New Assessment of Trabecular Bone Mechanical Properties by Intraoral

本研究的目的是开发一种新的方法，通过口内X线片定量评估颌骨松质骨力学性能。方法：取2只成年恒河猴下颌骨无牙区，解剖4块(20×15 mm)骨块。用60kv和6.4mAs拍摄口腔内X线片。测定骨小梁面积(T.Ar)、骨小梁表面长度(TSL)、骨小梁数目(Tb.N)、结节数(N.ND)、末端数(N.Trn)和分维(Fd)。4块骨块采用Micro-CT连续扫描，层厚0.08 mm。根据Micro-CT图像建立了三维有限元模型，并计算了力学性能的弹性模数。将4个骨块共16个部位的骨小梁结构参数与弹性模量值进行比较。结果TAR、N.ND与弹性模量呈显著正相关。(P&lt；0.05)。Tb.N、N.Tm、Fd与弹性模量呈显著负相关(P&lt；0.05)。而TSL与弹性模数之间无显著相关性。多元回归分析表明，弹性模量可用T.Ar和Fd[弹性系数=0.07T.Ar-5.08Fd+6.85]来解释(RSquare=0.91P&lt；0.000 1)。结论：口内X线片可以定量评价颌骨松质骨的力学性能。

The purpose of this study was to develop a new method which quantitatively assesses mechanical properties of trabecular bone of the jaws by intraoral radiographs. Methods: 4 bone blocks (20*15 mm) were dissected from mandibular edentulous area obtained from two adult monkeys. Intraoral radiographs of these blocks were taken with 60 kV and 6.4 mAs. Parameters of trabecular bone structure were determined as follows; trabecular area (T.Ar), trabecular surface length (TSL), trabecular number (Tb.N), number of node (N.Nd), number of terminus (N.Trn), and fractal dimension (FD). 4 bone blocks were serially scanned by micro-CT with slice thickness of 0.08 mm. A three-dimensional finite element model was created from micro-CT images and elastic modulus of mechanical properties was also calculated. Parameters of trabecular bone structure in a total of 16 regions obtained from 4 bone blocks were compared with elastic modulus. Results Significant positive correlations were found among TAr, N.Nd and elastic modulus. (P<0.05). Significant negative correlations were found among Tb.N, N.Tm, FD and elastic modulus (P<0.05). However, there was no significant correlation between TSL and elastic modulus. Multiple regression analysis revealed that elastic modulus was explained by T.Ar and FD [elastic modulus=0.07 * T.Ar -5.08 * FD + 6.85] (R square = 0.91, P<0.000 1).Conclusion: Our results suggest that mechanical properties of trabecular bone of the jaws may be quantitatively assessed by intraoral radiographs.