Location Depending Textures of the Human Dental Enamel

Abstract

Dental enamel is the most highly mineralised and hardest biological tissue in human body [1]. Dental enamel is made of hydroxylapatite (HAP) - Ca5(PO4)3(OH), which is hexagonal (6/m). The lattice parameters are a = b = 0.9418 nm und c = 0.6875 nm [1]. Although HAP is a very hard mineral, it can be dissolved easily in a process which is known as enamel demineralization by lactic acid produced by bacteria. Also the direct consumption of acid (e.g. citric, lactic or phosphoric acid in soft drinks) can harm the dental enamel in a similar way. These processes can damage the dental enamel. It will be dissolved completely and a cavity occurs. The cavity must then be cleaned and filled. It exists a lot of dental fillings, like gold, amalgam, ceramics or polymeric materials. After filling other dangers can occur: The mechanical properties of the materials used to fill cavities can differ strongly from the ones of the dental enamel itself. In the worst case, the filling of a tooth can damage the enamel of the opposite tooth by chewing if the interaction of enamel and filling is not equivalent, so that the harder fillings can abrade the softer enamel of the healthy tooth at the opposite side. This could be avoided if the anisotropic mechanical properties of dental enamel would be known in detail, hence then another filling could be searched or fabricated as an equivalent opponent for the dental enamel with equal properties. To find such a material, one has to characterise the properties of dental enamel first in detail for the different types of teeth (incisor, canine, premolar and molar). This is here exemplary done for a human incisor tooth by texture analysis with the program MAUD from 2D synchrotron transmission images [2,3,4].

Acquisition and evaluation procedure to improve the accuracy ofSAED

“…As another example, a/c lattice parameter ratios for dental enamel bioapatite between 1.371 and 1.378 were obtained, which are in good agreement with X‐ray synchrotron data (Al‐Jawad et al, 2012 ; Raue & Klein, 2010 ). Additionally, in a specific area of the dental enamel cross section, systematic shift of 0 kl reflections of ca 1.5% in terms of d ‐value (0.05 Å) was observed (Figure 8 ), while the position of hk 0 reflection coincides with literature data for inorganic hydroxyapatite (ICSD‐26204).…”

Analysis of the Early Stages and Evolution of Dental Enamel Erosion

“…The exposed larger crystals have also been suggested to be more acid-resistant, which would affect the development process, as the enamel presents areas that are more easily demineralized (25,26). Apatite crystal structure heterogeneity (27) may also play a role in this trend, as well as the different crystal arrangements in the enamel (28)(29)(30).…”

Effective property of tooth enamel: Monoclinic behavior

“…The primary structural unit of enamel is the rod which consists of many well-organized and packed hydroxyapatite (HAp) fibers with variable orientations (Al-Jawad et al, 2007;Jeng et al, 2009;Raue and Klein, 2010). Generally, the enamel rods grow perpendicular to the dentine-enamel junction and are separated by thin organic sheaths (He and Swain, 2008).…”