Citric acid promotes effective in vitro decontamination of titanium while supporting surface, electrochemical, and biological properties compared with conventional chemical agents.

OBJECTIVES: This in vitro study evaluated the antimicrobial, physicochemical, electrochemical, and biological effects of chemical agents used for titanium (Ti) surface decontamination, with emphasis on identifying an optimal citric acid (CA) concentration for peri-implant disease management. MATERIALS AND METHODS: Surface integrity, electrochemical behavior, and protein adsorption were analyzed after 1-min immersion in phosphate-buffered saline (PBS; control), 0.2% chlorhexidine (CHX), 3% hydrogen peroxide (HP), 1% sodium hypochlorite (SH), and CA (10, 20, 30, and 40%). Antimicrobial activity was assessed using a two-phase polymicrobial biofilm model under aerobic and anaerobic conditions. Biological effects of chemicals were evaluated by fibroblast viability. Pre-osteoblast viability and mineralization were performed on biofilm-treated surfaces. RESULTS: SH and CA40 induced morphological damage, whereas CA10-30 preserved surface integrity and showed nobler electrochemical behavior. Regarding antimicrobial activity, SH, CA30, and CA40 significantly reduced biofilm (≈6 log; p < 0.05), demonstrating a concentration-dependent CA effect, whereas CHX and HP performed similarly to PBS. Biologically, protein adsorption was comparable across groups, and CHX reduced early viability (24 h) (p < 0.05). However, after 14 days, CHX- and CA30-treated surfaces promoted greater mineralized nodule formation (p < 0.05). SIGNIFICANCE: CHX and HP did not reduce biofilm after 1-min immersion, highlighting limitations of these short exposure protocols. In contrast, CA30 demonstrated a favorable balance between antimicrobial efficacy, controlled surface alterations, and biological effects, supporting its potential as an adjuvant chemical strategy for peri-implantitis treatment.