Modern Teeth Research Articles

From Local Farms to Supermarket Foods: The Story of the Homogenization of the Argentine Diet Told by the IsotopeRatios of Modern Teeth.

Nutritional changes over the last century, driven by globalization, hypermarketization, and malnutrition, are global in scale. Large countries in the Global South might be resilient to dietary homogenization due to their natural diversity of regions and ecosystems, which might have prevented the adoption of supermarket diets. Argentina has a wide array of ecosystems and historically different subsistence diets dependent on regional characteristics. We analyzed the spatiotemporal variation of stable isotope values in Argentina using modern teeth to test for regional dietary patterns and its consistence over time. We collected teeth from voluntary donors born between 1940 and 2010, from 72 locations across Argentina. A total of 119 teeth were analyzed for the markers δ13Cdentine, δ13Cenamel, δ15N, and δ34S. A reconstruction of isotopic niches was performed to estimate dietary patterns across different regions and time periods. This study is the first to analyze changes in modern dietary patterns in Argentina using isotopic data measured in contemporary teeth. We showed latitudinal, longitudinal, and temporal differences in isotopic values, reflecting the variation in available resources within the country. Changes in the diet were observed over time, including declining δ15N values, a reduction in δ34S range, and a trend toward homogenization of δ13Cenamel values. Conversely, δ13Cdentine values remained constant over time, maintaining latitudinal patterns and regional differences across regions. This study increases our understanding of modern population dietary patterns both spatially and over the last 70 years. Our findings suggest that the Argentine population has shifted toward a supermarket diet in recent years.

Automated High-Throughput Biological Sex Identification from Archeological Human Dental Enamel Using Targeted Proteomics.

Biological sex is key information for archeological and forensic studies, which can be determined by proteomics. However, the lack of a standardized approach for fast and accurate sex identification currently limits the reach of proteomics applications. Here, we introduce a streamlined mass spectrometry (MS)-based workflow for the determination of biological sex using human dental enamel. Our approach builds on a minimally invasive sampling strategy by acid etching, a rapid online liquid chromatography (LC) gradient coupled to a high-resolution parallel reaction monitoring (PRM) assay allowing for a throughput of 200 samples per day (SPD) with high quantitative performance enabling confident identification of both males and females. Additionally, we developed a streamlined data analysis pipeline and integrated it into a Shiny interface for ease of use. The method was first developed and optimized using modern teeth and then validated in an independent set of deciduous teeth of known sex. Finally, the assay was successfully applied to archeological material, enabling the analysis of over 300 individuals. We demonstrate unprecedented performance and scalability, speeding up MS analysis by 10-fold compared to conventional proteomics-based sex identification methods. This work paves the way for large-scale archeological or forensic studies enabling the investigation of entire populations rather than focusing on individual high-profile specimens. Data are available via ProteomeXchange with the identifier PXD049326.

Effects of particle size, storage conditions, and chemical pretreatments on carbon and oxygen isotopic measurements of modern tooth enamel

Isotopic analysis of human tooth enamel can provide life history information useful in forensic identification. These applications depend on the availability of reference data documenting isotopic values for individuals with known life history and on the comparability of data from reference and case work samples. Here we build on previous methodological research, which has largely focused on paleontological and archaeological samples, and conduct experiments using enamel from modern human teeth targeting three sample preparation variables (sample particle size, storage conditions, and chemical pretreatments). Our results suggest that differences in particle size affect the efficiency of sample reactions during pretreatment and analysis, with coarse particles giving reduced loss of enamel carbonate during acid pretreatments but producing slightly higher oxygen isotope values than fine particles during analysis. Data for samples stored in dry and ambient environments following pretreatment were indistinguishable, suggesting no exchange of oxygen between samples and ambient water vapor. Finally, chemical pretreatments with a range of commonly used reactants and conditions showed a pervasive, moderate oxygen isotope shift associated with acetic acid treatment, which may be caused by exchange of enamel hydroxyl groups with reagents or rinse waters. Collectively, the results emphasize the importance of methodological standardization to improve comparability and reduce potential for bias in the forensic application of tooth enamel isotope data.

Effect of the Teeth Whitening Procedure on the Mineral Composition of Oral Fluid.

The basis of modern tooth whitening systems is the use of a whitening gel, which usually contains hydrogen peroxide or carbamide peroxide. The study included 81 patients aged 22 to 35 years with a tooth color A2 and a darker color on the Vita Classic scale. The purpose of our research was to identify a new approach to whitening teeth to improve safety and gentleness. To perform this, we assessed the effect of the tooth whitening procedure on the mineral composition of the oral fluid. A new approach to the teeth whitening procedure was to use a mouth retractor and a tool for aspirating the whitening gel, which we developed. Before the procedure, a protective film-forming aerosol, which included sodium ascorbate, was applied. After the tooth whitening procedure, the enamel was remineralized with a sealing liquid for 14 days. The concentrations of calcium and phosphorus in the oral fluid were determined using a spectrophotometer with a set of reagents (Human). The results obtained indicate that the new approach to the teeth whitening procedure contributed to less pronounced changes in the concentrations of calcium (+29.07, p < 0.001) and phosphorus (-14%, p < 0.001) in the oral fluid immediately after the procedure and in combination with the standard procedure for teeth whitening; immediately after this procedure, the calcium concentration increased by 74.4% (p < 0.001), and the phosphorus concentration decreased by 23.07% (p < 0.001). The use of remineralizing agents led to a faster recovery of the initial levels of calcium and phosphorus in the oral fluid.

Enigmatic carbonate isotope values in shark teeth: Evidence for environmental and dietary controls

Shark teeth are abundant in the fossil record and integrate physiological information, ecological interactions, and paleo-oceanographic conditions in their chemistry. Fossil shark teeth are well suited for stable isotope analysis because their enameloid is resistant to diagenetic alteration due to its high chemical stability. Although often used in paleoecological studies of mammals, carbonate carbon isotope compositions (δ13CCO3) in shark enameloid have remained enigmatic. Here, we investigate multiple stable isotope systems (δ13Corg, δ13CCO3, δ18OCO3, δ18OPO4) within modern shark teeth to determine relationships between the different systems and build an interpretative framework for future studies of both modern and fossil sharks. There is a weaker than expected correlation between δ18OPO4 and δ18OCO3 values in modern shark teeth (r2 = 0.44), which contrasts with mammalian studies to date and suggests this metric is not an appropriate test for diagenetic alteration in fossil shark teeth. Organic carbon isotope composition (δ13Corg) measured from modern dental collagen ranges from −16.0‰ to −10.8‰. The enameloid δ13CCO3 values we measured are much higher than collagen, ranging from −6.0‰ to 10.3‰, and there is no direct relationship between δ13Corg and δ13CCO3 values in shark teeth. Instead, we found the fractionation (ε) between δ13Corg and δ13CCO3 values to correspond with δ18OCO3 values but not δ18OPO4 values. This could be due to the carbon source in shark enameloid being partitioned between dietary carbon and dissolved inorganic carbon (DIC) or physiological differences in the tooth formation process changing the fractionation of carbonate isotopes. We applied the fractionation factor from modern teeth to carbonate isotope compositions of fossil shark teeth to predict δ13Corg values. Although the carbon sources to shark enameloid carbonate needs further investigation, our results suggest that fossil shark teeth could provide insights into carbon cycling of ancient marine ecosystems.

Comparison of powdered enamel sample pretreatment methods for strontium isotope analysis

Most researchers assume minimal impact of pretreatment on strontium isotope ratios ( 87 Sr/ 86 Sr) for bones and teeth, and methods vary tremendously. We compared 14 pretreatment methods, including no prep other than powdering enamel, ashing, soaking in water, an oxidizing agent (bleach or hydrogen peroxide) or acetic acid (0.1 M, 1.0 M, and 1.0 M buffered with calcium acetate), and a combination of these steps. We prepared and analyzed aliquots of powdered molar enamel from three proboscideans (one modern captive Indian elephant, Elephas maximus indicus ; one Pleistocene mastodon, Mammut americanum ; and one Miocene gomphothere, Afrochoerodon kisumuensis ). Each pretreatment was performed in triplicate and we measured 87 Sr/ 86 Sr, Sr concentration, and uranium (U) concentration, using the same lab space and instrumentation for all samples. Variability in 87 Sr/ 86 Sr and Sr and U concentrations was considerable across pretreatments. Mean 87 Sr/ 86 Sr across methods ranged from 0.70999 to 0.71029 for the modern tooth, 0.71458 to 0.71502 for the Pleistocene tooth, and 0.70804 to 0.70817 for the Miocene tooth. The modern tooth contained the least Sr and negligible U. The Pleistocene tooth contained slightly more Sr and measurable amounts of U, and the Miocene tooth had approximately 5x more Sr and U than the Pleistocene tooth. For all three teeth, variance in 87 Sr/ 86 Sr, Sr concentrations, and U concentrations among replicates was statistically indistinguishable across pretreatments, but there were apparent differences among pretreatments for the modern and Pleistocene teeth. Both contained relatively little Sr, and it is possible that small amounts of exogenous Sr from reagents, building materials or dust affected some replicates for some pretreatments. For the modern tooth, median 87 Sr/ 86 Sr varied considerably (but statistically insignificantly) across pretreatments. For the Pleistocene tooth, variability in median 87 Sr/ 86 Sr was also considerable; some pretreatments were statistically distinct but there were no obvious patterns among methods. For the Miocene tooth, variability in median 87 Sr/ 86 Sr was much smaller, but there were significant differences among pretreatments. Most pretreatments yielded 87 Sr/ 86 Sr and Sr concentrations comparable to, or lower than, untreated powder, suggesting selective removal of exogenous material with high 87 Sr/ 86 Sr. Further evaluation of the mechanisms driving isotopic variability both within and among pretreatment methods is warranted. Researchers should clearly report their methods and avoid combining data obtained using different methods. Small differences in 87 Sr/ 86 Sr could impact data interpretations, especially in areas where isotopic variability is low.

Carbon, nitrogen, and oxygen stable isotopes in modern tooth enamel: A case study from Gorongosa National Park, central Mozambique

The analyses of the stable isotope ratios of carbon (δ13C), nitrogen (δ15N), and oxygen (δ18O) in animal tissues are powerful tools for reconstructing the feeding behavior of individual animals and characterizing trophic interactions in food webs. Of these biomaterials, tooth enamel is the hardest, most mineralized vertebrate tissue and therefore least likely to be affected by chemical alteration (i.e., its isotopic composition can be preserved over millions of years), making it an important and widely available archive for biologists and paleontologists. Here, we present the first combined measurements of δ13C, δ15N, and δ18O in enamel from the teeth of modern fauna (herbivores, carnivores, and omnivores) from the well-studied ecosystem of Gorongosa National Park (GNP) in central Mozambique. We use two novel methods to produce high-precision stable isotope enamel data: (i) the “oxidation-denitrification method,”which permits the measurement of mineral-bound organic nitrogen in tooth enamel (δ15Nenamel), which until now, has not been possible due to enamel’s low organic content, and (ii) the “cold trap method,” which greatly reduces the sample size required for traditional measurements of inorganic δ13Cenameland δ18Oenamel(from ≥0.5 to ≤0.1 mg), permitting analysis of small or valuable teeth and high-resolution serial sampling of enamel. The stable isotope results for GNP fauna reveal important ecological information about the trophic level, dietary niche, and resource consumption. δ15Nenamelvalues clearly differentiate trophic level (i.e., carnivore δ15Nenamelvalues are 4.0‰ higher, on average, than herbivores), δ13Cenamelvalues distinguish C3and/or C4biomass consumption, and δ18Oenamelvalues reflect local meteoric water (δ18Owater) in the park. Analysis of combined carbon, nitrogen, and oxygen stable isotope data permits geochemical separation of grazers, browsers, omnivores, and carnivores according to their isotopic niche, while mixed-feeding herbivores cannot be clearly distinguished from other dietary groups. These results confirm that combined C, N, and O isotope analyses of a single aliquot of tooth enamel can be used to reconstruct diet and trophic niches. Given its resistance to chemical alteration, the analysis of these three isotopes in tooth enamel has a high potential to open new avenues of research in (paleo)ecology and paleontology.

Changes in the oral status and periodontal pathogens in a Sardinian rural community from pre-industrial to modern time

The oral microbial profile in humans has evolved in response to lifestyle changes over the course of different eras. Here, we investigated tooth lesions and the microbial profile of periodontal bacteria (PB) in dental calculus of a Sardinian pre-industrial rural community. In total, 51 teeth belonging to 12 historical individuals buried in an ossuary in the early 1800s and 26 modern teeth extracted from 26 individuals from the same geographical area were compared to determine the oral health status, bacterial load and amount of most relevant PB. Total caries and bacterial genomes count appeared to be sex-related in historical samples. Historical females presented a higher incidence of caries, PB pathogens and a higher bacterial load than historical males. Furthermore, we compared the PB profile of the historical individuals with the modern ones, revealing a notable increase in modern individuals of PB belonging to “Red complex bacteria” often associated with periodontitis and other chronic diseases of modern life. Our findings could be explained through an analysis of environmental factors such as socioeconomic, hygienic and healthy conditions that can have a great impact on oral health and bacterial composition among individuals of the same and different eras.

Protocol matters: A need for standardized procedure in cementochronology

Cementochronology has long been associated in the literature with a high correlation between chronological and estimated age, and low differences between the two ages. The excessive accuracy was rather suspicious, and the method did not even appear in common forensic practice. An important step towards more widespread use of the method is the need to standardize work procedures, including indexes for recording the quality of cementum, preparation of thin sections and the age calculation. In our study, we used the standardized protocol for the preparation of thin sections in a set of Czech modern teeth of known age and sex. In the initial phase, 11.5% of the teeth were discarded due to severe caries in the medial part of the root. In a set of single extractions (55 teeth from 55 individuals), we focused on the detailed results of the age estimation, using precision and accuracy indicators. We also used different dental development data to calculate age, given inconsistencies in the use of eruption / mineralization. In a set of multiple extractions (68 teeth from 22 individuals), intra-individual variability was examined. The result of the application of the standardized protocol is an estimate of age with an absolute inaccuracy of −1.7 years and a relative inaccuracy of 5.4%. Calculation of precision and accuracy in the set of single extractions, however, showed the method’s limitations: the imprecision measuring the variability of cementum increments counts increased with chronological age, as did the inaccuracy. The use of different dental development data did not significantly increase the accuracy of the age estimation results. Intra-individual variability remains poorly understood – in the set of multiple extractions the differences within one individual ranged between 0.9 and 10.8 years.

Simultaneous analysis of stable and radiogenic strontium isotopes in reference materials, plants and modern tooth enamel

Radiogenic strontium isotopes (87Sr/86Sr) are a useful tool in forensics, ecology, bioarcheology and paleoanthropology allowing investigation of present and past migration and landscape use. The measurement of the 87Sr/86Sr ratio traditionally assumes a constant stable (88Sr/86Sr) isotope ratio. However, some studies indicate that these stable Sr isotopes may display mass-dependent fractionation, suggesting that the 88Sr/86Sr ratio may fingerprint previously unknown dietary and physiological information. Here we present a survey of the variability of δ88Sr values, along with the 87Sr/86Sr ratios, in fourteen reference materials of geological and biological origin using MC-ICPMS. The measurements employ a simple sample-standard bracketing method and zirconium external correction. Comparisons with double-spiked δ88Sr TIMS analyses show a very good agreement (0.014 ‰; n = 10). We then applied this method to explore the fractionation of the 88Sr/86Sr ratio in tooth enamel of mammals from two modern food-chains (Kruger National Park and Western Cape, South Africa), and from modern South African chacma baboon populations. Clear differences in the δ88Sr values are observed between plants and teeth of herbivores (~ −0.26 ‰; n = 5), but the distinction between herbivores and carnivores requires further investigation. Variations between tooth enamel of young and adult baboons suggests that the δ88Sr is a promising indicator of weaning behaviors. Our method implementation and preliminary results highlight the importance of coupled radiogenic and stable Sr isotope determination in extant and extinct vertebrates.

Dental cementum virtual histology of Neanderthal teeth from Krapina (Croatia, 130-120 kyr): an informed estimate of age, sex and adult stressors.

The evolution of modern human reproductive scheduling is an aspect of our life history that remains vastly uncomprehended. The present work aims to address this gap by validating a non-destructive cutting-edge methodology to infer adult life-history events on modern teeth with known life history and then applying it to fossil specimens. We use phase-contrast synchrotron X-ray microtomography to visualize the dental cementum of 21 specimens: nine contemporary humans; 10 Neanderthals from Krapina (Croatia, 130-120 kyr); one Neolithic Homo sapiens from Ajmana (Serbia); and one Mesolithic H. sapiens from Vlasac (Serbia). We were able to correctly detect and time (root mean square error = 2.1 years; R2 = 0.98) all reproductive (menarche, parturition, menopause) and other physiologically impactful events in the modern sample. Nonetheless, we could not distinguish between the causes of the events detected. For the fossil specimens, we estimated age at death and age at occurrence of biologically significant events. Finally, we performed an exploratory analysis regarding possible sexual dimorphism in dental cementum microstructure, which allowed us to correctly infer the sex of the Neolithic specimen, for which the true value was known via DNA analysis.

Supernumerary roots in maxillary deciduous canines: A rare anomaly with a long history

ObjectiveTo describe two maxillary deciduous bi-rooted canines, one archeological and one modern, and examine the possible etiology of this condition. DesignTwo cases of bi-rooted canines were described and compared to published examples. Both specimens were radiographed and measured and compared to one-rooted samples. The archeological specimen was scanned using CBCT to facilitate detailed examination of the deciduous teeth. The extracted modern tooth was embedded in epoxy resin and two coronal sections were cut, one through the crown and one through the roots and examined with a light microscope. ResultsThe bi-rooted canines were larger than the control samples. They showed none of the features commonly associated with gemination. The radiographs and scans showed that the canine roots in the archeological case diverged mesio-distally like the buccal roots in the adjacent first deciduous molar. In the clinical case, the root trunk was elongated mesio-distally and the furcation was located very close to the apex with a C-shaped root canal. ConclusionsBoth variants of the condition described above are rare in deciduous canines. They do not seem to be associated with fusion or gemination. However, as the teeth are relatively flattened bucco-lingually and we tentatively propose that this form results from spatial constraints during the early stages of crown development that have contributed to the development of additional roots. The megadont dimension of the recent bi-rooted deciduous canine may affect root development and the necessity of two mesio-distally located roots for anchorage in the maxilla.

Mass fractionation of Rb and Sr isotopes during laser ablation-multicollector-ICPMS: in situ observation and correction

BackgroundOne of the most critical issues concerning in situ mass spectrometry lies in accounting for elements and molecules that overlap target isotopes of analytical interest in a sample. This study traced the instrumental mass fractionation of Rb and Sr isotopes during laser ablation-multicollector-inductively coupled plasma mass spectrometry (LA-MC-ICPMS) to obtain reliable 87Sr/86Sr ratios for high-Rb/Sr samples.FindingsIn the LA-MC-ICPMS analysis, Kr interferences were corrected using Ar and He gas blanks measured without ablating material. Contributions from doubly charged Er and Yb ions were corrected using the intensities of half masses and isotopic compositions reported in the literature. After Kr correction, the calculated 166Er2+ intensity of NIST SRM 610 approached the measured intensity at mass 83, and the 173Yb2+/171Yb2+ ratio agreed with the recommended value within error ranges. Kr- and REE2+-stripped peak intensities were further corrected for Rb interference. Use of the Sr mass bias factor for the calculation of measured 87Rb/85Rb yielded 87Sr/86Sr ratios consistent with the recommended and expected values for low-Rb/Sr materials, such as NIST SRM 616, modern shark teeth, and plagioclase collected from Jeju Island, but failed to account for the 87Rb interference from high-Rb/Sr materials including NIST SRM 610 and SRM 612. We calculated in situ mass bias factor of Rb from the known 87Sr/86Sr ratios of the standards and observed a correlation between Rb and Sr mass fractionation, which allowed inference of the Rb bias from the standard run. Reliable 87Sr/86Sr and 85Rb/86Sr ratios were obtained for SRM 610 and SRM 612 using the inferred mass bias factor of Rb calculated by the standard bracketing method.ConclusionsThis study revealed that Rb and Sr isotopes behave differently during LA-MC-ICPMS and suggests the potential usefulness of the standard bracketing method for measuring the Rb–Sr isotopic compositions of high-Rb/Sr materials.

Investigation of ancient teeth using Raman spectroscopy and synchrotron radiation Fourier-transform infrared (SR-µFTIR): mapping and novel method of dating

Raman spectroscopy and Synchrotron Radiation Fourier-Transform Infrared (SR-µFTIR): Mapping have been increasingly applied as a good tool in archaeological research. The chronology of ancient samples is an essential step in archeology, and carbon dating using atomic force microscopy is the main technique. Nevertheless, the availability of instrumentation, sample preparation, and cost are barriers that limit the wide usage. The study was aimed to develop a method utilizing Raman spectroscopy and Synchrotron Radiation Fourier-Transform Infrared (SR-µFTIR) Mapping to identify ancient teeth and sort them chronologically. Furthermore, Raman spectroscopy was used to evaluate the preservation of collagen and the crystallinity of Apatite in ancient teeth. The age of fourteen ancient teeth descent from different individuals (8 from Roman period-1500BC and 4 from Byzantine period-641AD) was confirmed using carbon dating via atomic force spectrometry. The ancient teeth along with modern teeth were investigated using microRaman spectroscopy (oscillation and mapping). The typical Raman spectrum of the dentin for ancient samples was recorded and then compared to the modern teeth. The ratio of the phosphate 𝑃𝑂4 3− the band at 963 cm-1 to organic CH band at 2950 cm-1 was calculated for all samples. Raman mapping was recorded for cross-section teeth samples. The AMS data showed that the ages of the samples were 3400-3800 and 1240-1350 years for Roman and Byzantine teeth, respectively. The phosphate ν1 𝑃𝑂4 3− vibration band at (963 cm-1 ) in ancient teeth was shifted 3 cm-1 toward higher wavenumber compared to modern dentin samples (960 cm-1 ). The intensity and broadening of the carbonate apatite band at 1050 cm-1 were directly proportional to the aging. The intensity of the organic part triplet peaks at (2882, 2950, 2962) decreased with age. The ratio of phosphate band to organic C-H band was 0.346-0.388 and 0.122-0.136 for Roman and Byzantine teeth, respectively. According to the Raman mapping, the organic material in ancient teeth degraded and diffused, while in modern tooth it concentrated. Raman spectroscopy (intensity at 963 cm1 to 2950 cm-1) can be used as a qualitative tool to chronologically sort the archeological teeth samples before the use of carbon dating. The preliminary dating by Raman spectroscopy can recognize if a tooth or bone sample is archaeological or not. This step may save time and money and shall be assigned as a pre-request for AMS analysis. Raman mapping may help to explore archeological samples for best-preserved organic matter, hence identify the best candidates for further analysis (DNA extraction). In the future, the proposed method can be expanded and applied in specific cases in ancient osteology.

Taxonomy, diet and geographical provenance of fossil species of Sigmodon from west central Mexico during the late Pleistocene

The information of diet, habitat and geographic location of animals obtained from fossil deposits is important to understand the environmental changes of a place that occurred through time. Most of the paleoecological research in Mexico is centered on large mammal taxa. A minimal research effort is allocated to small vertebrates which due to their relative brief longevity and small territories, provide fine-scale paleoenvironmental information. In the present work, the occlusal morphology of the first molar was analyzed, as well as the dental microwear marks and the 87Sr/86Sr isotopic ratio in fossil and extant relatives of the genus Sigmodon from La Cinta-Portalitos locality, situated on the northern portion of the Cuitzeo Basin, central western Mexico. Goals included determining species richness within Sigmodon, as well as dietary behavior and geographic origin. Based on the comparison of the occlusal morphology of fossils and modern teeth, three fossil species were distinguished: S. hispidus, S. leucotis and S. alleni. Microwear patterns showed that S. hispidus population could be associated to a grazer diet, inhabiting open areas, similar to the extant populations. The species S. leucotis exhibited a microwear signature associated to a grazer diet as well, and S. alleni revealed a fruit–grass–insect feeding behavior. Finally, in the case of S. hispidus, the 87Sr/86Sr isotopic signature proved to be like that of the bedrock, so the S. hispidus population was local and a suitable indicator of paleoenvironmental conditions of La Cinta-Portalitos.

Phytochemical Screening of Tannins in Selected Indigenous Plants Species Used as Chewing Sticks in Ekiti State, Nigeria

Chewing sticks form an alternative to modern tooth pastes and brush and their use in brushing the teeth predates the later. The astringent and antimicrobial properties of tannins in chewing sticks give it one of its therapeutic values. This paper present a critical look at the analysis of tannins in selected indigenous plant species used as chewing sticks in Ekiti State, Nigeria. Forty eight (48) plant species belonging to 28 different families observed to be used for dental and oral health care in the study area were screened for the presence of tannins. Result of tannin phytochemical screening revealed that 34 (70.83%) contained tannins, while the remaining 14 (29.17%) do not contain tannin. In conclusion, the results showed that most of the Nigerian chewing sticks do contain tannins which have antibacterial activities which may contribute to the reported anticaries effect of chewing sticks. These sticks may be sources for new lead antibacterial agents for therapeutic or preventive applications. Based on the result obtained, it was recommended that users of chewing sticks should be sensitized on the type of chewing sticks that are of potential therapeutic benefit (anti-microbial) to the mouth health especially those containing tannins. DOI : 10.7176/JBAH/9-24-05 Publication date: December 31 st 2019

Application of Trace Elemental Profile of Known Teeth for Sex and Age Estimation of Ajnala Skeletal Remains: a Forensic Anthropological Cross-Validation Study.

Teeth store crucial information needed for medical, environmental, genomics, public health, and forensic anthropological research work. The prolonged forensic utility of teeth is ensured by their extended postmortem longevity as they can resist almost all sorts of chemical, biological, and physical degradations or destructions. The main aim of the present investigation was to utilize the discriminant functions and regression equations generated from the elemental profile of known teeth for estimating sex and age of unknown human skeletal remains excavated from an abandoned well at Ajnala (Amritsar, India). The written records mentioned that 282 Indian mutineer soldiers were killed in July 1857, their cadavers were dumped in the disused well, and then a religious structure was built over the periphery of the said well. These human remains, along with some contextual items, were excavated non-scientifically in April 2014. Preliminary results obtained from application of different forensic anthropological techniques like stable isotope, pulp-tooth area ratio, and mtDNA analyses have indicated that these remains belonged to adult males. In present study, the elemental concentrations of 100 mandibular molars of known age and sex were estimated from wavelength-dispersive X-ray fluorescence spectrophotometer (WD-XRF) analyzer. The statistical equations so generated from elemental concentrations of known teeth were applied to estimate the probable age and the sex of unknown mandibular teeth (N = 100) collected from Ajnala skeletal assemblage. The elements Pb and As were detected in ancient teeth only whereas the detection of elements like Ba, Se, and Te was limited to modern teeth samples only. When the statistical equations so generated were applied to elemental concentrations of Ajnala teeth, it was found that 96% teeth belonged to adult males and the remaining ones were classified to be that of females. Though sexual differences were observed in concentrations of majority of elements, statistically significant differences were found in elemental concentrations of very few teeth. Age estimates of unknown teeth were found in the age ranges of 19 to 48years. Thus, the trace elemental analysis results supported the written records that the victims were adult males. The cross-validated application of elemental profiles of known teeth for establishing the identity of unknown teeth is the first forensic anthropological study reported from India. Though the obtained accuracy levels were not found within acceptable forensic threshold limits, the present study results may guide future researches involving human hard tissues. It may be concluded that trace elemental concentrations of teeth may be influenced by the factors like age and sex of an individual and thus cannot be used for accurate and reliable forensic sex or age estimations. Dental trace elemental composition can be used as a forensic tool only if used in conjunction with other morphological or molecular analysis of the unknown dental remains.

Morphology of Root and C-Shape Canal in Prehispanic and Modern Maya Groups from Northern Yucatan

One-rooted mandibular second molars arelabelled “C-molar” because of the root’s morphology.The frequency of C-molars is strongly associatedwith ethnic origin, being most common in North-EastAsians. The present study analyzed the frequency ofone-rooted molars and associated pulpal chamber in 48Prehispanic Mayans and in 142 modern subjects studiedat the School of Endodontics, UADY. The frequency ofone-rooted molars in the Prehispanic sample is 35%,with 32% of these having C-canals. Similarly, 42 of 142 (30%) modern teeth exhibit a C-canal. The similaritybetween ancient and modern samples suggests thatgenetic admixture since the European conquest has notaffected trait expression, and it implies that the Mayaexpress the Sinodontic pattern of dental morphology.Endodontically, the significant correlation betweenC-molar and C-canal is an advantage for recognizingthe canal’s anatomy if treatment is indicated.

A comparison of machine learning techniques for taxonomic classification of teeth from the Family Bovidae

This study explores the performance of machine learning algorithms on the classification of fossil teeth in the Family Bovidae. Isolated bovid teeth are typically the most common fossils found in southern Africa and they often constitute the basis for paleoenvironmental reconstructions. Taxonomic identification of fossil bovid teeth, however, is often imprecise and subjective. Using modern teeth with known taxons, machine learning algorithms can be trained to classify fossils. Previous work by Brophy et al. [Quantitative morphological analysis of bovid teeth and implications for paleoenvironmental reconstruction of plovers lake, Gauteng Province, South Africa, J. Archaeol. Sci. 41 (2014), pp. 376–388] uses elliptical Fourier analysis of the form (size and shape) of the outline of the occlusal surface of each tooth as features in a linear discriminant analysis (LDA) framework. This manuscript expands on that previous work by exploring how different machine learning approaches classify the teeth and testing which technique is best for classification. In addition to LDA, four other machine learning techniques were considered (neural networks, nuclear penalized multinomial regression,random forests, and support vector machines) with support vector machines and random forests performing the best in terms of log loss and classification rate.

DNA extraction from Modern Teeth Using Commercially Available DNA Extraction Kits Designed for Buccal Samples

Event Abstract Back to Event DNA extraction from Modern Teeth Using Commercially Available DNA Extraction Kits Designed for Buccal Samples Ann-Elodie Robert1*, Caroline Spencer1, Deedra Hughes2, Tracey Dawson-Cruz3 and Murrell Godfrey1 1 University of Mississippi, United States 2 Mississippi Forensic Laboratory, United States 3 Virginia Commonwealth University, United States DNA can be extracted through different media, which includes but is not limited to blood, saliva, bones and even teeth. Most nuclear DNA and mitochondrial DNA (mtDNA) extraction kits are applied to blood or buccal cell samples and many of them are not capable of extracting DNA from ancient remains. The aim of this study was to compare two mtDNA extraction kits used to the extract DNA from teeth. Two extraction kits were examined 1) the QIAmp DNA Blood Mini Kit, used along with a protocol modified by the Dawson-Cruz lab at Virginia Commonwealth University, and 2) a Mitochondrial DNA Polymorphisms in Human Evolution Kit designed by Carolina Biological Supply Company. The first step of this study involved the extraction of DNA from teeth samples. Five unknown male teeth and five unknown female teeth were used in this study. These teeth were extracted within the last 2 years. Once the DNA extraction from the teeth samples were completed, amplification of both the nuclear and mtDNA was performed. Quantitation of the DNA extract was the last part of the experiment to be performed. The successful extraction of both nuclear and mtDNA was initially confirmed through gel electrophoresis and UV-Vis spectroscopy. DNA analysis was then performed using the ABI 7500 Genetic Analyzer to obtain a DNA profile and sex confirmation. Future goals of this study include applying extraction methods on teeth and other remains that range from decades to centuries old. Ultimately the goal is to design a method for extraction and analysis of DNA from ancient remains Keywords: forensic, teeth, DNA, extraction, Analytical, modified kits Conference: National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) 45th Annual Conference , Orlando, Florida, United States, 17 Sep - 20 Sep, 2018. Presentation Type: Oral Presentation Topic: Biochemistry Citation: Robert A, Spencer C, Hughes D, Dawson-Cruz T and Godfrey M (2019). DNA extraction from Modern Teeth Using Commercially Available DNA Extraction Kits Designed for Buccal Samples. Front. Chem. Conference Abstract: National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) 45th Annual Conference . doi: 10.3389/conf.fchem.2018.01.00020 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 03 Oct 2018; Published Online: 17 Jan 2019. * Correspondence: Ms. Ann-Elodie Robert, University of Mississippi, Oxford, United States, arobert@go.olemiss.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Ann-Elodie Robert Caroline Spencer Deedra Hughes Tracey Dawson-Cruz Murrell Godfrey Google Ann-Elodie Robert Caroline Spencer Deedra Hughes Tracey Dawson-Cruz Murrell Godfrey Google Scholar Ann-Elodie Robert Caroline Spencer Deedra Hughes Tracey Dawson-Cruz Murrell Godfrey PubMed Ann-Elodie Robert Caroline Spencer Deedra Hughes Tracey Dawson-Cruz Murrell Godfrey Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.