Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 23 0 2026 05 30 4430 4430 EN Sara Alijani Department of Orthodontics, School of Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran Jamshid Nemati Mechanical Engineering Department, Bu-Ali Sina University Faculty of Engineering, Hamadan, Iran Mozhde Borjali Borjali 1. Department of Orthodontics, School of Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran 3. Department of Clinical Biochemistry, School of Medicine, Torbat Heydariyeh University of Medical Sciences, Aysa Nezakatmaab Department of Orthodontics, School of Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran Behnaz Alafchi Department of Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran 2022 04 11 2024 05 12 Objectives: The interaction of mouthwashes with orthodontic elastomeric materials may alter their mechanical properties. The main purpose of this study was to evaluate the impact of 0.05% sodium fluoride Oral-B PRO-Expert Multi Protection and fluoride-free Listerine Advanced with Tartar Protection mouthwashes on the force decay behavior of memory elastomeric chains. Materials and Methods: In this in vitro study, 90 pieces of closed gray memory elastomeric chains were randomly allocated to three distinct groups (n=30): control, sodium fluoride, and Listerine. The control samples remained fully submerged in artificial saliva over the course of the experiment. Test samples were placed daily for 1 minute in either sodium fluoride or Listerine mouthwash, then in a solution consisting of equal parts of mouthwash and artificial saliva for 30 minutes, followed by a thorough rinse with distilled water, and then placed back in the artificial saliva. Tensile tests were conducted at various time points (baseline, 1 hour, and 1, 7, and 28 days) (n=6). Data were analyzed by one-way and two-way ANOVA, and Tukey’s post-hoc test (alpha=0.05). Results: All groups exhibited a continuous force decay over time (P<0.001). The experimental groups demonstrated significantly greater force decay compared to the control group (P<0.001). The sodium fluoride group exhibited significantly greater force decay compared to the Listerine group at all measured time points (P<0.001) except on day 28 (P=0.970). Conclusion: Both mouthwashes accelerated the force degradation of memory elastomeric chains, with sodium fluoride causing a greater reduction except on day 28. https://fid.tums.ac.ir/index.php/fid/article/view/4430 https://fid.tums.ac.ir/index.php/fid/article/download/4430/2214