Microencapsulated Hydroxyapatite-TEGDMA Systems for Self-Healing in Dental Applications

The development of microcapsules for the controlled release of active substances offers an innovative strategy in restorative dentistry, expanding the possibilities beyond traditional methods. In this study, microcapsules loaded with triethylene glycol dimethacrylate (TEGDMA) and different concentrations of hydroxyapatite (HAP)-0%, 5%, 10%, 15%, and 20%, referred to as M0, M5, M10, M15, and M20-were synthesized through in situ polymerization within an oil-in-water emulsion. Their morphology, size, and nanostructure were examined using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of characteristic chemical bonds, whereas high-performance liquid chromatography (HPLC) quantified residual TEGDMA monomer. Low-field nuclear magnetic resonance (NMR) further confirmed the presence and the distribution of the liquid healing agent inside the microcapsules. The analyses indicated that microcapsules incorporating 20% hydroxyapatite exhibited superior structural organization and improved shell integrity, highlighting their potential in the remineralization processes. Overall, these results support the potential of HAP-TEGDMA microcapsules for incorporation into dental composites to facilitate microcrack repair and promote dental tissue regeneration.