Enamel hypoplasia in the Middle Pleistocene hominids from Atapuerca (Spain)

The prevalence and chronology of enamel hypoplasias were studied in a hominid dental sample from the Sima de los Huesos (SH) Middle Pleistocene site at the Sierra de Atapuerca (Burgos, northern Spain). A total of 89 permanent maxillary teeth, 143 permanent mandibular teeth, and one deciduous lower canine, belonging to a minimum of 29 individuals, were examined. Excluding the antimeres (16 maxillary and 37 mandibular cases) from the sample, the prevalence of hypoplasias in the permanent dentition is 12.8% (23/179), whereas the deciduous tooth also showed an enamel defect. No statistically significant differences were found between both arcades and between the anterior and postcanine teeth for the prevalence of hypoplasias. In both the maxilla and the mandible the highest frequency of enamel hypoplasias was recorded in the canines. Only one tooth (a permanent upper canine) showed two different enamel defects, and most of the hypoplasias were expressed as faint linear horizontal defects. Taking into account the limitations that the incompleteness of virtually all permanent dentitions imposes, we have estimated that the frequency by individual in the SH hominid sample was not greater than 40%. Most of the hypoplasias occurred between birth and 7 years (N = 18, X = 3.5, SD = 1.3). Both the prevalence and severity of the hypoplasias of the SH hominid sample are significantly less than those of a large Neandertal sample. Furthermore, prehistoric hunter-gatherers and historic agricultural and industrial populations exhibit a prevalence of hypoplasias generally higher than that of the SH hominids. Implications for the survival strategies and life quality of the SH hominids are also discussed. © 1995 Wiley-Liss, Inc.     

Dental health of elderly confederate veterans: evidence from the Texas State Cemetery

Analysis of the skeletal remains of 50 Confederate veterans provided a unique opportunity to explore the dental health of a geriatric sample. These men, who died between 1907-1932, had an average age at death of 76.7 years. Ninety percent were institutionalized at the Confederate Home for Men (Austin, TX) prior to their deaths. This elderly sample was assessed in terms of caries, antemortem tooth loss (AMTL), abscesses, and linear enamel hypoplasias. On a per tooth basis, the AMTL rate was 57.2%. Of 39 dentate men, 33 (84.6%) had dental caries, and 24.4% (121 of 496) of teeth were carious. Ten (25.0%) of the dentate men had hypoplastic teeth. At least one abscess was seen in 14 (28%) of 50 individuals. Results from this geriatric institutionalized sample are compared to contemporaneous historical samples. Disparities in dental health among these groups may be due to differences in average age at death, and these comparisons allow a better understanding of dental changes that occur with age. The sample is also compared to modern elderly samples: modern groups have higher caries rates, possibly because they retained more teeth. This finding may be due in part to diets in the United States becoming increasingly cariogenic over time. In addition, dental care has moved from the reactive practices seen in the nineteenth and early twentieth centuries (such as tooth extractions) to modern proactive solutions dedicated to preserving and restoring teeth (such as tooth brushing, fluoride treatments, and dental fillings).     

Environmental stress in the Early Mediaeval Slavic population at Borovce (Slovakia)

Several palaeopathological indicators examined in skeletal samples are caused by stress during childhood and remain visible in adults. In this study, dental enamel hypoplasia was observed in 451 individuals from the Early Mediaeval (8th to beginning of 12th c. AD) Slavic skeletal series at Borovce (Slovakia). The presence of enamel hypoplasia was scored in all types of deciduous and permanent teeth. More than one-fourth (27.2%) of the individuals with preserved permanent teeth showed enamel hypoplasia. No significant differences in the occurrence of the enamel lesions were found between males and females. The age at development of hypoplasias was estimated for 74 individuals by measuring the distance of the defect from the cemento-enamel junction. The hypoplastic defects appeared most frequently between 2.5 and 3.0 years. Following the trends observed in the distribution of age at development of the enamel lesions between subadults and adults, individuals stressed earlier in life had a reduced ability to cope with later insults. High prevalence of enamel hypoplasia, especially among 10–14-year-old growing juveniles, has led to the assumption that the Borovce population lived a considerably long period under conditions of high environmental pathogen load, and probably also suffered from some nutritional deficiencies.     

Skeletal biology of the Taino: a preliminary report

Preliminary data on the skeletal biology of 78 Taino skeletons belonging to Juan Dolio, an archaeological site of the Maguana province, 80 Km. east of S. Domingo, are presented. The minimum number of individuals, sex, age, stature, and morphologic and morphometric characters were determined. Dental wear and pathology of cranial and post-cranial bones were also recorded.     

Linear enamel hypoplasias as indicators of systemic physiological stress: evidence from two known age-at-death and sex populations from postmedieval London

Enamel hypoplasias are useful indicators of systemic growth disturbances during childhood, and are routinely used to investigate patterns of morbidity and mortality in past populations. This study examined the pattern of linear enamel hypoplasias in two different burial populations from 18th and 19th Century church crypts in London. Linear enamel hypoplasias on the permanent dentitions of individuals from the crypt of Christ Church, Spitalfields, were compared to enamel defects on the teeth of individuals from St. Bride's. The method used involves the identification of enamel defects at a microscopic level, and systemic perturbations are detected by matching hypoplasias among different tooth classes within each individual. The pattern of linear enamel hypoplasias was contrasted between individuals from the burial sites of Spitalfields and St. Bride's, between males and females, and between those aged less than 20 years of age and those aged over 20 years at death. Six different parameters were examined: frequency of linear enamel hypoplasias, interval between defects, duration of hypoplasias, age at first occurrence of hypoplasia, age at last occurrence of hypoplasia, and the percentage of enamel formation time taken up by growth disturbances. All individuals in the study displayed linear enamel hypoplasias, with up to 33% of total visible enamel formation time affected by growth disruptions. Multiple regression analysis indicated a number of significant differences in the pattern of enamel hypoplasias. Individuals from Spitalfields had shorter intervals between defects and greater percentages of enamel formation time affected by growth disturbances than did individuals from St. Bride's. Females had greater numbers of linear enamel hypoplasias, shorter intervals between defects, and greater percentages of enamel formation time affected by growth disturbances than males. There were also differences in the pattern of enamel hypoplasias and age at death in this study. Individuals who died younger in life had an earlier age at first occurrence of enamel hypoplasia than those who survived to an older age. The pattern of enamel hypoplasias detected in this study was influenced by tooth crown geometry and tooth wear such that most defects were found in the midcrown and cervical regions of the teeth, and greater numbers of defects were identified on the anterior teeth. Differences in sensitivity of the parameters used for the detection of enamel hypoplasias were found in this study. The percentage of visible enamel formation time affected by growth disturbances was the parameter that identified the greatest number of significant differences among the subgroups examined.     

Biocultural analysis of sex differences in mortality profiles and stress levels in the late medieval population from Nova Raca, Croatia

Human skeletal remains of 104 individuals from the late medieval (14th-18th century) Nova Raca cemetery, in continental Croatia, are described. Historic data from the parish Book of the Dead, relevant to a period in the early 19th century, suggest that females may have been under greater stress than males. To test this hypothesis, the skeletal material is analyzed for the presence and distribution of enamel hypoplasias and cribra orbitalia. Observations are also made on the presence and pattern of dental disease, skeletal infection, trauma, osteoarthritis, vertebral degenerative changes, and Schmorl's depression frequencies. The mortuary sample, consisting of 36 subadults and 68 adults, exhibits underrepresentation of subadults, and differential adult male/female mortality profiles. Peak female mortality is between 21-25 years, compared to peak male mortality between 31-35 years. Average adult female age at death is 29.9 years, compared to 34.1 years in adult males. Significant sex differences are present in the frequencies of enamel hypoplasia. Adult females have higher frequencies of hypoplastic teeth, and a larger number of defects in the teeth affected than in males. Subadults in the series also exhibit higher frequencies of hypoplastic teeth, and a larger number of defects in the teeth affected than in adults, documenting a relationship between enamel hypoplasia-causing stress events and reduced life expectancy. Significant sex differences are also present in dental pathology frequencies, possibly reflecting differences in resource access. Sex differences in vertebral osteoarthritis and Schmorl's depression frequencies may reflect differential activity patterns.     

Stress physiologique et état de santé des plus anciens Hommes anatomiquement modernes du sud-est de l’Europe (données dentaires,couche 6-1, Buran-Kaya III,Crimée)

Buran-Kaya III site, in Crimea, provides an exceptional stratigraphic sequence, extending from Middle Paleolithic to Neolithic. Among the archaeological layers allocated to the Gravettian (sensu lato), more than 170 anthropological remains have been discovered in the layer 6-1. They represent the oldest Upper Paleolithic modern humans from Eastern Europe in a well-documented archaeological context. The aim of this article, based on dental remains and enamel dental hypoplasias in particular, is to evaluate the health of the modern humans, which lived more than 32,000 years BP ago in Crimea. This study puts into the light the low frequency of hypoplasias (occurring in the two youngest individuals). This article complete the rare studies concerning the presence of this physiological stress during the Early Upper Paleolithic and confirm the scarcity of enamel dental hypoplasias and dental pathologies, such as caries, at this period.     

L'Azilien ancien de Cueva Oscura de Ania (Las Regueras, Asturias, Espagne)

Recent definition of the Cantabrian Lower Azilian has turned the Late Upper Magdalenian/Azilian transition into one of the most interesting archaeological ages in the area. This period is considered representing the earliest Azilian groups in Asturias. Critic review of Cueva Oscura de Ania record, in the center of Asturias, has allowed us to give full details of the Lower Azilian archaeological characteristics. Cueva Oscura de Ania archaeological collection shows archaic traits, close to those from Cueva de Los Azules and Cueva de La Riera, two eastern asturian sites. These likenesses suggest a high stylistic and technical uniformity in distant areas during a critical period, when Palaeolithic groups changed their subsistence strategies. Cueva Oscura de Ania archaeological and polinic records suggest that this deposit was built at the beginning of the paleoclimatic phase known as Alleröd/Cantabrian VIII (12 000-10?800 BP), when numerous cantabrian sites suffered high erosion processes. All these circumstances convert Cueva Oscura de Ania in a fundamental site to get a best knowledge of the origin and development of the Cantabrian Azilian. The study of its bone collection allows us outline new hypothesis about this archaeological period.     

Human mandibular incisors from the late Middle Pleistocene locality of Hoedjiespunt 1, South Africa.

The Hoedjiespunt 1 locality is an archaeological and palaeontological site located on the Hoedjiespunt Peninsula at Saldanha Bay, South Africa. In 1996 two human teeth, a left central mandibular incisor and a left lateral mandibular incisor, were discovered during excavations in the late Middle Pleistocene palaeontological layers. These teeth are described and are found to belong to a single subadult individual. Despite their developmental stage, these incisors already display early signs of wear. Their crown diameters are larger than modern and archaeological African comparative material and are most closely comparable with crown diameters of an early Middle Pleistocene and late Middle Pleistocene dental sample from Africa, Europe and Asia. In the light of this metrical evidence, data on two previously excavated maxillary molars, most probably belonging to the same individual, were re-examined. It was found that the Hoedjiespunt 1 hominid possessed dental metrical features (large anterior teeth and small molars) comparable with other African and European hominids referred to the Middle Pleistocene.     

A human phalanx from the lower palaeolithic site of cueva victoria (murcia,Spain)

The morphological, metrical, and discriminant function analysis of a phalanx from the Lower Pleistocene site of Cueva Victoria suggests that it differs significantly from carnivores and non-human primate groups, and closely resembles theHomo group studied. The phalanx has been classified as a IInd. phalanx of the 5th. finger of the right hand.     

Geographic Variation in Nonmetric Dental Traits of the Deciduous Molars of Pan and Gorilla

Physical anthropologists often use nonmetric dental traits to trace the movement of human populations, but similar analysis of the teeth of nonhuman primates or the deciduous teeth is rare. Because nonmetric dental characteristics are manifestations of genetic differences among groups, they vary among geographically distant members of the same species and subspecies. We use 28 nonmetric dental traits in the deciduous molars to compare genetically and geographically distinct groups of extant African apes (Gorilla and Pan). Previous researchers have studied these traits in the adult or juvenile teeth of great apes and humans, and we score our observations according to established standards for hominins. We observe marked differences in trait frequencies between Gorilla and Pan, Pan troglodytes and P. paniscus, and two P. troglodytes subspecies but we find no significant differences between geographically isolated groups within the subspecies. Trait frequencies differ from those found in previous studies that contained fewer individuals. We find that the deciduous molars show similar variation to adult premolars and molars within Pan and Gorilla. This suggests that the deciduous dentition of these and other apes may contain diagnostic traits that are not currently in use.     

Accessing Developmental Information of Fossil Hominin Teeth Using New Synchrotron Microtomography-Based Visualization Techniques of Dental Surfaces and Interfaces

Quantification of dental long-period growth lines (Retzius lines in enamel and Andresen lines in dentine) and matching of stress patterns (internal accentuated lines and hypoplasias) are used in determining crown formation time and age at death in juvenile fossil hominins. They yield the chronology employed for inferences of life history. Synchrotron virtual histology has been demonstrated as a non-destructive alternative to conventional invasive approaches. Nevertheless, fossil teeth are sometimes poorly preserved or physically inaccessible, preventing observation of the external expression of incremental lines (perikymata and periradicular bands). Here we present a new approach combining synchrotron virtual histology and high quality three-dimensional rendering of dental surfaces and internal interfaces. We illustrate this approach with seventeen permanent fossil hominin teeth. The outer enamel surface and enamel-dentine junction (EDJ) were segmented by capturing the phase contrast fringes at the structural interfaces. Three-dimensional models were rendered with Phong’s algorithm, and a combination of directional colored lights to enhance surface topography and the pattern of subtle variations in tissue density. The process reveals perikymata and linear enamel hypoplasias on the entire crown surface, including unerupted teeth. Using this method, highly detailed stress patterns at the EDJ allow precise matching of teeth within an individual’s dentition when virtual histology is not sufficient. We highlight that taphonomical altered enamel can in particular cases yield artificial subdivisions of perikymata when imaged using X-ray microtomography with insufficient resolution. This may complicate assessments of developmental time, although this can be circumvented by a careful analysis of external and internal structures in parallel. We further present new crown formation times for two unerupted canines from South African Australopiths, which were found to form over a rather surprisingly long time (> 4.5 years). This approach provides tools for maximizing the recovery of developmental information in teeth, especially in the most difficult cases.     

Enamel hypoplasia in the deciduous teeth of great apes: variation in prevalence and timing of defects

The prevalence of enamel hypoplasia in the deciduous teeth of great apes has the potential to reveal episodes of physiological stress in early stages of ontogenetic development. However, little is known about enamel defects of deciduous teeth in great apes. Unresolved questions addressed in this study are: Do hypoplastic enamel defects occur with equal frequency in different groups of great apes? Are enamel hypoplasias more prevalent in the deciduous teeth of male or female apes? During what phase of dental development do enamel defects tend to form? And, what part of the dental crown is most commonly affected? To answer these questions, infant and juvenile skulls of two sympatric genera of great apes (Gorilla and Pan) were examined for dental enamel hypoplasias. Specimens from the Powell‐Cotton Museum (Quex Park, UK; n = 107) are reported here, and compared with prior findings based on my examination of juvenile apes at the Cleveland Museum of Natural History (Hamman‐Todd Collection; n = 100) and Smithsonian Institution (National Museum of Natural History; n = 36). All deciduous teeth were examined by the author with a ×10 hand lens, in oblique incandescent light. Defects were classified using Fédération Dentaire International (FDI)/Defects of Dental Enamel (DDE) standards; defect size and location on the tooth crown were measured and marked on dental outline charts. Enamel defects of ape deciduous teeth are most common on the labial surface of canine teeth. While deciduous incisor and molar teeth consistently exhibit similar defects with prevalences of ～10%, canines average between 70–75%. Position of enamel defects on the canine crown was analyzed by dividing it into three zones (apical, middle, and cervical) and calculating defect prevalence by zone. Among gorillas, enamel hypoplasia prevalence increases progressively from the apical zone (low) to the middle zone to the cervical zone (highest), in both maxillary and mandibular canine teeth. Results from all three study collections reveal that among the great apes, gorillas (87–92%) and orangutans (91%) have a significantly higher prevalence of canine enamel defects than chimpanzees (22–48%). Sex differences in canine enamel hypoplasia are small and not statistically significant in any great ape. Factors influencing intergroup variation in prevalence of enamel defects and their distribution on the canine crown, including physiological stress and interspecific dento‐gnathic morphological variation, are evaluated. Am J Phys Anthropol 116:199–208, 2001. © 2001 Wiley‐Liss, Inc.     

Enamel hypoplasias and physiological stress in the Sima de los Huesos Middle Pleistocene hominins

This study presents an analysis of linear enamel hypoplasias (LEH) and plane-form defects (PFD) in the hominine dental sample from the Sima de los Huesos (SH) Middle Pleistocene site in Atapuerca (Spain). The SH sample comprises 475 teeth, 467 permanent and 8 deciduous, belonging to a minimum of 28 individuals. The method for recording PFD and LEH is discussed, as well as the definition of LEH. The prevalence of LEH and PFD in SH permanent dentition (unilateral total count) is 4.6% (13/280). Only one deciduous tooth (lower dc) showed an enamel disruption. Prevalence by individual ranges from 18.7-30%. The most likely explanation for the relatively low LEH and PFD prevalence in the SH sample suggests that the SH population exhibited a low level of developmental stress. The age at occurrence of LEH and PFD was determined by counting the number of perikymata between each lesion and the cervix of the tooth. Assuming a periodicity of nine days for the incremental lines, the majority of LEH in the SH sample occurred during the third year of life and may be related to the metabolic stress associated with weaning.     

Size and morphology of the permanent dentition in prehistoric Ohio Valley Amerindians.

Metric and morphological characterizations of the permanent teeth from a total of 155 prehistoric Amerindians are presented. The individuals represent samples from three Ohio Valley burial complexes (considered together as the Late Diffuse group): Glacial Kame, Adena and Ohio Hopewell. Metric data include common measures of central tendency and dispersion. From these measures estimates and analyses of the magnitude of sexual dimorphism and relative variability are presented as well as analyses of the patterns of these estimates. Forty morphological characters are also tabulated. The results indicate a number of provisional hypotheses: the generally larger tooth size of the Late Archaic Indian Knoll when compared to the Late Diffuse groups is consistent with the hypothesis of mitigated selective pressures in more technologically advanced groups; although tooth size is smaller in the Late Diffuse groups, dental morphology is as complex, or more so when compared to the Indian Knoll group. Since morphology and size do not covary exactly the biocultural forces resulting in smaller tooth size do not seem to act as strongly on dental morphology; odontological differences within the Late Diffuse arise primarily between the Glacial Kame-Adena and the Ohio Hopewell. These differences correspond to major biocultural changes in this area; although provisional hypotheses concerning odontological variability are erected, hypotheses concerning evolutionary trends must await the discovery of evolving lineages within these groups; similarities are noted among all compared groups including the pattern and magnitude of sexual dimorphism and relative variability. These parameters may be similar for all eastern Amerindians during this period; finally, the morphology of the deciduous dentition, which generally predicts that of the permanent teeth, is found to be less complex than the permanent teeth. This may be the result of a selective disadvantage for the individuals in the deciduous dentition sample which is reflected in the dentition.     

The number of missing teeth in people of the Edo period in Japan in the 17th to 19th centuries

doi: 10.1111/j.1741‐2358.2011.00511.x The number of missing teeth in people of the Edo period in Japan in the 17th to 19th centuries Objective: The aims of this study were to examine the number of missing teeth in the people of the Edo period (or number of remaining teeth) and to contribute to the 8020 movement proposed in Japan to help people retain 20 or more of their own teeth until the age of 80. Background: The study of dentition in ancient skeletal remains of our ancestors from multiple perspectives can yield information that can contribute to the study of physical anthropology and the leading edge of modern dental research. Materials and methods: The materials were 82 excavated individuals (52 males and 30 females) from 1603 to 1868 whose maxillas and mandibles were both examinable. The age and sex were estimated by anthropological methods, and the individuals were divided into five groups. The status of missing teeth was compared between groups, and a chi‐square test was used to test significant differences between groups. The rates of tooth loss were examined in the maxillas and mandibles. Results: In the people of the Edo period, many teeth remained in good condition until early to late middle age. There were more remaining teeth in these individuals than in modern‐day individuals. However, the Edo people clearly showed increased tooth loss with age. There were no differences in tooth loss by sex. The tooth type with a high rate of tooth loss was posterior teeth, but incisor loss also occurred with ageing. Mandibular canines were most likely to be remaining. Conclusion: The Edo people had more remaining teeth than modern‐day society. This finding was unexpected. The notion that “people of long past ages lost more teeth more quickly” does not seem to apply to people in the Edo period in Japan.     

Deciduous dentition and eruption pattern in late Miocene Pachyrukhinae (Hegetotheriidae,Notoungulata) from La Pampa Province,Argentina

The study of juvenile remains of Paedotherium Burmeister from Cerro Azul Formation (La Pampa Province, Argentina; late Miocene) is presented. Upper and lower deciduous dentition (or permanent molars supposed to be associated with non-preserved deciduous teeth) are recognised. Several ontogenetic stages are distinguished among juveniles, according to the degree of wear and the replaced deciduous teeth. Besides, some morphological and metrical differences are observed along the crown height. Deciduous cheek teeth are high-crowned and placed covering the apex of the corresponding permanent tooth. The height of the crown and the degree of wear allow establishing the pattern of dental replacement of deciduous and permanent premolars in a posterior–anterior direction (DP/dp4–2 and P/p4–2), as well as the eruption of M/m3 before DP/dp4 is replaced. Some of the studied remains are recognised as young individuals of Tremacyllus Ameghino, but with complete permanent dentition, which leads to propose a different timing in the dental replacement with respect to Paedotherium; they also allow the establishment of an opposite premolar eruption pattern, from P/p2 to P/p4. This knowledge of the deciduous dentition of Paedotherium suggests the need of revising the morphological and metrical characters previously used for defining species within this taxon.     

Factors affecting the distribution of enamel hypoplasias within the human permanent dentition

Frequencies and morphological and chronological distributions of enamel hypoplasias are presented by tooth type (permanent I1 to M2s), based on a sample of 30 prehistoric Amerindians with complete and unworn dentitions. There is nearly a tenfold variation in frequency of defects by tooth, ranging from 0.13 per mandibular second molar to 1.27 per maxillary central incisor. The six anterior teeth average between 0.70 and 1.27 defects/tooth, whereas the eight posterior teeth average between 0.43 and 0.13 defects/tooth. Earlier developing teeth, such as incisors, have earlier peak frequencies of defects (2.0-2.5 years), while later developing teeth, such as second molars, have subsequent peak frequencies (5.0-6.0 years). These variations are relevant when comparing hypoplasia data based on different teeth. Differences in hypoplasia frequencies among teeth are not solely due to variation in time of crown development, as is usually reported. Rather, there is evidence for biological gradients in susceptibility to ameloblastic disruption. Anterior teeth are more hypoplastic than posterior teeth. More developmentally stable "polar" teeth are more hypoplastic than surrounding teeth. Polar teeth may be more susceptible to hypoplasias because their developmental timing is less easily disrupted. In all teeth, hypoplasias are most common in the middle and cervical thirds. Crown development and morphological factors, such as enamel prism length and direction, may influence the development and expression of enamel surface defects.     

Discrete dental trait asymmetry in Mexican and Belizean groups

Discrete dental trait asymmetry was scored on four Mexican Indian and two Afro-Belizean groups. The Mexican populations show significantly higher mean asymmetry than the two populations from Belize even though the Belizean groups have larger teeth. Point biserial coefficients of correlation between asymmetry of discrete traits and tooth size is low and in most cases not significant. This study indicates that populational and ethnic differences exist in the asymmetry of discrete traits, suggesting that these traits may be used to investigate the etiology of dental asymmetry, and the relative roles of genetics and environment.