Influence of myofunctional therapy on the perioral muscles. Clinical and electromyographic evaluations.

The purpose of this study was to evaluate the influence of oral myofunctional therapy on the superior and inferior orbicularis oris (OOS and OOI) and mentalis (MT) muscles at rest and with lips closed in mouth breathing patients with no nasal airway obstruction. The sample consisted of 13 children aged 5-10 years. Clinical and electromyographic evaluations were performed before and after treatment. The results showed that muscles (P < 0.05) and functions (P < 0.01) improved after therapy, which can be observed by clinical evaluations. The electrical activity increase between rest and closed lip positions was statistically significant for the muscles studied. Before therapy the significant minimal level (s.m.l.) was P < 0.01 and after therapy it was P < 0.05. When the difference between the rest and closed lip positions before and after therapy was compared, a statistically significant decrease (P < 0.05) in the electrical activity of the OOI and MT muscles was observed. There was no correlation between the root-mean-square (RMS) of the OOI and MT muscles with the morphological and functional evaluations. The therapy can improve morphology and function of the muscles in mouth breathing patients with no nasal airway obstruction.