Objective To evaluate the effect of carbamide peroxide (CP) bleaching agents at different concentrations and with different carriers on the micro-leakage of composite resin interface. Methods Class V cavity (2 mm in diameter and 2 mm in depth) preparations were made at the enamelo-cemental junction on the buccal and lingual surfaces of 35 extracted human premolars. The cavities were filled with hybrid composite resin. The teeth were stored for 24 h in distilled water at 37°C before thermocyling for 500 times between 5 and 55 °C. The teeth were then randomly assigned into 7 groups, and in groups 1-6, the bleaching gels containing 10% or 20% of CP were applied on the buccal and lingual surface of the teeth for two weeks (6-8 h/day, 37 °C, 100% relative humidity) using Carbopol, PVP or Poloxamer as the thickening carriers, respectively. The seventh group served as the control without bleaching treatment. Nail polish was applied to the surface of the tooth, and all the teeth were immersed in ammoniacal silver nitrate solution followed by developing solution. The teeth were finally sectioned through the midline of the restoration and observed under stereomicroscope. SEM micrographs were also made to observe the interface. Results With the same bleaching agent, the micro-leakage in the gingival wall was slightly greater than in the occlusive wall, but the difference was not significant. Only 20% CP with Poloxamer as the thickening agent significantly increased the leakage of dentine-resin composite interface, and 10% and 20% CP with Carbopol or PVP as the thickening agents and 10% CP with Poloxamer produced minimal effects on filling the micro-leakage. Conclusion Thickening carriers and the concentration of CP (20% or below) have no significant effect on micro-leakage of composite resin.%目的 评价以不同载体配制的不同浓度过氧化脲(CP)漂白剂对复合树脂边缘微渗漏的影响.方法 在35颗离体前磨牙颊舌面牙颈部制备V类洞(直径2 mm,洞深2 mm,釉牙骨质界在洞中央或接近颈缘),树脂粘接修复,室温放置30 min后37℃水浴24 h,之后进行500次冷热循环.随机分为7组.1-6组分别用以卡波姆(Carbopo1)、聚乙烯吡咯烷酮(PVP)、泊洛沙姆(Poloxamer)为增稠载体的含100 g/L CP、200 g/L CP的漂白剂在37 ℃、100%湿度条件下每天漂白8 h,持续2周.7组为对照组.在牙齿表面涂指甲油.将牙齿浸泡于500 g/L氨化硝酸银液(pH8.0)中,24 h后再浸泡于显影液中8h.通过充填体中央颊舌向纵行剖开牙齿,在体视显微镜、扫描电镜下观察剖面充填体的渗漏情况.结果 同种材料龈壁的微渗漏虽然略大于牙合壁,但这种差异没有显著性.各实验组在牙合壁的微渗漏和对照组没有显著差别,龈壁除了以Poloxamer为增稠载体的20%CP渗漏明显增加外,其余组和对照组均没有显著差异;不同载体或不同浓度之间,牙合壁、龈壁的微渗漏在组间没有显著差异.结论 增稠载体和CP浓度(20%或以下)对树脂充填体的微渗漏没有显著影响.
展开▼
