Dental implants are widely utilized to reinforce fixed or removable dental prostheses and to replace them with normal teeth function. Hydrogel-based coatings can be used to improve the biocompatibility, osseointegration, and antimicrobial effects of dental implants. Hydrogels can work as a drug release system, and various bioactive compounds, such as antibiotics and growth factors, can be incorporated into hydrogels as dental implant coating agents to improve the properties of the implants. The therapeutic efficacy of hydrogel as coating agents of dental implants can be further improved by the incorporation of compounds such as titanium dioxide (TiO2), dopamine, fluoride substituted hydroxyapatite (FHA), tetraethyl orthosilicate (TEOS), and silica nanoparticles (SNs) into the structure of hydrogels. Overall, the results of this study showed that using hydrogel-based coatings and improving their efficacy through the incorporation of various compounds (e.g., TiO2, FHA, TEOS, and SNs) are promising approaches to modifying the surface of implants to improve their biocompatibility, stability, peri-implantitis, and impaired osseointegration for biomedical applications.