Objective : An oral appliance （OA） can alleviate upper airway obstruction by pulling the mandible forward during sleep. While a large mandibular advancement with an OA decreases the number of apnea and hypopnea events, long-term use may cause side effects such as toothache, and stiffness and pain in the temporomandibular joint.
This study aimed to evaluate the effectiveness of different mandibular positions for obstructive sleep apnea （OSA） and determine the optimal therapeutic mandibular position.
Methods : Thirty-two patients （17 males, 15 females） with mild to moderate OSA participated in this prospective study. All patients were randomly allocated to receive a 50％ mandibular advancement or a 75％ mandibular advancement with an OA. The pre- and post-treatment apnea-hypopnea index （AHI）, apnea index （AI）, and Epworth Sleepiness Scale （ESS） were compared. Treatment effectiveness and treatment success were compared between groups.
Results : AHI improved significantly in both groups, and AI improved significantly in the group with 50％ mandibular advancement. No significant improvements in the ESS were observed in either group. There was no significant difference in treatment effectiveness between groups. Regarding the proportion of females and males whose treatment was effective in the two groups, there were significantly more females than males.
Conclusions : For patients with mild to moderate OSA, 50％ mandibular advancement is recommended as the initial therapeutic mandibular position. It is suggested that gender differences also affect treatment effectiveness.
