Zhang Shizhen, Wei Xiaoyu, Wang Lufei, Wu Zhouqiang, Liu Lu, Yan Xinyu, Lai Wenli, Long Hu
State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
Department of Oral and Craniofacial Health Sciences, University of North Carolina Adams School of Dentistry, Chapel Hill, NC 27599, USA.
Diagnostics (Basel). 2022 Jan 23;12(2):285. doi: 10.3390/diagnostics12020285.
This study aims to evaluate the overall bone thickness (OBT) and cortical bone thickness (CBT) of mandibular symphysis and to determine the optimal sites for the insertion of orthodontic mini implants. Cone-beam computed tomography (CBCT) images of 32 patients were included in this study. The sample was further categorized into three facial types: low-, average-, and high-angle. OBT and CBT were measured at the mandibular symphysis region. All measurements were performed at six different heights from the cementoenamel junction [CEJ] and at seven different angles to the occlusal plane. Analysis of variance (ANOVA) was used for statistical comparison and a value less than 0.05 was considered statistically significant. Our results revealed that neither OBT nor CBT was influenced by age or sex, except for the observation that CBT was significantly greater in adults than in adolescents. OBT and CBT were significantly greater in low-angle cases than in average- and high-angle cases. Both OBT and CBT were significantly influenced by insertion locations, heights and angles, and their interactions. CBT and OBT were greatest at the location between two lower central incisors, and became greater with increases in insertion height and angle. Both recommended and optimal insertion sites were mapped. The mandibular symphysis region was suitable for the placement of orthodontic mini implants. The optimal insertion site was 6-10 mm apical to the CEJ between two lower central incisors, with an insertion angle being 0-60 degrees to the occlusal plane.
本研究旨在评估下颌联合处的整体骨厚度（OBT）和皮质骨厚度（CBT），并确定正畸微型种植体植入的最佳部位。本研究纳入了32例患者的锥形束计算机断层扫描（CBCT）图像。样本进一步分为三种面型：低角、平均角和高角。在下颌联合区域测量OBT和CBT。所有测量均在距牙骨质釉质界[CEJ]的六个不同高度以及与咬合平面的七个不同角度进行。采用方差分析（ANOVA）进行统计比较，P值小于0.05被认为具有统计学意义。我们的结果显示，OBT和CBT均不受年龄或性别的影响，不过观察到成人的CBT显著大于青少年。低角病例的OBT和CBT显著大于平均角和高角病例。OBT和CBT均受植入位置、高度和角度及其相互作用的显著影响。CBT和OBT在两颗下中切牙之间的位置最大，并随着植入高度和角度的增加而增大。绘制了推荐的和最佳的植入部位。下颌联合区域适合放置正畸微型种植体。最佳植入部位是在两颗下中切牙之间的CEJ根尖6 - 10毫米处，植入角度与咬合平面呈0 - 60度。
