Electromyographic muscular activity improvement in Class II patients treated with the pre-orthodontic trainer.

Objective: A study was designed to determine changes in the amplitude of the EMG muscular activity of the Masseter and Temporalis muscles at clench in children with a Class II, division 1 malocclusion treated with the pre-orthodontic Trainer functional appliance, for 12 months.

Study Design: 36 Class II, division 1 malocclusion patients (mean age 7.6 ± 1.