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）与5%氯化亚锡（stannous chloride, SnCl₂）的实验性牙科护膜（experimental varnish）对牛牙本质侵蚀-磨耗损伤的防护效果。研究以牛牙颈牙本质样本为受试对象，先经0.3%柠檬酸（pH 2.6）预处理10分钟完成预侵蚀造模，随后将样本随机分为4组（每组n=10）：对照组（CG）：不含活性成分的实验性牙科护膜；nHAP组（nHG）：含20% nHAP的实验性牙科护膜；氯化亚锡组（SnG）：含5% SnCl₂（锡离子浓度24800 ppm）的实验性牙科护膜；复合组（nHSnG）：含20% nHAP与5% SnCl₂（锡离子浓度18300 ppm）的实验性牙科护膜。涂布受试材料后，连续5天开展侵蚀-磨耗挑战实验。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。数据分析采用单因素方差分析（one-way ANOVA）结合Bonferroni校正检验，检验水准设定为α=0.05。结果显示，与其余两组相比，SnG组与nHSnG组的防侵蚀磨耗效果更显著（p<0.05）；且SnG组与nHSnG组的牙本质结构缺损量无统计学差异（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）；两组间的闭合牙本质小管数量无显著差异（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）的实验性牙科护膜，均可作为预防牙本质侵蚀-磨耗的潜在有效策略；其中复合组nHSnG还可有效闭塞牙本质小管。