Instituto de Física, UNAM, Circuito de la Investigación Científica s/n., Cd. Universitaria, Coyoacán 04510, México, D.F., Mexico.
Mater Sci Eng C Mater Biol Appl. 2013 Dec 1;33(8):4568-74. doi: 10.1016/j.msec.2013.07.014. Epub 2013 Jul 19.
The crystallinity index (CI) is a measure of the percentage of crystalline material in a given sample and it is also correlated to the degree of order within the crystals. In the literature two ways are reported to measure the CI: X-ray diffraction and infrared spectroscopy. Although the CI determined by these techniques has been adopted in the field of archeology as a structural order measure in the bone with the idea that it can help e.g. in the sequencing of the bones in chronological and/or stratigraphic order, some debate remains about the reliability of the CI values. To investigate similarities and differences between the two techniques, the CI of sound human tooth enamel and synthetic hydroxyapatite (HAP) was measured in this work by X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR), at room temperature and after heat treatment. Although the (CI)XRD index is related to the crystal structure of the samples and the (CI)FTIR index is related to the vibration modes of the molecular bonds, both indices showed similar qualitative behavior for heat-treated samples. At room temperature, the (CI)XRD value indicated that enamel is more crystalline than synthetic HAP, while (CI)FTIR indicated the opposite. Scanning (SEM) and transmission (TEM) images were also used to corroborate the measured CI values.
结晶度指数 (CI) 是衡量给定样品中结晶物质百分比的指标，它也与晶体内部的有序程度相关。在文献中，有两种方法被报道用于测量 CI：X 射线衍射和红外光谱。尽管这些技术确定的 CI 已经在考古学领域被用作骨骼结构有序度的衡量标准，其想法是它可以帮助例如按时间顺序和/或地层顺序对骨骼进行排序，但关于 CI 值的可靠性仍存在一些争议。为了研究这两种技术之间的相似性和差异，本工作通过 X 射线衍射 (XRD) 和傅里叶变换红外光谱 (FTIR) 在室温下以及热处理后测量了健康人牙釉质和合成羟基磷灰石 (HAP) 的 CI。尽管 XRD 指数与样品的晶体结构有关，而 FTIR 指数与分子键的振动模式有关，但两种指数对热处理后的样品都表现出相似的定性行为。在室温下，XRD 指数表明牙釉质比合成 HAP 更具结晶性，而 FTIR 指数则相反。扫描电镜 (SEM) 和透射电镜 (TEM) 图像也被用于证实所测量的 CI 值。
