The influence of fluoride varnish on the attrition of dentine

Objectives: Previous investigations have shown the potential for fluoride to be protective in an abrasion/erosion laboratory model. The aim of this study was to investigate the effect of high concentrations of fluoride delivered in a varnish on attrition of dentine. Methods: Fifteen caries free, intact lower third molar teeth, were sectioned and the enamel removed by a water-cooled diamond disc. Polished dentine surfaces were divided into 8 areas, four of which were randomly covered with a high concentration fluoride varnish for 24 hours. The samples were subjected to 5000 cycles of attrition bathed under artificial saliva. Results: Microhardness testing adjacent to the wear scars showed no statistical difference between the fluoride 71.85HV (SD7.37) treated and control surfaces 72.67HV (7.78). The volume of the wear scar was statistically greater for the fluoride treated surface at 38.42um3 (SD 13.25) and 32.54 um3 (17.13) for the control areas. A one sample t test showed a statistically significant difference between the two modalities of p = 0.014. Conclusions: The low pH of the fluoride varnish appears to have increased the amount of wear from attrition in this laboratory study.