In Vitro Evaluation of Antimicrobial Mouthwashes on Biofilm Formed on Polyethylene Terephthalate Glycol–Based Orthodontic Template Aligner Materials

Abstract

Orthodontic template aligners used for attachment bonding are thermoformed polymeric materials that may act as vectors for microbial contamination despite their short intraoral use. This study evaluated the antimicrobial efficacy of seven mouthwash solutions on biofilms formed by Streptococcus mutans, Streptococcus oralis, and Candida albicans on a polyethylene terephthalate glycol–based template aligner material. After 24 h biofilm formation, samples were exposed to the tested mouthwashes for 1 min and microbial viability was assessed by optical density measurements. The solution containing fluoride and cetylpyridinium chloride showed the highest antibacterial activity, while the essential oil–based formulation exhibited the strongest antifungal effect. In contrast, fluoride-only solutions showed reduced efficacy, and one plant-based formulation demonstrated a slight stimulatory effect on Candida albicans. These findings indicate that the antimicrobial performance of mouthwashes on template aligner materials depends primarily on their chemical composition rather than fluoride content alone.