Effects of ammonium hexafluorosilicate concentration on dentin tubule occlusion and composition of the precipitate

Ammonium hexafluorosilicate [SiF: (NH(4))(2)SiF(6)] was prepared in order to overcome the tooth discoloration caused by diamine silver fluoride [AgF: (NH(3))(2)AgF] application. We employed a single concentration of SiF solution in our previous study; therefore, it is still unclear how the concentration of SiF solution affects the occlusion of dentin tubules and composition of the precipitate. Objective. The aim of this study was to evaluate the effects of changing the concentration of SiF on its clinical use as a dentin hypersensitivity treatment. Methods. To simulate dentin tubules subject to dentin hypersensitivity, dentin disks were treated with EDTA for 2 min. Then, the disks were treated with several concentrations of SiF solution (from 100 to 19,400 ppm) for 3 min. The occlusion of dentin tubules was evaluated using scanning electron microscopy (SEM), and the composition of the precipitate formed in the tubules after SiF treatment was assessed using energy dispersive X-ray analysis (EDXA). Results. SEM photographs demonstrated that dentin tubules after treatment with SiF were occluded homogeneously and fully regardless of the concentration of SiF solution. The Ca/P molar ratio of the precipitate formed in dentin tubules after SiF treatment was increased with the concentration of SiF solution. Significance. It was concluded that the capacity to occlude dentin tubules was the same regardless of the concentration of SiF solution. However, the composition of the precipitate formed in the tubules was dependent on the concentration of SiF solution. (C) 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.