Diffusion coefficient of fluoride in dental plaque

Abstract

A recent paper by Watson et al. (J Dent Res 84:4, 2005) reported ex vivo measurements of fluoride ion penetration into dental plaque formed on removable implants worn by human volunteers. These data showed that brief exposures - 30 sec to 2 min - of plaque biofilms to 1000 ppm fluoride were insufficient to deliver the full concentration of fluoride throughout the depth of the biofilm. Here, I report the extraction of the numerical estimate of the effective diffusivity of fluoride in dental plaque from these valuable data. The reason to bother determining the diffusion coefficient is that this is an intrinsic parameter that can be compared between studies and can form the basis of predictive calculations.