Antimicrobial-Releasing Implant Substrates for Combating Oral Biofilms: An In Vitro Study

Peri-implantitis, a biofilm-associated inflammatory disease, significantly threatens dental implant longevity. Current treatments face limitations due to biofilm robustness. This study evaluates the efficacy of antimicrobial-releasing titanium-silica (Ti/SiO₂) composite implant systems against multispecies oral biofilms, aiming to advance innovative localized and targeted peri-implantitis prevention and management strategies.

Ti/SiO₂ inserts were engineered with macroporous Ti6Al4V discs produced by additive manufacturing (AM) and a sol-gel-derived mesoporous SiO₂ barrier for controlled antimicrobial release across the discs. Chlorhexidine (CHX), as the gold standard antimicrobial agent in dental practice, was tested for its release efficacy using either a laboratory-prepared chlorhexidine diacetate solution (CHX-DA) or the commercial formulation Corsodyl. Phosphate-buffered saline (PBS) and Brain Heart Infusion-2 (BHI-2) medium served as control solutions. After establishing the CHX-DA release profile, multispecies biofilms were grown on the inserts. The antimicrobial efficacy of the release systems was assessed via viability-qPCR, scanning electron microscopy (SEM), and metabolic acid profiling. All experiments were conducted four times.

A mean pore diameter of 5.6 nm was observed for the discs, resulting in a steady drug release rate (≈0.00077 mmol/L CHX-DA/day). The antimicrobial-fed inserts showed less biofilm formation, with ≥ 2 log₁₀ reductions in viable bacteria compared to controls. CHX-DA and Corsodyl showed effective suppression of pathogenic bacteria and reductions in metabolic acid production. SEM analysis revealed morphological changes in bacterial cells on treated surfaces.

Antimicrobial-releasing Ti/SiO₂ implant discs demonstrated sustained efficacy in biofilm prevention and treatment, indicating their feasibility as a future strategy for peri-implantitis management.