Low Tongue Posture Improvement Effect of Orofacial Myofunctional Therapy Comprehensive Study of Nasal Ventilation Condition Using Computational Fluid Dynamics and Dental Arch Morphology

Oral myofunctional therapy (OMFT) has been proposed as a potential treatment for improving low tongue posture (LTP) and alleviating obstructive sleep apnea. However, its effectiveness remains uncertain. This study aimed to quantify the effects of OMFT on LTP. This study analysed pre- and post-treatment cone-beam computed tomography images from 43 children with LTP treated with rapid maxillary expansion (RME) only (mean age: 9.09 years, no-OMFT group), 46 children with LTP treated with RME plus OMFT (mean age: 9.40 years, OMFT group), and 20 children (mean age: 9.87 years, control group). The primary outcomes measured were intraoral airway volume (an indicator of LTP), nasal airway pressure differences (assessed using computational fluid dynamics), and maxillary dental arch width. Comparisons were made among groups, with the frequency and relationship between these measures investigated. There were no significant differences between OMFT and no-OMFT groups before treatment. Post-treatment, the OMFT group showed significantly smaller intraoral airway volume (0.66 cm3) compared to the no-OMFT group (1.34 cm3). Nasal airway pressure drop was also significantly lower in the OMFT group (44.2 Pa) than in the no-OMFT group (143.3 Pa). The LTP improvement rate was significantly higher in the OMFT group (76.1%) than in the no-OMFT group (51.2%). Similarly, the improvement rate of nasal airway obstruction was significantly higher in the OMFT group than in the no-OMFT group. OMFT improves LTP and nasal airway obstruction. Improvements in nasal airway obstruction by OMFT are likely correlated with the observed improvements in LTP.