上顎阻生門牙之形成原因及其矯正處理方法

Etiology of Impacted Maxillary Permanent Central Incisor and Associated Orthodontic Management

目的：探討台灣兒童上顎阻生門牙形成之原因。材料與方法：從 2005年至2014年台中榮總牙科部之根尖相片中選取 1025 張前牙X光片，其中有64個患者的68顆上顎前牙有阻生門牙。回顧這些X光片並評估造成阻生門牙形成之原因。結果：最常見造成上額門牙阻生之原因為牙根彎曲（24個），其他原因為多生牙（21個），牙痛（8個），異位牙胚（4個），囊腫（4個）。另外有2個阻生牙是不明原因的，有一個是因為乳牙延遲脫落。結論：造成台灣兒童上頸阻生門牙最常見的原因為牙根彎曲，其次為多生牙。

Purpose. To investigate etiologies associated with impacted maxillary permanent central incisors, retrospectively. In later part of this article, we also reviewed the literature of the orthodontic management of impacted maxillary permanent central incisors. Methods. Standardized periapical radiographs of upper anterior region from 2005 to 2014 in Department of Orthodontics and Pediatric Dentistry, Taichung Veterans General Hospital, Taiwan, were reviewed. From the 1025 reviewed upper anterior periapical radiographs, a total of 64 patients with 68 impacted maxillary permanent central incisors were found and were subsequently evaluated for the etiologies which cause impaction. Results. The most common etiology of impacted maxillary permanent central incisor was root dilaceration (n=24 ). The other etiologies were: supernumerary teeth (n=21 ), odontoma (n= 8 ), malpositioned tooth germ (n=4 ), odontogenic cyst (n=4 ). There were no obvious etiologies in 2 patients, therefore were classified as idiopathic, may be due to crowding or primary failure of eruption. 1 patient had over-retained primary maxillary central incisor. Conclusions. In the present study, the most common etiology of impacted maxillary permanent central incisor in Taiwanese children was root dilaceration, followed by supernumerary teeth.