Human Teeth Samples Research Articles

Prehispanic Maya diet and mobility at Nakum, Guatemala: A multi-isotopic approach

The site of Nakum has been the subject of extensive archaeological investigation, but little is known of the subsistence practices or mobility of the Prehispanic Maya who lived there. This study employed a multi-isotopic approach to investigate the diet and mobility of the Nakum Maya. Despite the poor preservation typical of tropical environments, the isotopic compositions of five human bone samples were compared to carbon, nitrogen, and sulphur isotope baselines developed from 16 archaeological faunal specimens from Nakum. The bone collagen carbon and nitrogen results indicate that the Nakum Maya consumed a maize-based diet supplemented with other cultigens and animal protein. Stable carbon isotope values from the bioapatite of five human bone and seven human tooth samples show that maize was an important dietary component throughout life, although two individuals consumed less maize during childhood. The bone collagen sulphur data and strontium isotope results from three teeth indicate that the Nakum individuals consumed local foods. However, two human oxygen isotope values were lower than the local range developed from human bone and tooth enamel samples, indicating these individuals moved to the site from outside the Maya region. Although the faunal sulphur values were much higher than expected at an inland site due to the underlying marine carbonate limestone geology, one faunal sample exhibited a very low value, suggesting that it was imported to the site over a considerable distance. Finally, this is the first study to publish baseline sulphur isotope values derived from Maya faunal remains and contributes to a better understanding of this isotope system in the Maya region.

Inhibitory potential of EGCG on Streptococcus mutans biofilm: A new approach to prevent Cariogenesis

Dental caries is a common cause for tooth loss and Streptococcus mutans is identified as the etiologic pathogen. This study evaluates the inhibitory potential of Epigallocatechin gallate (EGCG) on S.mutans glucansucrase enzyme and its biofilm. Glucansucrase binding and the inhibitory potential of EGCG was validated using AutoDock tool and enzyme inhibitory assay. Biofilm inhibitory potential was also confirmed using Scanning Electron Microscopic (SEM) analysis in human tooth samples. Molecular docking revealed that EGCG interacted with GLU 515 and TRP 517 amino acids and binds to glucansucrase. SEM analysis revealed inhibition of S.mutans biofilm by various concentrations of EGCG on surfaces of tooth samples. Bioinformatics and biological assays confirmed that EGCG potentially binds to the S. mutans glucansucrase and inhibits its enzymatic activity. Enzymatic inhibition of glucansucrase attenuated biofilm formation potential of S. mutans on tooth surface. Thus, we conclude that EGCG inhibitory potential of S. mutans biofilm on the tooth surface is a novel approach in prevention of dental caries.

Forensic STR Identification of Human Teeth Samples Exposed to Various Acidic and Alkaline Chemical Conditions in the Iraqi Population

Forensic odontology has transformed human identification of forensic applications. This study evaluated the effect of various acidic and alkaline chemical solutions on dental DNA STR loci used in human identification. Teeth samples were divided into 3 groups of hydrochloric acid (HCl), nitric acid (HNO3) and sodium hydroxide (NaOH), in comparison to control teeth or blood DNA samples of the same individual. Following DNA extraction, a total of ten STR loci (CSF1PO, FGA, D13S317, D16S539, D21S11, D2S1338, TH01, D18S51, D5S818 and D8S1179) were amplified and sequenced. Results showed that DNA concentrations and purities decreased significantly in HCl and HNO3chemical conditions, but were less affected in NaOH whereas only HNO3showed DNA degradation. In addition, amplification of dental STR loci showed lower size products than their control blood counterparts. Moreover, the number of amplified STR loci in samples exposed to HNO3 and HCl were fewer than those in NaOH. To evaluate STR loci, sequencings analysis was performed to compare STR motif frequency, DNA identity, and gaps between teeth and blood DNA. Results showed that the ratio of tooth/blood STR frequency was significantly different among HNO3, HCl and NaOH (25%, 8.5% and 33.4%, respectively). Moreover, gap percentages were lower in samples exposed to NaOH and HNO3 than HCl (9.8 and 9.3 vs 12.2%).Furthermore, NaOH alkaline solution had higher percent identities of STR loci, between teeth and blood DNA, than HNO3 or HCl acidic conditions (58.7 versus 48.9 and36.8%, respectively). The highest STR identity percentages was found for CSF, D18S5, and D2S1338(64.7, 59.1, and 57.1%; respectively) whereas D5S818 was the lowest (16.9%).The most stable human identifier in the Iraqi population was the CSF locus whereas D5S818 was the least stable. In conclusion, dental DNA STR loci are more sensitive to HNO3 than HCl or NaOH, which affected sequence STR frequency, identity and gap.

Paleodietary trends in Late Holocene hunter-gatherers from southwestern La Pampa province, Argentina. First results from the Médano Petroquímica site through stable isotope analysis (δ13C and δ15N)

The aim of this work is to explore general trends and intra-site variability in human paleodiet from Médano Petroquímica, a burial site created by pre-Hispanic hunter-gatherers and located in the southwest of La Pampa province, Argentina. Measurements of carbon (13C/12C) and nitrogen (15N/14N) stable isotopes were performed on the human bone and tooth samples of 16 individuals from five of the burials identified in the site (EA, H4, H5, H6-1, and H7). The multivariate diet reconstruction model used indicates the consumption of land/terrestrial resources within a food web based mainly on C3 producers. The results suggest a relatively high trophic position for these individuals, which is consistent with a marked dependence on animal protein, particularly that of herbivores, such as Lama guanicoe, Rhea spp. (and/or its eggs), and omnivorous animals. A relatively greater dispersion observed in δ13Cap values in comparison with δ13Ccol and δ15N values is partially attributed here to greater intra-site variability in the non-protein portion of diet relative to the protein component.

Ultrastructural and Chemical Composition of Dentin and Enamel in Lab Animals.

Statement of the Problem:Human tooth is clinically the most appropriate material that can be used for in-vitro dental research. However, there are limitations and drawbacks for using human teeth. Therefore, alternatives to samples of human teeth for dental studies are necessary. Purpose: This study purposed to evaluate and compare the microstructure and chemical composition of enamel and dentin of teeth in some lab animals. Materials and Method: In this experimental study, teeth of mouse, rabbit, guinea pig, dog, cat, and sheep were used. Scanning electron microscope observations and X-ray diffraction analysis were performed on samples. Results: This study revealed resemblance in general structure of dentin and enamel between mentioned animals and human. The minimum mean of dentinal tubules diameter is found in guinea pig (0.5µ), while the highest is in cat (1.5µ). Also the lowest and the highest mean intertubular distance was measured respectively in guinea pig (3µ) and sheep (4.8µ) and the maximum and minimum mean diameter of rods was measured in rabbit (6.6µ) and guinea pig (1.5µ), respectively. Conclusion:The recorded details and the measured values indicate great resemblance between dog and human dentin and enamel. Cat is in the second place for dentinal studies; sheep and guinea pig have the least resemblance to human within the scope of the reviewed criteria.

Accurate Sr isotope determination of human bone and tooth samples by LA‐MC‐ICP‐MS: A comment on “Meijer et al., (2019)”

AbstractThe in‐situ Sr isotope determination of low‐Sr bioapatites is challenging and requires monitoring several interferences, among others, Ar‐CaPO. In particular, the analysis of human bones and teeth has revealed several pitfalls, which affect the ability to obtain accurate results. In this commentary, I review the data from the paper of Meijer et al. (2019), trying to address some accuracy issues arising, in my opinion, from polyatomic interferences. After a tentative calibration of their data, using the 1/88Sr signal (V−1) as a proxy of the Sr content, the enamel specimens (enamel Ar‐CaPO corrected 87Sr/86Sr ratio = 0.7078 ± 0.0032; mean ± 2σ) are closer to the likely local bioavailable Sr (bone Ar‐CaPO corrected 87Sr/86Sr ratio = 0.7071 ± 0.0011; mean ± 2σ).

Hyperspectral imaging system associated with novel subtracting image processing algorithm for dental caries early detection

Early detection of caries is vital for demineralization reverse offering a less pain, as well as accurate and precise caries removal. In this study, the difference in optical properties of normal tissue and human caries lesion has been used for early diagnosis, using laser induced fluorescence spectroscopy. The human tooth sample was illuminated with visible band sources (488, 514 and 633 nm) with power 5 mW. The reflected and emitted light of tested sample was collected using hyperspectral camera in an attempt to generate multispectral images (cubic image). The variation of reflected and emitted power as function in wavelength was employed to generate characteristic spectrum of each tooth tissue. Human teeth caries tissue lesion releases its excess power by emitting fluorescence light producing chemical footprint signature; this signature is dependent on the elemental composition of tooth elements and caries state. This non-invasive, non-contact and non-ionizing imaging system with associated novel pattern recognition algorithm was employed to diagnose and classify dental (enamel and dentin), caries, and white spot lesion. It was reported that the perceived fluorescence emission is function of the illuminating wavelength. While enamel and dentin caries were distinguished and characterized at 633 nm illuminating wavelength; white spot lesion cannot be detected. The enamel caries, dentin caries, and white spot lesion were contoured and recognized at 488 nm and 514 nm wavelengths. Therefore full recognition was achieved through generated cubic image after sample irradiation at 488 nm and 514 nm. This non-invasive, non-contact, and non-ionizing imaging technique with customized image processing algorithm offered high sensitivity, high resolution, and early caries detection with optimum performance at 514 nm.

Determination of natural radionuclides and some metal concentrations in human tooth samples in the Rize province, Turkey

ABSTRACT The main purpose of this study was to identify the concentrations of naturally occurring radionuclides (226Ra, 232Th and 40K) and some metals (Fe, Ni, Cu, Zn, Pb and Cd) in tooth samples collected from humans living in the Rize province of Turkey. It was found that the activity concentrations ranged from 8.1 to 114.51 Bq kg−1 for 226Ra, from 10.44 to 97.3 Bq kg−1 for 232Th and from 14.53 to 489.27 Bq kg−1 for 40K. The mean activity concentration values of 226Ra and 232Th in tooth samples were higher than the average world values for bones. Furthermore, when the metal concentrations were examined, there was no regular increase or decrease according to age or sex. The results of the metal analysis on the tooth samples were compared with the results of similar studies and were generally found to be consistent.

The comparison of DNA extraction techniques in human bone and tooth samples exposed to high heat

In the identification of forensic cases, it is critical to obtain information to identify the victimÂ’s identity from burnt bone and tooth remains. When bone and tooth are burned, both their physical and chemical properties change significantly, which prevents anthropological evaluations and successful DNA profiling for identification purposes. Heat causes difficulties in the identification techniques in which bones and teeth are used, depending on the degree of heat exposure. For this reason, with the changes occurring in bone and tooth during combustion, it is necessary to evaluate the results of observation and analysis, and to be used the information obtained in a certain order. It is very difficult to extract DNA from the samples obtained from fire, explosion, motor vehicle and aircraft accidents and other traumatic events by traditional methods. The only biological material available to determine the typing and the identification of missing persons or unknown remains in different situations, such as mass fatality events, wars or socio-political events, is often only human remains. Effective DNA extraction procedures are critical steps in successful DNA analysis of skeletal remains. Due to variations in DNA and heterogeneity within the bone, unfortunately, the only reliable method for obtaining DNA from overly degraded specimens such as burnt bones and teeth in the literature, is still not available. In the study, present extraction methods are compared and as a result it was suggested that phenol-chloroform and Qiagen DNA Mini Kit could be used in routine with a newly developed modified procedure in order to increase efficiency and efficiency in forensic genetic identification.

Evaluation of crystalline indexes obtained through infrared spectroscopy and x-ray diffraction in thermally treated human tooth samples

The crystalline indexes obtained through infrared spectroscopy (CIIR) and X-ray diffraction (CIXRD) were used to analyze the structural changes of dentin and enamel in human teeth when subjected to heat treatments between room temperature (25 °C) to 1200 °C in atmospheric air and argon. Thermogravimetric (TGA) and differential scanning calorimetry (DSC) analyses of sound powders were also used to support the analysis. As the temperature increased, the CIXRD increased exhibiting a behavior like that of the crystal grain size, and the CIIR increased until the β-TCP phase appeared. These results indicated that the CIIR was more variable to structural changes than the CIXRD.

Disentangling isolated dental remains of Asian Pleistocene hominins and pongines.

Scholars have debated the taxonomic identity of isolated primate teeth from the Asian Pleistocene for over a century, which is complicated by morphological and metric convergence between orangutan (Pongo) and hominin (Homo) molariform teeth. Like Homo erectus, Pongo once showed considerable dental variation and a wide distribution throughout mainland and insular Asia. In order to clarify the utility of isolated dental remains to document the presence of hominins during Asian prehistory, we examined enamel thickness, enamel-dentine junction shape, and crown development in 33 molars from G. H. R. von Koenigswald's Chinese Apothecary collection (11 Sinanthropus officinalis [= Homo erectus], 21 “Hemanthropus peii,” and 1 “Hemanthropus peii” or Pongo) and 7 molars from Sangiran dome (either Homo erectus or Pongo). All fossil teeth were imaged with non-destructive conventional and/or synchrotron micro-computed tomography. These were compared to H. erectus teeth from Zhoukoudian, Sangiran and Trinil, and a large comparative sample of fossil Pongo, recent Pongo, and recent human teeth. We find that Homo and Pongo molars overlap substantially in relative enamel thickness; molar enamel-dentine junction shape is more distinctive, with Pongo showing relatively shorter dentine horns and wider crowns than Homo. Long-period line periodicity values are significantly greater in Pongo than in H. erectus, leading to longer crown formation times in the former. Most of the sample originally assigned to S. officinalis and H. erectus shows greater affinity to Pongo than to the hominin comparative sample. Moreover, enamel thickness, enamel-dentine junction shape, and a long-period line periodicity value in the “Hemanthropus peii” sample are indistinguishable from fossil Pongo. These results underscore the need for additional recovery and study of associated dentitions prior to erecting new taxa from isolated teeth.

The SEM electron-mirror effect in human tooth and synthetic hydroxyapatite samples.

The characteristics of the electron-mirror effect (EME) image depend on both the scanning electron microscope parameters and the sample's physical properties. The behavior of human tooth (dentin and enamel) and synthetic hydroxyapatite samples submitted to the EME procedure is presented in this work. Polyethylene terephthalate (PET) and epoxy resin, two good EME producers, were used for comparison. A distorted EME image was observed in the obtained dentin's surface, but enamel and synthetic hydroxyapatite surfaces did not produce the EME. After ex situ calcination treatments of the teeth at 700 and 1,200°C, the EME was observed in dentin, enamel, and synthetic hydroxyapatite, but highly deformed EME images were produced. We show that these last observations are the result of the well-known charge-edge effect. After EME analysis, the calculated dielectric constant was 8.7 for dentin and 3.8 for PET. RESEARCH HIGHLIGHTS: Electron-mirror effect (EME) was observed in dentin but not in enamel or synthetic hydroxyapatite. Highly deformed EME images are produced in all samples after calcination at above 700°C. For dentin the calculated dielectric constant was 8.7 and for PET is was 3.8.

Design and implementation of novel hyperspectral imaging for dental carious early detection using laser induced fluorescence.

Early detection of carious is vital for demineralization reversal, offering less pain, as well as precise carious removal. In this study, the difference in optical properties of normal tissue and human carious lesion has been used for early diagnosis, using laser induced fluorescence spectroscopy. The optical system consists of light source in visible band and hyperspectral camera, associated with designed digital image processing algorithm. The human tooth sample was illuminated with visible band sources at 488, and 514 nm with energy of 5 m watt. The reflected and emitted light from the tested sample was captured using hyperspectral camera in an attempt to generate multispectral images (cubic image). The variation of reflected and emitted energy as function of wavelength was employed to generate characteristic spectrum of each tooth tissue. Human teeth carious tissue lesion releases its excess energy by emitting fluorescence light producing chemical footprint signature; this signature is dependent on the elemental composition of tooth elements and carious state. This non-invasive, non-contact and non-ionizing imaging system with associated novel pattern recognition algorithm was employed to diagnose and classify different carious types and stages. It was reported that the perceived fluorescence emission is function of the illuminating wavelength. While enamel and dentin carious were distinguished and characterized at 514 nm illuminating wavelength; white spot lesion were contoured and recognized at 488 nm. Therefore, full recognition could be achieved through generated cubic image after sample irradiation at 488 nm and 514 nm. In conclusion, this study reports on a customized optical image system that can offer high sensitivity, high resolution, and early carious detection with optimum performance at 514 nm and 488 nm.

Social differences in Neolithic/Bronze Age Myanmar: 87Sr/86Sr in skeletal remains from Oakaie 1 and Nyaung'gan

Here we begin to investigate prehistoric kinship and social differentiation in ancient Myanmar, through analyses of strontium isotopes in human tooth samples from excavated skeletal remains of 18 individuals from the archaeological sites of Oakaie 1 and Nyaung'gan, in Sagaing Division, central Myanmar. The archaeological deposits at these sites span the Late Neolithic and Early Bronze Age (approximately 12th to 8th c. BCE). These isotopic data are interpreted in association with bioarchaeological, material culture and stratigraphic data. These preliminary results suggest a differentiation in mean strontium signatures between the sites, which are <3 km apart, but with sex-based patterns within the sites. This indicates kinship was a strong organizing principle, with little long-distance migration, despite apparently considerable long-distance exchange networks active by the early Bronze Age in Myanmar.

Reminova and EAER: Keeping Enamel Whole through Caries Remineralization.

This article aims to outline the early development of a King's College London dental spinout company, Reminova, formed to commercialize a novel clinical method of caries remineralization: electrically accelerated and enhanced remineralization (EAER). This method is being developed to address the unmet clinical need identified by modern caries management strategies to keep enamel "whole" through remineralization of clinical caries as a form of nonoperative caries treatment for initial-stage and moderate lesions. A progressive movement within dentistry is shifting away from the restorative-only model, which, it is suggested, has failed. The high prevalence of initial-stage caries across populations provides a significant opportunity to prevent restorations and reduce repeat restorations over a patient's lifetime. Reminova has set out to provide a method to repair lesions without drilling, filling, pain, or injections. The article outlines the rationale for and the chronological stages of the technology and company development. It then outlines corroborative evidence to show that EAER treatment can, in this preliminary in vitro investigation, remineralize clinically significant caries throughout the depth of the lesion as measured by Knoop microhardness and corroborated by scanning electron microscopy. Furthermore, the presented data show that EAER-treated enamel is harder than the healthy enamel measured nearby in each sample and is very similar in appearance to healthy enamel from the subjective interpretation made possible by scanning electron microscopy imagery. The data presented also show that this more "complete" remineralization to a high hardness level has been achieved with 2 remineralizing agents via in vitro human tooth samples. The broad clinical potential of this new treatment methodology seems to be very encouraging from these results. Reminova will strive to continue its mission, to ensure that, in the future, dental teams will not need to drill holes for the treatment of initial-stage and moderate caries lesions.

Effect of Fruit Juices and Other Beverages on Loss of Tooth Structure

Objective: To determine the effect of seven different beverages on tooth enamel. Material and Methods: Human teeth samples were immersed in each beverage (Pepsi, Red Bull, Orange juice, Apple juice, Lemon juice, Coffee and Green tea). Specimens were divided into seven groups by beverage type (n = 5 per group). Weight of the enamel was measured before and after immersion in different beverages daily for at periodic intervals of 24hrs, 7 days, 15 days and 30 days. The data were recorded after weighing the teeth at each time. The beverages were replaced daily. Anova and Tukey post hoc test was performed to compare the differences in percent weight loss. The significance level was set at 5%. Results: There was change in the mean percent weight loss amongst the different beverages with orange juice showing a high reduction in comparison to green tea and coffee. The mean weight reduction of orange juice was by 21% followed by Red Bull (13%), Pepsi (11%), Lemon juice (16%), Apple juice (16%), coffee (3%) and green tea (3%). Conclusion: This study shows that different beverages have erosive potential on teeth depending on the duration of the exposure.

The variation in surface morphology and hardness of human deciduous teeth samples after laser irradiation

The variation in surface morphology and hardness of human deciduous teeth samples has been investigated after laser irradiation at different wavelengths and energies. Nd:YAG was employed as a source of irradiation for IR (1064 nm) and visible (532 nm) radiation, whereas an excimer laser was used as the source of UV (248 nm) radiation. Scanning electron microscope (SEM) analysis was carried out to reveal the surface morphological evolution of teeth samples. Vickers microhardness tester was employed to investigate the modifications in the hardness of the laser-treated samples. It is observed from SEM analysis that IR wavelength is responsible for ablation of collagen matrix and intertubular dentine. For visible radiation, the ablation of collagen along with hydroxypatite is observed. With UV radiation, the ablation of peritubular dentine is dominant and is responsible for the sealing of tubules. The decrease in hardness at lower energy for both wavelengths is due to the evaporation of carbon content. With increasing energy, evaporation of water along with carbon content, and resolidification and re-organization of inorganic content causes the increase in hardness of the treated dentine. SEM as well as microhardness analyses reveal that laser wavelengths and energy of laser radiation significantly influence the surface morphology and hardness of samples.

Scale of human mobility in the southern Andes (Argentina and Chile): A new framework based on strontium isotopes.

The goal of this article is to assess the scale of human paleomobility and ecological complementarity between the lowlands and highlands in the southern Andes during the last 2,300 years. By providing isotope results for human bone and teeth samples, we assess a hypothesis of "high residential mobility" suggested on the basis of oxygen isotopes from human remains. We develop an isotopic assessment of human mobility in a mountain landscape combining strontium and oxygen isotopes. We analyze bone and teeth samples as an approach to life-history changes in spatial residence. Human samples from the main geological units and periods within the last two millennia are selected. We present a framework for the analysis of bioavailable strontium based on the combination of the geological data with isotope results for rodent samples. The 87 Sr/86 Sr values from human samples indicate residential stability within geological regions along life history. When comparing strontium and oxygen values for the same human samples, we record a divergent pattern: while δ18 O values for samples from distant regions overlap widely, there are important differences in 87 Sr/86 Sr values. Despite the large socio-economic changes recorded, 87 Sr/86 Sr values indicate a persisting scenario of low systematic mobility between the different geological regions. Our results suggest that strontium isotope values provide the most germane means to track patterns of human occupation of distinct regions in complex geological landscapes, offering a much higher spatial resolution than oxygen isotopes in the southern Andes.

Non-destructive Microstructural Evaluation of Intact and Restored Human Teeth Using Tabletop X-Ray $$\upmu $$ μ CT System

This study explores the feasibility of a micro-focus based tabletop X-ray $$\upmu $$ CT system for the micro-structural characterization of human teeth and later its application to the non-destructive evaluation of teeth restored with different composite resin for their interface integrity and micro-imperfections. In the first part of this study, extracted human primary and permanent molar teeth were used to explore potential of micro-focus based tomography setup for their micro-structural characterization. The details of root canal structure of human teeth were visualized and quantified with polychromatic $$\upmu $$ CT. In the second part identification and comparison of defects in a set of six human teeth samples, which were restored with two different composite resins, was carried out. Group ‘A’ samples were restored using a submicron hybrid composite material and Group ‘B’ were restored with a Nano-hybrid restorative composite material. The quantitative analysis of $$\upmu $$ CT data for composite resin restored teeth showed more number of voids or defects in Group ‘A’ restorations compared to Group ‘B’. A comparative evaluation of $$\upmu $$ CT techniques based on synchrotron source and micro-focus source is also illustrated to show their respective merits and limitations.

Relative performance of two DNA extraction and library preparation methods on archaeological human teeth samples

ABSTRACTDNA extraction and library preparation are crucial steps in any ancient DNA study. Although palaeogenomic researchers are facing a growing choice of DNA extraction and sequencing library preparation methods, how their performance varies with DNA preservation remains unclear. To help elucidate this question, we compared the performance of two common DNA extraction and Illumina library preparation methods on a set of archaeological human samples, considered to contain ancient DNA of intermediate to good preservation (5–50% endogenous DNA). Results indicate that while the levels of contamination and endogenous DNA recovered are comparable for both silica-in-solution and silica-column based extractions, the ability of the former to accommodate larger starting quantities of sample material confers notable benefits with regards to library complexity, and furthermore seems to aid with the recovery of shorter endogenous DNA molecules. While our observations gained from comparing the single-stranded with double-stranded DNA library construction methods largely replicate earlier observations, the combination of our data with previously published datasets demonstrate that the benefits gained using single-stranded methods are inversely proportional to the endogenous DNA content in the ancient sample.