Effect of fluoridated alcoholic and non-alcoholic mouth rinses on the load-deflection rate of orthodontic archwires: an in vitro study

Background: Fluoride mouthrinses are routinely prescribed during orthodontic treatment; however, their interaction with different archwire materials may influence mechanical performance, particularly load-deflection characteristics. The aim of the study was to evaluate the effect of fluoridated alcoholic and non-alcoholic mouthrinses on the load-deflection properties of various orthodontic archwires. Methods: This experiment was conducted in vitro and involved 75 orthodontic archwire samples of 0.016-inch thickness, consisting of stainless steel, Ni-Ti, Cu-NiTi, β-Ti, and aesthetic-coated wires. The samples were categorized based on the type of liquid medium used: distilled water, fluoride alcoholic mouthwash, and fluoride non-alcoholic mouthwash. Archwires were soaked in the medium for 1.5 hours at 37°C, after which three-point bending tests were carried out by the help of a universal testing machine, and load deflection data were analyzed statistically using one-way ANOVA and Tukey’s post-hoc tests. Results: Significant increases in load-deflection in stainless steel, Cu-NiTi, β-Ti, and aesthetic archwires were seen using fluoride-containing mouthwash, suggesting stiffness enhancement. The most changes in stiffness were noted in aesthetic and Cu-NiTi wires, but not for Ni-Ti archwires which showed no significant change. Conclusions: Fluoride-containing mouthrinses exert material-dependent effects on orthodontic archwires, with alcoholic formulations producing the greatest alteration. Ni-Ti wires showed superior stability, whereas aesthetic and Cu-NiTi wires were most affected.