Surface engineering of biomaterials in orthopedic and dental implants: Strategies to improve osteointegration, bacteriostatic and bactericidal activities

Background: The success of biomedical implants in orthopedic and dental applications is usually limited due to insufficient bone-implant integration, and implant-related infections. Biointerfaces are critical in regulating their interactions and the desirable performance of biomaterials in biological environment. Surface engineering has been widely studied to realize better control of the interface interaction to further enhance the desired behavior of biomaterials. Purpose and Scope: This review aims to investigate surface coating strategies in hard tissue applications to address insufficient osteointegration and implant-related infection problems. Summary: We first focused on surface coatings to enhance the osteointegration and biocompatibility of implants by emphasizing calcium phosphate-related, nanoscale TiO₂-related, bioactive tantalum-based and biomolecules incorporated coatings. Different coating strategies such as plasma spraying, biomimetic deposition, electrochemical anodization and LENS are discussed. We then discussed techniques to construct anti-adhesive and bactericidal surface while emphasizing multifunctional surface coating techniques that combine potential osteointegration and antibacterial activities. The effects of nanotopography via TiO₂ coatings on antibacterial performance are interesting and included. A smart bacteria-responsive titanium dioxide nanotubes coating is also attractive and elaborated. Conclusion: Developing multifunctional surface coatings combining osteogenesis and antimicrobial activity is the current trend. Surface engineering methods are usually combined to obtain hierarchical multiscale surface structures with better biofunctionalization outcomes.