Repassivation of Titanium Surface with Different Disinfectants After Implantoplasty: Effects on Corrosion, Ion Release, Cytotoxicity and Bacterial Behaviour—An In Vitro Study

Objective: Implantoplasty smoothens exposed implant surfaces but disrupts the titanium oxide layer, reducing corrosion resistance, increasing ion release, and facilitating bacterial colonization. Restoring a stable and biologically favorable surface is therefore critical. Chemical agents capable of repassivating titanium may enhance surface integrity and antibacterial performance, yet the optimal agent remains unclear. This study evaluated the repassivation effects of common disinfectants on corrosion resistance, ion release, cytotoxicity, and antibacterial activity. Methods: One hundred twenty-eight discs underwent manual implantoplasty and were treated with citric acid (CA), ethylenediaminetetraace acid (EDTA), hydrogen peroxide (H2O2) or saline (S). Surface topography and wettability were analyzed using white-light interferometry and contact angle measurements. Corrosion behavior was assessed via open-circuit potential monitoring and potentiodynamic polarization in Hank’s solution. Titanium ion release was quantified over 21 days using inductively coupled plasma mass spectrometry. Cytotoxicity was evaluated in human fibroblast and osteoblast cultures exposed to sample extracts. Bacterial adhesion and viability of Streptococcus sanguinis and Pseudomonas aeruginosa were analyzed by scanning electron microscopy and confocal laser scanning microscopy after 24 h and 48 h. Results: H2O2 increased surface roughness, while CA and EDTA showed no effect. All agents enhanced hydrophilicity, with CA and H2O2 producing the greatest increase in surface energy. CA showed the highest corrosion resistance and lowest ion release. No treatment exhibited cytotoxicity, and all reduced bacterial adhesion, with CA and H2O2 showing superior bactericidal activity. Conclusions: CA and H2O2 improved surface properties after implantoplasty, with CA providing the most favorable combination of corrosion resistance, minimal ion release and antibacterial effect.