枸橼酸酸蚀牙本质的最佳浓度和时间

Optimal concentration and time for citric acid to etch the dentin disc

背景:虽然目前枸橼酸溶液已被逐渐运用于制作牙本质敏感模型方面的研究,但仍未得出一个有效的统一浓度及酸蚀时间。目的:观察不同浓度枸橼酸酸蚀牙本质盘不同时间的效果,以获得研究牙本质敏感症的可靠体外实验模型。方法:选取30颗前磨牙并制作成牙本质盘,经碳化硅水磨砂纸抛光、枸橼酸酸蚀处理,扫描电镜观察牙本质盘表面酸蚀后的形态学特征,测量牙本质小管的直径,比较分析不同浓度枸橼酸溶液(5%,10%,15%)分别酸蚀不同时间(30,60,120,180s)对牙本质样本表面玷污层的去除效果、开放牙本质小管的能力。结果与结论:枸橼酸溶液具有较强的酸蚀作用,其去除玷污层的能力随着酸蚀时间延长及溶液浓度的增加而加强。5%枸橼酸溶液酸蚀各时间组、10%和15%枸橼酸溶液酸蚀30s或60s时去除玷污层能力有限,仍有牙本质小管受到不同程度的玷污层覆盖;10%、15%浓度组各酸蚀120,180s均可使表面玷污层去除,暴露牙本质小管。15%枸橼酸酸蚀120,180s组的牙本质小管直径较10%浓度组大(P<0.05),而10%枸橼酸酸蚀120,180s组的牙本质小管直径差异无显著性意义(P>0.05)。提示10%枸橼酸溶液酸蚀牙本质样本120s是去除玷污层,暴露牙本质小管的最佳方法。

BACKGROUND： Although the citric acid solution has been gradually applied to prepare models of dentine hypersensitivity, but there is still not a uniform concentration and etching time. OBJECTIVE： To study the effect of different concentrations and different etching time of citric acid on the dentin disc to acquire a reliable in vitro model for the research of dentin hypersensitivity. METHODS： Thirty premolars were selected and made into the dentin discs. Each dentin disc surface was wet polished using silicone carbide papers to form a smooth and platten surface. The morphology of dentin discs surface etched by the citrate acid was observed by scanning electron microscopy and the diameter of the dentin tubules was measured. A comparative analysis was made on the ability of different concentrations of citric acid solution （5%, 10%, 15%） at different times （30, 60, 120, 180 s） to remove the smear laye on the dentin surface and open the dentinal tubules. RESULTS AND CONCLUSION： The etching capability of citric acid to remove the smear layer was enhanced with the etching time expansion and concentration increase. Each time group of 5% citric acid and 30 s and 60 s groups of 10% and 15% citric acid had the limited ability to remove the smear layer, since some dentinal tubules were still subjected to be covered by different levels of smear layer. When the etch time was 120 s and 180 s of 10 % and 15% concentration groups, they all had the capability to remove the smear layer completely and expose dentin tubules. The diameter of the dentin tubules of 120 s and 180 s groups when citric acid concentration was 15% was larger than that of 10% groups, with a statistically significant difference （P〈0.05）. Furthermore, the diameter of dentin tubules in 10% groups when the etch time was 120 s and 180 s had no significant difference （P〉0.05）. 10% citric acid to etchthe dentin discs for 120 s was demonstrated as the best etching condition for removing the smear layer and acquiring a reliable in vitro model for the research of dentin hypersensitivity.