Electrochemical Behavior and Cytocompatibility of Titanium Dental Implants Under Different Chemical Treatments

Background: This study aimed to evaluate the impact of different chemical treatments on titanium implant surfaces and their biological compatibility. Methods: Titanium dental implants were immersed in Ringer's solution, hydrogen peroxide (3%), citric acid (40%), EDTA (40%), or a citric-phosphoric acid mixture. Electrochemical behavior was analyzed using open-circuit potential monitoring and electrochemical impedance spectroscopy over 168 h. Cytocompatibility was assessed by culturing human gingival mesenchymal stem cells (MSCs) directly on treated implants and in conditioned media, followed by viability evaluation through CCK-8 assays. Results: Citric acid and Ringer's solution preserved passive film stability and supported high MSC viability (>75%) with minimal cytotoxic effects. Hydrogen peroxide and the citric-phosphoric acid mixture caused pronounced surface corrosion, decreased impedance stability, and significantly reduced cell viability (57-65%). EDTA-treated surfaces showed intermediate results, with moderate viability but impaired cell adhesion. Conclusion: The findings highlight the dual influence of chemical decontamination on implant stability and biological response. Citric acid and Ringer's solution appear to be safer protocols for surface decontamination, whereas hydrogen peroxide and mixed acid treatments should be applied with caution due to their detrimental electrochemical and cytotoxic effects.