Dentine hypersensitivity. I. Effects produced by the uptake in vitro of metal ions, fluoride and formaldehyde onto dentine

Abstract

Dentine has been shown to possess affinity for a large number of varied compounds, many of which have been shown effective in clinical trials, for the treatment of dentine hypersensitivity. The mode of action of these compounds is unclear. The aim of this study was to investigate the uptake of metal ions, fluoride and formaldehyde in solution onto dentine in vitro and determine whether therapeutic effects could be mediated through occlusion of dentinal tubules. Etched dentine sections were exposed for 1 h to 1000 ppm solutions of fluoride and metal salts. Levels of fluoride and respective metals could be extracted and measured from the specimens. Saliva pretreatment had a variable but small effect on uptake of each ion, but post treatment washings reduced all levels of retained fluoride and metals. X-ray microanalysis indicated surface or immediate subsurface deposits of metals. However, surface changes were only consistently produced by zinc and more particularly tin salts. Both zinc and tin salts produced covering or obturation of tubules. The surface effects of zinc could largely be reversed by washing, but not those of tin. Formaldehyde alone or in the presence of saliva produced no effects. A 4-week study involving twice daily exposure of specimens to saliva and fluoride, metals or formaldehyde yielded essentially the same results. It is unlikely that, except for tin, the compounds tested achieve their apparent clinical effects mediated by direct occlusion of dentinal tubules.

Strontium effects on root dentin tubule occlusion and nanomechanical properties

“…Our SEM-EDX evaluation could not detect a strontium containing layer after the specimens were soaked in DI-water for mechanical property measurement in Experiment 1. The levels of strontium incorporated into the surface of dentin may be below the detection limits of EDX, or the strontium salts formed may be soluble under the analysis conditions in the present study as reported by Addy and Mostafa [48]. Conversely, specimens kept on moist sponges (saturated with artificial saliva, simulating the reservoir, as in Experiment 2, showed strontium acetate particles reaching 20 m into tubules and general evidence of strontium presence through the dentin with SEM and EDX (Fig.…”

“…Strontium treatments created surface crystals, deposits on demineralized dentin surface in vitro, but they were easily washed away with water [48]. In vivo and in situ studies with strontium acetate [26,27,30] show greater tubule occlusion compared to our in vitro study models.…”

Assessment of Tooth Sensitivity Using a Desensitizer Before Light-activated Bleaching

“…13,16 Although the desensitizing agent contains 2% sodium fluoride, which occludes dentinal tubules [17][18] and increases enamel hardness, 19 this was shown to not interfere with the whitening effect of in-office or at-home bleaching.…”

Comparative Evaluation of Stannous Fluoride vs Potassium Nitrate in the Management of Dentinal Hypersensitivity

“…Hydrolysis and oxidation of the active ingredient occur with a consequent reduction in effectiveness. [19] More recent research, Thrash et al [20][21] supported the theory that the time required for a decrease in sensitivity is between two and four weeks from initiation of treatment. The effectiveness of the sole diode laser, was investigated by several research groups.…”