METHODS: Seventy-five healthy bovine incisors were divided into five groups (n = 15). Fifteen teeth (Group 1) remained intact, whereas 60 (Groups 2 to 5) underwent at-home bleaching with 16% carbamide peroxide. The bonding procedures were as follows: Group 1: Bonding of resin composite to unbleached enamel; Group 2: Bonding immediately after bleaching; Group 3: Application of a 10% sodium ascorbate solution for 10 min before bonding; Group 4: Enamel removal to the depth of 0.5 mm; and Group 5: Increased curing time of the bonding agent to 80 instead of 20 s. After 24 h, the specimens were subjected to micro-shear testing, and the failure mode was determined.
RESULTS: ANOVA revealed a significant difference in bond strength among the groups (P < 0.001). The mean bond strength was significantly lower in group 2 than in other groups (P < 0.05), which showed comparable bond strength to each other (P > 0.05). Adhesive failure was the most predominant failure type in all groups. The mixed failure occurred with a frequency of 26.7% in groups 3 and 5. The Fisher\'s exact test revealed a significant difference in failure modes among the groups (P = 0.047).
CONCLUSIONS: The three experimental procedures used in this study, including the application of 10% sodium ascorbate before bonding, enamel removal to the depth of 0.5 mm, and increasing the curing time of the bonding agent to 80 s, were effective in restoring the compromised bonding to recently bleached enamel.
方法:将75例健康牛门牙分为5组(n=15)。15颗牙齿(第1组)保持完整,而60(第2至第5组)接受了16%过氧化脲的家庭漂白。粘合程序如下:第1组:将复合树脂粘合到未漂白的牙釉质上;第2组:漂白后立即粘合;第3组:在粘合前施用10%抗坏血酸钠溶液10分钟;第4组:去除牙釉质至0.5毫米的深度;第5组:将粘合剂的固化时间增加到80而不是20秒。试样进行微剪切测试,并确定了故障模式。
结果:方差分析显示各组间的粘结强度有显著差异(P<0.001)。第2组的平均粘结强度明显低于其他组(P<0.05),显示出彼此相当的粘结强度(P>0.05)。粘合失效是所有组中最主要的失效类型。混合故障在第3组和第5组中发生的频率为26.7%。Fisher精确检验显示各组间失效模式存在显著差异(P=0.047)。
结论:本研究中使用的三个实验程序,包括在粘合前应用10%抗坏血酸钠,去除牙釉质至0.5mm的深度,并将粘合剂的固化时间增加到80s,有效恢复与最近漂白的釉质的粘合。