Influence of Er,Cr:YSGG laser on root dentin submitted to erosive and/or abrasive challenges

Abstract This study evaluated how Er,Cr:YSGG laser, associated or not with 5% fluoride varnish, influences the surface roughness and volume loss of bovine root dentin submitted to erosive and/or abrasive wear. One hundred and twenty dentin specimens were divided into the groups: without preventive treatment (WPT), 5% fluoride varnish (FV); Er,Cr:YSGG laser irradiation (L), and varnish combined with laser (FV + L). The specimens (n = 10) were subdivided into: 1 = erosion (E); 2 = abrasion (A); and 3 = erosion followed by abrasion (E + A). The erosive solution used was a soft-drink (pH = 2.42 at 4ºC) applied in 5-min cycles twice a day for 10d. Abrasive wear involved brushing for 60s with an electric brush (1,600-oscillations/s) at a load of 2.0N. Surface roughness and volume loss were evaluated using a laser scanning confocal microscope. Roughness data were submitted to one-way ANOVA and Tukey post-hoc test. For volume loss, the Kruskal-Wallis and Dunn’s post-hoc tests were used (α = 5%). The lowest values of roughness were found in the control areas of all subgroups (p > 0.05). In the experimental area, the [(WPT) + (E+A)] subgroup had a significantly higher roughness (5.712 ± 0.163 μm 2 ) than the other subgroups (p摘要 本研究探究了Er,Cr:YSGG激光（Er,Cr:YSGG laser）联合或不联合5%氟保护漆（5% fluoride varnish），对经侵蚀性和/或磨耗性磨损处理的牛牙根牙本质（bovine root dentin）的表面粗糙度及体积损失的影响。将120份牙本质标本分为以下组别：无预防处理组（WPT）、5%氟保护漆组（FV）、Er,Cr:YSGG激光照射组（L）以及氟保护漆联合激光组（FV+L）。每份标本（n=10）再细分为3个亚组：1=侵蚀组（E）、2=磨耗组（A）、3=先侵蚀后磨耗组（E+A）。本研究采用的侵蚀液为pH值2.42的碳酸饮料，于4℃下保存，以每日2次、每次5分钟的周期进行处理，持续10天。磨耗性磨损实验采用负载2.0N、振荡频率为1600次/秒的电动牙刷刷洗60秒。通过激光扫描共聚焦显微镜（laser scanning confocal microscope）评估标本的表面粗糙度与体积损失。粗糙度数据采用单因素方差分析（one-way ANOVA）及Tukey事后检验进行统计学分析；体积损失数据则采用Kruskal-Wallis检验与Dunn事后检验（检验水准α=5%）。所有亚组的对照区域均呈现最低粗糙度（p>0.05）；在实验区域中，[(WPT)+(E+A)]亚组的粗糙度（5.712±0.163 μm²）显著高于其余亚组（p