Erosion protection of low‐concentration fluoride on human tooth enamel: results from surface morphology and nanomechanical and anti‐wear properties

Dental erosion results in excessive tooth wear. The contribution of low-concentration fluoride used daily in the prevention and treatment of erosion has not been fully understood. In this study, the effects of fluoride (225 ppm F−) on the surface morphology and nano-mechanical and anti-wear properties of human tooth enamel were investigated to explore whether low-concentration NaF solution could help protect tooth enamel from erosion. In total, 40 enamel samples were divided into 5 groups, viz. group O: original surface with no treatment, group F: fluoride treatment (NaF, 225 ppm F−, pH 6.3), group E: erosion treatment (0.001 M citric acid, pH 3.2, 3 min), group EF: erosion treatment and then fluorination and group FE: fluoride treatment and then erosion. The mechanical and anti-wear properties of enamel samples were examined using a nano-indentation/scratch technique. Both surface morphology and scratch morphology of enamel samples were observed with scanning electron microscopy. The results showed that, from the perspectives of surface morphology and anti-wear properties, fluorination with low-concentration fluoride (225 ppm F−) before erosion has a certain potential for protection against dental erosion. Fluoride treatment after erosion has no obvious impact on the remineralisation of eroded enamel.