Vieira K A, Steiner-Oliveira C, Soares L E S, Rodrigues L K A, Nobre-dos-Santos M
Department of Pediatric Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, São Paulo, 13414-900, Brazil.
Lasers Med Sci. 2015 Feb;30(2):901-7. doi: 10.1007/s10103-013-1493-0. Epub 2013 Dec 6.
This study aimed to evaluate the effects of repeated CO2 laser applications on the inhibition of enamel demineralization. Sixty-five human dental enamel slabs were randomly assigned to the following groups (n = 13): control (C), one application of the CO2 laser (L1), two applications of the CO2 laser (L2), three applications of the CO2 laser (L3), and four applications of the CO2 laser (L4). Enamel slabs were irradiated by a 10.6-μm CO2 laser operating at 5 J/cm(2). The slabs were subjected to a pH-cycling regimen and then analyzed by FT-Raman spectroscopy, energy-dispersive X-ray fluorescence spectrometry (EDXRF), cross-sectional micro-hardness, and scanning electron microscopy (SEM). Statistical analysis was performed using ANOVA and Tukey tests (p < 0.05). FT-Raman spectroscopy showed a reduced carbonate content for L1, L3, and L4 groups when compared to C (p < 0.05). The EDXRF data showed no statistical differences between the control and irradiated groups for calcium and phosphorus components (p > 0.05). Cross-sectional micro-hardness data showed a statistically significant difference between the control and all irradiated groups (p < 0.05), but no difference was found among the irradiated groups (p > 0.05) up to 30-μm depth. A tendency of lower demineralization occurred in deeper depths for L3 and L4 groups. The SEM results showed that with repeated applications of the CO2 laser, a progressive melting and recrystallization of the enamel surface occurred. Repeated irradiations of dental enamel may enhance the inhibition of enamel demineralization.
本研究旨在评估重复应用二氧化碳激光对抑制牙釉质脱矿的效果。65块人牙釉质片被随机分为以下几组（n = 13）：对照组（C）、二氧化碳激光照射1次（L1）、二氧化碳激光照射2次（L2）、二氧化碳激光照射3次（L3）和二氧化碳激光照射4次（L4）。牙釉质片用波长10.6μm、能量密度为5 J/cm²的二氧化碳激光照射。这些牙釉质片经过pH循环处理，然后通过傅里叶变换拉曼光谱（FT - Raman）、能量色散X射线荧光光谱法（EDXRF）、横断面显微硬度测试和扫描电子显微镜（SEM）进行分析。采用方差分析和Tukey检验进行统计学分析（p < 0.05）。FT - Raman光谱显示，与对照组相比，L1、L3和L4组的碳酸盐含量降低（p < 0.05）。EDXRF数据显示，对照组和照射组之间钙和磷成分无统计学差异（p > 0.05）。横断面显微硬度数据显示，对照组与所有照射组之间存在统计学显著差异（p < 0.05），但在深度达30μm时，照射组之间无差异（p > 0.05）。L3和L4组在更深的深度有较低脱矿的趋势。SEM结果表明，随着二氧化碳激光的重复应用，牙釉质表面发生了渐进性的熔化和再结晶。重复照射牙釉质可能增强对牙釉质脱矿的抑制作用。
