关键词: 恒牙融合牙, 牙融合, 正畸治疗, 影像学诊断, 病例报告

Abstract:

Non?syndromic fused permanent teeth （NSFPT） is a dental developmental anomaly caused by non?systemic factors. Fused permanent teeth commonly occur between the maxillary central incisor and lateral incisor， while NSFPT resulting from fusion of bilateral maxillary permanent central incisors is extremely rare. This study reported a case of NSFPT， formulated an orthodontic treatment plan， and reviewed the relevant literature. The patient was a 15-year-old female whose chief complaint was irregular teeth and protruded lips. She had no history of systemic diseases. Imaging examination revealed increased sella-nasion-subspinal angle（SNA）， sella-nasion-supramental angle（SNB）， and upper incisor to sella-nasion plane angle（U1-SN） in the patient， as well as complete crown?root fusion of the bilateral maxillary permanent central incisors. The diagnoses were fused teeth of 11 and 21， Angle Class Ⅱ division 1 malocclusion， and convex facial profile. The proposed treatment plan involved extraction of the fused teeth and bilateral mandibular second premolars， followed by combined orthodontic?prosthodontic treatment to restore normal facial profile and dental arch morphology. However， the patient declined treatment due to personal reasons. For patients with fused teeth， diagnosis should be established through intraoral examination combined with imaging studies. Orthodontic treatment planning for such cases requires comprehensive consideration of multiple factors， including the degree of dental crowding and the facial profile， to determine whether extraction-based treatment is indicated. Early detection and intervention are essential to minimize the impact on the patient’s facial aesthetics and dentition， and to reduce the complexity of subsequent orthodontic treatment.

Key words: Fused permanent teeth, Tooth fusion, Orthodontic treatment, Imaging diagnosis, Case report