Tooth size and morphology in a recent Australian aboriginal population from Broadbeach, South East Queensland

Gender and age effects on dental and palatal arch dimensions among full siblings

PURPOSE

This study was conducted to investigate the dental and palatal arch dimensions of male and female siblings in relation to gender and age, using three-dimensional (3D) digital casts.

METHODS

This study involved 54 subjects (27 pairs) of male-female siblings aged 15 to 45 years. Dental casts were digitized and analyzed for tooth size (TS), arch width (AW), arch length (AL), arch length discrepancy (ALD), and palatal arch dimensions (PAD). The data obtained were subjected to t-tests, and the palatal curvature (PC) was modeled using a fourth-order polynomial.

RESULTS

Significant differences (P < 0.05) between the sexes were found in the mesiodistal TS, particularly in all canines, as well as 16, 36, 46, and 41. Maxillary AW and AL were also significantly (P < 0.05) influenced by sexes. Most arch parameters were more prominent in male siblings, and the effect of age on PC differed between the sexes. In addition, the PC of adolescent females was mostly superimposed on adult females relative to males.

CONCLUSION

Among siblings, males were found to have significantly larger dental arch dimensions than females. Furthermore, PC showed some differences between the sexes in both the frontal and sagittal planes.

Interpretative potential of dental metrics for biodistance analysis in hunter-gatherers from central Argentina. A theoretical-methodological approach

The use of dental metrics as a reliable tool for the assessment of biological distances has diversified dramatically in the last decades. In this paper some of the basic assumptions on this issue and the potential of cervical measurements in biodistance protocols are discussed. A sample of 1173 permanent teeth from 57 male and female individuals, recovered in Chenque I site (western Pampas, central Argentina), a Late Holocene hunter-gatherer cemetery, is examined in order to test the impact of exogenous factors that may have influenced the phenotypic manifestation and affected dental crown sizes. The statistical association between dental metric data, obtained by measuring the mesiodistal and buccolingual diameters of the crown and cervix, and the quantification of hypoplastic defects as a measure to evaluate the influence of the environment in the dental phenotypic expression is evaluated. The results show that socioenvironmental stress did not affect dental metrics and that only the more stable teeth (first incisors, canines, first premolars and first molars) and three variables (buccolingual diameter of the crown and both mesiodistal and buccolingual measurements of the cervix) should be included in multivariate analyses. These suggestions must be strengthened with additional studies of other regional samples to identify factors of variation among populations, so as to develop general guidelines for dental survey and biodistance analysis, but they are a first step for discussing assumptions usually used and maximizing the available information for low-density hunter-gatherer societies.

The Watinglo mandible: a second terminal Pleistocene Homo sapiens fossil from tropical Sahul with a test on existing models for the human settlement of the region

This paper analyses a fossil human mandible, dated to circa 10ka, from Watinglo rockshelter on the north coast of Papua New Guinea. The fossil is metrically and morphologically similar to male mandibles of recent Melanesians and Australian Aborigines. It is distinguished from Kow Swamp and Coobool Creek male mandibles (Murray Valley, terminal Pleistocene) by being smaller and having different shape characteristics, as well as smaller teeth and a slower rate of tooth wear. It pairs with the Liang Lemdubu female (Late Glacial Maximum, Aru Islands) in suggesting that the morphology of the terminal Pleistocene inhabitants of tropical Sahul was gracile compared to their contemporaries within the southern Murray drainage. An explanatory scenario for this morphological contrast is developed in the context of the Homo sapiens early fossil record, Australasian mtDNA evidence, terminal Pleistocene climatic variation, and the possibility of multiple entry points into Sahul.

The Neanderthalian molar from Hunas, Germany

In this paper, we present a well-preserved isolated human molar found in 1986 in the Hunas cave ruin, south-east Bavaria. The tooth was located at the bottom of layer F2, which belongs to a long stratigraphic sequence comprising faunal remains as well as archaeological levels (Mousterian). A stalagmite from layer P at the base of the stratigraphic sequence was recently dated to 79.373+/-8.237 ka (base) and 76.872+/-9.686 ka (tip) by TIMS-U/Th (Stanford University). We identified the tooth as a right (possibly third) mandibular molar. Characteristic parameters such as crown and root morphology, fissure pattern, enamel thickness, occlusal and interproximal wear, dental dimensions and indices, and radiological features indicate that the Hunas molar represents the tooth of a Neanderthal. This is corroborated by both the palaeontological and archaeological findings (Mousterian) of layer F2.

Index of Dates from Archaeological Sites in Queensland

<p>This volume presents an indexed compilation of chronometric determinations obtained from archaeological sites in the state of Queensland (including Torres Strait), Australia, to the end of 2000. The list includes conventional radiocarbon (14C), accelerator mass spectrometry (AMS), thermoluminescence (TL) and optically-stimulated luminescence (OSL) determinations. In total, 849 dates are listed from 258 sites. This listing is intended as a reference work only and no analysis of the dataset is undertaken in this volume.</p>

Ethnic dental analysis of shovel and Carabelli's traits in a Chinese population

Chinese populations differ from Caucasoids by having a high prevalence of shovel trait and a low prevalence of Carabelli's trait. This study was conducted to investigate the association between the shovel and the Carabelli's traits in a Chinese population. The research design investigated a Chinese population that resides in southern Taiwan. The ancestors of this Chinese population migrated to Taiwan from mainland China, mainly from Fukien and Kwangtung. The effects of sex and age on Carabelli's trait were controlled in this investigation, as was the association between tooth size and Carabelli's trait. Results show that males were more likely to have Carabelli's trait expressed on teeth than females. The buccolingual diameter of Carabelli's trait teeth was larger than that of teeth without the trait. After controlling for sex, age, and tooth size, the existence of the shovel trait increased the likelihood of having Carabelli's trait by a factor of five and a half, which is a significant effect.

Radiographic study of the broadbeach aboriginal dentition

This study forms part of a larger anthropological investigation of the Ngaraangbal Aboriginal Tribe's ancestral burial ground at Broadbeach, Australia. It examines the dentition, records the associated pathology in a noninvasive manner, and relates this to the likely subsistence diet of the tribe. The Broadbeach osteological collection was returned for reburial in 1985; however, radiographic and photographic records of 36 adult males were available. These form the basis of our study. The pathology noted in the study sample was compared with a representative sample (n = 38) of pre-European Aboriginal remains from throughout Queensland for verification purposes only. Rates of dental pathology and injury were calculated from the radiographic and photographic records. There was a significant rate of tooth-wear related intra-bony pathology (4.0%), moderate to severe alveolar bone loss, and heavy dental attrition, of which the mandibular posterior teeth were the most severely affected. Caries prevalence (0.8%) was low for hunter-gatherer populations. A large number of molar pulp chambers had a distinctive "cruciate" morphology resulting from the formation of secondary dentine and pulp stones. Injuries and abnormalities included upper central incisor avulsion (58.3%) and taurodontism. These results support the proposal that the Ngaraangbal tribe was a hunter-gatherer population subsisting on an abrasive diet that included marine foods.

Logistic analysis of shovel and Carabelli's tooth traits in a Caucasoid population

Caucasoid populations differ from Mongoloids by having a high prevalence of Carabelli's trait and a low prevalence of shovel trait. This study was conducted to investigate the association between the shovel and the Carabelli's traits in a Caucasoid population. The research design sought a Caucasoid population at Milwaukee of Wisconsin in United States. The Caucasoid group selected for study was the European descendant. The effects of sex and age on Carabelli's trait were controlled in this investigation, as was the association between tooth size and Carabelli's trait. Results show that males were more likely to have Carabelli's trait expressed on teeth than females. The buccolingual diameter of Carabelli's trait teeth was larger than that of teeth without the trait. After adjusting for sex, age, and tooth size, the existence of the shovel trait decreased the likelihood of having Carabelli's trait which shows an significant effect.

Logistic analysis of the effects of shovel trait on Carabelli's trait in a Mongoloid population

Mongoloid populations differ from Caucasoids by having a high prevalence of shovel trait and a low prevalence of Carabelli's trait. This study was conducted to investigate the effects of the shovel trait on Carabelli's trait in a Mongoloid population. The research design sought a population that resides in an isolated area and exhibits low admixture with neighboring populations. The Mongoloid group selected for study was the Bunun tribe of aborigines who inhabit an alpine area in Taiwan. The effects of sex and age on Carabelli's trait were controlled in this investigation, as was the association between tooth size and Carabelli's trait. Results show that males were more likely to have Carabelli's trait expressed on teeth than females. The buccolingual diameter of Carabelli's trait teeth was larger than that of teeth without the trait. After adjusting for sex, age, and tooth size, the existence of the shovel trait increased the likelihood of having Carabelli's trait by a factor of three, an effect that is significant.

Dental and cranial affinities among populations of east Asia and the Pacific: the basic populations in east Asia, IV

The origins of the four major geographical groups recognized as Australomelanesians, Micronesians, Polynesians, and East and Southeast Asians are still far from obvious. The earliest arrivals in Sahulland may have migrated from Sundaland about 40,000-50,000 years B.P. and begun the Australomelanesian lineage. The aboriginal populations in Southeast Asia may have originated in the tropical rain forest of Sundaland, and their direct descendants may be the modern Dayaks of Borneo and Negritos of Luzon. These populations, the so-called "Proto-Malays," are possible representatives of the lineage leading to not only modern Southeast Asians, but also the Neolithic Jomon populations in Japan. The present study suggests, moreover, that the Polynesians and western Micronesians have closer affinities with modern Southeast Asians than with Melanesians or Jomonese.

Negritos, Australian aborigines, and the "proto-sundadont" dental pattern: the basic populations in east Asia, V

Five evolutionarily significant dental traits were identified from a B-square distance analysis of nine crown characters recorded for several populations of East Asia and Oceania. Intergroup variation in these traits distinguishes three major divisions of the Mongoloid dental complex: sundadonty, sinodonty, and the dental pattern of Australian Aborigines. The Australian crown features may be characterized as having high frequencies of evolutionarily conservative characters. Negritos, one of the probable representatives of indigenous inhabitants of Southeast Asia who may have shared a common ancestor with Australians, possess the more derived sundadont dental pattern. As far as the five crown traits treated here are concerned, Australian dental features may be described as conforming to a "proto-sundadont" dental pattern, applying Turner's terminology. This pattern may represent a microevolutionary step prior to the emergence of the sundadont and sinodont patterns.

Concepts of occlusion: Australian evidence

Longitudinal studies of aboriginal children over a 20-year period have drawn attention to the wide variation in morphological features of the dentition and the way in which occlusal relationships develop. This paper summarizes some important determinants of optimal occlusal development, namely, tooth size relationships within and between dentitions, the patterns of alveolar growth, and tooth migrations during the transition from primary to permanent teeth and the nature of growth changes in the dental arches. Dental occlusion constantly changes throughout life in response to changing functional requirements. Observations limited to cross-sectional material provide an incomplete, and sometimes misleading, concept of dental occlusion and masticatory function.

Expression of the entoconulid (sixth cusp) on mandibular molar teeth of an Australian aboriginal population

The expression and genetic basis of the entoconulid (sixth cusp) on mandibular molars were examined in a geographically isolated group of aboriginals from Yuendumu in the Northern Territory of Australia. Four grades of trait expression, ranging from trace to small, medium, and large cusps, were defined on dental casts of 399 subjects. Frequencies of occurrence were among the highest reported in human populations. Approximately 80% of dm2s showed the trait, whereas frequencies in the permanent dentition ranged from around 50% on M2 to 70% on M1 and 80% on M3. The degree of expression increased distally along the molar series, with only 3% of dm2s showing large cusps compared with 25% of M3s. Fluctuating asymmetry was highest for M2 and lowest for dm2. No strong evidence for sexual dimorphism in occurrence or degree of expression was found. Based on a quasi-continuous threshold model, a genetic contribution to entoconulid variability was observed that was strongest for M1. Significant associations were noted between entoconulid expression on mandibular molars and metaconule expression on maxillary molars, indicating that similar developmental mechanisms may influence these traits. The entoconulid and the metaconule both provide additional bulk on the distal occlusal surface of molar teeth, an area subjected to early wear during mastication in aboriginals.

Craniofacial variation in Australasian and Pacific populations

Stepwise discriminant function analysis and Mahalanobis's generalized distance are applied to 36 measurements recorded in crania from Australasia and Oceania for assessing biological relationships and possible origins of these populations. Craniofacial variation in Australia is found to be clinal. There is extreme diversity in the Murray River Valley and southern Queensland cranial series. Multiple origins of the Australians are not supported by these results. Although selection and other processes cannot be completely ruled out, gene flow and restrictions to the exchange of genes can explain most of the morphological patterning observed. Breadth and length dimensions of the vault, interorbital breadth, biorbital breadth, palate length, and upper facial height are among the most important discriminators. Viewed within the broader context of Asia and the Pacific, Australians represent a biologically distinct population, one sharing ancestral ties with Melanesians but not with the recent populations of Asia and the rest of the Pacific. The latter represent a second major population complex.

Shape components of the maxillary molars in Australian aboriginals

Principal components analysis was used to quantify the variability in crown outlines of maxillary molars in Australian Aboriginals. The outlines were measured by 36 radii from the central pit to the crown periphery. The first component, responsible for over half of the total variance, was concerned with general crown size. Four remaining components were retained to indicate sources of variability resulting from contrasting degrees of development or reduction of different crown components. Shape changes from the first to third molars were identified with components representing overall size reduction, diminution of the hypocone, and metacone elements and mesiodistal compression. An anteroposterior gradient along the molar series in average scores and variances for all components resulted from the progressive reduction of distal crown elements, increasing mesiodistal compression, and greater morphological variation.

Contours of maxillary molars studied in Australian aboriginals

Distances from the central pit to the perimeter of the crown of permanent upper molars were measured on standardized occlusal photographs of dental casts representing 210 male and 181 female Aboriginals from Yuendumu in the Northern Territory of Australia. In both males and females the first molar was the largest tooth but it showed least variability. Variabilities of the distances tended to be greater for radii constructed in the buccolingual direction than for the transverse mesiodistal radii. The most marked size reduction in the molar series from first to third related to the distolingual part of the crown, which was also the most variable region. Size differences between molars in the mesial contour radii were not marked. Sexual dimorphism was evident in most crown radii, being most marked for the second molar.

Three-dimensional measurement of the occlusal surfaces of lower first molars of Australian aboriginals

The occlusal surfaces of lower first molars of Australian Aboriginals were measured in three dimensions with the aid of Moiré contourography. Molar cuspal heights in this population were higher than in Japanese (Mongoloid) but lower than in Dutch (Caucasoid) populations. Intercuspal distances were considerably larger than those in the two other populations. Populational differences in occlusal features may influence both craniofacial structures and jaw movements in the three populations. Low correlations between the cuspal heights and the intercuspal distances in the other two populations were also found in this population, indicating that human molar cuspal height is independent of the transverse size of the crown. Mean values for the height of the three principal cusps in lower first molars were less than those in upper ones. However, the height of the hypoconid, which was the highest in the lower molar cusps, showed almost the same mean value as the height of the upper three principal cusps, indicating that the height of the main functional cusp, in both upper and lower first molars, was almost the same.

Affinities between contemporary and skeletal Jewish and non-Jewish groups based on tooth morphology

Samples from five Jewish and six non-Jewish populations were compared in terms of the frequencies of 19 dental morphological variables. All but one of the samples came from Europe, North Africa, or the Middle East. Nine were from contemporary populations, and two were skeletal. Of the skeletal groups, one was Jewish, excavated on Mount Zion, Jerusalem, and dated at around 3,000 years old; and the other non-Jewish, excavated on the east coast of Australia, and dated at between 1,000 and 200 years old. Assessment of affinity between the different groups was based on smallest space analysis and cluster analysis. The results demonstrated relative proximity of the Jewish groups (with one exception), despite the fact that they came from a wide geographical area. In particular, the sample from Mount Zion showed greater affinity with three of the four living Jewish populations than with most non-Jewish groups. The skeletal Australian sample formed a cluster of its own, distinct from all the other groups. For six of the groups, the relationships based on tooth morphology showed good correspondence with known relationships based on single locus polymorphisms. The similarity of the Jewish groups to each other in terms of both tooth morphology and single locus polymorphisms was of special interest, since differences in other morphological and anthropometric characteristics, thought to be the result of selection, are known to exist between the Jewish populations.

The Carabelli trait in the mixed deciduous and permanent dentitions of five South African populations

The Carabelli trait in South African negroids, caucasoids, Coloured (Peninsula and Namaqualand) and Indians, classified according to Alvesalo, Nuutila and Portin (1975; Acta odont. scand. 33, 191-197) showed generally peak frequency of expression for dm2 falling into class 3 and for M1 into class 4, that dm2 displays more negative expression (class 2 and 3) and M1 more positive expression (class 4 and 5) and that overall expression in dm2 is higher than in M1. The Indian group was an exception with peak frequencies in class 2 for dm2 and class 1 (right) and class 2 (left) for M1. There was no sex dimorphism and there was a tendency for concordance of expression between sides but not within sides.

Molar size sequence in Australian Aboriginals

Percentage frequencies for molar size sequence of first and second molars were calculated in a group of contemporary Australian Aboriginals using mesiodistal and buccolingual dimensions, as well as crown areas. Comparisons were made between sexes, arches, and dimensions within the Aboriginal group and also between Aboriginal data and those published for other populations. The frequencies of the M2 greater than M1 molar size sequence in the Aboriginals fell within the range of frequencies reported for other contemporary populations. Differences in the frequencies of the M2 greater than M1 sequence between the sexes and between arches, together with the relatively high frequency of asymmetry in molar size sequence within Aboriginals, supported the notion that local environmental conditions acting during odontogenesis, together with differential responses to other environmental influences, play an important role in determining observed patterns of molar tooth size.