Abstract
The aim of this work was to obtain further information about the mechanisms of fluoride profiles in cementum. Fluoride was administrated to rats at varying doses (0, 50, l00ppmF in drinking water) and for different lengths of time (4, 13 and 25 weeks). A series of fluoride concentrations across the full thickness of molar cementum in rats were measured by means of an abrasive microsampling technique. The average fluoride concentrations in cementum increased significantly with each increasing dose and length of fluoride administration. The relative reductions of the average fluoride concentrations were 94.2〜36.5% at 50ppmF and 62.2〜49.0 % at 100ppmF in the outer layers (1〜60μm) and 91.5〜24.1 % at 50ppmF and 74.1〜7.6% at 100ppmF in the middle (61〜120μm) layers of the cementum after stopping fluoride administrations. The reduction rates were more related to the duration of cessation than to the fluoride concentrations in drinking water or regions of cementum. Two possible reasons are that the new cementum formation occurred after the withdrawal of fluoride administrations and that some fluoride release occurred from cementum surfaces when the fluoride supply was stopped. I conclude that the fluoride concentration in rat molar cementum were related to the length of fluoride cessation and regions of cementum.
