高角Ⅱ类开𬌗患者上下颌前牙根长及中切牙冠根形态的锥形束CT研究

Cone-beam computed tomography study of root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in high-angle Class Ⅱ open bite patients

摘要

目的 探讨高角Ⅱ类前牙开𬌗患者的上下颌前牙牙根长度及中切牙冠根形态，为临床正畸治疗提供参考。方法 本研究已通过单位伦理委员会审查批准，并获得患者知情同意。对81例高角Ⅱ类患者 （前牙开𬌗40例、正常覆𬌗41例）正畸治疗前的锥形束CT（cone-beam computed tomography，CBCT）图像进行分析，运用Dolphin软件对上下颌前牙的牙根长度以及中切牙冠根形态进行研究，并行统计学分析。结果 高角Ⅱ类开𬌗患者（开𬌗组）与高角Ⅱ类正常覆𬌗患者（正常覆𬌗组）的上颌尖牙和侧切牙牙根长度差异无统计学意义，但开𬌗组上颌中切牙（11.12 ± 1.37）mm、下颌中切牙（10.15 ± 1.09）mm、下颌侧切牙（11.27±1.15）mm和下颌尖牙（12.81 ± 1.48）mm的牙根长度均较正常覆𬌗组短且差异均具有统计学意义（P<0.05）;另一方面，开𬌗组的上颌中切牙冠根成角（1.10° ± 3.62°）显著小于正常覆𬌗组（4.53° ± 2.30°）（P<0.01），而开𬌗组的下颌中切牙冠根成角与正常覆𬌗组的差异无统计学意义。结论 高角Ⅱ类开𬌗患者的上下颌中切牙、下颌侧切牙和下颌尖牙牙根均较高角Ⅱ类正常覆𬌗患者短，高角Ⅱ类开𬌗患者上颌中切牙牙冠长轴相对于牙根长轴偏唇侧，冠根成角较小，利于开𬌗患者的前牙转矩控制或内收移动。

Abstract

Objective This study aimed to explore the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in patients with high-angle skeletal Class Ⅱ open bite, aiming to provide a reference for clinical treatment. Methods This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. CBCT images of eighty-one untreated patients (40 anterior open bite patients and 41 normal overbite patients) with high-angle skeletal Class Ⅱ malocclusion were selected before treatment. Dolphin software was used to study the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology, and the differences between the two groups were analyzed. Results There was no statistical significance in the root length of maxillary lateral incisor and canine between the open bite group and the normal overbite group, significant differences were found in the root length of maxillary central incisor （11.12 ± 1.37） mm、mandibular central incisor（10.15 ± 1.09）mm, mandibular lateral incisor（11.27 ± 1.15）mm and mandibular canine（12.81 ± 1.48）mm between the open bite group and the normal overbite group（P<0.05）. On the other hand, the two groups were significantly different in crown-root morphology of the maxillary central incisor (1.10° ± 3.62° vs. 4.53° ± 2.30°, P<0.01) but not in the mandibular central incisor. Conclusion The root length of the maxillary central incisor, mandibular central incisor, mandibular lateral incisor, mandibular canine in high-angle Class Ⅱ open bite patients is shorter than that in high-angle Class Ⅱ normal overbite patients, and the long axis of the crown of the maxillary central incisor in high-angle Class Ⅱ open bite patients obviously deviates toward the labial side relative to the long axis of the root. The crown-root angle is smaller, which is beneficial to torque control or adduction movement of the anterior teeth in high-angle Class Ⅱ open bite patients.

关键词

高角 / Ⅱ类错?? / 正畸 / 前牙开?? / 前牙 / 牙根长度 / 冠根形态 / 锥形束CT

Key words

high-angle / Class Ⅱ malocclusion / orthodontics / anterior open bite / anterior teeth / root length / crown-root morphology / cone-beam computed tomography

Author summay

任庆源，主治医师，硕士，Email：[e-mail]