Objectives : Patients with obstructive sleep apnea （OSA） have been reported to have narrowed airways during sleep and a reduced capacity to expand the upper airway. Therefore, we examined the oral function of patients with OSA and healthy controls by measuring their maximum tongue pressure and evaluating the results of a questionnaire survey on sleep status.
Methods : Twenty-nine patients were enrolled in the OSA group and 29 in the control group. Each participant completed a questionnaire on sleep status. Tongue pressure was measured three times, and the highest value was defined as the maximum tongue pressure （MTP）.
Results : The OSA group had significantly higher percentages of mouth-opening during sleep and xerostomia upon awakening than did the control group （p＝0.01 and p＜0.001, respectively）. The OSA group also had significantly lower MTP than those in the control group （p＝0.004）, and male patients in the OSA group had significantly lower MTP than those in the control group （p＝0.0314）.
Conclusions : These results suggest that the activity of the genioglossus and other oral muscles is lower in patients with OSA than that in healthy participants. Anatomical sex differences may influence the mechanism of tongue pressure development and the effectiveness of treatment with oral appliances. Myofunctional therapy as an adjuvant therapy can help to improve respiratory function during sleep by increasing the strength of the tongue muscles and upper airway dilator muscles, which also enlarge the upper airway in patients with OSA who have low oral function.

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Objective : The Japanese Academy of Dental Sleep Medicine （JADSM） conducted a questionnaire survey of its members to investigate the impact of Coronavirus Disease 2019 （COVID-19） on sleep dentistry in Japan.
Method : A questionnaire was prepared by the Medical Safety Committee of the JADSM and sent by email to its members.
Results : Responses were obtained from 183 （21.2％） members. The implementation rate of each infection control measure increased after the COVID-19 outbreak compared to before it. Regarding masks, gloves, and hand disinfection, more than 70％ of facilities were already using them before the pandemic. As problems in clinical practice, many dentists indicated a shortage of personnel and infection-control equipment （alcohol, masks, and gloves）.
While there was a decrease in obstructive sleep apnea （OSA） patients in PSG testing, oral appliance （OA） referrals, and OA outpatients after the pandemic, there were some areas of practice that showed an increasing trend, such as an increase in patients with sleep bruxism and pediatric sleep disorders.
Conclusion : There is a need to standardize sleep dentistry in conformity with the situation after the pandemic.

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Large torus mandibularis can be a cause of obstructive sleep apnea （OSA） because the tongue is shifted backward due to decreased oral cavity volume. We report a case in which the severity of OSA was reduced after removal of the torus mandibularis in a patient with severe OSA.
A 62-year-old male patient came to our hospital with a chief complaint of right-sided mandibular molar pain and bilateral lingual prominence of the mandible. The patient also complained of snoring, headache, and xerostomia upon awakening, so he was referred to a respiratory physician for overnight polysomnography. As a result, he was diagnosed with severe OSA with torus mandibularis, as his AHI was 70.0 times/hour. After torus mandibularis resection, the tongue position was corrected from posterior to anterior and the symptoms of OSA improved, but severe OSA remained with an AHI of 33.3 times per hour. The patient was not obese and had no adenoid hypertrophy or nasal disease, but the skeletal factor of mandibular retrusion was thought to be the cause of OSA. Therefore, treatment with an oral appliance was performed. In this case, the cause of OSA was thought to involve a decrease in oral cavity volume due to torus mandibularis as well as mandibular retrusion.

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