Treatment methods for obstructive sleep apnea （OSA） in Japan include nasal continuous positive airway pressure （nCPAP） therapy and oral appliance （OA） therapy, and OA is primarily used for mild OSA. Although the treatment of OSA associated with cardiovascular disease has been discussed, the significance of treating OSA associated with mild OSA is not clear, and the effect of OA therapy is not apparent in many cases. In addition, treatment of OSA associated with cardiovascular disease is often applied to patients without symptoms, and adherence to nCPAP is often poor. This paper reviews studies on the effects of OSA on concomitant cardiovascular disease and the consequences of nCPAP and OA therapy. As a cardiologist, I would like to express my opinion on OA therapy for OSA, including therapy for milder OSA cases.
Although OA therapy is widely used internationally and not only for mild OSA, the significance of treatment for mild OSA remains largely unclear. In future, OA therapy may have great potential for treating OSA complicated by cardiovascular diseases. By clarifying the significance of treatment for mild OSA and asymptomatic OSA, the number of situations in which OA therapy is used will increase. I sincerely hope that dentists will become more interested in treating OSA patients by asking about sleepiness symptoms and functional problems during the day and monitoring lifestyle-related disease management, including blood pressure.

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Obstructive sleep apnea （OSA） is one of the most common types of sleep disordered breathing （SDB） and is associated with cardiovascular disease and neuropsychiatric disorders. For simple snoring and mild to moderate OSA, oral appliance （OA） therapy is often as effective as continuous positive airway pressure （CPAP） therapy and is a good indication. Dental titration is one of the most important dental techniques for the treatment of OA in SDB.

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Objective : The Japanese Academy of Dental Sleep Medicine conducted a questionnaire survey to investigate the current status of education on dental sleep medicine for dental students in Japan.
Method : Questionnaires concerning education on dental sleep medicine were sent to and collected from teaching staff at dental universities and colleges in Japan.
Results : Responses were obtained from 29/29 schools. The average duration of education including lectures and practical training was 2.7 hours （sleep physiology）, 2.5 hours （sleep disorders）, and 3.4 hours （OSA: obstructive sleep apnea）. In terms of educational content, the three items on sleep physiology were taught in 79-97％ of schools. Of the nine items on sleep disorders, central apnea and sleep bruxism were taught in more than 50％ of schools, but sleep-related gastroesophageal reflux and drug and substance induced insomnia/hypersomnia were taught in only 28％. For the 22 items related to OSA, more than 75％ of schools offered lectures on OSA diagnostic criteria, anatomical factors, and oral appliances, while less than 40％ offered lectures on pediatric OSA characteristics, sleep diary, nasal endoscopy, and orthodontic treatment.
Conclusion : The content of lectures, availability of practical training, lecture time, and courses taught varied among universities. This survey revealed the need for the Japanese Academy of Dental Sleep Medicine to create an educational guideline for dental sleep medicine, reflecting the contents of this questionnaire.

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Objectives : The aim of this study was to determine the utility of respiratory resistance as a predictor of oral appliance （OA） treatment response in obstructive sleep apnea （OSA）.
Methods : Twenty-seven patients with OSA （mean respiratory event index （REI）: 17.5±6.5） were recruited. At baseline, the respiratory resistance （R20） was measured by impulse oscillometry （IOS） with a fitted nasal mask in the supine position, and cephalometric radiographs were obtained to analyze the pharyngeal airway space （SPAS: superior posterior airway space, MAS: middle airway space, IAS: inferior airway space）. The R20 and radiographs after the OA treatment were evaluated, and the changes from the baseline were analyzed. A sleep test with OA was carried out using a portable device. The subjects were divided into Responders and Non-responders based on an REI improvement ≥50％ from the baseline, and the R20 reduction rate between the two groups was compared.
Results : The subjects comprised 20 responders and 7 non-responders. The R20 reduction rate with OA was significantly greater in responders than in non-responders （14.4±7.9％ versus 2.4±9.8％, p＜0.05）. In responders, SPAS, MAS, and IAS were significantly widened and R20 was significantly decreased with OA （p＜0.05）. There was no significant difference in non-responders （p＞0.05）. A logistic multiple regression analysis showed that the R20 reduction rate was predictive for OA treatment responses （2％ incremental odds ratio （OR）, 24.5; 95％CI, 21.5-28.0; p＝0.018）.
Conclusion : This pilot study confirmed that respiratory resistance may have significant clinical utility in predicting OA treatment responses.

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