Anti-erosion effect of an experimental varnish on eroded dentin

Abstract This in vitro study evaluated the effect of an experimental varnish containing 20% nano-hydroxyapatite (nHAP) associated with 5% stannous chloride (SnCl2) against erosive-abrasive wear on bovine dentin. Samples of bovine cervical dentin were pre-eroded (0.3% citric acid, pH 2.6 for 10 minutes) and randomized into 4 groups (n=10): Control group - experimental varnish without active ingredient (CG); experimental varnish containing 20% nHAP (nHG); experimental varnish containing 5% SnCl2 (24.800 ppm Sn2+) (SnG); experimental varnish containing 20% nHAP associated with 5% SnCl2 (18.300 ppm Sn2+) (nHSnG). After applying the materials, the erosive-abrasive challenges were performed for five days. Erosive dentin loss and analysis of the pattern of dentinal obliteration were performed by 3D confocal laser microscopy. A one-way ANOVA/Bonferroni test was performed to analyze the data (α=0.05). The SnG and nHSnG experimental groups presented more effectiveness in preventing erosive wear when compared to the other groups (p<0.05). There was no statistically significant difference between the SnG and nHSnG groups (p = 0.731) in tooth structure dentin loss. Regarding the amount of open dentinal tubules, the highest amount of obstructed dentinal tubules was demonstrated in SnG and nHSnG (p < 0.05) when compared to the others. Between SnG and nHSnG there was no significant difference (p = 0.952) in the amount of closed dentinal tubules in the dentin. Experimental varnishes containing 5% SnCl2 associated or not with 20% nHAP showed to be a promising strategy in preventing erosive-abrasive wear of dentin. In addition, nHSnG was able to obliterate dentinal tubules.

摘要 本体外研究评估了一种含20%纳米羟基磷灰石（nano-hydroxyapatite, nHAP）并联合5%氯化亚锡（stannous chloride, SnCl₂）的实验性牙用护漆对牛牙本质侵蚀磨耗的防护效果。牛颈牙本质样本经0.3%柠檬酸（pH 2.6）预侵蚀处理10分钟后，被随机分为4组（每组n=10）：对照组（Control group, CG），即不含活性成分的实验性牙用护漆；20%nHAP组（nHG），含20%纳米羟基磷灰石的实验性牙用护漆；5%SnCl₂组（SnG），含5%氯化亚锡（Sn²+浓度为24800 ppm）的实验性牙用护漆；20%nHAP联合5%SnCl₂组（nHSnG），含20%纳米羟基磷灰石联合5%氯化亚锡（Sn²+浓度为18300 ppm）的实验性牙用护漆。涂布受试材料后，对所有样本开展为期5天的侵蚀磨耗刺激实验，采用三维共聚焦激光显微镜（3D confocal laser microscopy）检测牙本质侵蚀缺损量并分析牙本质小管闭塞模式，采用单因素方差分析/Bonferroni检验对数据进行统计分析，检验水准设为α=0.05。结果显示，与其余两组相比，SnG组与nHSnG组在预防牙本质侵蚀磨耗方面效果更显著（p<0.05）；SnG组与nHSnG组在牙本质缺损量上无统计学差异（p=0.731）。在开放牙本质小管数量方面，SnG组与nHSnG组的牙本质小管闭塞率更高（p<0.05），优于其余两组；两组在闭合牙本质小管数量上无显著差异（p=0.952）。研究表明，含5%氯化亚锡（无论是否联合20%纳米羟基磷灰石）的实验性牙用护漆均可作为预防牙本质侵蚀磨耗的潜在有效策略，此外，20%nHAP联合5%氯化亚锡的实验性护漆可有效实现牙本质小管闭塞。