Effect of Chlorhexidine Digluconate on Oral Bacteria Adhesion to Surfaces of Orthodontic Appliance Alloys

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 archwires were exposed to minimal bactericidal concentrations of solution and bacteria. Commercial antiseptic products, especially Perio Plus, showed a 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. A greater inhibition of streptococci adherence was observed on SS, while that of A. actinomycetemcomitans was observed on NiTi. V. parvula inhibition was product-dependent. Although there were differences between the strains and the tested agents, it can be concluded that Perio Plus most effectively inhibited the adhesion of all tested bacteria to the SS and NiTi alloys. A. actinomycetemcomitans was most sensitive to all tested agents, while S. mutans showed the highest resistance. The effectiveness of the tested agents was better on NiTi alloys.