Structure and Chemical Composition of ca. 10-Million-Year-Old (Late Miocene of Western Amazon) and Present-Day Teeth of Related Species

Abstract

Molecular information has been gathered from fossilized dental enamel, the best-preserved tissue of vertebrates. However, the association of morphological features with the possible mineral and organic information of this tissue is still poorly understood in the context of the emerging area of paleoproteomics. This study aims to compare the morphological features and chemical composition of dental enamel of extinct and extant terrestrial vertebrates of Crocodylia: Purussaurus sp. (extinct) and Melanosuchus niger (extant), and Rodentia: Neoepiblema sp. (extinct) and Hydrochoerus hydrochaeris (extant). To obtain structural and chemical data, superficial and internal enamel were analyzed by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (SEM-EDS). Organic, mineral, and water content were obtained using polarizing microscopy and microradiography on ground sections of four teeth, resulting in a higher organic volume than previously expected (up to 49%). It is observed that both modern and fossil tooth enamel exhibit the same major constituents: 36.7% Ca, 17.2% P, and 41% O, characteristic of hydroxyapatite. Additionally, 27 other elements were measured from superficial enamel by inductively coupled mass spectrometry (ICP-MS). Zinc was the most abundant microelement detected, followed by Pb, Fe, Mg, and Al. Morphological features observed include enamel rods in the rodent teeth, while incremental lines and semiprismatic enamel were observed in the alligator species. The fossil enamel was in an excellent state for microscopic analyses. Results show that all major dental enamel’s physical, chemical, and morphological features are present both in extant and extinct fossil tooth enamel (>8.5 Ma) in both taxa.

High-Value Compounds in Papaya By-Products (Carica papaya L. var. Formosa and Aliança): Potential Sustainable Use and Exploitation

“…Addicionally, the reported findings are similar to those presented by Martial-Didier et al [30], who reported potassium as the most abundant mineral presented in the peels of Solo papaya variety. Minerals, which are abundant in papaya by-products, are necessary for teeth structure (Ca) [31], and bones (Ca, Mg, Mn, B) [32], while microminerals like Cu, Fe, Mn, Se, and Zn are crucial for enzyme structure and biological functions [33].…”

Damage from Carbonated Soft Drinks on Enamel: A Systematic Review

“…Furthermore, an organic acid produced by the fermentation of sugar in beverages by oral microorganisms present in plaque further leads to demineralization and caries. The characteristics of dental enamel are not common at the macro- and micro-structural morphological level [ 58 , 59 ]. Therefore, the mechanism of enamel erosion must be analyzed from a microscopic point of view [ 60 , 61 ].…”

Paleontology in the 21st Century

“…Phylogenetically and physiologically informative tissues were probed by synchrotron [ 34 ] to support the previous identification of reproductive tissues in dinosaurs [ 35 , 36 ]. Technologies continue to broaden not only the type of questions to be asked, but the type of fossils we can analyze, from coprolites [ 33 ], teeth [ 37 ], and invertebrates [ 22 , 38 , 39 ] to dinosaurs [ 25 , 34 , 40 , 41 , 42 , 43 , 44 ], mammals [ 45 ], and our own lineage [ 29 , 32 , 46 ].…”

“…Finally, taphonomic reconstructions remain an important part of paleobiology, and this Special Issue includes multi-dimensional studies on taphonomy using rare earth element studies (REE) to trace the movement of pore waters through bone during fossilization to elucidate the mechanisms contributing to molecular preservation in various dinosaur bone and other fossils [ 40 , 41 , 42 , 43 ]. However, the recovery of proteins also requires a better understanding of taphonomic modifications, as noted in [ 37 ] and previously discussed in [ 47 ].…”