RESUMO
OBJECTIVES: The purposes of this study were (1) to identify possible differences in muscular and orofacial functions between children with obstructive sleep apnea (OSA) and with primary snoring (PS); (2) to examine the standardized difference between normal values of myofunctional scores and those of subjects with OSA or PS; and (3) to identify the features associated with OSA. METHODS: Participants were 39 children (mean age 8 ± 1.2 years) of which, 27 had a diagnosis of OSA and 12 had PS. All participants were examined by an otorhinolaryngologist and underwent overnight polysomnography. Orofacial characteristics were determined through a validated protocol of orofacial myofunctional evaluation with scores (OMES), surface electromyography of masticatory muscles, and measurements of maximal lip and tongue strength. Reference values in the OMES were included to quantify the standardized difference (effect size = ES) relative to the groups studied and in the regression analysis. RESULTS: The OSA group had lower scores in breathing and deglutition, more unbalanced masticatory muscle activities than PS group (P < 0.05), but both groups had similar reductions in orofacial strength. OSA had a large ES (Cohen's d > 0.8) in all analysed OMES scores, while PS group showed small and medium differences in breathing and mastication scores, respectively. The mobility of the stomatognathic components score was the most important to contribute for group status (57%, P < 0.0001) in the regression analysis. CONCLUSION: Children with tonsillar hypertrophy and OSA had relevant impairments in orofacial functions and lesser muscular coordination than children with PS.