Er,Cr∶YSGG激光预备离体牙Ⅴ类洞对树脂充填微渗漏的影响

The Effect of Er,Cr∶YSGG Laser Irradiation on the Microleakage of Class Ⅴ Composite Resin Restoration

目的应用离体牙研究比较Er,Cr∶YSGG激光备洞与牙钻备洞对树脂充填微渗漏的影响。方法将30颗离体牙随机分为3组制备Ⅴ类洞:牙钻预备加酸蚀处理(对照组)、单纯激光预备组、激光预备加酸蚀处理组,每组10颗牙,经冷热循环染色后,在体视显微镜下记录微渗漏程度并应用非参数统计方法分析数据。结果在冠侧洞缘,激光预备加酸蚀处理组微渗漏与对照组差异无显著意义,单纯激光预备组微渗漏较对照组严重(P<0.05);在牙龈侧洞缘,单纯激光预备组充填体边缘微渗漏情况与对照组差异无显著意义,而激光预备加酸蚀组的充填体边缘微渗漏比对照组显著减少(P<0.01)。结论用Er,Cr∶YSGG激光预备Ⅴ类洞不能增加树脂与牙体组织的结合减少微渗漏的发生;而应用激光同时行酸蚀处理可以增强树脂充填体与牙本质间的结合,减少牙龈侧洞缘微渗漏。

Objective To compare the microleakage after composite resin filling to class Ⅴ cavities prepared by Er,Cr∶YSGG laser versus conventional mechanical treatment in vitro. Methods Thirty healthy human third molars were randomly assigned to three equal groups (n=10). Group 1: class Ⅴ cavities were prepared with a high-speed diamond bur and treated with 15% phosphoric acid. Group 2: cavities were prepared by the Er,Cr∶YSGG laser with water cooling. Group 3: cavities were prepared by laser and then acid etched by 15% phosphoric acid. Prime & BondR NT Adhesive System and X-FlowTM flowable resin composite were used for restorations. All samples were thermocycled and stained in 0.1% methylene blue, dye penetration was scored by means of a stereomicroscope. Data were analyzed using non-parametric statistical tests (Kruskal-Wallis and Mann-Whitney). Results On the occlusal margins, microleakage in acid etched cavities (group 1) was significantly lower than that achieved after laser treatment (group 2)(P<0.05); no statistical difference between groups 1 and 3. On the gingival margins, microleakage in group 3 was significantly lower than that in group 1(P<0.01); no statistical difference between groups 2 and 3. Conclusions Er,Cr∶YSGG Laser irradiation of enamel and dentin is not a valid alternative to acid-etching pretreatment for resin composite material adhesion. The use of acid etching in conjunction with laser cavity preparation decreases the microleakage in resin filling in dentin surfaces.