Effect of Fluoride and Chlorhexidine Combination on Enamel Demineralization/Remineralization

Objectives: to evaluate in situ the effect of the chlorhexidine and fluoride combination on biofilm composition and enamel demineralization/remineralization.

Methods: Fifteen volunteers wearing palatal appliances containing 4 bovine enamel slabs (2 with sound enamel; 2 with demineralized enamel) participated in this blinded, crossover study conducted in 4 phases of 14 days. The treatment groups were: CHX (0.12% chlorhexidine); F (0.05% NaF); CHX+F; control (no treatment). The solutions were rinsed 1 min/day. The sound slabs were covered by a plastic mesh and were used to evaluate demineralization. The demineralized slabs (Queiroz et al, 2003) were used to evaluate remineralization. During each phase, one drop of a 20% sucrose solution was applied on each sound slab 8 times a day. After each phase, the percentage of surface microhardness change (% SMH change) was determined on all slabs for comparison with the baseline values. The biofilm mineral content (F, Pi, Ca, insoluble polysaccharide) was analyzed on sound enamel. Data were statistically analyzed considering the randomized experimental design and the difference between mean values for each test was evaluated using Friedman's test (5%).

Results: The concentrations of F in the biofilm exposed to the F, CHX and control treatments were significantly less than those of the group treated with CHX+F (p < 0.05), but the difference among the groups was not significant (p > 0.05). The inorganic composition of the biofilm increased when exposed to sucrose, and mainly in the CHX+F. A significant increase in insoluble polysaccharides was found in the F group. The smallest concentrations of calcium, fluoride and phosphorus ions were detected in the control group. In the demineralized slabs, there was no difference in relation to the % SMH change among the groups.

Conclusion: The association of chlorhexidine to fluoride did not interfere to the halogen capacity of increasing enamel remineralization nor controlling the demineralization.