Reduction in dentin permeability using a slurry containing dicalcium phosphate and calcium hydroxide

Abstract Treatments that obdurate dentin tubules have been used for reducing dentin hypersensitivity. The purpose of this study was to determine the effect of a treatment with a slurry of micron sized calcium phosphate on the hydraulic conductance (L_p) of etched dentin discs in vitro. The treatment slurry was prepared by mixing a powder mixture of dicalcium phosphate anhydrous and calcium hydroxide with a solution that contained sodium fluoride and carboxymethyl cellulose. The mean baseline L_p (in mL cm⁻² s^–1 H₂O cm^–1) was 2.07 ± 1.45 (mean ± SD; n = 13)). After one treatment and 2, 4, and 7 days of incubation in a protein‐free saliva‐like solution (SLS), the mean relative L_p, presented as % of baseline, were 65 ± 16, 42 ± 27, 36 ± 26, and 33 ± 27 (n = 13), respectively. The L_p values of the baseline and treatment after incubation in the SLS were significantly (p < 0.05) different. Scanning electron microscopic examination showed partial obturation of dentin tubules in the treated dentin. X‐ray diffraction and chemical analyses indicated the major product formed from the slurry was a fluoride‐containing hydroxyapatite. Treatment appeared effective in further reducing L_p of dentin discs after incubation in the SLS. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006