Impact of appliance therapy on orofacial muscle activity in mouth breathers: an electromyographic study.

Objectives: Mouth breathing is a condition that alters normal skeletal and dental development while also affecting the surrounding orofacial muscles. Electromyography (EMG) provides an objective method to assess these muscular changes. This study aimed to evaluate the activity of the buccinator, orbicularis oris, mentalis, sternocleidomastoid, and trapezius muscles in mouth breathers before and after interceptive therapy and compare these findings with those of nasal breathers.

Method and materials: Children aged 6 to 12 years were selected based on inclusion/exclusion criteria and categorized into two groups: Group I (mouth breathers, n=18) and Group II (nasal breathers, n=18). The electromyographic activity of all the five selected muscles were recorded at rest and during maximal contraction using an EMG Retrainer (Chattanooga Group Inc, DJO UK Ltd, Guildford Surrey, GU2 8XG United Kingdom), an intraoral device used to measure muscle activity, particularly in the orofacial region. Statistical analysis was performed using SPSS version 22.0, with significance set at p<0.05. The Mann-Whitney U test was used for intergroup and intragroup comparisons.

Results: Results showed significant differences in muscle activity before and after appliance therapy, particularly in the buccinator, mentalis, orbicularis oris, trapezius, and sternocleidomastoid muscles. Post-therapy, the orbicularis oris and buccinator muscles exhibited notable differences in mouth breathers.

Conclusion: Surface EMG can be a valuable diagnostic and biofeedback tool in pediatric interceptive orthodontics, aiding in treatment assessment and relapse prevention.