Maruya Yuriko, Hino Ryoko, Tadano Manami, Hoshikawa Seira, Otake Shinji, Chiba Yuta, Saito Kan
Division of Pediatric Dentistry, Department of Oral Health and Development Sciences, Tohoku University Graduate School of Dentistry, Sendai, Japan.
Front Oral Health. 2024 Oct 16;5:1474190. doi: 10.3389/froh.2024.1474190. eCollection 2024.
Abnormal positioning and dislocation of the central incisor can disturb tooth eruption. Generally, inversely impacted maxillary central incisors do not erupt naturally. Performing traction and applied extrusion of an inversely impacted maxillary central incisor with a high inclination angle of the crown is challenging. This study aimed to examine the possibility of orthodontic treatment for severely inversely impacted maxillary central incisors in a series of case studies.
The inclination angle of the tooth crown, curvature of the tooth root, and length of the formed tooth root were measured using radiography. The teeth were then fenestrated and traction was applied using a lingual arch appliance with elastics.
The average crown axis inclination was 113°, the degree of root curvature was 97.3°, and the root formation was 36.1%. Although the crown axis inclination and root curvature were severe, all the incisors were aligned in the correct position as vital teeth through surgical and orthodontic treatments.
Traction should be performed in the early period of incisor development when root formation is not progressing, regardless of the tooth angle.
中切牙位置异常和脱位会干扰牙齿萌出。一般来说，上颌中切牙倒置阻生不会自然萌出。对上颌中切牙倒置阻生且牙冠倾斜角度较大进行牵引和施加推压是具有挑战性的。本研究旨在通过一系列病例研究探讨严重倒置阻生上颌中切牙正畸治疗的可能性。
使用X线摄影测量牙冠倾斜角度、牙根曲率和已形成牙根的长度。然后对牙齿进行开窗，并使用带弹力的舌弓矫治器施加牵引。
牙冠轴平均倾斜度为113°，牙根曲率为97.3°，牙根形成率为36.1%。尽管牙冠轴倾斜度和牙根曲率严重，但通过手术和正畸治疗，所有切牙均作为有活力的牙齿排列到正确位置。
无论牙齿角度如何，在牙根形成未进展的切牙发育早期应进行牵引。
Zotero 插件