Ultrasonographic Evaluation of Masticatory and Suprahyoid Muscles in Obstructive Sleep Apnea Patients Treated with Mandibular Advancement Devices; A Pilot Study

Objective This study aimed to assess the thickness and ultrasonographic pattern of the masticatory and suprahyoid muscles in OSA patients and compare the effects of mono-bloc (MB) and bibloc (BB) mandibular advancement devices (MADs) via ultrasonographic measurements. Methods This pilot study of 20 patients with mild-to-moderate OSA who were diagnosed by full-night polysomnography (manually scored by the American Academy of Standards and Methods (AASM) manual, version 2.4) and treated randomly with mono-bloc or bibloc MAD (n = 10). The baseline thickness and pattern (types I, II, and III) of the masticatory and suprahyoid muscles were assessed by an oral radiologist. The same procedure was repeated at the 3-month and 6-month follow-up time points for participants after appliance use. Results Both types of MAD devices significantly increased the thickness of all muscles (p < 0.05). The changes in ultrasonographic muscle patterns were significant only in the BB group for the SCM muscle (p = 0.006). no other significant changes were observed in the studied ultrasonographic muscle patterns in the MB and BB devices up to 6 months (P > 0.05). No significant differences in muscle thickness or patterns were detected between the MB and BB modalities (P > 0.05). Conclusion The results of the present study indicate that MAD treatments do not have contraindications based on changes in muscle thickness and ultrasonographic muscle patterns. However, the BB group showed significant changes in the SCM ultrasonographic muscle pattern. Nevertheless, further studies are required to validate these findings.