Abstract:

Objective　To investigate the effect of hydrochloric acid solution with different pH value and etching time on the enamel surface. Methods　Forty enamel specimens were prepared，each sample surface was divided into untreated and treated surfaces. Based on the experimental conditions，the samples were randomized into 8 groups：the groups with etching time being 30 s and pH values of hydrochloric acid solution being 1.6，2.4，3.2 and 4.0 were groups A1，A2，A3 and A4；the groups with etching time being 60 s and pH values of hydrochloric acid solution being 1.6，2.4，3.2 and 4.0 were groups B1，B2，B3 and B4. Microhardness and amount of enamel loss were measured by microhardness tester and CLSM respectively. The results were analyzed by two factors factorial design ANOVA test. Results　After etching，microhardness values of group A1 to A4 decreased by （42.1 ± 5.8），（23.6 ± 5.7），（10.9 ± 6.9） and （-0.6 ± 2.6）MPa，respectively；in group B1 to B4 they decreased  by （59.3 ± 6.6），（35.4 ± 9.2），（15.7 ± 5.1） and （7.7 ± 3.1）MPa. CLSM observation showed that the enamel loss in group A1 to A4  was （793.4 ± 43.0），（319.2 ± 20.4），（15.8 ± 2.4） and （-1.4 ± 3.3） nm，respectively；in group B1 to B4 it was （1366.6 ± 174.8），（437.2 ± 41.0），（75.1 ± 6.4） and （1.3 ± 3.2）nm. ANOVA anslysis showd that etching time and pH value of hydrochloric acid solution had significant effects on the decrease of microhardness values and enamel loss. Conclusion　The different etching time and pH values of hydrochloric acid solution have significantly influence upon microhardness and enamel loss. There is an interactive effect between etching time and pH values of hydrochloric acid solution on the enamel loss.

Key words: dental erosion, enamel, hardness

摘要：

目的　探究不同pH值的盐酸溶液和酸蚀时间对釉质表面的影响。方法　制作40个釉质片样本，每个样本表面分为未处理面和处理面。根据处理面酸蚀条件分为8组，其中酸蚀时间为30 s，pH值分别为1.6、2.4、3.2、4.0的4组记为A1、A2、A3、A4组；酸蚀时间为60 s，pH值分别为1.6、2.4、3.2、4.0的4组记为B1、B2、B3、B4组。利用显微硬度计测量样本表面显微硬度；激光共聚焦显微镜测量样本未处理面和处理面之间形成的高度差（即釉质丧失量）。对结果进行两因素析因设计资料的方差分析。结果　酸蚀后，A1～A4组样本表面显微硬度值分别下降（42.1 ± 5.8）、（23.6 ± 5.7）、（10.9 ± 6.9）和（-0.6 ± 2.6）MPa；B1～B4组样本表面显微硬度值分别下降（59.3 ± 6.6）、（35.4 ± 9.2）、（15.7 ± 5.1）和（7.7 ± 3.1）MPa。A1～A4组样本未处理面和处理面之间的高度差分别为（793.4 ± 43.0）、（319.2 ± 20.4）、（15.8 ± 2.4）和（-1.4 ± 3.3）nm；B1～B4组样本未处理面和处理面之间的高度差分别为（1366.6 ± 174.8）、（437.2 ± 41.0）、（75.1 ± 6.4）和（1.3 ± 3.2）nm。方差分析结果显示，酸蚀时间和盐酸溶液的pH值对釉质表面显微硬度值下降量及釉质丧失量均有显著影响。结论　酸蚀时间和盐酸溶液的pH值均是影响釉质表面显微硬度值下降量及釉质丧失量的因素，且酸蚀时间和盐酸溶液的pH值对釉质丧失量的影响存在交互作用。

关键词: 酸蚀, 釉质, 硬度