Moradi Mina, Hormozi Elham, Shamohammadi Milad, Rakhshan Vahid
Department of Orthodontics, School of Dentistry, North Khorasan University of Medical Sciences, Bojnurd, Iran.
Department of Orthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
Int Orthod. 2018 Dec;16(4):623-637. doi: 10.1016/j.ortho.2018.09.017. Epub 2018 Oct 17.
To increase bond strength of brackets bonded to composite restorations, underlying composite restorations are usually roughened. This and subsequent bracket debonding might deteriorate smoothness of composite restoration, leading to clinical and aesthetic problems. Since this was not assessed before, this study was conducted.
Seventy intact human premolars were collected and filled with composite restorations. They were randomly divided into 3 groups: control (n=10), surface treatments before bracket bonding (bur, sandblasting, overall n=40), and surface roughening without bracket bonding (bur, sandblasting, overall n=20). The 40 specimens with bracket bonding steps were divided into two subgroups of with and without polishing after debonding of brackets (each n=10). After aging the composites in two steps and treating surfaces according to abovementioned protocols, their surface topographies were evaluated under stereomicroscopy (80×), scanning electron microscopy (using Zachrisson-Arthun index, at 500× and 1000× zooms), and by profilometry. Profilometry parameters and Zachrisson-Arthun index were statistically compared among different groups (α=0.05, 0.005).
According to Kruskal-Wallis test, all profilometry parameters or the Zachrisson and Arthun index were significantly different between groups involving bracket debonding and control (P≤0.001). Three-way ANOVA indicated that bracket debonding, polishing after debonding, and surface treatments before bracket bonding had a significant effect on Ra and Rz (P≤0.05). Tukey post hoc test showed that bur and sandblasting methods were not significantly different (P>0.05).
Bur-roughening or sandblasting of composite surface before bonding brackets can increase surface roughness, while polishing can reduce it back to control levels.
为提高粘结在复合树脂修复体上的托槽的粘结强度，通常会对其下方的复合树脂修复体进行粗糙化处理。这以及随后的托槽脱粘可能会破坏复合树脂修复体的光滑度，导致临床和美观问题。由于此前未对此进行评估，因此开展了本研究。
收集70颗完整的人类前磨牙，并用复合树脂进行充填。将它们随机分为3组：对照组（n = 10）、托槽粘结前进行表面处理组（车针、喷砂，共n = 40）以及未进行托槽粘结的表面粗糙化处理组（车针、喷砂，共n = 20）。将40个进行了托槽粘结步骤的标本分为托槽脱粘后有无抛光的两个亚组（每组n = 10）。按照上述方案对复合树脂进行两步老化并处理表面后，在体视显微镜（80倍）、扫描电子显微镜（使用扎克里松 - 阿尔通指数，500倍和1000倍放大倍数）下以及通过轮廓仪评估其表面形貌。对不同组之间的轮廓仪参数和扎克里松 - 阿尔通指数进行统计学比较（α = 0.05，0.005）。
根据克鲁斯卡尔 - 沃利斯检验，涉及托槽脱粘的组与对照组之间，所有轮廓仪参数或扎克里松和阿尔通指数均存在显著差异（P≤0.001）。三因素方差分析表明，托槽脱粘、脱粘后抛光以及托槽粘结前的表面处理对Ra和Rz有显著影响（P≤0.05）。Tukey事后检验表明，车针和喷砂方法之间无显著差异（P>0.05）。
在粘结托槽前对复合树脂表面进行车针粗糙化处理或喷砂可增加表面粗糙度，而抛光可将其降低至对照水平。
