RESUMO
Cross-population applicability of osteological and dental methods is a known issue in forensic anthropology, but very little is known about whether differences between populations are due to ancestry, environment effects, or even the statistical approach utilized for developing the methods. This study wishes to add to the discussion of population-specificity of dental age estimation methods and examine the impact of their statistical basis on their accuracy and precision. These parameters were estimated by testing 12 different dental age estimation techniques on a sample of 182 panoramic radiographs of children between the ages of 6 and 15 years (110 girls and 72 boys) from the city of Mérida in Yucatán, México. None of the 12 methods selected is based on Mexican samples. Dental maturation was scored following and methods tested employed two dental scoring schemes: Moorrees, Fanning, and Hunt's (MFH) 13-/14-stage system and Demirjian's 8-stage system. Results show that methods derived from more geographically specific groups do not fare better or worse than methods developed on more diverse and inclusive international samples, even if no methods specific to Mexicans were tested. While some of the methods performed very well, and they were not based on a Mexican sample, this suggests that population-specific dental age estimation methods may be relatively unimportant or that population differences in dental maturation are very small. Other issues seemed to have a greater impact on accuracy and precision, such as age dependency, inclusion of the third molar in age assessments, age truncation and age heaping in reference samples, the dental scoring scheme used, and how predicted age is calculated mathematically. As such, findings in this study suggest that validation tests of age estimation methods may not be a useful or reliable means to assess population differences and that these differences need to be more systematically assessed if an argument is to be made for the increased accuracy and precision of population-specific methods. The statistical basis of dental prediction methods seems to have a more significant role in their accuracy and precision outside of their reference sample.
Assuntos
Determinação da Idade pelos Dentes/métodos , Odontologia Legal/métodos , Adolescente , Variação Biológica da População , Criança , Feminino , Humanos , Masculino , México/etnologia , Radiografia Panorâmica , Valores de Referência , Reprodutibilidade dos TestesRESUMO
OBJECTIVE: The ancient Maya used to practice dental inlays as part of the cultural traditions. Most of those inlays remain in place after more than one thousand years. The purpose of this paper is to investigate the incidence of pulp pathosis associated with ancient Maya dental inlays to assess the impact that such common practice had on the population's oral health. DESIGN: We scored 193 anterior inlaid teeth from 107 pre-Hispanic Maya dentitions studied at three archaeological storage facilities (Universidad Autonoma de Yucatan, Harvard University, Atlas of Guatemala Project). Two hundred eleven untreated frontal teeth of pre-Hispanic Mayan collections were used as controls. We performed macroscopic, radiographic and microscopic analyses to assess the frequency of caries, pulp calcifications, internal root resorption (IRR), and periapical lesions (PALs). RESULTS: In the inlaid teeth, the frequencies of pulp calcifications, IRR, caries and PALs were 59.8%, 2.2%, 18.5% and 19.2%, respectively. Compared with untreated teeth, inlaid specimens exhibited greater susceptibility to caries, pulp calcifications, IRR and PALs than untreated teeth (pulp calcifications: 44.5%, IRR: 0%, caries: 1.4%, and PAL: 1.9%). Age-at-death did not have any significant influence on susceptibility to pulp calcifications, IRR, caries or PALs. CONCLUSIONS: We noted relatively low pulp irritation and a low frequency of carious infections, IRR and PALs in Mayan inlaid teeth. However, these levels exceeded the frequencies of untreated teeth from the same area and time period. We follow that the cements used by the pre-Hispanic Maya to fix the inlays into their sockets provided excellent sealing characteristics on average.
Assuntos
Polpa Dentária/patologia , Indígenas Centro-Americanos/história , Restaurações Intracoronárias/história , América Central , História Antiga , HumanosRESUMO
The present paper proposes a new approach to the estimation of intra-site variability of dental morphological traits when they are dichotomized into presence vs absence. It rests on the assumption that (1) higher intra-site variability is the expression of intense population dynamics and gene flow; and (2) maximum variability is reached when each trait is expressed in the population with a frequency of 50%. The approach simulates the calculation of frequency of heterozygotes in Mendelian traits (2xiyi), where xi and yi are the frequency of presence and absence of the trait. For every population, the final value corresponds to the average of (2xiyi) calculated from all the scored traits. Two separate analyses were performed using 50 and 40 traits recorded in 11 Prehispanic Maya skeletal collections from the Yucatán Peninsula. Resulting average values were related to the sites' positions within the region's social, political and economic sphere of influence. Dental collections that were obtained from important city centers or by grouping many sites from a single region present the highest values of internal variability, followed by sites known to have played an important role in trade activities or in other socio-political contexts. At the other end, dental collections that represent smaller communities or more isolated, kin-related groups are set at the lower ranks of internal variability. One-way ANOVA tests for both 50 and 40 variables show that sample means present significant differences between the extreme ends of the ranked set of samples.
Assuntos
Fósseis/anatomia & histologia , Dente/anatomia & histologia , Etnicidade/genética , Etnicidade/história , Fósseis/história , Fluxo Gênico , História Antiga , Humanos , México , Paleodontologia , Dinâmica Populacional/históriaRESUMO
AIM: To assess the prevalence of C-shaped canal systems in mandibular second molars, in samples of modern and pre-Hispanic Mayan individuals in Yucatán, Mexico, and to analyse the trait through time and attempt to find new evidence of ethnical bonds between populations. METHODOLOGY: Three hundred and forty-one randomly selected patients were treated in the Endodontic Clinic at the Dental school of the Universidad Autónoma de Yucatán, and 48 mandibular second molars from pre-Hispanic Mayan collections were macroscopically and radiographically inspected. Statistical analysis was performed with a Fisher's exact test to compare the prevalence of C-shaped canal systems in modern and archaeological samples. RESULTS: In the clinical observation, 118 of 341 (35%) patients treated endodontically had C-shaped mandibular second molars. In the radiographical evaluation, 17 of 48 (35%) archaeological molars had fused roots and pulp chamber morphology categorized as C-shaped. There were no significant differences between the frequencies in both samples. CONCLUSION: This study highlighted that a one-rooted mandibular molar was likely to have a C-shaped canal. The similarity between ancient and modern samples indicates that the genetic make-up since the European conquest has not affected the expression of this trait. This study supports the theory that the Mayan population has a relationship with the Northeast Asian population.
Assuntos
Endodontia , Fósseis , História Antiga , Humanos , MéxicoRESUMO
Non-specific stress markers such as linear enamel hypoplasia (LEH) have been associated in the literature with a large number of possible conditions disrupting the individual's homeostasis, though metabolic strain originating synergistically by disease and malnutrition has been held to be the main cause behind enamel disruption. The analysis of LEH in the Maya Classic period site of Xcambó, located along the northern coast of the Yucatán peninsula, reveals high exposure to stressful conditions during infancy regardless of age and sex. Yet, the inhabitants of the site were of a medium to high social and economic status, with access to balanced and protein-rich nutritional resources, which should have functioned as a cultural buffer to the impact of stress. In the light of this apparent contradiction, this paper discusses the impact of environmental conditions on the record of metabolic stress. Our conclusions pose a cautionary caveat for inferring nutrition and status in ancient pre-antibiotic populations solely from the occurrence of linear enamel hypoplasia.
Assuntos
Hipoplasia do Esmalte Dentário/epidemiologia , Hipoplasia do Esmalte Dentário/história , Fósseis , Paleodontologia , Adolescente , Adulto , Criança , Pré-Escolar , Dente Canino , Hipoplasia do Esmalte Dentário/fisiopatologia , Dentição , Feminino , História Antiga , Humanos , Incisivo , Masculino , México/epidemiologia , Estado Nutricional/fisiologia , Prevalência , Estresse Fisiológico/fisiologia , Adulto JovemRESUMO
The present investigation aims at contributing to the ongoing discussion on the unconfirmed identity of the Red Queen, a Classic Maya dignitary discovered in Temple XIII at Palenque, Mexico, by comparing her reconstructed facial profile to the portraiture of known female personages from the site. The comparison rests upon individual cranial features, like buccal prognatism, nasal root and inclination, chin prominence and the artificially shaped forehead. The similarities between the reconstruction, the female's funerary mask and local portraiture appear to identify the Red Queen as Lady Ix Tz'akb'u Ajaw (Ahpo Hel), the wife of Janaab' Pakal, one of the famous Maya rulers of the Classic Period. The proposed match and her family relationship with the king might explain the spatial closeness of their burial places in the Temple of the Inscriptions and Temple XIII.