Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, Rua Célia de Oliveira Meirelles 350, University of São Paulo, Ribeirão Preto, SP 14024-070, Brazil.
Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, Rua Célia de Oliveira Meirelles 350, University of São Paulo, Ribeirão Preto, SP 14024-070, Brazil.
Photodiagnosis Photodyn Ther. 2023 Dec;44:103862. doi: 10.1016/j.pdpdt.2023.103862. Epub 2023 Oct 27.
Violet LED has been used for internal bleaching, however its implications on coronary dentin composition are unclear. The present study aims to evaluate the effect of bleaching with violet LED, either associated with 35 % hydrogen peroxide or not, on microhardness, chemical composition, and morphological characteristics of coronal dentin.
Thirty maxillary canines were selected to obtain 30 blocks of coronal dentin, distributed in 3 groups (n = 10): 35 % hydrogen peroxide (HP); violet LED (LED); HP 35 % + LED, (HP+LED). The chemical analysis was performed by FTIR and the morphological evaluation of the dentin structure by confocal laser scanning microscopy before (T0) and after treatment (T1). The microhardness analysis was performed by microdurometer after bleaching. The data were submitted to repeated measures ANOVA test (P> 0.05).
The intensity of the inorganic peaks decreased after bleaching for all groups (P = 0.003). There was an increase in the organic peak intensity after bleaching with HP, a decrease for LED, while HP+LED did not change the intensity (P = 0.044). Moreover, the inorganic/organic ratio decreased for HP (P = 0.022), while for LED and HP+LED there was no significant changes (P>0.05). HP and HP+LED showed lower microhardness values compared to LED (P< 0.05). Regarding morphological changes, an increase in the perimeter of the dentinal tubules was found for all groups, with the smallest increase being observed for LED.
HP bleaching decreased the chemical stability and microhardness of the coronal dentin, while the violet LED treatments had no significant impact on dentin stability. In all groups, there was an increase in exposure of the dentinal tubules after bleaching, which was less pronounced with the violet LED bleaching.
紫光灯已被用于内部漂白，但它对牙本质冠状结构的影响尚不清楚。本研究旨在评估紫光灯联合或不联合 35%过氧化氢对牙本质冠状结构的微硬度、化学成分和形态特征的影响。
选择 30 颗上颌尖牙，以获得 30 个牙本质冠状块，分为 3 组（n=10）：35%过氧化氢（HP）组；紫光灯（LED）组；35%过氧化氢联合紫光灯（HP+LED）组。用傅里叶变换红外光谱仪进行化学分析，用共聚焦激光扫描显微镜评估牙本质结构的形态学，处理前（T0）和处理后（T1）分别进行。漂白后用显微硬度计进行微硬度分析。数据用重复测量方差分析（P>0.05）。
所有组的无机峰强度在漂白后均降低（P=0.003）。HP 漂白后有机峰强度增加，LED 漂白后降低，而 HP+LED 组的强度没有变化（P=0.044）。此外，HP 组的无机/有机比值降低（P=0.022），而 LED 和 HP+LED 组无显著变化（P>0.05）。HP 和 HP+LED 组的微硬度值均低于 LED 组（P<0.05）。形态学变化方面，所有组的牙本质小管周长均增加，其中 LED 组增加幅度最小。
HP 漂白降低了牙本质冠状结构的化学稳定性和微硬度，而紫光灯处理对牙本质稳定性无显著影响。在所有组中，漂白后牙本质小管的暴露均增加，而紫光灯漂白后增加幅度较小。
