Faculty of Medicine, University of Geneva, Geneva, Switzerland.
Department of Economics and Quantitative Methods, University of Genoa, Genoa, Italy.
Am J Dent. 2021 Feb;34(1):31-38.
To examine the marginal adaptation in enamel and dentin of mixed Class V saucer shaped restorations where cavities were prepared by two different lasers.
A handpiece-integrated Er:YAG laser @ 4.5 W, 300 mJ, 15 Hz (LiteTouch III) and a novel CO2 laser @ 12.95 W, 19.3 mJ, 671 Hz (Solea 9.3 µm). Diamond bur preparation with a 25 µm diamond bur (Intensiv) in a red contra angle at high speed under water spray cooling served as the control. Eight cavities per group were readied and restored under simulation of dentin fluid with a one bottle universal adhesive (One Coat 7 Universal) and a nanohybrid resin composite (Everglow), applied in two layers. For every preparation technique, the adhesive system was applied in the selective-etch and the self-etch mode, resulting in six experimental groups. Marginal analysis was performed immediately after polishing and after simultaneous thermal (5-50°C, 2 minutes each) and mechanical (max. 49 N; 200,000 cycles) loading by using a SEM (x200 magnification).
Significant differences were found for all groups - except groups 2 and 5 - between initial and terminal results and between the groups as well (P< 0.05, 2-way ANOVA with Fisher's post-hoc test). The bur prepared group with selective-etch technique showed the best overall results after loading, followed by Er:YAG prepared self-etch group and CO2-prepared selective-etch group.
By using a universal one-component adhesive system, marginal adaptation in enamel and in dentin depended on the preparation method and on the adhesive's application technique as well. When using lasers, Er:YAG in self-etch mode and CO2 9.3 µm in selective-etch mode total marginal adaptation showed results which were comparable to conventional bur preparation with selective-etch technique.
研究两种不同激光制备混合 V 类碗形窝洞时牙釉质和牙本质的边缘适应性。
采用手柄集成的 Er:YAG 激光（@ 4.5 W，300 mJ，15 Hz）和新型 CO2 激光（@ 12.95 W，19.3 mJ，671 Hz）。水喷雾冷却下高速旋转的 25 µm 金刚石车针（Intensiv）进行金刚石车针预备作为对照组。每组准备 8 个窝洞，在模拟牙本质液的情况下用一瓶通用粘结剂（One Coat 7 Universal）和纳米复合树脂（Everglow）进行双层充填。每种预备技术均采用选择性酸蚀和自酸蚀粘结系统，共分为 6 个实验组。使用 SEM（放大倍数 x200）分别在即刻抛光后和同时进行热（5-50°C，2 分钟/次）和机械（最大 49 N；200,000 次循环）负载后进行边缘分析。
除了第 2 组和第 5 组外，所有组在初始和最终结果以及组间均存在显著差异（P< 0.05，2 因素方差分析，Fisher 事后检验）。经选择性酸蚀技术预备的车针组在加载后整体结果最好，其次是 Er:YAG 自酸蚀预备组和 CO2 选择性酸蚀预备组。
使用通用单组分粘结系统时，牙釉质和牙本质的边缘适应性取决于预备方法和粘结剂的应用技术。当使用激光时，Er:YAG 自酸蚀模式和 CO2 9.3 µm 选择性酸蚀模式的总边缘适应性结果与传统的选择性酸蚀技术的车针预备结果相当。
