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 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.