Department of Restorative Dentistry, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil.
School of Dentistry, Federal University of Mato Grosso do Sul - UFMS, Campo Grande, MS, Brazil.
Photodiagnosis Photodyn Ther. 2023 Dec;44:103813. doi: 10.1016/j.pdpdt.2023.103813. Epub 2023 Sep 23.
To evaluate in vitro the effect of dental bleaching using high concentration hydrogen peroxide (HP) photoactivated with violet LED on fracture strength and hybrid layer formation.
forty endodontically-treated bovine teeth were randomized into four groups (n = 10): C - Control, HP - 35% hydrogen peroxide, HP-BL - 35% hydrogen peroxide photoactivated with blue LED, HP-VL - 35% hydrogen peroxide photoactivated with violet LED. Three bleaching sessions with an interval of 7 days between them were performed. After 10 days of the last bleaching session, the dental crowns were restored and submitted to the fracture strength test. Five specimens from each group were used to evaluate the hybrid layer formation by scanning electron microscope (SEM) images. One-way ANOVA and Kruskal-Wallis test were used for parametric and non-parametric data, respectively. Significance level of 5% was adopted to all the tests.
No differences on fracture strength among the groups were observed (p > 0.05). HP and HP-BL showed alterations on hybrid layer formation compared to C group (p < 0.05), but not for HP-VL (p > 0.05). No differences on hybrid layer formation were observed among HP, HP-VL and HP-BL groups (p > 0.05).
Dental bleaching, photoactivated or not, did not affect the fracture strength of endodontically-treated teeth. Regardless of the protocol used, hydrogen peroxide altered the hybrid layer formation at some level when the restoration was placed after 10 days of the last bleaching session.
评估经高强度过氧化氢（HP）经紫光灯激活后的光动力漂白对牙体断裂强度和混合层形成的体外影响。
40 颗牙髓治疗后的牛牙随机分为四组（n=10）：C-对照组、HP-35%过氧化氢、HP-BL-经蓝光灯激活的 35%过氧化氢、HP-VL-经紫光灯激活的 35%过氧化氢。三组漂白间隔 7 天，共进行三次。末次漂白 10 天后，对牙冠进行修复并进行断裂强度测试。每组取 5 个样本用扫描电子显微镜（SEM）图像评估混合层形成情况。采用单因素方差分析和 Kruskal-Wallis 检验分别对参数和非参数数据进行分析。所有检验的显著性水平均为 5%。
各组牙体断裂强度无差异（p>0.05）。HP 和 HP-BL 与 C 组相比，混合层形成出现改变（p<0.05），但 HP-VL 无改变（p>0.05）。HP、HP-VL 和 HP-BL 三组混合层形成无差异（p>0.05）。
光动力漂白或非光动力漂白均未影响牙髓治疗后的牙体断裂强度。无论采用哪种方案，末次漂白 10 天后进行修复时，过氧化氢均会在一定程度上改变混合层形成。
