Effect of xylitol:sorbitol on fluoride enamel demineralization reduction in situ

OBJECTIVES: To evaluate if sugar alcohols would reduce enamel demineralization enhancing the fluoride (F) effect. METHODS: A crossover in situ study was conducted in four phases, during which 10 volunteers were submitted to one of the treatments: (I) Distilled and deionized water, as a negative control; (II) F (226 microg F/ml as NaF; concentration used in commercial mouthrinse); (III) X:S (xylitol:sorbitol 1:3; final concentration 1.6M; 28% of sugar alcohols) and (IV) F+X:S (same final concentration that groups II and III). The volunteers wore palatal appliances containing four bovine enamel blocks of known surface microhardness (SMH), covered with a 'test plaque' of mutans streptococci, which were immersed during 1 min in one of the allocated treatment solutions simultaneously that the volunteers rinsed their mouths with the same solution. After the rinsing the appliances were put in the mouth and after 20 min a cariogenic challenge was made with 20% sucrose solution during 1 min. After further 45 min the 'test plaque' was collected for F analysis, enamel SMH was again determined and the percentage of change in relation to baseline was calculated; F uptake in enamel was also determined. RESULTS: With respect to all the analyses made, the group F+X:S did not differ from the F treatment (p>0.05) and the groups treated with F and F+X:S differed from the negative control (p<0.05). CONCLUSIONS: The results suggest that xylitol:sorbitol may not enhance the effect of fluoride present in mouth rinse on the reduction of enamel demineralization.