delayed was significantly increased (P＜0.05) but lower compared with control group with no bleaching (P＜0.05)The bond strength of enamel treated with 10％CP were significant increase compared with treated with 20％CP at the same carrier (P＞0.05).Conclusion Bonding immediately after bleaching, the enamel bonding strength decreased as CP concentration increase; in some degree two weeks delayed bonding or antioxidant treatment increased the enamel bonding strength and decreased bonding time after bleaching; thickening agents had no notable effect on the strength of enamel bonding.