Effect of chewing gums with xylitol, sorbitol and xylitol-sorbitol on the remineralization and hardness of initial enamel lesions in situ

BACKGROUND The purpose of this study was to determine the effect of three chewing gums and paraffin on the remineralization and the hardness of demineralized enamel. MATERIALS AND METHODS A total of 12 subjects wore intraoral palatal appliances with two demineralized bovine enamel slabs. The study consisted of four experimental periods each lasting 21-days, during which subjects were assigned to one of three gum-chewing regimens: gum containing sorbitol, xylitol and a mixture of sorbitol and xylitol and with paraffin as control. The appliances were worn during gum-chewing for 20 min and then retained for 20 min 4 times/day. The slabs were subjected to energy dispersive X-ray spectroscopy analysis and surface microhardness measurements before in setting into the appliance and after the experimental period. The data were subjected to analysis of variance for repeated measures. A P < 0.05 was considered statistically significant. RESULTS Mineral analysis revealed no significant difference between the baseline and after chewing periods for all groups (P > 0.05). No significant difference was found among the groups either for the baseline measurements or after chewing periods (P > 0.05). All groups showed higher microhardness values after the chewing periods than the baseline except for the Vivident Xylit group (P < 0.05). CONCLUSION The chewing of gum had no effect on the Ca/P ratio of demineralized enamel surfaces. The hardening of the demineralized enamel surfaces may vary according to the type of chewing gum.