A dental formulation for the treatment of tooth sensitivity comprising: up to 50% by weight of one or more solid solutions, the one or more solid solutions comprising a solvent component and a solute component, wherein the solvent component is selected from hydroxyapatite, fluorapatite, oxyapatite, chlorapatite, substituted apatites, or mixtures thereof； wherein the solute component comprises potassium ions； wherein the one or more solid solutions are comprised of substantially spherical particles； wherein the particles comprise a single microcrystalline phase, and wherein at least 5% of the particles are below 3 microns in size, is provided. Preferably the dental formulation is a dentifrice, a gel or a dental strip. One or more calcium ions in the apatite lattice may be replaced by one or more different divalent cations, preferably selected from Zn, Ag and Sn. One or more phosphate ions may be replaced by one or more different anions in the apatite lattice preferably selected from carbonate, hydrogen carbonate or silicate anions. Preferably the particles are prepared by flame spray synthesis.
