This study aimed to analyse the effect of chlorhexidine digluconate (CHX DG) mouthwash on the adhesion of oral bacteria to orthodontic appliances. The interactions of four bacteria (S. mutans, A. actinomycetemcomitans, S. oralis, and V. parvula) with two alloys (stainless steel [SS] and nickel-titanium [NiTi]) and three CHX DG solutions (commercial products Curasept and Perio Plus, and pure CHX DG, all with 0.12% active substance) were tested. The adhesive effect on the orthodontic wires was evaluated after 24 h for S. oralis and after 72 h for the other bacteria. The minimum bactericidal concentration of the solution for each bacterial strain was determined using the dilution method to test the antibacterial action. Salivary-pretreated orthodontic arch wires were exposed to minimal bactericidal concentrations of solution and bacteria. Commercial antiseptic products, especially Perio Plus, showed better inhibition of bacterial adhesion to both alloys than pure CHX DG solution (p<0.05). A. actinomycetemcomitans was most inhibited in the adhesion of all bacteria by the CHX DG products. Greater inhibition of streptococci adherence was observed on SS, while A. actinomycetemcomitans on NiTi. Inhibition of V. parvula was product dependent. In conclusion bacterial adhesion depends on the alloys, antiseptic products, and the bacteria. CHX DG is effective at inhibiting bacterial adhesion to orthodontic elements and is recommended for the chemical control of biofilms during orthodontic treatment with fixed appliances.

The growing antibiotic resistance of microorganisms causing postoperative infections following orthopedic surgeries underscores the urgent need for localized antiseptic and lavage delivery systems to enhance infection control. This study evaluates the in vitro effectiveness of antiseptic and lavage solutions—including polyhexanide, povidone-iodine, low-concentration hypochlorite, Ringer’s solution, and saline—against Staphylococcus epidermidis, Staphylococcus aureus MRSA, Cutibacterium acnes, Corynebacterium amycolatum, Pseudomonas aeruginosa, and Candida albicans. Using microplate models (Minimum Inhibitory Concentration, Minimum Biofilm Eradication Concentration, and Biofilm-Oriented Antiseptic Test assays), flow-based models (Bioflux system), and surfaces relevant to orthopedic implants (e.g., stainless steel disks/screws, Co-Cr-Mo, Ti-Al-Nb orthopedic alloys, and ultra-high molecular weight polyethylene), as well as a bio-nano-cellulose scaffold representing tissue, we assessed solutions activity. The cytotoxicity of the solutions was evaluated using osteoblast and keratinocyte cell lines, with additional in vivo insights gained through the Galleria mellonella larval model. Results show that polyhexanide-based solutions outperformed povidone-iodine in biofilm eradication in most tests applied, particularly on complex surfaces, whereas iodine demonstrated higher cytotoxicity in applied in vitro and in vivo tests. Low-concentration hypochlorite solutions exhibited minimal antibiofilm activity but also showed no cytotoxicity in cell line and G. mellonella larval models. These findings highlight the importance of careful antiseptic selection and rinsing protocols to balance infection control efficacy with tissue compatibility in orthopedic applications.