Visible Light Triggered Chlorhexidine Release of Nitrogen-Doped TiO₂ Nanoparticle Dental Desensitizer

The purpose of this study was to develop a novel dental desensitizer with nitrogen-doped TiO₂ nanoparticles that show an optical response under visible light and investigate the triggered release of chlorhexidine from these nanoparticles in response to remote visible-light irradiation. Diffusive ultraviolet-visible spectroscopy indicated that N-doped TiO₂ nanoparticles solvothermally treated at 130°C for 2 h showed the highest absorbance at 470 nm. X-ray photoelectron spectroscopy confirmed that nitrogen was substantially doped into the TiO₂ lattice via the existence of N–Ti–O or N–Ti–N linkages (396.1 eV of N 1s). Chlorhexidine-release and agar-diffusion antibacterial tests revealed that visible-light irradiation statistically accelerated the chlorhexidine release and antibacterial activity. An agar overlay biocompatibility test showed that only the 0.1% chlorhexidine experimental group was biocompatible according to ISO 7405. Therefore, N-doped TiO₂ nanoparticles should enable the development of new visible-light-mediated antibacterial desensitizers in the field of dentistry.