Period Of Tooth Formation Research Articles

The monks of San Millán: Investigating the transition between pre-monastic and monastic diet using carbon and nitrogen isotope ratios in incremental dentine

From the early Medieval period, Christian monasteries were wealthy and powerful, and played a central role in both religious and political life. Those who entered the monasteries did so at the age of 7–8 years and were drawn from a wide range of social strata. From that point, they were subject to the dietary rules imposed by the rules of each monastic order. In order to assess the origins and diet of 10 monks who lived in the monastery of San Millán de la Cogolla Yuso (La Rioja, Spain) during the 17th – 18th century, collagen from small sections of human dentine (representing the childhood diet) and from ribs (an average of the last 5–10 years of adult diet) was measured to establish lifetime variations in the isotope ratios of carbon (δ13C) and nitrogen (δ15N). Bulk collagen δ13C (overall mean = -18.2‰ +/-0.4) and δ15N (overall mean = 12.6‰ +/-0.8) values from the ribs suggest 2 adult cohorts: one with a diet based on C3 plants and a high intake of protein from meat or dairy products and some marine resources and a second cohort with some C4 plant consumption alongside meat and dairy. Data from the dentine sections revealed different dietary patterns during the period of tooth formation among the monks, suggesting that 4 of them entered the monastery after consuming lower status diets during childhood.

Laser ablation strontium isotopes and spatial assignment show seasonal mobility in red deer (Cervus elaphus) at Lazaret Cave, France (MIS 6)

Zooarchaeological analysis is a useful means of exploring faunal palaeoecology, paleoclimate and past human behaviours. The Middle Pleistocene archaeological site Lazaret Cave, located in modern-day Nice, France, features a vast assemblage of faunal remains pertinent to the understanding of early Neanderthal subsistence behaviours as well as red deer (Cervus elaphus) ecology during MIS 6. This pilot study examines materials from archaeological layer UA25, a short-term occupation layer at Lazaret dating to ~150,000 years ka, which has revealed 28 early Neanderthal remains as well as thousands of faunal bones, of which red deer and ibex (Capra ibex) are most abundant. Molars from three red deer mandibles and a single ibex were analysed for strontium (87Sr/86Sr) isotopic analysis using laser ablation mass spectrometry to determine animal movements during tooth formation, combined with intra-tooth oxygen (δ18O) isotope analysis to determine seasonality. The isotope data was modelled within a local 87Sr/86Sr isoscape and computational spatial assignment was undertaken to reconstruct potential summer and winter ranges of red deer. Results from this pilot study show seasonal mobility within 20 km of Lazaret, identifying two possible summer and winter ranges for the red deer excavated from UA25. Both possible summer ranges are located at higher elevations further from Lazaret while winter ranges have been assigned to lower elevations closer to the coastline and closer to Lazaret. The ibex shows no 87Sr/86Sr variation throughout the first, second and third molar and the spatial assignment indicates it lived proximal to the site during the period of tooth formation. In addition to providing the first evidence of red deer spatial ecology in southern France during MIS 6, we also infer from the faunal isotope data that hominins at Lazaret Cave were likely hunting red deer in autumn and winter when they were closer to the cave site, while hunting in summer would have required up to 20 km of travel.

Enamel biomineralization under the effects of indomethacin and celecoxib non-steroidal anti-inflammatory drugs

The aim of this study was to explore the effects of nonsteroidal anti-inflammatory drugs on biomineralization of enamel. Sixty C57Bl6 male mice were used, which were assigned into three groups: celecoxib (n = 20) or indomethacin (n = 20) treatment for a period of 28 days or received no medication (control group, n = 20). Visual inspection and microcomputed tomography were used to analyze enamel morphology. Scanning electron microscopy–Energy dispersive X-ray and Knoop microhardness test were used to quantify chemical element content (Ca, P, C, O) and enamel microhardness, respectively. Tissues were collected to investigate the synthesis, activity or nuclear translocation of metalloproteinase-20, transcription factor Runx2, dentin sialoprotein and cyclooxygenase-2 enzyme by means of immunohistochemistry, in situ zymography and indirect immunofluorescence. Treatment with indomethacin and celecoxib reduced the Ca and P content, microhardness and mineral density in enamel. Treatment with nonsteroidal anti-inflammatory drugs caused an accumulation of metalloproteinase-20 and overall increased enzymatic activity in enamel matrix, while the synthesis of the transcription factor Runx2 was inhibited by these drugs. Interestingly, indomethacin inhibited Runx2 translocation to the nucleus whereas celecoxib did not. Those findings show that non-steroidal anti-inflammatory drugs impact the enamel biomineralization and could be involved in the etiology tooth enamel defects if used during the period of tooth formation and mineralization.

Stable isotope analysis of white-tailed deer teeth as a paleoenvironmental proxy at the Maya site of La Joyanca, northwestern Petén, Guatemala

ABSTRACTCarbon and oxygen isotopes ratios from herbivore teeth have previously been used as paleo-environmental proxies in temperate zones. However, their utility in tropical zones remains uncertain. In this study, sequential sub-samples from white-tailed deer (Odocoileus virginianus) teeth (second and third molars) from the Maya archaeological site of La Joyanca, located in northwestern Petén, Guatemala, show that δ18O of enamel carbonate corresponds broadly to modern observed precipitation δ18O over the 10-month period of tooth formation, capturing rainfall seasonality. The analyses also detect significant diachronic differences in the δ18O between the periods 1100–1000 BP (850–950 A.D.) and 1000–900 BP (950–1050 A.D.) at La Joyanca. The δ13C in both periods are indicative of a C3-plant based diet, which suggests cultivation of maize did not differentially affect deer diet during this period.

Little Ice Age drought event reconstructed from isotopic analysis of archaeological springbok (Antidorcas marsupialis) teeth

In this paper, we use δ13C and δ15N of serial samples of dentine collagen from archaeological springbok teeth as a novel high-resolution but short-term palaeoenvironmental proxy. Two adult and seven juvenile springbok (Antidorcas marsupialis) teeth from the archaeological site SK400 were analyzed. This site, located in the Namaqualand desert on the west coast of South Africa has yielded a large number of small-medium bovids, likely all springbok. These springbok were killed in a single episode between 1438 and 1641CE, during the Little Ice Age (LIA). The juvenile springbok were significantly more depleted in 13C and enriched in 15N compared with the adults. During the four to six months over which their teeth developed, the juveniles consumed a higher proportion of C3 plants and were exposed to greater aridity than the adults at equivalent ages. Based on dental wear, the adults are estimated to be between 3.5 and 7.5years old at death, so the isotope values in their teeth record diet and environmental conditions several years earlier. In addition, the juveniles (but not the adults) show a trend towards more negative δ13C values and very high δ15N (up to +18.9‰) during the period of tooth formation, truncated by the animals' death. We infer that the animals were killed during an extreme drought. Informed by the archaeological evidence, we surmise that this was probably a herd of springbok on ‘trek’ in search of food and water, as this species is known to do during droughts. Although palaeoenvironmental proxies for the region as a whole suggest that Namaqualand was cool and wet during the Little Ice Age, this study indicates at least one period of drought, contributing to the developing picture of highly variable climates in southern Africa during the Holocene.

Toddlers in Transition: Linear Enamel Hypoplasias in the Hadza of Tanzania

AbstractBioarchaeologists often use linear enamel hypoplasias (LEH) as a proxy for systemic physiological stress in prehistoric populations. Increased incidences of LEH have been observed in many cases associated with rapid social or environmental changes, such as with the Neolithic transition and agricultural intensification. Still, there have yet to be studies published of LEH incidence among living peoples in the process of transitioning from foraging to a farming economy. It is important to document LEH occurrence in living groups with known subsistence strategies to better contextualise interpretations of bioarchaeological populations. Here, we present LEH data for a sample of the Hadza of Tanzania. We compare LEH incidence and frequency on the permanent anterior teeth of individuals who spent their infancy and early childhood (i) in the bush consuming wild foods; (ii) in the village with a weaning diet dominated by domestic cereals; and (iii) transitory, dividing their time between the bush and village. Our results demonstrate that Hadza living in the bush during the period of tooth formation less frequently have LEH on these teeth, and have fewer of them on average, than do villagers. This is particularly so for the comparison of men. The transient group is intermediate in LEH incidence, although not significantly different from the bush and village samples. A lower LEH frequency in the bush Hadza is consistent with a diet that meets nutrient requirements of tooth formation, but higher incidence in the village sample suggests interruption of enamel secretion, most likely due to malnutrition. Such studies provide valuable context with which to interpret and understand bioarchaeological evidence, and to track effects of sedentisation on the biology of modern foragers. Copyright © 2017 John Wiley & Sons, Ltd.

Tooth enamel sampling strategies for stable isotope analysis: Potential problems in cross-method data comparisons

The stable isotope composition of a given sample of tooth enamel is a function of the mineralisation process, the isotopic composition of the input signal, and sampling geometry. As the dominant axis of tooth growth is orientated from the occlusal surface to the enamel–root junction, the isotopic composition of an enamel sample that spans the full length of this axis is often taken to represent a whole-tooth or ‘bulk’ average, while serial (or ‘intra-tooth’) samples taken along the same axis are considered to track isotopic variation across the period of tooth formation. A ‘bulk’ sample of enamel should therefore approximate the mean of the ‘serial’ samples, and in teeth that form over a complete annual cycle ‘bulk’ and ‘serial’ sampling methods are often assumed to possess an annual–seasonal relationship. However, this does not take into account the effect of the mineralisation process and sampling geometry on the derived isotope signals. Here we investigate the reproducibility of both the ‘bulk’ and ‘serial’ sampling methods as independent, stand-alone techniques and then explore the assumed relationship between the two. Each method shows good reproducibility in the oxygen (δ18O) and carbon (δ13C) isotope results across paired left and right molars. However, cross method comparisons reveal a systematic offset between bulk and serial results within a single population, with 19 out of 23 δ18O bulk-tooth values being lower, and 22 out of 23 δ13C bulk-tooth values being higher, than the means of their respective intra-tooth sequences. In 4 out of 19 cases for δ18O and 6 out of 22 cases for δ13C the bulk-tooth results fall completely out of the range observed in the corresponding intra-tooth sequence. This finding has implications for cross-method data comparisons and questions the assumed temporal relationship between ‘serial’ and ‘bulk’ isotope data.

Melketenner som biomarkører i epidemiologisk forskning

Human primary teeth can give important information about trace element exposure prenatally and in early childhood – the period of tooth formation and the most vulnerable period in life. Trace elements from the environment and from nutrition are built into the tooth tissues during the period of tooth formation. As tooth tissues develop incrementally, according to a known pattern, and are very stable, teeth may function as recorders or biomarkers of different exposures during the period of tooth formation. In this paper the use of primary teeth as biomarkers of exposure is presented with a special focus on the use within epidemiology

Systemic Benefits of Fluoride and Fluoridation

AbstractClinical trials, animal studies, and in vitro tests demonstrate effectiveness of exposure to topical (posteruptive) fluoride in caries prevention and reduction of enamel dissolution. However, careful analyses of human epidemiologic data on caries increments, following communal water fluoridation, show unquestionably that fluoride has an important preemptive effect on caries in permanent teeth, particularly on pit and fissure surfaces. These preemptive or systemic benefits also apply to the use of fluoride supplements or fluoridated salt when used continuously during the period of tooth formation. The role of systemic fluoride in caries prevention is neither “minimal” nor “of borderline significance.” On the contrary, it is a major factor in preventing pit and fissure caries, the most common site of tooth decay. Maximal caries‐preventive effects of water fluoridation are achieved by exposure to optimal fluoride levels both pre‐ and posteruptively.

Intertooth patterns of hypoplasia expression: implications for childhood health in the classic Maya collapse.

Enamel hypoplasias, which record interacting stresses of nutrition and illness during the period of tooth formation, are a key tool in the study of childhood health in prehistory. But interpretation of the age of peak morbidity is complicated by differences in susceptibility to stress both between tooth positions and within a single tooth. Here, hypoplasias are used to evaluate the prevailing ecological model for the collapse of Classic Period Lowland Maya civilization, circa AD 900. Hypoplasias were recorded in the full dentition of 160 adult skeletons from six archaeological sites in the Pasion River region of Guatemala. Instead of constructing a composite scale of stress experience, teeth are considered separately by position in the analysis. No statistical differences are found in the proportion of teeth affected by hypoplasia between "Early," Late Classic, and Terminal Classic Periods for anterior teeth considered to be most susceptible to stress, indicating stability in the overall stress loads affecting children of the three chronological periods. However, hypoplasia trends in posterior teeth may imply a change in the ontogenetic-timing of more severe stress episodes during the final occupation and perhaps herald a shift in child-care practices. These results provide little support for the ecological model of collapse but do call to attention the potential of posterior teeth to reveal subtle changes in childhood morbidity when consideredindividually.

Long term results of chemotherapy on the developing dentition: caries risk and developmental aspects

The dental health of 45 children who had been placed on long term evaluation after chemotherapy treatment for malignancies was examined in this study. All children had received cytotoxic drugs during the period of tooth formation. It was found that they had more filled or diseased permanent teeth than control children. Their current caries activity as indicated by initial white spot lesions was also higher. Forty-three of the children showed evidence of disturbed amelogenesis. This had resulted in aesthetically displeasing grooves, pits and discoloration. Twenty-three of the children were counseled on the possibility of cosmetic dentistry. Delayed eruption and shortened, malformed roots were also found on several patients. It was concluded that these patients constitute a high risk dental care group.

Amounts of Fluoride in Self-Administered Dental Products: Safety Considerations for Children

With the increased use of various fluoride preparations for caries prevention, all dental personnel should know their potential toxicity and the margins of safety associated with their use. An understanding of the body's mechanisms for handling fluoride provides a rational basis for assessing the possible risks of excessive fluoride ingestion. Five to 10 g of sodium fluoride is considered a certainly lethal dose for a 70-kg adult. One quarter of the certainly lethal dose can be ingested without producing serious acute toxicity and is known as the safely tolerated dose. Comparisons of certainly lethal and safely tolerated doses for commonly used fluoride agents and procedures show that they can be applied with little or no risk of adverse acute effects, as long as they are used judiciously. If their use is abused, there is a risk of illness or even death. If amounts of fluoride close to the certainly lethal dose are ingested, the speed of initiating proper treatment is critical for survival. Vomiting should be induced, if it is not spontaneous; fluoride-binding liquids, such as milk or liquid or gel antacids, administered; and the patient taken to the nearest hospital for emergency care. Frequent ingestion of low but excessive quantities of fluoride during the period of tooth formation can lead to dental fluorosis. Particular concern is warranted for the ingestion of fluoride-containing toothpastes by young children and the inappropriate use of dietary fluoride supplements in communities with sufficient fluoride already present in drinking water.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinicopathologic features of fluoride toxicosis in cattle.

Cattle normally ingest variable low-level amounts of fluorides with no known adverse effects, but when excessive amounts are ingested, adverse effects are induced. Several sources may contribute to the total fluoride intake. The many recognized factors that influence structural and functional responses of animals to fluorides are cited. Signs and lesions of fluoride toxicosis in cattle have been characterized. Major fluorotic lesions occur in the permanent teeth and in the bones. Dental lesions occur when excessive amounts of fluoride are ingested during the period of tooth formation and calcification. Bone effects can be induced at any time during an animal's life. A table relating structural changes and functional processes in cattle of various ages has been compiled as a guide for diagnosing and evaluating fluoride toxicosis. Recommended fluoride tolerance levels for cattle have been established. Prevention and control of fluoride toxicosis in cattle can be accomplished when the nature of the disease is realized; the symptomatology, lesions and pathogenesis are properly interpreted, correlated and evaluated; and the source(s) of excessive fluorides are eliminated.

An Evaluation of the Role of Vitamins and Minerals in the Control of Caries

It has been possible to produce clear evidence that certain -vitamins and minerals are required for the formation of teeth of normal structure. It has been very difficult, however, to demonstrate that mature teeth require these nutrients in amounts greater than are needed to prevent gross and obvious signs of deficiency in other tissues. My first task will be to review the evidence in support of these statements. I shall, thereby, indicate why it appears that a mineral or vitamin deficiency must be present during the period of tooth formation if the tooth is to be affected in a manner which could lower its susceptibility to decay. As a sort of after-piece to the first topic, I shall attempt to present a summary of the somewhat controversial evidence which has been produced to show that single mineral or vitamin deficiencies are important causal factors in dental caries. The effects of inadequate diets on developing teeth cannot always be stated in quantitative terms. Our best device, at present, for indicating the importance of the effects produced by nutritional deficiencies on teeth is to compare these effects with those produced on another tissue, such as bone. When such comparisons are made, we shall see that in many circumstances, developing teeth appear to be less liable to alteration by metabolic abnormalities than is forming bone. We shall also see that mature teeth, in so far as any objective criteria are concerned, appear to be almost, if not entirely, removed from the direct influence of nutrition.

Effect of Artificially Induced Hyperpyrexia on Tooth Structure of the Rabbit

The increasing therapeutic importance of artificially induced fever raises the question of its effect on developing tooth structure. Damage to the enamel by infections accompanied by high fever during the period of tooth formation has been recognized clinically for many years. It is evidenced as a hypoplastic condition with superficial pits and grooves, often markedly disfiguring the anterior teeth. Detrimental effects in the dentin would be an internal dystrophy and would escape clinical notice but might well be expected under conditions which would affect the enamel.Normal dentin is a homogeneously calcified tissue produced by the dental pulp. It is laid down around the periphery of the pulp in periodic increments as an organic matrix which is subsequently calcified to a bone-like consistency. Unlike bone, dentin once formed is not subject to further physiologic change to any marked degree, and hence it affords a permanent record of any variations in the calcification process. The dentin of the continuo...