Castor oil-based gel containing calcium phosphate/sorbitan monopalmitate nanocomposite as proof of concept for tooth sensitivity treatment

Desensitizing gel has been used increasingly to produce stable minerals and occlude exposed dentine tubules in order to eliminate dentine hypersensitivity. In this study, calcium phosphate particles were synthesized in different ratios in the presence of a mixture of sorbitan monopalmitate and castor oil at 60 °C to generate water-in-oil emulsion, which was followed by gel formation. The rheological properties of the prepared gel samples were studied, and they showed weak gel behavior. The smallest particle size of calcium phosphate embedded in the gel sample was approximately 0.2 µm. This type of gel can release calcium and phosphate ions to initiate ion binding on the dental surface, thereby resulting in complete occlusion of the dentinal tubule approximately 10 h after the gel application. Moreover, cytotoxicity test revealed that the gel exhibited good compatibility with human cells at extract concentrations of < 1 mg/mL. In conclusion, the most effective gel CO-SMP4 could be utilized for the production of tooth desensitizing gels meant for home use that can effectively alleviate dentine hypersensitivity.