Assessment of the relationship between tooth inclination and gingival and alveolar bone dimensions using computed tomography of the maxillary anterior teeth: a cross-sectional study

ABSTRACT Objective: The present study aimed to investigate the relationship between tooth inclination and gingival and bone dimensions in maxillary anterior teeth. Methods: This cross-sectional study included cone-beam computed tomography (CBCT) images of 160 maxillary anterior teeth (30 individuals). Tooth inclination, gingival and bone thickness, and distances from cementoenamel junction to alveolar bone crest and gingival margin were measured in the labial surface. The correlations were analyzed using Pearson and partial correlation tests (p≤0.05). Results: In the central incisors, tooth inclination was positively and significantly related to apical bone thickness (R = 0.34, p= 0.001). In the canines, tooth inclination was negatively and significantly related to cervical bone thickness (R = - 0.34, p= 0.01) and positively associated to apical bone thickness (R = 0.36, p= 0.01) and to gingival margin-cementoenamel junction distance (R = 0.31, p= 0.03). In the lateral incisors, tooth inclination was not associated with gingival or bone dimensions. Conclusions: In the central incisors, the greater the labial tooth inclination, the greater is the apical bone thickness. In the canines, the greater the labial tooth inclination, the smallest is the cervical bone thickness, the greater is the apical bone thickness, and the greater is the gingival margin. Gingival and bone dimensions should be assessed when planning orthodontic treatment involving buccal movement of central incisors and canines.

摘要 目的：本研究旨在探讨上颌前牙的牙齿倾斜度与牙龈及牙槽骨尺寸之间的关联。方法：本横断面研究纳入了30名受试者的160颗上颌前牙的锥形束计算机断层扫描（cone-beam computed tomography, CBCT）影像。于唇面测量牙齿倾斜度、牙龈及骨厚度，以及牙釉质牙骨质界（cementoenamel junction）至牙槽嵴顶与牙龈缘的距离。采用Pearson相关分析与偏相关分析进行相关性检验，检验水准为p≤0.05。结果：对于上颌中切牙，牙齿倾斜度与根尖骨厚度呈显著正相关（R=0.34，p=0.001）。对于上颌尖牙，牙齿倾斜度与颈区骨厚度呈显著负相关（R=-0.34，p=0.01），与根尖骨厚度（R=0.36，p=0.01）及牙龈缘-牙釉质牙骨质界距离（R=0.31，p=0.03）呈显著正相关。对于上颌侧切牙，牙齿倾斜度与牙龈及骨尺寸无显著关联。结论：在上颌中切牙中，唇向牙齿倾斜度越大，根尖骨厚度越高。在上颌尖牙中，唇向牙齿倾斜度越大，颈区骨厚度越小，根尖骨厚度越高，牙龈缘与牙釉质牙骨质界的距离越大。在制定涉及中切牙与尖牙颊向移动的正畸治疗计划时，应评估牙龈与牙槽骨尺寸状况。