渗透树脂对漂白过的早期牙釉质龋的治疗效果研究

目的 评价渗透树脂对漂白过的早期牙釉质龋的治疗效果。方法 135个牛切牙标本浸入到脱矿液中24 h，形成白垩色斑点损伤后，随机均分成3组（n=45）：漂白组用40%的过氧化氢漂白、渗透组用渗透树脂处理、漂白渗透组用40%的过氧化氢漂白后再以渗透树脂处理，所有样本pH循环28 d以模拟口腔状况。分别测定白垩色斑点病损前（基础值）、病损后和实验后牙釉质的颜色和显微硬度（SMH）和表面显微硬度恢复率（SMHR）。计算出3组颜色变化［ΔE（病损后-基础值）、ΔE（实验后-基础值）、ΔE（实验后-病损后）］，并利用扫描电镜评估渗透组和漂白渗透组的渗透情况。结果 3组病损前和病损形成后的SMH差异无统计学意义，实验后SMH 及SMHR均呈渗透组＞漂白渗透组＞漂白组的变化趋势（P＜0.05）。渗透组和漂白组的ΔE（实验后-基础值）和ΔE（实验后-病损后）差异有统计学意义（P＜0.05），漂白组高于渗透组，但仍明显不如漂白渗透组的整体美白效果。扫描电镜下可见漂白渗透组树脂渗透比较均匀，固化树脂材料之间有不同的超微结构。结论 在树脂渗透前采用漂白处理能有效提高显微硬度并且提高美白效果。

Study on the therapeutic effect of penetrating resin on bleached early enamel

Objective To evaluate the therapeutic effect of penetrating resin on bleached early enamel caries.Methods A total of 135 cattle incisors were immersed in the demineralization fluid for 24 h. After the formation of chalk stains, they were randomly divided into 3 groups (n=45): the bleaching group (bleached with 40% hydrogen peroxide), the infiltration group (treated with infiltrated resin) and the bleaching and permeation group (bleached with 40% hydrogen peroxide and then treated with an infiltrated resin). All samples were pH-cycled for 28 d to simulate oral conditions. The color and surface microhardness (SMH) and surface microhardness recovery (SMHR) of the enamel were determined before and after the lesion. Three sets of color changes ΔE (post-disease-basic value), ΔE (post-experimental-basic value) and ΔE (post -experimental-post-loss)] and surface microhardness recovery rate were calculated, and osmotic evaluation was performed using scanning electron microscopy. Results There were no significant differences in SMH before and after the lesion formation between the three groups. After the experiment, the SMH and SMHR were in the infiltration group>bleaching infiltration group>bleaching group (P＜0.05). There were significant differences in ΔE (post-experimental-basal value) and ΔE (post-experimental-post-loss) between the infiltration group and the bleaching group (P＜0.05). The whitening effect was higher in bleaching group than that of infiltration group, but still significantly worse than that of bleaching infiltration group.Under the scanning electron microscope, it can be seen that the bleaching and permeating group has relatively uniform resin penetration, and there were different ultrastructures between the cured resin materials. Conclusion The bleaching treatment before resin penetration can effectively improve the microhardness and the whitening effect.