IJOMAHIP Published Article Details

Abstract Background. Orthodontic elastomeric modules are widely used to deliver continuous forces during orthodontic treatment but may undergo mechanical degradation when exposed to chemical and environmental conditions in the oral cavity. Levosalbutamol is a selective β2-adrenergic agonist commonly administered through inhalers for asthma management. During inhaler use, aerosolized medication and formulation components may contact the oral cavity and potentially interact with orthodontic elastomeric materials. Because these materials are polyurethane-based, repeated exposure to inhaler aerosols may alter their mechanical properties, including tensile strength. However, the effect of repeated levosalbutamol inhaler exposure on the tensile strength of orthodontic elastomeric modules has not been specifically established, warranting further investigation under simulated intraoral conditions. Methods. An in vitro randomized controlled experimental study was conducted using 68 unused clear E-link polyurethane orthodontic elastics randomly allocated into four groups (n = 17): baseline, artificial saliva control, artificial saliva with two puffs/day of levosalbutamol bronchodilator inhaler, and artificial saliva with four puffs/day of levosalbutamol bronchodilator inhaler. Tensile strength was measured using a calibrated Universal Testing Machine. Data were analyzed using one-way analysis of variance (ANOVA) followed by Tukey's Honestly Significant Difference (HSD) post hoc test, with statistical significance set at p < 0.05. Results. Repeated levosalbutamol bronchodilator inhaler exposure significantly reduced the tensile strength of E-link orthodontic elastics. The baseline group demonstrated the highest mean tensile strength, whereas the four-puff exposure group showed the lowest. One-way ANOVA revealed significant differences among the four experimental groups (p< 0.001), and Tukey's HSD test demonstrated significant pairwise differences between all groups. Conclusion. Repeated exposure to levosalbutamol bronchodilator inhaler aerosols significantly reduced the tensile strength of the tested polyurethane orthodontic elastomeric modules under simulated intraoral conditions. These findings indicate a potential effect of inhaler exposure on the mechanical integrity of the tested material in vitro. However, the findings cannot establish effects on clinical force delivery, replacement intervals, or patient outcomes. Further in vivo studies are needed to determine the clinical significance of these findings. Keywords: Bronchodilator inhaler; in vitro; levosalbutamol; orthodontic elastomeric module; orthodontic materials; polymer degradation; tensile strength