头影测量中冠长轴与牙长轴倾斜在正常牙的表现

摘要

目的 本研究通过测量并分析正常(拾)头影测量中的切牙冠长轴与牙长轴的倾斜角度,以期为错(拾)畸形的方案选择及疗效评判提供参考.方法 按照Andrews正常(拾)六项标准纳入120名受试者,于自然头位下拍摄头颅侧位片,并测量其上下颌切牙冠长轴与真性垂线(TV)、(拾)平面(OP)及牙长轴的交角.结果 上颌切牙冠长轴与TV交角为11.72°±4.71°,与OP交角为73.29°±5.69°,与上颌切牙长轴交角为20.04°±3.71°;下颌切牙冠长轴与TV、OP和牙长轴的交角分别为16.03°±5.40°、81.76°±4.81°和14.82°±4.01°.多数上颌切牙冠长轴与牙长轴夹角分布于15°~25°之间,多数下颌切牙冠长轴与牙长轴夹角分布于10°~20°之间.结论 在使用头颅侧位片制订治疗方案和评估疗效时,除了关注上下颌切牙的牙长轴倾斜程度,还应考虑上下颌切牙的冠长轴倾斜情况.%Objective We measured and analyzed the angle between the longitudinal axis of incisor crown and tooth to provide a reference for orthodontists for selecting orthodontic methods and evaluating treatment results.Methods A total of 120 participants were included according to the criteria of Andrews' six keys, and cephalometric radiograph under the instruc-tions of modified natural head position acquirement method was performed. The angles of maxillary incisor crown longitudinal axis, tooth longitudinal axis, occlusion plane (OP), and true vertical (TV) plane were measured, as well as mandibular incisors. Results As for maxillary incisors, the angle between crown longitudinal axis and TV plane, OP, and tooth longitudinal axis were 11.72°±4.71°, 73.29°±5.69°, and 20.04°±3.71°, respectively. For mandibular incisors, the angle between crown longi-tudinal axis and TV plane, OP, and tooth longitudinal axis were 16.03°±5.40°, 81.76°±4.81°, and 14.82°±4.01°, respectively. For the maxillary incisor, the angles between crown longitudinal axis and tooth longitudinal axis were mainly within 15° to 25°, whereas those for mandibular incisors were within 10° to 20°.Conclusion The longitudinal axis inclinations of the maxillary and mandibular incisor crown and of the incisor tooth need to be considered when cephalometric radiographs are used for treatment planning or for evaluating the treatment result.