School of Materials, The University of Manchester, Manchester M13 9PL, UK.
Acta Biomater. 2013 Sep;9(9):8337-45. doi: 10.1016/j.actbio.2013.06.018. Epub 2013 Jun 19.
The internal crystalline structure of a human molar tooth has been non-destructively imaged in cross-section using X-ray diffraction computed tomography. Diffraction signals from high-energy X-rays which have large attenuation lengths for hard biomaterials have been collected in a transmission geometry. Coupling this with a computed tomography data acquisition and mathematically reconstructing their spatial origins, diffraction patterns from every voxel within the tooth can be obtained. Using this method we have observed the spatial variations of some key material parameters including nanocrystallite size, organic content, lattice parameters, crystallographic preferred orientation and degree of orientation. We have also made a link between the spatial variations of the unit cell lattice parameters and the chemical make-up of the tooth. In addition, we have determined how the onset of tooth decay occurs through clear amorphization of the hydroxyapatite crystal, and we have been able to map the extent of decay within the tooth. The described method has strong prospects for non-destructive probing of mineralized biomaterials.
利用 X 射线衍射断层扫描技术，对人磨牙的内部晶状结构进行了非破坏性的横截面成像。从对硬生物材料具有较大衰减长度的高能 X 射线收集的衍射信号，在透射几何结构中被收集。将这与计算机断层扫描数据采集相结合，并对其空间起源进行数学重建，可以获得牙齿中每个体素的衍射图案。使用这种方法，我们观察到了一些关键材料参数的空间变化，包括纳米晶粒度、有机物含量、晶格参数、晶体学择优取向和取向度。我们还将单位晶胞晶格参数的空间变化与牙齿的化学成分联系起来。此外，我们通过羟磷灰石晶体的明显非晶化确定了龋齿的发生过程，并能够在牙齿内定位龋齿的程度。该描述的方法具有对矿化生物材料进行非破坏性探测的广阔前景。
