Effect of ammonium hexafluorosilicate on dentin tubule occlusion for the treatment of dentin hypersensitivity.

To evaluate the occluding ability of ammonium hexafluorosilicate (SiF). Dentin disks prepared from human extracted teeth were grouped as follows to prepare different situations of dentin hypersensitivity: (1) those sonicated for 20 minutes; (2) those treated with 0.5 mol/L EDTA for 2 minutes; (3) those treated with 6% citric acid for 2 minutes; (4) those treated with 50% citric acid for 2 minutes. Then, SiF or diamine silver fluoride (AgF) was applied to the dentin disks and the dentin tubule occlusion was observed with scanning electron microscopy (SEM). The percent of open tubules before and after SiF or AgF treatment were measured by NIH image using SEM photographs. Also, the dentin permeability was measured. SEM micrographs demonstrated that the dentin tubules were completely occluded by the precipitate after SiF treatment. Also, the dentin permeability was reduced to 10.3%. In contrast, most of the dentin tubules remained open after AgF treatment. EDXA analysis showed that the precipitate in the dentin tubules that forms after SiF treatment contains Si, Ca and P, indicating a silica-calcium phosphate complex.