Influence of Dentifrices pH on Enamel Microhardness In Vitro

Abstract

Purpose was to evaluate the effect of toothpastes pH on enamel remineralization. Six fluoride toothpaste and one without fluoride were applied to the enamel slabs. Twenty eight enamel slabs were divided into seven groups and subjected to a daily cycling regimen with brushing treatments, demineralization and remineralization in artificial saliva. The surface microhardness (SMH) was calculated from the mean values obtained from six indentations (Vickers hardness number (VHN)) on the enamel surface at baseline and after 12 days. pH of the dentifrices was determined in a slurry with deionized water (1:3). Changes of the enamel surface microhardness at baseline and after remineralization stage were measured and analyzed using the Student t-test and one-way ANOVA. All groups treated with fluorides showed higher SMH values compared to control group. Toothpastes with lower pH (Pronamel, Sensodyne F, Sensodyne Rapid) were statistically superior to other fluoride dentifrices and control group after 12 days pH-cycling regimen (p < 0.001). Obtained results showed that slightly acidified fluoridated toothpastes may have a positive influence on enamel remineralization process.