New insights in prism orientation within human enamel

Abstract

The knowledge about the orientation of the prisms in human dental enamel is mainly based on morphological observations (light optical, SEM etc.). Hence there are many schematic drawings, showing the orientation as seen in the microscope. Locally resolved direct measurements of the orientations, proofing the observations, have not been done in detail up to now. X-ray diffraction methods adapted from material science are used in this study, providing directly the orientation of the crystallites in the examined positions. Hereby new and better detailed information was obtained, showing the orientation of the prisms and giving information about their intrinsic structure. Based on the measurements, existing prism orientation models can be enhanced and two structural suggestions can be made, showing possible inner building principles for the prisms. Future planned measurements will even allow deciding which of the two models is more likely.

Detection of carious lesions utilizing depolarization imaging by polarization sensitive optical coherence tomography

“…26 While this is the case in the left third, the enamel rods in the center third are commonly parallel oriented to the incident beam and the retardation remains constant over the depth. Reversely, the orientation image allows an estimation of the rod structure in this center image region, but further investigations of the polarization sensitive image formation with regards to the precise spatial distribution 27 are necessary for a conclusive interpretation. For dentin, less birefringence related to its substructure 26 and a decreased DOPU, which has been previously observed 28 and occurs due to multiple scattering, 29 allow a delimitation from the surrounding enamel, as well as the in the intensity images visible DEJ.…”

Influence of Enamel Thickness on Bleaching Efficacy: An In-Depth Color Analysis

“…At ΔE1 time, the presence of aprismatic enamel “1AE” influenced the CP bleaching, showing less color change in comparison with group without aprismatic enamel “1E”. Enamel is formed by apatite crystals arranged as layers of prisms in different directions [ 19 ]. So, aprismatic layer is found in the most superficial area of enamel, in which crystals are arranged parallel to each other and perpendicular to enamel surface.…”

Hierarchical Biomineralization: from Nature's Designs to Synthetic Materials for Regenerative Medicine and Dentistry

“…The techniques used include sectioning [24] , serial photographing of sections [25] , x-ray diffraction [26] , graphical computer modelling [27] , combined computer modelling with scanning electron microscopy (SEM) [28] , and synchrotron x-ray microtomography [29] . For example, Raue et al [30] used synchrotron x-ray diffraction to understand the orientation of nanocrystals through texture analysis, which in turn provides insights into the orientation of the enamel prisms. Moreover, Hunter-Shreger band (HSB) is a group of 10-13 enamel prisms, which causes an optical phenomenon due to the difference of the directionality of the enamel prisms.…”