Effect of low level fluoride on demineralization kinetics of human dental enamel

Abstract The purpose of this study was to examine the effect of fluoride levels similar to those reported for saliva from low fluoridated and high fluoridated water areas on the demineralization of human permanent enamel. An adaptation of the method described by Robinson et al. was used. Sections of sound enamel were immersed in a vial containing demineralizing solution [2.0mM Ca(NO 3 ) 2 , 1.2mM KHPO 4 in 50mM acetic acid, pH 4.8] for 1 hour. The demineralizing solution contained 0, 0.02 or 0.05ppm fluoride, added as NaF was prepared. Twenty microliters aliquots were taken from the demineralizing solution at the time point up to 1 hour, with a sampling frequency bias towards the early time point. The phosphate content of the removed sample was determined by colorimetry. When the mineral loss curves for fluoridated and non-fluoridated demineralizing solutions were compared, there were significant differences between both groups. There was a decrease in the net mineral loss when fluoride was used. This result suggested that salivary fluoride levels of 0.02ppm and 0.05ppm had a protective effect against demineralization.