Pediatric Dentistry and Orthodontics Department, School of Dentistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
Angle Orthod. 2012 Jan;82(1):62-6. doi: 10.2319/031811-192.1. Epub 2011 Jul 20.
To verify whether bone mineral density (BMD) of cortical bone, trabecular bone, and total bone influence the primary stability of orthodontic miniscrews and to verify whether there is a correlation between the measurement of BMD by cone-beam computed tomography (CBCT) and central dual-energy x-ray absorptiometry (DEXA).
Twenty bovine bone sections were extracted from the pubic and iliac bones from regions with cortical thicknesses of approximately 1 mm. The BMD of the total bone block was evaluated using two methods: CBCT and DEXA. The BMD of cortical, trabecular, and total bone in the region of interest (ROI) were also evaluated by CBCT. After scanning the bone blocks, 20 self-drilling miniscrews (INP®) 1.4 mm in diameter and 6 mm long were inserted into them. The peak implant insertion torque (IT) was registered. After this, the pull-out test (PS) was performed and the maximum force registered. The Pearson correlation test was applied to verify the correlations between variables.
The BMD of the total bone block verified by CBCT and DEXA showed a positive and strong correlation (r = 0.866, P = .000). The BMD of the ROI for cortical bone influenced the IT (r = 0.518, P = .40) and the PS of miniscrews (r = 0.713, P = .001, Table 2). However, the total bone BMD (verified by CBCT and DEXA) and trabecular bone BMD presented weak and not statistically significant correlations with primary stability.
There was a positive correlation between total bone block BMD measured by DEXA and CBCT. The cortical BMD influenced the IT and PS.
验证皮质骨、松质骨和总体骨的骨密度（BMD）是否会影响正畸微螺钉的初始稳定性，并验证锥形束 CT（CBCT）和中央双能 X 射线吸收法（DEXA）测量的 BMD 之间是否存在相关性。
从耻骨和髂骨中提取 20 个皮质厚度约为 1mm 的牛骨切片。使用两种方法评估总骨块的 BMD：CBCT 和 DEXA。还通过 CBCT 评估 ROI 中皮质骨、松质骨和总体骨的 BMD。扫描骨块后，将 20 个直径为 1.4mm、长 6mm 的自攻式微螺钉（INP®）插入其中。记录峰值种植体插入扭矩（IT）。之后进行拔出试验（PS），并记录最大力。应用 Pearson 相关检验验证变量之间的相关性。
通过 CBCT 和 DEXA 验证的总骨块 BMD 呈正强相关（r=0.866，P=0.000）。皮质骨 ROI 的 BMD 影响 IT（r=0.518，P=0.40）和微螺钉的 PS（r=0.713，P=0.001，表 2）。然而，总骨 BMD（通过 CBCT 和 DEXA 验证）和松质骨 BMD 与初始稳定性呈弱相关且无统计学意义。
DEXA 和 CBCT 测量的总骨块 BMD 之间存在正相关。皮质骨 BMD 影响 IT 和 PS。
