Department of Operative Dentistry, School of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran.
Med Oral Patol Oral Cir Bucal. 2012 Nov 1;17(6):e1082-8. doi: 10.4317/medoral.17916.
The effect of 15% carbamide peroxide bleaching gel on color stability and surface topography of a giomer and a microfilled composite resin was evaluated in the present in vitro study.
Forty discs measuring 10 mm in diameter and 1 mm in thickness were prepared from a giomer and a microfilled composite resin. Each material yielded 20 discs with completely smooth surfaces. Then a spectrophotometer was used to measure L* (lightness), a* (redness, greenness) and b* (blueness, yellowness) color coordinates of all the discs. Subsequently, the specimens were subjected to 15% carbamide peroxide bleaching gel. After measuring the color coordinates once again, color changes (ΔE*) were calculated by the CIELAB system. Four specimens from each material (two specimens before bleaching agent application and two specimens thereafter) were viewed under an atomic force microscope (AFM) for surface topography evaluation. Data were analyzed by Mann-Whitney U and Kruskal-Wallis tests at α=0.05.
There were no statistically significant differences in color changes (ΔE*) between the two materials (P>0.05). In addition, no significant differences were detected in surface roughness between composite resin and giomer discs before and after bleaching (P>0.05 for both). However, in both materials the differences in surface roughness were significant before and after bleaching procedures (P<0.001).
Based on the results of the present study it was concluded that 15% carbamide peroxide does not induce clinically detectable color changes in composite resin and giomer despite an increase in surface roughness.
本体外研究评估了 15%过氧化脲漂白凝胶对玻璃离子水门汀和微填料复合树脂颜色稳定性和表面形貌的影响。
从玻璃离子水门汀和微填料复合树脂中制备直径为 10mm、厚度为 1mm 的 40 个圆盘。每种材料都产生了 20 个完全光滑表面的圆盘。然后使用分光光度计测量所有圆盘的 L*（亮度）、a*（红度、绿度）和 b*（蓝度、黄度）的颜色坐标。随后，将样本置于 15%过氧化脲漂白凝胶中。再次测量颜色坐标后，通过 CIELAB 系统计算颜色变化（ΔE*）。从每种材料的四个样本（漂白剂应用前后的两个样本）中用原子力显微镜（AFM）进行表面形貌评估。使用曼-惠特尼 U 和克朗-沃尔利斯检验，α=0.05 进行数据分析。
两种材料之间的颜色变化（ΔE*）没有统计学差异（P>0.05）。此外，在漂白前后，复合树脂和玻璃离子水门汀圆盘的表面粗糙度没有显著差异（两者均为 P>0.05）。然而，在两种材料中，漂白前后的表面粗糙度差异均具有统计学意义（P<0.001）。
根据本研究的结果，15%过氧化脲不会导致复合树脂和玻璃离子水门汀发生临床可察觉的颜色变化，尽管表面粗糙度增加。
