Multifunctional Bioceramic Coatings for Dental Implants: Advances in Antibacterial Activity, Corrosion Resistance and Osseointegration with Clinical Perspectives and a Focus on Zirconia-Based Systems

Abstract

Background/Objectives: Titanium alloy Ti6Al4V remains the gold standard in dental implantology due to its excellent mechanical properties, corrosion resistance, and biocompatibility. However, implant-associated infections and insufficient osseointegration continue to represent major clinical challenges, mainly related to bacterial biofilm formation and suboptimal surface–tissue interactions. Biofilm formation refers to the adhesion, accumulation, and growth of microbial communities embedded within a self-produced extracellular polymeric matrix on implant surfaces, which contributes to bacterial persistence and resistance to host defense mechanisms. This review aims to critically evaluate recent advances in multifunctional bioceramic coatings for dental implants, with a particular focus on zirconia (ZrO2)-based systems and their antibacterial mechanisms. Methods: A structured literature analysis was conducted using major scientific databases including PubMed, Scopus, and Web of Science, focusing mainly on studies published between 2015 and 2025 related to CaP, Ag, and ZrO2-based coatings for dental implants. The review examines their physicochemical properties, antibacterial strategies, ion release behavior, and biological responses, including osteogenic activity and biofilm inhibition. Particular attention is given to hybrid systems integrating multiple functional phases. Results: CaP coatings exhibit excellent osteoconductivity and promote early osseointegration but show limited intrinsic antibacterial activity. Ag-based coatings provide strong broad-spectrum antimicrobial effects through controlled Ag+ ion release, although concerns regarding cytotoxicity and dose-dependent responses remain. ZrO2 coatings significantly enhance corrosion resistance and surface stability, while their antibacterial performance can be improved through nanostructuring, laser surface modification, and ionic doping. Hybrid Ag–CaP–ZrO2 coatings demonstrate improved antibacterial activity, enhanced corrosion resistance, and better regulation of ion release kinetics and osteogenic response compared with single-component coating systems. Conclusions: Multifunctional bioceramic coatings represent a promising strategy for improving the performance of dental implants and addressing the dual challenge of infection control and tissue integration. However, challenges remain regarding long-term stability, controlled ion release, and limited clinical validation. Future research should focus on the development of smart, stimuli-responsive coatings and standardized evaluation protocols to facilitate clinical translation.