两种漂白技术对牙釉质、牙本质及釉牙本质界颜色变化及反弹的影响

Assessment of Color Changes and Color Rebounds in Enamel,Dentin-enamel junction,and Dentine during Vital Bleaching

目的:通过评价家庭漂白和诊室漂白技术对牙釉质、牙本质及釉牙本质界颜色的影响,探讨活髓牙漂白牙齿颜色改变的机理及反弹情况。方法:收集12颗因正畸治疗而拔除的前磨牙,沿颊舌向正中切开,近远中两样本随机分成A、B两组(n=12)。A组用10%过氧化脲进行14 d漂白处理,B组用38%过氧化氢14 d 3次漂白处理,A组分别在漂白阶段(第3天、第7天、第14天)及颜色反弹阶段(第3天、1周、2周、3周、4周、5周)拍照,B组分别在漂白阶段(第3天、第7天、第14天)及颜色反弹阶段(第3天、1周、2周、3周、4周、5周)拍照,处理数码照片,分析记录每个样本在不同时间点牙釉质、牙本质及釉牙本质界同一位点的L^*a^*b^*值。重复测量方差分析不同时间点牙釉质、牙本质及釉牙本质界颜色改变的差异;两独立样本t检验比较漂白14 d及漂白结束后5周两组之间牙釉质、牙本质和釉牙本质界颜色的差异并计算反弹率。结果:经过14 d的漂白,A组和B组的牙釉质和釉牙本质界的ΔE均明显大于牙本质(P<0.01),A组牙釉质的ΔL^*值明显大于牙本质,Δb^*值明显小于牙本质(P<0.05)。漂白结束后5周观察期内,A组牙釉质和釉牙本质界的ΔE及ΔL^*值明显大于牙本质,Δb^*值明显小于牙本质(P<0.01);在漂白结束后2~5周,B组牙釉质和釉牙本质界的ΔE值明显大于牙本质(P<0.01),漂白结束后1~5周,牙釉质的Δb^*值小于牙本质(P<0.05)。观察期内Δa^*值的变化很小,在0.67~2.44之间,牙釉质、牙本质和釉牙本质界的反弹率均大于30%。A组和B组之间的比较分析结果表明漂白14 d A组牙釉质的ΔL^*值明显高于B组(P<0.01),漂白结束后第5周,B组牙本质的ΔL^*值高于A组,釉牙本质界的Δb^*值低于A组(P<0.05)。结论:活髓牙漂白过程中,牙釉质和釉牙本质界的颜色改变在整个牙齿的颜色改变中可能有重要的贡献,而牙本质所起的作用可能很小。

Objective:To investigate the changes of color and color rebounds in the enamel,dentine,and DEJ following 14 days vital bleaching treatment and to determine the mechanism of vital tooth bleaching.Methods:12 extracted premolars were sectioned bucco-lingually in half and randomly bleached with 10%carbamide peroxide(CP)(group A)or 38%hydrogen peroxide(HP)(group B)for 14 days with two bleaching techniques.Photographs were taken prior to bleaching,day 3,7,and 14 during bleaching,and day 3,7,14,21,28,and 35 after bleaching in group A;and day 1,7,and 14 during bleaching,and day 3,7,14,21,28,and 35 after bleaching in group B.All photographs were digitized,calibrated,and converted to L^*,a^*,b^*values and analyzed using repeated measures analysis of variance.Results:On day 14,theΔE of enamel and DEJ were significantly higher than that of dentine in group A and B(P<0.01).TheΔL^*of DEJ was significantly higher than that of dentine,while theΔb*was opposite(P<0.05).In group A,5 weeks after bleaching,theΔE andΔL*of enamel and DEJ were significantly higher than that of dentine,while theΔb*was opposite(P<0.01).In group B,2 to 5weeks after bleaching,Δb^*of enamel was significantly lower than that of dentine,andΔE of enamel and DEJ were significantly higher than that of dentine(P<0.05).With respect toΔa^*,only small changes amounting to 0.67 to 2.44 could be observed after bleaching treatment in all specimens.The color relapse rate(CRR)of enamel,dentine,and DEJ were all more than 30%in 5 weeks after bleaching.On day 14,ΔL^*of enamel in group A was significantly higher than group B(P<0.01).ΔL^*of dentine in group B was significantly higher than group A,whileΔb^*was opposite(P<0.05)in 5 weeks after bleaching.Conclusion:The color changes in enamel and DEJ might have a certain contribution to that of tooth color during tooth bleaching,while the color changes in dentine might play a small role in the color changes of the whole tooth.