In vitro hydroxyapatite formation of a TTCP and DCPA based dentine desensitiser

The objective of this study was to characterise apatite formation ability of a tetra calcium phosphate (TTCP) and dicalcium phosphate anhydrous (DCPA) based desensitising product, Teethmate (TM). Methods: Cylindrical samples of TM were produced and immersed in TRIS buffer and artificial saliva (AS) for selected time periods. This was followed by characterisation of the phases formed using 31P Magic Angle - Nuclear Magnetic Resonance Spectroscopy, X-ray powder diffraction and Fourier-transform infrared spectroscopy. Dentine discs treated with the material were analysed by scanning electron microscopy (SEM) to evaluate crystal shape and tubules occlusion. Results: SEM analysis showed the formation of plate-like crystals occluding the dentinal tubules. Solid-state characterisation analyses showed that TM cement samples immersed in TRIS-buffer (pH: 7.3) formed hydroxyapatite phases within approximately six hours of immersion. HA formation was less rapid for the samples stored in AS (pH: 6.5). Conclusions: This study shows that a TTCP-DCPA based desensitising product (TM) converts to HA in vitro and provides an effective option for the treatment of dentine hypersensitivity.