The influence of recommended mouthwashes against coronavirus disease 2019 on the shear bond strength of orthodontic brackets

Objective: To assess the effect of recommended mouthwashes used for coronavirus disease 2019 (COVID-19) prevention on the shear bond strength (SBS) of orthodontic brackets. Material and Methods: Sixty extracted human maxillary premolars were bonded with metal brackets (3M Unitek, California, USA) using an orthodontic bonding agent (Transbond XT, 3M Unitek, California, USA). The teeth were then randomly allocated into four groups ( n = 15) to undergo rinsing with 1% hydrogen peroxide (H 2 O 2 ), 0.5% povidone-iodine (PVP-I), and alcohol mouthwash for 30 s twice daily over 4 weeks, with immersion in artificial saliva during the remaining time. The control group was immersed in artificial saliva throughout the study for comparison. SBS was evaluated using a universal testing machine, and the adhesive remnant index (ARI) score was assessed. Data were analyzed using one-way analysis of variance followed by the Bonferroni test and the Chi-square test, respectively. Results: In comparison to the control groups (13.04 ± 3.55 Megapascal [MPa]), alcohol mouthwash showed a significantly lower SBS (10.14 ± 1.91 MPa). However, there were no statistically significant differences observed in the H 2 O 2 (12.65 ± 2.73 MPa) and PVP-I (12.56 ± 2.70 MPa) groups. The ARI scores revealed no significant differences among the groups. Conclusion: The use of 1% H 2 O 2 and 0.5% PVP-I mouthwashes did not affect SBS, suggesting their viability for pre-procedural use in COVID-19 prevention during fixed orthodontic treatment. However, caution is advised when using alcohol mouthwash due to its negative impact on SBS.