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The late third-millennium BC Longshan period was a crucial time for state formation in central China. During these centuries, long-distance networks expanded and shared material culture and then cultural practices spread across wider areas precipitating social and ideological developments that presaged the rise of states and cities on the Central Plain. In this research, the authors use multiple (strontium, oxygen and carbon) isotope analyses from the dental enamel of 67 individuals buried at the Xiajin cemetery, Shanxi Province. The results indicate significant long-distance migration among females during the Longshan period, which the authors interpret as evidence of exogamous marriage for political alliance-building--a phenomenon found more widely across Eurasia at the start of the Bronze Age. Keywords: central China, Neolithic, Bronze Age, Taosi culture, burial, isotopic analysis, migration, exogamy, Introduction The Longshan period (c. 2500-1900 BC) was a crucial time for state formation in central China. During this period, inter-regional networks developed rapidly, transmitting shared material forms and cultural [...]

Gigantopithecus blacki was a giant hominid that inhabited densely forested environments of Southeast Asia during the Pleistocene epoch.sup.1. Its evolutionary relationships to other great ape species, and the divergence of these species during the Middle and Late Miocene epoch (16-5.3 million years ago), remain unclear.sup.2,3. Hypotheses regarding the relationships between Gigantopithecus and extinct and extant hominids are wide ranging but difficult to substantiate because of its highly derived dentognathic morphology, the absence of cranial and post-cranial remains.sup.1,3-6, and the lack of independent molecular validation. We retrieved dental enamel proteome sequences from a 1.9-million-year-old G. blacki molar found in Chuifeng Cave, China.sup.7,8. The thermal age of these protein sequences is approximately five times greater than that of any previously published mammalian proteome or genome. We demonstrate that Gigantopithecus is a sister clade to orangutans (genus Pongo) with a common ancestor about 12-10 million years ago, implying that the divergence of Gigantopithecus from Pongo forms part of the Miocene radiation of great apes. In addition, we hypothesize that the expression of alpha-2-HS-glycoprotein, which has not been previously observed in enamel proteomes, had a role in the biomineralization of the thick enamel crowns that characterize the large molars in Gigantopithecus.sup.9,10. The survival of an Early Pleistocene dental enamel proteome in the subtropics further expands the scope of palaeoproteomic analysis into geographical areas and time periods previously considered incompatible with the preservation of substantial amounts of genetic information. The enamel proteome from a 1.9-million-year-old Gigantopithecus tooth shows that the Gigantopithecus and Pongo (orangutan) lineages diverged 12-10 million years ago., Author(s): Frido Welker [sup.1] , Jazmín Ramos-Madrigal [sup.1] , Martin Kuhlwilm [sup.2] , Wei Liao [sup.3] [sup.4] , Petra Gutenbrunner [sup.5] , Marc de Manuel [sup.2] , Diana Samodova [sup.6] [...]

A study was conducted to examine the effect of the interaction among bleaching, erosion, and dentifrice abrasivity, on enamel and dentin. Findings indicate that dental erosion and the more abrasive dentrifice increased toothbrushing wear on enamel surfaces, while bleaching showed no deleterious effect.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.forsciint.2009.07.017 Byline: Nidhi Gupta, Kiran Jadhav, B.R. Ahmed Mujib, Vikram S. Amberkar Keywords: Enamel; Tooth prints; Biometrics, Verifinger; AFIS software Abstract: Enamel in teeth, as documented is the hardest substance in the entire human body. Tooth prints are the enamel rod end patterns on the tooth surface. Could this fact be a boon in utilizing it for an individual's identification in the hands of forensic experts? A study has been attempted towards the same. These tooth prints were recorded for 60 extracted tooth specimens after acid etching using a cellophane tape. Subsequently a digital image of the print was obtained which was subjected to biometric conversion using Verifinger standard SDK version 6.0 software followed by the use of Automated Fingerprint Identification System (AFIS) software for comparison of the tooth prints. In results we observed that tooth prints were composed of varied patterns and sub-patterns. A comparison was made between the tooth prints of different and the same individual and also between different classes of teeth (incisors, canines, premolars and molars). None of the patterns exhibited intra- and inter-individual similarity. Nor did any particular class of the tooth could be preferentially used over the other for an individual identification. This field demands a need for further exploration towards the use of tooth prints for establishing an individual's identity. Author Affiliation: Dept. of Oral and Maxillofacial Pathology, Bapuji Dental College, Davangere, Karnataka, India Article History: Received 22 February 2009; Revised 18 June 2009; Accepted 28 July 2009

The archaeological study of the dental morphology of pre-European-contact American Indians, based on the analysis of the ectopic enamel of labial talon cusp, is presented.

An in vitro study analyzing the effects of argon laser (AL) irradiation on carieslike lesion formation in primary tooth enamel is presented.

The defects of enamel hypoplasia can be related to the layered structure of enamel which represents the sequence of development in tooth crowns. From such studies, it is possible to see that furrow-type enamel defects (the most common form of hypoplasia seen with the naked eye) are just the most prominent expression of a continuum which extends ever smaller, down to a microscopic disturbance to a single layer in the crown formation sequence. Furthermore, the progressive decrease in spacing between development layers which occurs down the crown sides, from occlusal to cervical, affects both the prominence and apparent width of the defects. This makes it difficult to use measurements as a means of estimating the duration of the disturbance causing a particular defect. The difficulty is even greater for the less common pitted or exposed-plane-type defects, for which the apparent width bears very little relationship with the duration of the growth disturbance. The defects of enamel hypoplasia can therefore be understood clearly only when examined under the microscope in relation to the structures which mark the development sequence of the tooth crown. KEY WORDS: hypoplasia; dental development; dental enamel defects; perikymata

The criticisms made by Michael L. Blakey and George J. Armelagos regarding the Hypoplastic Area method for research in dental anthropology are flawed in several aspects. Blakey and Armelagos' method is applicable only when comparing one tooth at a time. Furthermore, Blakey's method is incomparable with the Hypoplastic Area method due to differences in the measurement of enamel hypoplasia lesions.

The article written by B.E. Ensor and J.D. Irish on the hypoplastic area method for analyzing enamel hypoplasia published in the American Journal of Physical Anthropology is erroneous in various aspects. Contrary to their claims, a specific method for evaluating the level of hypoplasia for comparative purposes has already been developed. They have also failed to recognize a method for measuring a dental defect 'area.'

Studies of tooth crown morphology alone have proven valuable in defining human population differentiation. We test the hypothesis that quantitative comparisons of more complex whole tooth structure may prove informative in understanding human diversity. Three disparate populations in Native American genetic history were compared: Kodiak Island Western Eskimos, Peruvian Inca Amerindians, and Southeast Asians. Enamel depth (an increasing gradient extended from Southeast Asians to the Inca) and root parameters were the most discriminating variables. The observed microevolution appears to result from variation in timing of known X-linked, Y-linked, and autosomal genes that affect either ameloblast or odontoblast differentiation. The dental traits were sexually dimorphic, the effect being more pronounced in aboriginal Americans, with male teeth having robust roots and thin enamel compared to female. Southeast Asians were isometrically related. The prominence of sexual dimorphism and the importance of sex-linked genes in the determination of the dental phenotypes suggest that sexual selection was one evolutionary force acting on early Asian populations. Subsequently, the selection appears to have been relaxed in Southeast Asians. Observed divergence of tooth shape among the populations, i.e., differences in the appropriation process of tooth primordia, was mainly the consequence of genetic drift modulating heterochronic regulators of homeotic genes. KEY WORDS Teeth, Whole tooth, Enamel dept, Development, Differentiation, Sex linked, Phylogenetic

The tooth enamel of the earliest cetacean, Pakicetus, is described and compared to enamel of a primitive artiodactyl and a variety of primitive ungulate families. Pakicetus enamel organization, which is considered primitive for Cetacea, consists of a combination of radial and decussating enamel types. Prism patterns include prisms with open (horseshoe-shaped) and closed (circular) boundaries. Pakicetus enamel is similar to that of many primitive ungulates, including Diacodexis, the earliest artiodactyl, and Mesonychidae, an archaic ungulate family that often is considered close to the ancestry of Cetacea. This finding is consistent with the hypothesis, originally proposed on the basis of other aspects of morphology, that artiodactyls, cetaceans, and Mesonychidae are closely related.

This study reports on a sample of 12 modern human incisors (from two archaeological sites) that were viewed with a scanning electron microscope and whose perikymata were counted. These 12 incisors more than doubles the previously published sample size of modern human incisors that have served as the published standard for perikymata number in human incisors and have been employed to define taxonomic relationships in fossil hominids. All previously published fossil specimens fall within the expanded range of modern human perikymata counts and can no longer be considered distinctively nonhuman in dental formation time. Five neandertal incisors from the Krapina site in Croatia, Yugoslavia, were also examined. These incisors substantially expand the previous data base for counts of perikymata in Homo sapiens neanderthalensis, likewise overlapping the previously published modern human range. Finally, the validity of methods that have been employed for deriving crown formation times from perikymata counts in fossil hominines is called into question. Utilizing the presently known perikymata ranges for modern humans, these methods do not predict the range of known crown formation times of modern humans as assessed from studies of living children.

Enamel of several fossil and recent arctoid carnivores was studied with light and scanning electron microscopy. As in other carnivorans, 3 types of Hunter-Schreger bands (HSB) were observed: undulating, acute-angled, and zigzag HSB, which differ in their 3-dimensional complexity. Data on arctoid carnivores were used to test the hypothesis that zigzag HSB evolved multiple times to resist cracking of the enamel under high tensile stress. Distribution of HSB, except presence of zigzag HSB in the herbivorous panda, Ailuropoda, supported the hypothesis. Key words: Amphicyonidae, Carnivora, enamel microstructure, Mustelidae, parallel evolution, Procyonidae, Ursidae, zigzag Hunter-Schreger bands

Although the degree of variability in the rate of enamel growth between human populations is largely unknown, many studies have assumed that published schedules of enamel growth are applicable to all populations. This study presents a population-specific model for enamel growth in skeletal individuals from medieval Danish friary cemeteries (ca. A.D. 1250 - 1537) and compares the model to previously published enamelization schedules. The rate of enamel development in the Danish model was determined from counts of striae of Retzius in permanent unworn mandibular canines. Perikymata on the surface of the teeth were also counted to determine the average amount of hidden enamel in the cuspal end of the canine. The Danish model was used to calculate the timing of enamel defects in 450 canines from the samples. Additionally, the defect data were examined using a published schedule (Massler et al., 1941) to uncover any differences in timing resulting from the type of model chosen. The results suggest that: (1) there is variability in enamelization schedules between populations and (2) using standard published schedules can result in mistakes in calculating the timing of enamel hypoplasia occurrence. This research was supported by the Anthropological Database at Odense University (ADBOU), the Fulbright Foundation, and the American Association of University Women.