Occlusion Of Dentinal Tubules By (nh₄)₂ Sif₆

Objective:To observe the effects of occlusion of (NH4)2SiF6 solution on dentinal tubules, and discuss the mechanisms of treatment in dentin hypersensitivityMethod:36 free dentinal discs were made from free third molars, and divided into 4 pretreatment groups. The first group was washed with dionized water in an ultrasonic bath for 5 min. The other groups were soaked in pretreatment solution for 2 minutes, namely 0.29mol/L EDTA,6% citric acid,50% citric acid, respectively. After pretreated, the teeth were treated for 3 minutes by investigational drug solution (0.476 mol/L (NH4)2SiF6) and two kind of compared drug solution (2.36mol/L Ag(NH3)2F). The openness of the dentinal tubules was observed and the F, P, Ca elements quality distribute of the premolars surface were measured by the electron spectrometer.Result:(1) After pretreated, the dentinal tubules of every group teeth were openness. Due to very strong the demineralization of the pretreatment solution, the second to fourth groups of the dentinal tubules were openness, except the dentinal tubules of the first group maintained original state.(2) After pretreated with Ag(NH3)2F solution, there were varying degrees of deposition on the group of the dentinal tubules, moreover, the openness area and mean diameter of these dentinal tubules decreased compare with three kind of pretreated solution, and existed significant difference (P<0.05)(3) After treated with (NH4)2SiF6 solution, the group of the dentinal tubules were sealed completely. The openness area and mean diameter of these dentinal tubules decreased obviously compare with three kind of pretreated solution and existed significant difference (P<0.05)(4) Compare with the group of treated by Ag(NH3)2F, the diameter of the dentinal tubules changed obviously (P<0.05), and the openness area of the dentinal tubules decreased obviously and existed significant difference (P<0.05). After treated by 0.476 mol/L (NH4)2SiF6 and 2.36mol/L Ag(NH3)2F solution, respectively, the openness area of the dentinal tubules decreased obviously and exited significant difference by SEM.Conclusion:(1) (NH4)2SiF6 and Ag(NH3)2F solution can seal off the dentinal tubules obviously. (2) (NH4)2SiF6 can react with dentinal to produce silico-calcium phosphate compound which can seal off the dentinal tubules under the circumstance of not changing tooth color.(3) (NH4)2SiF6 has the advantage of sealing off the dentinal tubule than Ag(NH3)2F, though they are also fluorine-contained medicines..