Comparison of the effects of clear aligners and fixed appliances on the oral microbiota and reactive oxygen species: a prospective study

Objective: This study aimed to compare the effects of clear aligners (CA) and fixed appliances (FA) on periodontal indices, oral microbiota, and reactive oxygen species (ROS). It also explored potential links between microbial changes, oxidative stress, and periodontal health.Methods: Twenty-four orthodontic patients matched at baseline were randomly allocated to the CA (n = 12) and FA (n = 12) groups. Saliva, supragingival plaque, and gingival crevicular fluid (GCF) were collected at baseline (T0), 3 months (T1), and 6 months (T2). Periodontal indices, including plaque index (PI) and gingival index (GI), were recorded. Microbial composition was assessed using 16S rDNA sequencing, and ROS levels in saliva and GCF were quantified using a double-antibody sandwich ELISA specific for ROS. Associations among microbiota, ROS, and clinical parameters were analyzed using Spearman correlation.