The Effects of Zinc-Containing Mouthwashes on the Force Degradation of Orthodontic Elastomeric Chains: An in Vitro Study

Abstract

Objective. This study aimed to evaluate and compare the force degradation of two types of elastomeric chains following different periods of immersion in zinc-containing mouthwashes. Materials and Methods. Four hundred and forty pieces of Elasto-Force and Super Elasto-Force elastomeric chains were divided into two control and eight experimental groups. The pieces were stretched to 25 mm on pins mounted on an acrylic block and stored in distilled water at 37°C. The experimental groups were immersed in four different types of mouthwash for one minute twice a day throughout the test period. Ten continuous thermocycles per day between cold and hot water baths (5-55°C) were carried out. Forces were measured at six-Time intervals (initial, 24 hours, 1, 3, 6, and 8 weeks). The mean force was calculated and compared among different elastomeric chains, mouthwashes, and times using the t-Test and one-way ANOVA test followed by Tukey's HSD test. The level of significance was set at 0.05. Results. Both types of elastomeric chains had significant force degradation over time (74-79% at 8 weeks). The Super Elasto-Force generated a higher force level than the Elasto-Force elastomeric chain at all time points. SmartMouth Clinical DDS mouthwash had a significantly lower effect on force degradation than other mouthwashes with no significant difference compared to control groups. Conclusions. Depending on these results: There is no clinically significant difference between both types of elastomeric chains, although Super Elasto-Force delivered a higher force level. The pH of the mouthwashes could play a role in force degradation over time, rather than other ingredients including zinc. The SmartMouth mouthwash had the minimum effect on force degradation of elastomeric chains, followed by Halita, Listerine Total Care Zero, and Breath Rx, respectively.