【Chris Chang Ortho】600. Atypical extraction strategy for bimaxillary protrusion treatment

A 23 y/o girl came for orthodontic treatment due to protrusive lips. The diagnosis is bimaxillary protrusion. The customary four bicuspid extraction treatment was indicated to provide space for anterior retraction. However, UR5 had received prior endodontic treatment and the prognosis is poor. Therefore bilateral maxillary 2nd premolars and bilateral mandibular 1st premolars were extracted instead. Aligners were delivered with additional infrazygomatic crest screws, and Class II intermaxillary elastics. The total treatment time was 22 months. The result were a normal facia-palatal inclination of anterior teeth and significant improvement of protrusive lips.

一名23歲的女性因嘴唇太凸而尋求矯正治療，經診斷為雙側上顎突出（bimaxillary protrusion）。原訂計畫為拔除上下顎四顆第一小臼齒來提供門牙後縮的空間，但是因為右上第二小臼齒齒質狀況不佳，所以改成上顎拔除雙側第二小臼齒，下顎仍拔除雙側第一小臼齒。治療採用隱形矯正器並搭配Infrazygomatic crest screws以及第二類橡皮筋，經過二十二個月的治療，不僅前牙角度恢復正常，且過凸的唇形也大幅改善。