青年人正常 前牙牙根与牙槽骨位置的CBCT研究

目的 探讨正常 前牙牙根与牙槽骨矢状向位置的关系。方法 选择73例正常 志愿者，其中男9例，女64例，年龄19~22岁，平均（19.89±0.70）岁。所有志愿者进行颅面部锥形束CT（CBCT）扫描并将数据导入专业软件，测量前牙牙根长轴与牙槽骨长轴的夹角，统计前牙牙根在牙槽骨中的位置，并进行下颌平面角与中切牙倾斜度和根尖区牙槽骨厚度的相关性分析。结果 正常 上、下颌中切牙和侧切牙牙根长轴与牙槽骨长轴的夹角小于尖牙（P＜0.01）。上颌前牙牙根多数位于牙槽骨唇侧（94.98%），少数位于牙槽骨中央（5.02%）；而下颌前牙多数位于牙槽骨中央（48.18%），部分位于牙槽骨唇侧（34.24%），位于牙槽骨舌侧最少（17.58%）。正常 下颌平面角（SN-MP）与上、下中切牙倾斜度（SN-U1、MP-L1）和下颌中切牙根尖区牙槽骨厚度（LW）呈负相关（r 分别为-0.498、-0.421和-0.383，P＜0.01）。结论 正常 上前牙牙根多位于牙槽骨唇侧，下前牙牙根多位于牙槽骨中央及唇侧；与低角患者相比，高角患者前牙较为直立且下颌中切牙根尖区牙槽骨厚度较薄。

A CBCT study of root position in relation to the anterior alveolar bone inyoung adults with normal occlusion

Objective To analyze the sagittal root position of anterior teeth of alveolar bone in young adults withnormal occlusion. Methods The subjects consisted of 73 young adults with normal occlusion, including 9 males cases and64 female cases. And their ages ranged from 19 to 22 years, with an average of (19.89±0.70) years. Cone beam CT (CBCT)images of the subjects' craniofacial region were selected, and the data were imported into the professional software. The anglebetween the axis of root and the axis of alveolar bone of anterior teeth and the position of the root in the alveolar bone weremeasured. The relationship between the mandibular plane angle and the inclination of the central incisor and the alveolarbone thickness of the apex of anterior teeth were respectively analyzed. Results The mean of the angle between the axis ofroot and the axis of alveolar bone of central incisors and lateral incisors was smaller than that of canine with normal occlusion(P < 0.01). Most of the roots of maxillary anterior teeth were located at the labial of alveolar bone (94.98%), a few at thecenter of alveolar bone (5.02%), while most of mandibular anterior teeth were located at the center of alveolar bone (48.18%),a few at the labial of alveolar bone (34.24%). The least was located at the lingual side of alveolar bone (17.58%). Withthe increase of SN-MP, the SN-U1, MP-L1 and the alveolar bone thickness in mandibular apical (LW) decreased (r were-0.498, -0.421 and -0.383 respectively, P＜0.01). Conclusion In normal occlusion, roots of the maxillary anterior teethare mostly located on the labial side of the alveolar bone, but they are mostly located on the labial side or the center of thealveolar bone in mandibular. Compared with the low-angle people, the angle of central incisors of the high-angle people isupright and the alveolar bone thickness of mandibular central incisors in the apical area is thin.