Al Haffar Iyad, Padilla Frédéric, Nefussi Raphael, Kolta Sami, Foucart Jean-Michel, Laugier Pascal
Laboratoire d'Imagerie Paramétrique, Université Pierre et Marie Curie Paris, Paris, France.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2006 Dec;102(6):782-91. doi: 10.1016/j.tripleo.2005.12.026. Epub 2006 Jul 27.
To demonstrate in vitro the feasibility of speed of sound (SOS) measurements through the mandible and to investigate the relationships between mandibular SOS, local bone mineral density (BMD), and the ratio between trabecular and cortical thicknesses (Tb.Th/Cort.Th). The long-term goal is to find a safe, simple test for bone quality in sites for dental implant placement.
Excised human mandibles (N = 23) were used for the measurement of sound transmission with two 1.6 MHz transducers. Three regions of interest (ROIs) were selected in each of the specimens, namely incisor, premolar, and molar regions. To determine short-term precision, 10 measurements (with repositioning between measures) were performed for each ROI. Local BMD and mandibular cross-sectional morphological characteristics were determined by dual x-ray absorptiometry (DXA) and computed tomography (CT).
The coefficient of variation for SOS was found to be 1%. SOS measurements at different sites were significantly different. A significant linear relationship was found between SOS and BMD (r2 = 0.62; P < .0001), whereas a nonlinear relationship was found between SOS and Tb.Th/Cort.Th (r2 = 0.53; P < .0001).
This in vitro study demonstrated the feasibility of SOS measurement through the mandible. Mandibular SOS reflects local BMD and Tb.Th/Cort.Th. In vivo studies are now required to confirm the predictive power of SOS measurement for bone quality assessment and its potential usefulness as a clinical diagnostic technique.
在体外证明通过下颌骨进行声速（SOS）测量的可行性，并研究下颌骨SOS、局部骨矿物质密度（BMD）以及小梁厚度与皮质厚度之比（Tb.Th/Cort.Th）之间的关系。长期目标是找到一种用于牙种植体植入部位骨质量的安全、简单的检测方法。
使用23个切除的人类下颌骨，通过两个1.6 MHz换能器进行声音传输测量。在每个标本中选择三个感兴趣区域（ROI），即切牙区、前磨牙区和磨牙区。为了确定短期精度，对每个ROI进行10次测量（每次测量之间重新定位）。通过双能X线吸收法（DXA）和计算机断层扫描（CT）确定局部BMD和下颌骨横截面形态特征。
发现SOS的变异系数为1%。不同部位的SOS测量值有显著差异。发现SOS与BMD之间存在显著的线性关系（r2 = 0.62；P <.0001），而SOS与Tb.Th/Cort.Th之间存在非线性关系（r2 = 0.53；P <.0001）。
这项体外研究证明了通过下颌骨进行SOS测量的可行性。下颌骨SOS反映局部BMD和Tb.Th/Cort.Th。现在需要进行体内研究，以确认SOS测量对骨质量评估的预测能力及其作为临床诊断技术的潜在用途。
