含氯化锶脱敏糊剂对牙本质小管的封堵效果及生物安全性评价

目的 研究含2%氯化锶的脱敏剂对牙本质小管的封堵效果，并对其生物安全性进行评价。方法 制备含2%十二烷基硫酸钠（ SLS）和2%氯化锶的脱敏糊剂（ DS1）。选择无龋坏无缺陷的牛下颌切牙制备牙本质片24个，随机分3组，分别置于DS1（实验组）、普通含氟牙膏（阴性对照组）和去离子水（空白对照组）中进行刷牙处理。牛牙表面连续处理7天后采用扫描电子显微镜（ SEM）及其图像分析研究含锶脱敏糊剂对牙本质小管的封堵率。另外，选择市售含氟牙膏（阴性对照）、不含SLS的脱敏糊剂（ DS2）及3种同类脱敏产品，采用滤膜扩散法进行体外细胞毒性研究，并评价脱敏糊剂DS1浸提液的口腔黏膜刺激反应和皮肤致敏反应。采用一次限量法研究脱敏糊剂的急性经口毒性（ LD₅₀）。结果 SEM分析表明，DS1对牙本质小管的封堵率为70.97%，阴性对照组为48.29%，两者之间及相比空白对照组，差异均具有统计学意义（ P ＜ 0.05）。DS1具有一定的细胞毒性，但未产生刺激和致敏反应。DS1的LD₅₀大于5 000 mg/kg，但呈现实际无毒的结果。结论 在本研究中，含有2%的SLS和2%的SrCl₂ · 6H₂O的脱敏糊剂具有良好的生物安全性，对牙本质小管的封堵效果较好。

Biosafety evaluation and dentinal tubule sealing effects of desensitizer containing strontium chloride

Objective The aim of this study was to evaluate the biosafety and the dentinal tubule sealing effects of dental desensitizer containing 2% SrCl2. Methods Desensitizers (DS1) containing 2% sodium lauryl sulfate (SLS) and 2% SrCl₂ · 6H₂O was prepared. Dentin slices were prepared from 24 bovine mandibular incisors without caries and structural defects, and were randomly divided into 3 groups. After 7 days of treatment on dentin samples, the occlusion rate of strontium-containing desensitizer on dentinal tubules were evaluated by scanning electron microscopy (SEM) and image analysis. The commercial fluoride toothpaste was used as the negative control. Desensitizers (DS2) without SLS and three same types of desensitizers were selected for analyzing the in vitro cytotoxicity. The filter diffusion test was used for analyzing the in vitro cytotoxicity of desensitizer samples. The oral mucosa irritation reaction and skin sensitization of the desensitizer leach liquor were evaluated. The acute oral toxicity (LD₅₀) of desensitizer was evaluated by limit test. Results The SEM image analysis showed that the dentin tubule occlusion rate of the experimental group treated by DS1 was 70.97%, and that of the negative control group was 48.29%. There was a significant difference (P<0.05) between the experimental group and the negative control group, as well as a significant difference between the blank control group and either of the above two groups. DS1 showed a certain in vitro cytotoxicity, but no irritation and skin sensitization. The value of LD₅₀ exceeded 5 000 mg/kg, which proved that DS1 was practically nontoxic. Conclusion In this study, desensitizers (DS1) containing 2% SLS and 2% SrCl₂ · 6H₂O showed good biosafety and dentinal tubule sealing ability.