Remineralization of Human Enamel by Fluoride Admixed with Xylitol

Although fluoride admixed with xylitol is added to sweets and toothpaste for prevention of tooth decay, the optimal concentration to be added had not been defined. Objectives: To evaluate the induction of high remineralization of human enamel by various low concentrations of fluoride admixed with xylitol. Methods: Extracted human wisdom teeth without lesions were placed in 50ml of 0.01M acetate buffer (pH4.0) to demineralize. The teeth were then placed in remineralizing solutions containing various low concentrations of fluoride admixed with 10% xylitol, and allowed to remineralize. Polished sections 100µm thick were made and contact microradiograms (CMRs) were taken. Microscopic images of the CMRs were downloaded onto a computer and the brightness of the remineralized parts were placed on a gray scale of 256 grades. These results were then used to calculate the degree of remineralization of each specimen. The concentration of calcium ions in remineralizing solutions was measured using a calcium ion electrode. The degree of saturation of each remineralizing solution was calculated with respect to fluoroapatite. Results: The degree of remineralization of no less than 0.8ppm fluoride admixed with 10% xylitol was greater than that of 0.4ppm fluoride. There was a significant difference (P<0.001) between 0.8ppm fluoride and control (0ppm). That is to say, the degree of remineralization had increased between 14 and 15 degrees of saturation with respect to fluoroapataite. Conclusions: As a result of the study, the remineralizing solution containing fluoride admixed with 10% xylitol was found to promote remineralization between 14 and 15 degrees of saturation with respect to fluoroapatite. Although both fluoride and xylitol are thought to promote remineralization, from this study, it can be suggested that the degree of saturation with respect to fluoroapatite should also be considered to difine the optimal concentration.