Dental Biofilm Fluid Fluoride Upon Increasing Frequencies of F-Toothpaste Use

Method:   In a double-blind, crossover, situ study, 18 volunteers wore a palatal appliance containing bovine enamel blocks, covered by a plastic mesh and exposed to 20% sucrose 8x/day to induce cariogenic biofilm formation. Volunteers brushed their teeth and the appliance 3 times/day, but a 1,100 ppm F, NaF-based toothpaste was used either 0, 1, 2 or 3 times/day. For groups 1 to 3 times/day, the last daily brushing was always performed with the fluoride toothpaste, and for the 0, 1 or 2 frequencies, a placebo toothpaste was used for the other brushings. After 14 days, dental biofilm formed on the blocks was collected after overnight clearance, the fluid extracted and analyzed for fluoride concentration using an inverted fluoride electrode. 

Result:   Fluoride concentration in dental biofilm (µM) increased linearly (p<0.05) with the increasing frequency of fluoride toothpaste use (3.7±2.9, 6.8±6.3, 6.6±4.5 and 10.4±16.0, respectively, for the 0, 1, 2 and 3 exposures/day).

Conclusion: The results show that increased frequencies of exposure to fluoride toothpaste enhance the residual fluoride concentration in dental biofilm, and suggest that biofilm enrichment with fluoride may play a role. Supported by FAPESP (2012/02815-9) and FUNCAMP (4252).