Sakr Charbel, Al-Mosawi Mohammed, Grünewald Tilman A, Cook Philip, Tack Pieter, Vincze Laszlo, Micha Jean-Sebastien, Anderson Paul, Al-Jawad Maisoon, Lichtenegger Helga C
University of Natural Resources and Life Sciences (BOKU) Vienna Austria.
European Synchrotron Radiation Facility Grenoble France.
J Appl Crystallogr. 2024 Sep 25;57(Pt 5):1514-1527. doi: 10.1107/S1600576724007180. eCollection 2024 Oct 1.
Energy-dispersive Laue diffraction (EDLD) is a powerful method to obtain position-resolved texture information in inhomogeneous biological samples without the need for sample rotation. This study employs EDLD texture scanning to investigate the impact of two salivary peptides, statherin (STN) and histatin-1 (HTN) 21 -terminal peptides (STN21 and HTN21), on the crystallographic structure of dental enamel. These proteins are known to play crucial roles in dental caries progression. Three healthy incisors were randomly assigned to three groups: artificially demineralized, demineralized after HTN21 peptide pre-treatment and demineralized after STN21 peptide pre-treatment. To understand the micro-scale structure of the enamel, each specimen was scanned from the enamel surface to a depth of 250 µm using microbeam EDLD. Via the use of a white beam and a pixelated detector, where each pixel functions as a spectrometer, pole figures were obtained in a single exposure at each measurement point. The results revealed distinct orientations of hydroxyapatite crystallites and notable texture variation in the peptide-treated demineralized samples compared with the demineralized control. Specifically, the peptide-treated demineralized samples exhibited up to three orientation populations, in contrast to the demineralized control which displayed only a single orientation population. The texture index of the demineralized control (2.00 ± 0.21) was found to be lower than that of either the STN21 (2.32 ± 0.20) or the HTN21 (2.90 ± 0.46) treated samples. Hence, texture scanning with EDLD gives new insights into dental enamel crystallite orientation and links the present understanding of enamel demineralization to the underlying crystalline texture. For the first time, the feasibility of EDLD texture measurements for quantitative texture evaluation in demineralized dental enamel samples is demonstrated.
能量色散劳厄衍射（EDLD）是一种无需样品旋转就能在非均匀生物样品中获取位置分辨织构信息的强大方法。本研究采用EDLD织构扫描来研究两种唾液肽，即磷蛋白（STN）和组蛋白-1（HTN）21末端肽（STN21和HTN21）对牙釉质晶体结构的影响。已知这些蛋白质在龋齿进展中起关键作用。将三颗健康恒牙随机分为三组：人工脱矿组、HTN21肽预处理后脱矿组和STN21肽预处理后脱矿组。为了解牙釉质的微观结构，使用微束EDLD对每个样本从牙釉质表面到250 µm深度进行扫描。通过使用白色光束和像素化探测器，其中每个像素充当光谱仪，在每个测量点单次曝光即可获得极图。结果显示，与脱矿对照组相比，肽处理脱矿样品中羟基磷灰石微晶的取向明显不同，织构变化显著。具体而言，肽处理脱矿样品显示出多达三个取向群体，而脱矿对照组仅显示一个取向群体。发现脱矿对照组的织构指数（2.00±0.21）低于STN21（2.32±0.20）或HTN21（2.90±0.46）处理样品的织构指数。因此，EDLD织构扫描为牙釉质微晶取向提供了新的见解，并将目前对牙釉质脱矿的理解与潜在的晶体织构联系起来。首次证明了EDLD织构测量用于脱矿牙釉质样品定量织构评估的可行性。
