Effect of pre-orthodontic trainer treatment on the masticatory and perioral muscles in patients with class II subdivision 1 malocclusion evaluated by surface EMG

Abstract

Introduction: Myofunctional appliances have been shown to have a positive effect on the muscles in the facial area. Surface electromyography (sEMG) is one of the reliable methods used to investigate these effects. Aim: The aim of this follow-up study is to evaluate the effect of a myofunctional appliance T4K on the perioral and masticatory muscles in patients with class II subdivision 1 malocclusion by sEMG. Materials and methods: Sixteen children were treated with a Trainer appliance (T4K) for 9 months. The appliance should be worn every day for 1 hour and overnight. The EMG recordings were performed at the beginning and at the end of the Trainer therapy. The anterior temporal and masseter muscles were examined during maximal clenching. The orbicularis oris and mentalis muscles were examined during swallowing and sucking. Statistical analysis was performed using IBM SPSS Statistics version 23.0. Results: The EMG values of the anterior temporal and masseter muscles during clenching increased significantly as a result of the treatment (p<0.05). At the end of the observation period, the EMG values of the mentalis muscle did not change during both sucking and swallowing (p>0.05), while the values of the orbicularis oris muscle increased significantly during sucking and swallowing (p<0.05). Conclusions: As a result of the treatment with Trainer appliance, the EMG activity of the perioral and masticatory muscle significantly increased, while no change was observed in the electrical activity of the mentalis muscle.