上下顎歯列弓幅径の不調和を有し，CO-CRディスクレパンシーが大きい骨格性Ⅱ級・開咬症例に対し，正中2分割Le FortⅠ型骨切り術と下顎枝矢状分割術を施行した1例

Abstract

It is known that stable orthodontic treatment for skeletal Class Ⅱ open-bite cases caused by retrognathia can attain over bite by mandibular counterclockwise rotation due to intrusion of upper and lower molars. Evaluation of the temporomandibular joint is essential in these cases, as there may be progressive resorption of the condyle. Furthermore, it is important to plan surgical treatment based on restoration of the mandibular position as close to the centric relation (CR) as possible. When there is disharmony in the arch width between both jaws due to a narrowed maxillary arch in adult patients, dental or skeletal expansion may be used to correct it. For skeletal expansion, distraction osteogenesis or segmental Le Fort I osteotomy is widely used. Compared to skeletal