过氧化氢酶对外漂白后树脂充填体边缘微渗漏的影响

目的： 观察过氧化氢酶对10%过氧化脲外漂白后复合树脂充填体边缘微渗漏的影响。方法： 选取牙体健康完整的人离体前磨牙40颗，随机分为4组，第1组不漂白直接进行树脂充填，第2组外漂白后立即树脂充填，第3组外漂白后将牙在人工唾液中浸泡3周再进行树脂充填，第4组外漂白后先用过氧化氢酶处理窝洞再进行树脂充填。然后将4组样本进行2000个周期的冷热循环，应用2%亚甲基蓝染色24 h，体视显微镜下观察剖面树脂充填体的微渗漏程度，采用SPSS17.0软件包对数据进行统计学分析。结果： 第1组微渗漏值最低，第2组微渗漏值最高，第3组微渗漏值显著高于第1组但与第2组相比无显著差异（P>0.05）；第4组微渗漏值较第2组显著下降（P<0.05）。结论： 10%过氧化脲外漂白致树脂充填体边缘微渗漏明显增加，树脂充填前应用过氧化氢酶处理窝洞，可有效减少微渗漏，延迟充填不能有效改善微渗漏。

Effect of catalase on marginal microleakage of resin restoration after external bleaching

PURPOSE: To investigate the effect of catalase on marginal microleakage of resin restoration after external tooth bleaching with 10% carbamide peroxide. METHODS: Forty extracted human premolars, both intact and health, were randomly divided into 4 groups: group 1, direct composite resin filling without bleaching; group 2, composite resin filling immediately after external bleaching; group 3, immersed in artificial saliva for 3 weeks after external bleaching ,then filling with composite resin; group 4 ,cavity treated with catalase after external bleaching and then filled with composite resin. After 2000 thermal cycles, the teeth were immersed in 2% methylene blue for 24 hours, then the microleakage of interface of resin restorations was observed under stereomicroscope. The data were analysed with SPSS17.0 software package. RESULTS: Group 1 displayed the least amount of microleakage, while group 2 showed the greatest amount of microleakage, group 3 behaved similarly as group 2, having great amount of microleakage, with no significant difference (P>0.05); the microleakage of group 4 decreased significantly (P<0.05) compared to group 2. CONCLUSIONS: The microleakage increases significantly after external bleaching with 10% carbamide peroxide, then decreases if cavities are treated with catalase, but delay filling can not improve microleakage effectively.