成人クラスII度II類分割咬合、ディープバイト、正中逸脱を伴う症例に対する非対称3プレモラー抜歯：症例報告

Class II subdivision with division-2 features and deep bite presents concurrent sagittal, transverse, and vertical challenges. Asymmetric extraction may correct the midline and crowding while enabling incisor decompensation and esthetic improvement with limited patient compliance.

A 39-year-old woman sought reduction of "protrusion" and improvement of smile esthetics, along with alignment of crowded maxillary incisors and correction of a rightward mandibular midline deviation.

Skeletal class II pattern with a right side class II subdivision, division-2 incisor inclination, deep bite, increased overjet, moderate crowding, and mandibular midline deviated 3 mm to the right.

An asymmetric 3-premolar extraction protocol (both maxillary first premolars and the mandibular second premolar on the class II side) was combined with controlled incisor mechanics, careful vertical control for bite leveling, space closure, and asymmetric finishing goals.

Treatment achieved full alignment, coincidence of dental and facial midlines, normalization of overjet, overbite, and improvement of smile esthetics and lip posture. The left side finished in class I, and the right side in a deliberate functional class II molar relationship consistent with the asymmetric plan. Radiographic skeletal and dentoalveolar measurements indicated a clinically meaningful reduction in the sagittal discrepancy.

For selected adult class II subdivision cases with division-2 features and deep bite, asymmetric 3-premolar extraction offers a predictable, compliance-light alternative to 4-premolar extraction or distalization. Intentional functional class II finishing on the affected side can be compatible with stable occlusion when midlines, overjet, overbite, and incisor torque are properly managed.