2007 Volume 50 Issue 3 Pages 313-320
Diamine silver fluoride (Saforide®) is used clinically to prevent the progress of dental caries and desensitize hypersensitive teeth. Unfortunately, diamine silver fluoride stains teeth black due to silver precipitation; therefore, it is mainly applied to deciduous teeth. To overcome this drawback, ammonium hexafluorosilicate(SiF:(NH_4)_2SiF_6)was prepared. Silica was employed instead of silver because it does not change the color of teeth, and is well known to induce apatite formation from simulated body fluids. The purpose of this study was to evaluate the occluding ability and duration of dentin tubule occlusion after SiF treatment in a simulated oral environment. The occluding ability of SiF was evaluated using human dentin disks. The surface of dentin disks was observed with a scanning electron microscope (SEM)immediately after SiF treatment and 7 days after immersion in synthetic saliva. SEM observation showed that open dentin tubules were occluded completely with silica-calcium phosphate precipitate immediately after SiF treatment. In addition, newly formed crystals covered the dentin surface 7 days after immersion in synthetic saliva. EDXA analysis showed that the precipitate formed in the dentin tubules after SiF treatment contains silica, calcium and phosphorous indicating silica-calcium phosphate complex. The Ca/P molar ratio of the precipitate formed with SiF treatment was 2.02, and the value gradually decreased after immersion in synthetic saliva. In contrast, the Ca/P molar ratio of newly formed crystals at the dentin surface showed a relatively constant value(Ca/P=1.16-1.28)throughout the experimental period. It seems that calcium-deficient apatite may be precipitated at the dentin surface due to the Ca/P ratio being significantly lower than that of intertubular dentin. SiF treatment induced calcium phosphate precipitation from synthetic saliva; therefore, it has a continuous effect on dentin tubule occlusion under a simulated oral environment.
