犬牙后移过程中牙根和牙槽骨的亨氏单位变化。
Hounsfield unit change in root and alveolar bone during canine retraction.
作者信息
Jiang Feifei, Liu Sean S-Y, Xia Zeyang, Li Shuning, Chen Jie, Kula Katherine S, Eckert George
机构信息
Postgraduate student, Department of Mechanical Engineering, Indiana University-Purdue University, Indianapolis, Ind.
Assistant professor, Department of Orthodontics and Oral Facial Genetics, Indiana University, Indianapolis, Ind.
出版信息
Am J Orthod Dentofacial Orthop. 2015 Apr;147(4):445-53. doi: 10.1016/j.ajodo.2014.11.027.
INTRODUCTION
The objective of this study was to determine the Hounsfield unit (HU) changes in the alveolar bone and root surfaces during controlled canine retractions.
METHODS
Eighteen maxillary canine retraction patients were selected for this split-mouth design clinical trial. The canines in each patient were randomly assigned to receive either translation or controlled tipping treatment. Pretreatment and posttreatment cone-beam computed tomography scans of each patient were used to determine tooth movement direction and HU changes. The alveolar bone and root surface were divided into 108 divisions, respectively. The HUs in each division were measured. Mixed-model analysis of variance was applied to test the HU change distribution at the P <0.05 significance level.
RESULTS
The HU changes varied with the directions relative to the canine movement. The HU reductions occurred at the root surfaces. Larger reductions occurred in the divisions that were perpendicular to the moving direction. However, HUs decreased in the alveolar bone in the moving direction. The highest HU reduction was at the coronal level.
CONCLUSIONS
HU reduction occurs on the root surface in the direction perpendicular to tooth movement and in the alveolar bone in the direction of tooth movement when a canine is retracted.
引言
本研究的目的是确定在可控的犬齿后移过程中牙槽骨和牙根表面的亨氏单位（HU）变化。
方法
选择18例上颌犬齿后移患者进行这项双盲设计的临床试验。将每位患者的犬齿随机分配接受平移或可控倾斜治疗。利用每位患者治疗前和治疗后的锥形束计算机断层扫描来确定牙齿移动方向和HU变化。牙槽骨和牙根表面分别被分为108个区域。测量每个区域的HU值。应用方差混合模型分析在P<0.05显著性水平下检验HU变化分布。
结果
HU变化随相对于犬齿移动的方向而变化。牙根表面出现HU降低。在垂直于移动方向的区域出现更大的降低。然而，牙槽骨中的HU在移动方向上降低。HU降低最高的是在冠部水平。
结论
当犬齿后移时，在垂直于牙齿移动方向的牙根表面以及在牙齿移动方向的牙槽骨中会出现HU降低。
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