Valizadeh Sara, Rahimi Khub Maryam, Chiniforush Nasim, Kharazifard Mohammad-Javad, Hashemikamangar Sedighe Sadat
Assistant Professor, Laser Research Center of Dentistry, Dentistry Research Institute, Restorative Dentistry Department, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
Dentist, Teharn University of medical Sciences, Tehran, Iran.
J Lasers Med Sci. 2020 Fall;11(4):450-455. doi: 10.34172/jlms.2020.70. Epub 2020 Oct 3.
This study aimed to assess the effects of CO2 and erbium-doped yttrium aluminum garnet (Er:YAG) lasers with and without fluoride varnish on demineralization around composite restorations. This in vitro experimental study evaluated 96 extracted human premolars. After preparation and restoration of class V cavities in the buccal surface of the teeth with composite resin, they were randomly divided into 8 groups of control, CO2 laser (L1), CO2 laser-NaF (L1F), NaF-CO2 laser (FL1), Er:YAG laser (L2), Er:YAG laser-NaF (L2F), NaF-Er:YAG laser (FL2) and NaF (F). The entire surface of the teeth, except for the restored cavity in the buccal surface and 1 mm around the margin, was coated with two layers of nail varnish. The teeth then underwent pH cycling for 10 days (3 hours in demineralizing solution and 21 hours in remineralizing solution) to artificially induce demineralization. The amount of calcium and phosphorous released into the cariogenic solution was quantified using atomic absorption spectroscopy and spectrophotometry. The Vickers hardness tester was used to measure the hardness of the tooth structure adjacent to composite restoration. Data were analyzed using one-way ANOVA and Tukey's test. The four groups of L1F, FL1, FL2 and L2F showed minimum loss of calcium and phosphorous ions, and the mean hardness of FL1 and FL2 groups was higher than that of other groups. The CO2 and Er:YAG lasers alone have no significant effect on the resistance of tooth structure to cariogenic solution. However, they can exert a synergistic effect when used along with NaF varnish. Fluoride varnish applied prior to laser irradiation confers further resistance to the tooth structure and positively affects its hardness.
本研究旨在评估二氧化碳激光和掺铒钇铝石榴石（Er:YAG）激光，以及使用和不使用含氟涂料对复合树脂修复体周围脱矿的影响。这项体外实验研究评估了96颗拔除的人类前磨牙。在用复合树脂制备并修复牙齿颊面的V类洞后，将它们随机分为8组，分别为对照组、二氧化碳激光组（L1）、二氧化碳激光 - 氟化钠组（L1F）、氟化钠 - 二氧化碳激光组（FL1）、Er:YAG激光组（L2）、Er:YAG激光 - 氟化钠组（L2F）、氟化钠 - Er:YAG激光组（FL2）和氟化钠组（F）。除颊面修复的窝洞及其边缘周围1毫米外，牙齿的整个表面均涂有两层指甲油。然后，牙齿进行10天的pH循环（在脱矿溶液中3小时，在再矿化溶液中21小时）以人工诱导脱矿。使用原子吸收光谱法和分光光度法对释放到致龋溶液中的钙和磷的量进行定量。使用维氏硬度测试仪测量复合树脂修复体相邻牙齿结构的硬度。数据采用单因素方差分析和Tukey检验进行分析。L1F、FL1、FL2和L2F这四组显示钙和磷离子的损失最小，并且FL1组和FL2组的平均硬度高于其他组。单独使用二氧化碳激光和Er:YAG激光对牙齿结构抵抗致龋溶液的能力没有显著影响。然而，当与含氟涂料一起使用时，它们可以发挥协同作用。在激光照射前应用含氟涂料可进一步增强牙齿结构的抵抗力，并对其硬度产生积极影响。
