Alaghehmand Homayoon, Rohaninasab Marzieh, Bijani Ali
Dental Materials Research Center, Department of Esthetic and Restorative Dentistry, Babol University of Medical Science, Babol, Iran.
Department of Esthetic and Restorative Dentistry, Dental School of Tehran University of Medical Science, International Campus, Tehran, Iran.
Dent Res J (Isfahan). 2019 Jan-Feb;16(1):47-52.
Bleaching may affect the bond strength of existing composite fillings and may weaken it. Hence, the aim of this study was to find the best method of in-office bleaching with the least effect on microshear bond strength (MSBS) of existing composite resin fillings to tooth structure.
In this study, Class V cavities were prepared on buccal surface of 50 extracted third human sound molars. The cavities in 25 teeth had enamel axial walls, Group E, which were divided into five subgroups of E1 through E5 and in 25 teeth had dentin axial walls, Group D, which were divided into five subgroups of D1 through D5. Cavities were treated with Single Bond 2 adhesive system and restored with composite resin (Z250). The corresponding subgroups received similar bleaching methods and materials; 1 - not bleached, 2 - hydrogen peroxide (HP) 25%, 3 - HP + ultraviolet light, 4 - HP + light-emitting diode-curing device, and 5 - HP + diode laser. Teeth colors were monitored before and after bleaching, and MSBS test and failure modes were examined. Results were analyzed with one-way ANOVA and Kruskal-Wallis tests. < 0.05 was considered significant.
One-way ANOVA did not show differences in MSBS of enamel subgroups but showed significant differences in dentin subgroups ( < 0.00). Adhesive fracture in all of the subgroups was the most frequent mode of failure. Kruskal-Wallis test showed that laser was the most effective instrument to change ΔE.
Diode laser was the best method for tooth bleaching because lowering the shear bond strength between composite resin and enamel was minimum and also had the most ΔE in tooth bleaching.
漂白可能会影响现有复合树脂充填物的粘结强度并使其减弱。因此，本研究的目的是找到对现有复合树脂充填物与牙体组织的微拉伸粘结强度（MSBS）影响最小的诊室漂白最佳方法。
本研究中，在50颗拔除的健康人第三磨牙的颊面制备V类洞。25颗牙齿的洞具有釉质轴壁，为E组，分为E1至E5五个亚组；25颗牙齿的洞具有牙本质轴壁，为D组，分为D1至D5五个亚组。用单组分粘结剂系统（Single Bond 2）处理窝洞，并用复合树脂（Z250）修复。相应的亚组接受相似的漂白方法和材料；1 - 未漂白，2 - 25%过氧化氢（HP），3 - HP + 紫外线，4 - HP + 发光二极管固化装置，5 - HP + 二极管激光。在漂白前后监测牙齿颜色，并进行MSBS测试和观察失败模式。结果采用单因素方差分析和Kruskal-Wallis检验进行分析。P < 0.05被认为具有统计学意义。
单因素方差分析显示釉质亚组的MSBS无差异，但牙本质亚组有显著差异（P < 0.00）。所有亚组中粘结剂断裂是最常见的失败模式。Kruskal-Wallis检验表明激光是改变ΔE最有效的器械。
二极管激光是牙齿漂白的最佳方法，因为其使复合树脂与釉质之间的剪切粘结强度降低最小，并且在牙齿漂白中ΔE最大。
