ORIGINAL ARTICLE
Nanoscale Evaluation of Enamel Surface Property Changes Induced by Remineralization with Fluoride and pH-cycling Time
2021 Volume 71 Issue 4 Pages 208-214
Details
2021 Volume 71 Issue 4 Pages 208-214
In this study, the effects of: 1) fluoride addition during remineralization, and 2) pH-cycling time of demineralization and remineralization on the nanoscale surface properties of enamel, were investigated by measuring micro-surface roughness and the amount of demineralization.
Human enamel samples were cut and polished. The specimens were randomly divided into 4 groups of 12 specimens each and subjected to 4 experiments. Two other specimens were used for morphological observation.
In Experiment 1, the specimens were immersed 4 times in both demineralization and remineralization solutions for 5 minutes each. In Experiment 2, the specimens were immersed 4 times in both demineralization and fluoride remineralization solutions for 5 minutes each. In Experiment 3, the specimens were immersed 20 times in both demineralization and remineralization solutions for 1 minute each. Finally, in Experiment 4, the specimens were immersed 20 times in both demineralization and fluoride remineralization solutions for 1 minute each. After being immersed in these solutions, micro-surface roughness (arithmetic mean roughness (Ra) and root mean square roughness (Rq)) and amount of demineralization were measured. Two-way ANOVA was used to analyze Ra, Rq averages, and the amount of demineralization with pH-cycling time and fluoride addition to the remineralization solution as the two factors. The microstructure of the samples was observed with an atomic force microscope (AFM) images.
Both Ra and Rq were significantly lower with fluoride addition (p < 0.05), but there was no significant difference with the pH-cycling time. The amount of demineralization showed no significant difference with both factors. In the AFM image, a larger crystal size was observed in the case of fluoride addition.
When the enamel surface properties were evaluated on a nanoscale, the results indicated that micro-surface roughness of enamel was reduced significantly with the addition of fluoride during remineralization but not by the size of the crystals． Furthermore, it was suggested that micro-surface roughness was related to the total pH cycling time.
