Tricalcium silicate induced mineralization for occlusion of dentinal tubules

Background: The aim of this study was to evaluate the dentinal tubule occluding ability of tricalcium silicate (Ca3SiO5 or C3S) in vitro. Methods: Dentine discs were prepared from extracted caries-free human third molars and etched with 0.02 M citric acid (pH 4) for 3 minutes in order to produce patent dentinal tubules. Tricalcium silicate pastes of different viscosities were applied to the surface of the dentine specimens for 3 minutes and then removed with a swab followed by deionized water rinse. The dentine specimens were immersed in artificial saliva for 7 days. The tubule occlusion, sealing depth and chemical composition of the dentine specimens and bonding force between the dentine matrix and mineralized layer were evaluated by scanning electron microscopy, energy dispersion X-ray spectroscopy, X-ray diffraction analysis and a nanoscratch test. Results: A homogeneous layer of mineral crystals was precipitated onto the dentine surface and caused significant occlusion of the dentinal tubules. The dentine permeability and sealing depth of the C3S increased with the decrease of viscosity of the paste. With a proper viscosity of C3S pastes, the interface between the mineralized layer and the dentine matrix bonded well. Conclusions: This study suggests that C3S may be an effective agent for the treatment of dentine hypersensitivity.