IADR Abstract Archives

Influence of F- on Enamel Demineralization: Real-Time in vitro Study

Objectives: A number of in vitro methods are available for testing of the anti-caries efficacy of fluoride ions. Most are indirect involving discontinuous analysis. The aim was to design an in vitro method for quantitative real-time measurements of changes in enamel mineral mass during exposure to caries simulating conditions at a range of F-concentrations. The secondary aim was to develop scanning microradiography (SMR) for accurate, real-time monitoring of the demineralization kinetics over periods of 48h, rather than 400h or more previously required.

Methods: Enamel sections (5 x 5 mm) of 2 mm thickness were cut from a caries–free permanent molar located in an SMR environmental cell through which demineralizing solution (0.1% acetic acid, pH 4.0) with additional F- concentrations of 0, 0.2, 1, 5, 25, 100, 300, 1000, 5000, 10,000 ppm were circulated through the SMR cell for 48h increasing F-concentrations. SMR was used to continuously measure the rate of enamel mineral loss (RMLenamel) at 3 points in each section.

Results: The rate of enamel loss was linear with time for all F-concentrations. Control (0ppm F-) RMLenamel= 5.00 x 10-4g cm-2s-1. 20% reduction in RMLenamel was observed with 0.2ppm F-and ~99% with 10,000ppm F-. A linear logarithmic relationship between % reduction (y) and fluoride concentration in ppm (x) was observed in the concentration range used (y = 7.93ln(x) + 35.5 (R2 = 0.81)).

Conclusions: A quantitative in vitro model suitable for determining the anti-caries efficacy of fluoride using SMR over shorter periods of time than previously used has been developed. The results demonstrate a logarithmic relation between reduction in rate of enamel mineral loss and F-concentration.

Funding EPSRC and GlaxoSmithKline


British Division Meeting
2011 British Division Meeting (Sheffield, England)
Sheffield, England
2011
169
Scientific Groups
  • Mohammed, Nasrine  ( Queen Mary, University of London, London, N/A, United Kingdom )
  • Lynch, Richard John Michael  ( GlaxoSmithKline, Weybridge, Surrey, N/A, United Kingdom )
  • Valsami-jones, Eva  ( National History Museum, Economic and Environmental Mineralogy, London, N/A, United Kingdom )
  • Anderson, Paul  ( Queen Mary, University of London, London, N/A, United Kingdom )
    • Oral Session
    Mineralised Tissue: Caries-related
    09/14/2011