Aim and objective: The purpose of this work is to investigate by electromyographic (EMG) surface analysis whether and how the variations in the occlusion due to the correction of the posterior crossbite using a rapid palatal expander (RPE) is accompanied by changes in the activity of the elevator muscles in the pediatric patients.
Background: Posterior crossbite is a disgnathic jaw relationship common in patients undergoing growth. In the last 10 years, several studies demonstrated the effectiveness and reproducibility of surface EMG in the objective evaluation of temporal muscle and masseter activity and how this evidence can be an interesting aid in dental clinical practice.
Case description: The case subject BF is an 11-year-old boy with a right I class relationship and a left II class relationship treated with a rapid palatal expansion protocol with a turn of the transversal screw twice a day (0.25 mm each turn) for a week. In this case report, EMG was used to evaluate the temporal muscle and masseter activity immediately before, immediately after, and 4 months after the RPE protocol.
Conclusion: Four months after the treatment, a condition of well-being and neuromuscular equilibrium such as that of starting was preserved.
Clinical significance: Electromyography is a noninvasive exam which evaluates the masticatory muscle activity by facial application of electrodes on masseter and temporal muscles. It can be an interesting aid in orthodontic clinical practice to evaluate preservation of a good muscular balance following orthodontic and orthognathic movements.
Keywords: Electromyography; Gnathology; Orthodontic; Posture Temporomandibular joint..