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International Journal of Molecular... Jun 2020Tooth enamel is the outer covering of tooth crowns, the hardest material in the mammalian body, yet fracture resistant. The extremely high content of 95 wt% calcium... (Review)
Review
Tooth enamel is the outer covering of tooth crowns, the hardest material in the mammalian body, yet fracture resistant. The extremely high content of 95 wt% calcium phosphate in healthy adult teeth is achieved through mineralization of a proteinaceous matrix that changes in abundance and composition. Enamel-specific proteins and proteases are known to be critical for proper enamel formation. Recent proteomics analyses revealed many other proteins with their roles in enamel formation yet to be unraveled. Although the exact protein composition of healthy tooth enamel is still unknown, it is apparent that compromised enamel deviates in amount and composition of its organic material. Why these differences affect both the mineralization process before tooth eruption and the properties of erupted teeth will become apparent as proteomics protocols are adjusted to the variability between species, tooth size, sample size and ephemeral organic content of forming teeth. This review summarizes the current knowledge and published proteomics data of healthy and diseased tooth enamel, including advancements in forensic applications and disease models in animals. A summary and discussion of the status quo highlights how recent proteomics findings advance our understating of the complexity and temporal changes of extracellular matrix composition during tooth enamel formation.
Topics: Animals; Dental Enamel; Dental Enamel Proteins; Extracellular Matrix; Humans; Proteome; Tooth
PubMed: 32585904
DOI: 10.3390/ijms21124458 -
Archives of Oral Biology Sep 2022The tufts of human dental enamel are structures located at the enamel-dentin junction and whose origin has not been clearly established. Although studies have...
OBJECTIVE
The tufts of human dental enamel are structures located at the enamel-dentin junction and whose origin has not been clearly established. Although studies have highlighted their protein content and hypomineralization, none has been able to shed light on their 3D structure. The aim of this study was to reveal the whole structure using high-resolution conventional microtomography.
DESIGN
Ten adult mandibular first and second molars and two primary mandibular first molars were sectioned and scanned with microcomputed tomography with a resolution between 4.7 and 5 micrometers. By determining the threshold discriminating dentin and tufts, we were able to reconstruct 3D meshes.
RESULTS
We revealed the exact pattern of the tufts in adult molars and discovered their distribution, their dynamics, and the existence of a regular undulation, forming a particular angle of approximately 30 degrees with the dentin surface. A spatial frequency of approximately 160 micrometers would be compatible with the variation in the orientation of groups of dental enamel rods. In contrast, the present setting is not sufficient to extract similar information for primary teeth.
CONCLUSIONS
Enamel tufts have a specific pattern, with an oriented draped form and are regularly spaced. The possible connection between these undulations and the Hunter-Schreger bands (diazonias and parazonias) needs to be studied.
Topics: Adult; Dental Enamel; Dentin; Humans; Molar; Tooth; X-Ray Microtomography
PubMed: 35738023
DOI: 10.1016/j.archoralbio.2022.105487 -
Journal of Separation Science Aug 2023Proteomics has become an attractive method to study human and animal material, biological profile, and origin as an alternative to DNA analysis. It is limited by DNA... (Review)
Review
Proteomics has become an attractive method to study human and animal material, biological profile, and origin as an alternative to DNA analysis. It is limited by DNA amplification in ancient samples and its contamination, high cost, and limited preservation of nuclear DNA. Currently, three approaches are available to estimate sex-osteology, genomics, or proteomics, but little is known about the relative reliability of these methods in applied settings. Proteomics provides a new, seemingly simple, and relatively non-expensive way of sex estimation without the risk of contamination. Proteins can be preserved in hard teeth tissue (enamel) for tens of thousands of years. It uses two sexually distinct forms of the protein amelogenin in tooth enamel detectable by liquid chromatography-mass spectrometry; the protein amelogenin Y isoform is present in enamel dental tissue only in males, while amelogenin isoform X can be found in both sexes. From the point of view of archaeological, anthropological, and forensic research and applications, the reduced destruction of the methods used is essential, as well as the minimum requirements for sample size.
Topics: Male; Female; Animals; Humans; Amelogenin; Reproducibility of Results; Peptides; DNA; Protein Isoforms; Dental Enamel
PubMed: 37232204
DOI: 10.1002/jssc.202300183 -
Applied Radiation and Isotopes :... Nov 2010When tooth enamel is exposed to ionizing radiation, radicals are formed, which can be detected using electron paramagnetic resonance (EPR) techniques. EPR dosimetry... (Review)
Review
When tooth enamel is exposed to ionizing radiation, radicals are formed, which can be detected using electron paramagnetic resonance (EPR) techniques. EPR dosimetry using tooth enamel is based on the (presumed) correlation between the intensity or amplitude of some of the radiation-induced signals with the dose absorbed in the enamel. In the present paper a critical review is given of this widely applied dosimetric method. The first part of the paper is fairly fundamental and deals with the main properties of tooth enamel and some of its model systems (e.g., synthetic apatites). Considerable attention is also paid to the numerous radiation-induced and native EPR signals and the radicals responsible for them. The relevant methods for EPR detection, identification and spectrum analyzing are reviewed from a general point of view. Finally, the needs for solid-state modelling and studies of the linearity of the dose response are investigated. The second part is devoted to the practical implementation of EPR dosimetry using enamel. It concerns specific problems of preparation of samples, their irradiation and spectrum acquisition. It also describes how the dosimetric signal intensity and dose can be retrieved from the EPR spectra. Special attention is paid to the energy dependence of the EPR response and to sources of uncertainties. Results of and problems encountered in international intercomparisons and epidemiological studies are also dealt with. In the final section the future of EPR dosimetry with tooth enamel is analyzed.
Topics: Animals; Dental Enamel; Electron Spin Resonance Spectroscopy; Free Radicals; Humans; Radiometry
PubMed: 20599388
DOI: 10.1016/j.apradiso.2010.05.016 -
Communications Biology Apr 2023Nitrogen isotopes are widely used to study the trophic position of animals in modern food webs; however, their application in the fossil record is severely limited by...
Nitrogen isotopes are widely used to study the trophic position of animals in modern food webs; however, their application in the fossil record is severely limited by degradation of organic material during fossilization. In this study, we show that the nitrogen isotope composition of organic matter preserved in mammalian tooth enamel (δN) records diet and trophic position. The δN of modern African mammals shows a 3.7‰ increase between herbivores and carnivores as expected from trophic enrichment, and there is a strong positive correlation between δN and δN values from the same individuals. Additionally, δN values of Late Pleistocene fossil teeth preserve diet and trophic level information, despite complete diagenetic loss of collagen in the same specimens. We demonstrate that δN represents a powerful geochemical proxy for diet that is applicable to fossils and can help delineate major dietary transitions in ancient vertebrate lineages.
Topics: Animals; Nitrogen Isotopes; Food Chain; Carbon Isotopes; Mammals; Collagen; Dental Enamel
PubMed: 37029186
DOI: 10.1038/s42003-023-04744-y -
Journal of Dentistry Jun 2014To summarise the chemical, biological and host factors that impact enamel mineral loss, to highlight approaches to contemporary management of clinical conditions... (Review)
Review
OBJECTIVES
To summarise the chemical, biological and host factors that impact enamel mineral loss, to highlight approaches to contemporary management of clinical conditions involving mineral loss and summarise emerging trends and challenges in this area.
DATA SOURCES
"Medline" and "Scopus" databases were searched electronically with the principal key words tooth, enamel, *mineral*, caries and erosion. Language was restricted to English and original studies and reviews were included. Conference papers and abstracts were excluded.
CONCLUSIONS
Enamel mineral loss leads to the degradation of the surface and subsurface structures of teeth. This can impact their shape, function, sensitivity and aesthetic qualities. Dental caries is a multifactorial disease caused by the simultaneous interplay of dietary sugars, dental plaque, the host and time. There is a steady decline in dental caries in developed countries and the clinical management of caries is moving towards a less invasive intervention, with risk assessment, prevention, control, restoration and recall. Tooth wear can be caused by erosion, abrasion and attrition. Dental erosion can be the result of acid from intrinsic sources, such as gastric acids, or extrinsic sources, in particular from the diet and consumption of acidic foods and drinks. Its prevalence is increasing and it increases with age. Clinical management requires diagnosis and risk assessment to understand the underlying aetiology, so that optimal preventative measures can be implemented. Overall, prevention of enamel mineral loss from caries and tooth wear should form the basis of lifelong dental management. Evidence based oral hygiene and dietary advice is imperative, alongside preventive therapy, to have a healthy lifestyle, whilst retaining hard tooth tissue.
Topics: Dental Caries; Dental Enamel; Humans; Risk Assessment; Tooth Abrasion; Tooth Attrition; Tooth Demineralization; Tooth Erosion
PubMed: 24993851
DOI: 10.1016/S0300-5712(14)50002-4 -
Radiation Protection Dosimetry Dec 2016In vivo electron paramagnetic resonance biodosimetry on tooth enamel is likely to be an important technology for triage of overexposed individuals after a major... (Review)
Review
In vivo electron paramagnetic resonance biodosimetry on tooth enamel is likely to be an important technology for triage of overexposed individuals after a major radiological incident. The accuracy and robustness of the technique relies on various properties of the enamel such as the geometry of the tooth, the presence of restorations, whitening treatments or exposition to sunlight. Those factors are reviewed, and their influence on dosimetry specifically for triage purposes is discussed.
Topics: Artifacts; Biological Assay; Biomarkers; Dental Enamel; Electron Spin Resonance Spectroscopy; Humans; Radiation Exposure; Radiation Monitoring; Radioactive Hazard Release; Reproducibility of Results; Sensitivity and Specificity; Technology Assessment, Biomedical; Triage
PubMed: 27473693
DOI: 10.1093/rpd/ncw212 -
Journal of Dental Research Mar 1979Important progress has been made relative to the growth, structure and function of enamel. Better understanding of the epithelial mesenchymal interactions during... (Review)
Review
Important progress has been made relative to the growth, structure and function of enamel. Better understanding of the epithelial mesenchymal interactions during odontogenesis has been gained through tissue culture, and the predominant role of the dental papilla has been established. Differences between rodent and human amelogenesis have been demonstrated. With radioautography and cytochemistry, a significant amount of new information has been obtained on the metabolism of the ameloblasts, concerning the synthesis of proteins, glycoproteins and proteoglycans, as well as calcium transport. Numerous biochemical investigations have been devoted to developing and mature enamel matrix. The organic components of human adult enamel are mainly constituted of lipids and proteins, but further investigations are still needed to elucidate their precise nature. The so-called key-hole configuration of adult enamel can be questioned when amelogenesis is considered since the tissue does not develop in a prismatic head-tail fashion. The most important results have probably been obtained in the field of individual enamel apatite crystals shape and ultrastructure as well as in the description of the precise patterns of their carious dissolution which bears great similarities to the dissolution of synthetic apatites in acids.
Topics: Amelogenesis; Animals; Apatites; Calcium; Crystallography; Dental Enamel; Dental Enamel Proteins; Dental Enamel Solubility; Enamel Organ; Epithelium; Glycoproteins; Humans; Mesoderm; Odontogenesis; Tooth Germ
PubMed: 368094
DOI: 10.1177/002203457905800220011 -
PloS One 2020Lower Eocene (Wasatchian-aged) sediments of the Margaret Formation on Ellesmere Island in Canada's High Arctic preserve evidence of a rainforest inhabited by alligators,...
Lower Eocene (Wasatchian-aged) sediments of the Margaret Formation on Ellesmere Island in Canada's High Arctic preserve evidence of a rainforest inhabited by alligators, turtles, and a diverse mammalian fauna. The mammalian fossils are fragmentary and often poorly preserved. Here, we offer an alternative method for their identification. Among the best preserved and extensive of the Eocene Arctic forests is the Strathcona Fiord Fossil Forest, which contains permineralized in situ tree stumps protruding from a prominent coal seam, but a paucity of vertebrate fossils. In 2010 and 2018, we recovered mammalian tooth fragments at the fossil forest, but they are so incomplete as to be undiagnostic by using their external morphology. We used a combination of light microscopy and SEM analysis to study the enamel microstructure of two tooth fragments from the fossil forest-NUFV2092B and 2092E. The results of our analysis indicate that NUFV2092B and 2092E have Coryphodon-enamel, which is characterized by vertical bodies that manifest as bands of nested chevrons or treelike structures visible in the tangential section under light microscopy. This enamel type is not found in other mammals known from the Arctic. Additionally, when studied under SEM, the enamel of NUFV2092B and 2092E has rounded prisms that open to one side and are surrounded by interprismatic matrix that is nearly parallel to the prisms, which also occurs in Coryphodon enamel, based on prior studies. The tooth fragments reported here, along with some poorly preserved bone fragments, thus far are the only documented vertebrate fossils from the Strathcona Fiord Fossil Forest. However, fossils of Coryphodon occur elsewhere in the Margaret Formation, so its presence at the fossil forest is not surprising. What is novel in our study is the way in which we identified the fossils using their enamel microstructure.
Topics: Animals; Arctic Regions; Canada; Dental Enamel; Forests; Fossils; Mammals; Microscopy, Electron, Scanning; Microscopy, Polarization; Tooth
PubMed: 32966343
DOI: 10.1371/journal.pone.0239073 -
Journal of Cancer Research and... 2020The objective of this study is to evaluate the effects of radiotherapy doses on mineral density and percentage mineral volume of human permanent tooth enamel.
OBJECTIVE
The objective of this study is to evaluate the effects of radiotherapy doses on mineral density and percentage mineral volume of human permanent tooth enamel.
MATERIALS AND METHODS
Synchrotron radiation Xray microcomputed tomography (SRμCT) and microhardness testing were carried out on 8 and 20 tooth samples, respectively. Enamel mineral density was derived from SRμCT technique using ImageJ software. Microhardness samples were subjected to Vickers indentations followed by calculation of microhardness and percentage mineral volume values using respective mathematical measures. Data were analyzed using paired t-test at a significance level of 5%. Qualitative analysis of the enamel microstructure was done with two-dimensional projection images and scanned electron micrographs using μCT and field emission scanning electron microscopy, respectively.
RESULTS
Vickers microhardness and SRμCT techniques showed a decrease in microhardness and an increase in mineral density, respectively, in postirradiated samples. These changes were related to mineral density variation and alteration of hydroxyapatite crystal lattice in enamel surface. Enamel microstructure showed key features such as microporosities and loss of smooth homogeneous surface. These indicate tribological loss and delamination of enamel which might lead to radiation caries.
CONCLUSIONS
Tooth surface loss might be a major contributing factor for radiation caries in head-and-neck cancer patients prescribed to radiotherapy. Such direct effects of radiotherapy cause enamel abrasion, delamination, and damage to the dentinoenamel junction. Suitable measures should, therefore, be worked out to protect nontarget oral tissues such as teeth while delivering effective dosages to target regions.
Topics: Dental Enamel; Hardness; Head and Neck Neoplasms; Humans; In Vitro Techniques; Microscopy, Electron, Scanning; Radiation Injuries; Surface Properties; Tooth Demineralization; X-Ray Microtomography
PubMed: 32719276
DOI: 10.4103/jcrt.JCRT_8_19