Incisor labial surface wear striations in modern humans and their implications for handedness in Middle and Late Pleistocene hominids

Over the past four decades several workers have argued that the orientations of striations on the labial surfaces of the front teeth of Middle and Late Pleistocene fossils attributed to Neanderthals and antecedent archaic hominids can tell us something about handedness. These researchers have suggested that such scratches result from stone tools scraping across the incisors during ‘stuff‐and‐cut’ behaviours, and that they reflect directions of hand movements and handedness. In this study, we examine comparable wear features on the incisors of anatomically modern humans to determine whether striation angle may reflect handedness. The teeth from 66 individuals representing four groups with known differences in subsistence practices (Aleut, Arikara, Illinois Bluff, and Puye) were examined. Photomicrographs were made of the maxillary central incisor labial surfaces of all individuals at 56× magnification. These photomicrographs were scanned to image files, and orientations of all visible wear striations were measured using a semi‐automated image analysis procedure. Approximately three‐quarters of all labial surfaces showed a preferred striation orientation. Of those, most had preferred apico‐cervical or vertical striation orientations, independent of cultural affiliation. Few showed the tendency toward diagonally‐oriented scratches expected if handedness is related to scratch orientation. We found no evidence for ‘stuff‐and‐cut’ striations, despite the fact that at least one of the groups studied—the Aleut—are documented to have used this behaviour. In sum, there is evidently no relationship between striation orientation and handedness in the groups studied. It is, therefore, unlikely that labial scratch orientation in Middle and Late Pleistocene hominids reflects handedness if they used their front teeth in a manner comparable to that of any of the anatomically modern groups considered here. Copyright © 1999 John Wiley & Sons, Ltd.     

Stress near the start of life? Localised enamel hypoplasia of the primary canine in late prehistoric mainland Southeast Asia

Localised hypoplasia of the primary canine (LHPC) is characterised by roughly circular defective areas of thinned or missing enamel on the labial surface. This defect is rarely reported in bioarchaeological research. Using samples from late prehistoric mainland Southeast Asia, this paper documents the prevalence of LHPC to produce baseline data for this defect. The samples are from seven archaeological sites in Thailand and collectively span from ca. 4000 to 1500 BP. In the combined samples, 32/79 (40.5%) of individuals and 47/199 (23.6%) of teeth had LHPC. The high occurrence of LHPC may suggest there was poor maternal and infant health. There is also a high occurrence of caries associated with LHPC, which has implications for the assessment of deciduous dental health. This paper stresses the importance of the collection of dental enamel defect data from deciduous teeth including LHPC in bioarchaeological research.     

Identification of metal residues associated with bit-use on prehistoric horse teeth by scanning electron microscopy with energy dispersive X-ray microanalysis

Our ability to identify evidence of the use of horses for transportation from archaeozoological remains is important for improving our understanding of the role of horses in socioeconomic changes throughout prehistory. When a horse is used with a bit, the bit can come into contact with the anterior (‘front’) surface of the lower second premolar (P₂). Here, results of X-ray microanalysis, undertaken in a variable pressure scanning electron microscope, of chemical elements on the anterior surface of four archaeological horse P₂ are presented. Analysis of dental materials (enamel and cementum) returned expected results, with calcium, phosphorous and oxygen dominating. Iron-rich residues are also identified on the front of two of the teeth, which are interpreted here as deriving from contact with iron bits. It is proposed that such analyses may provide a useful additional method for identifying bitting damage in archaeological horses or corroborating interpretations made from macroscopic examinations.     

Tooth wear in two ancient populations of the Khazar Kaganat region in the Ukraine

Tooth wear is a common phenomenon in archaeological material. It has been related to the abrasiveness of diet and to the tribological attrition of teeth of individuals. Numerous investigations have been carried out in north and middle American samples as well as African anthropological material. Not much is known about tooth wear in European cultures. Eleven skulls from Chervona Gusarovka, and 14 skulls from the Upper Saltov sites of the Khazar Kaganat region (8th–10th centuries AD) in eastern Ukraine, with different diets were examined. A total of 208 teeth were studied for tooth wear, caries prevalence and periodontal status. Abrasion grades were determined according to a standardised classification and statistically evaluated. Periodontal status was measured using the distance between the enamel‐cementum junction and alveolar crest and the gingival attachment level respectively. Tooth wear was significantly different (P < 0.01) between the two populations. A low caries prevalence of 4.2% in the Chervona Gusarovka population and 1.7% in the Upper Saltov population was found. Significantly more alveolar crest bone resorption on the lingual side was found in the premolars and anterior teeth of the Chervona Gusarovka population. No significant differences were found regarding gingival attachment levels and gingival recession. It is concluded that the content and mode of food preparation influenced tooth wear, as reflected by the prevalence of dental caries and periodontal diseases in these ancient populations. Copyright © 2006 John Wiley & Sons, Ltd.     

Dental Pathology,Trauma and Attrition in a Zambian Iron Age Sample: A Macroscopic and Radiographic Investigation

Using morphological and radiographic methods, we analysed the dentitions of 24 individuals from Ingombe Ilede and Isamu Pati Zambian Iron Age archaeological sites. In this study, we determined the frequency and distribution of attrition, pathological conditions and dental trauma. This research also presents the first view of dental health for an Iron Age population in southern Africa. In total, 482 teeth were available for this study with 287 teeth missing, where 50 of these were lost antemortem and one individual had an erupted supernumerary first mandibular incisor. With the use of radiography and morphology, 21.5% (104/482) of the analysed teeth had at least one pathological condition or evidence of dental trauma. Some interesting dental aspects found and discussed in this paper are linear enamel hypoplastic lesions, radicular resorption, periapical lesions, fractures, dental modification and carious lesions. Many of these features were diagnosed with radiography, and this was especially important for those found below the cemento‐enamel junction (p = 0.0202) that are less obvious with macroscopic investigation alone. Additionally, the quantity and direction of dental attrition was studied. There were observed sex differences with the direction of wear, likely representing a sex‐specific cultural practice of using teeth as tools. Overall, the results show that this sample suffered relatively little from dental problems, and many of those observed features were associated with the traumatic procedure of dental modification, whereas others were age and diet‐related. Additionally, with the use of radiography, rare dental fractures and other features were diagnosed; these results demonstrate the requirement for its application in dental studies on archaeological assemblages. Copyright © 2012 John Wiley & Sons, Ltd.     

Problems and pitfalls in the diagnosis of linear enamel hypoplasia in cheek teeth of cattle

Prevalence and intensity of enamel hypoplasia have been used as markers of generalized physiological stress during dental development in a wide range of mammalian taxa. We studied cattle (Bos taurus) cheek teeth exhibiting morphological characteristics that are of relevance to the diagnosis of enamel hypoplasia in this and other bovid species. These characteristics were multiple, more or less horizontally arranged (waveform) lines or grooves in the cementum of the tooth crown and the adjacent root area, leading to an imbricated appearance of the cementum. On macroscopic examination of tooth surfaces, these lines resembled linear enamel hypoplasia (LEH). Microscopic analysis of tooth sections, however, revealed that the lines occurred in the cementum only, and that the underlying enamel did not exhibit morphological irregularities. In cheek teeth of older cattle, a thick cementum layer is regularly found in the cervical crown portion and the adjacent root area. Apposition of this cementum is related to the uplifting of the teeth from their alveoli, a process that compensates for the shortening of the tooth crowns due to occlusal wear. In the studied specimens, a pronounced periodic nature of tooth uplifting and the related deposition of cementum is the likely cause for the observed imbricated appearance of the cementum. While this phenomenon may be misinterpreted as representing a case of LEH, presence of enamel hypoplasia in bovid teeth may be overlooked when the defects become filled with coronal cementum and are therefore not apparent on external inspection. This was the case in one of the cattle teeth analyzed by us, in which the hypoplastic enamel defects were, however, clearly discernible in ground sections. Microscopic analysis of tooth sections is recommended for recording of LEH in bovid teeth in cases where macroscopic examination of tooth surfaces alone does not produce unequivocal results.     

Micro‐CT Imaging and Analysis of Enamel Defects on the Early Late Pleistocene Xujiayao Juvenile

Dental pathologies and enamel defects in East Asian hominins have rarely been reported. Here, we systematically document and describe a suite of enamel defects in the Xujiayao juvenile maxilla, an East Asian hominin from the early Late Pleistocene that may represent an unknown hominin lineage. In addition, we determine the chronology of growth disruptions represented by matched linear enamel hypoplasias, evaluate the long‐held hypothesis that the large brownish pit on the I¹ is evidence of dental fluorosis and assess the utility of micro‐computed tomography (micro‐CT) techniques in analyzing enamel defects. With the use of binocular microscopy, scanning electron microscopy (SEM) and micro‐CT imaging techniques, the Xujiayao teeth were found to exhibit a high number of pit‐form defects seldom seen in the fossil record. By matching the timing of linear enamel hyperplasia across multiple teeth, a minimum of five developmental disruptions were identified, indicating that the Xujiayao juvenile experienced several growth disturbances during its short lifespan. Our SEM and micro‐CT analyses suggest that the large pit on the I¹ is an enamel hypoplasia due to its morphology and pre‐eruptive enamel thinning. It is not a post‐eruptive fluorotic pit, and there is no evidence of chalkiness or opacity associated with dental fluorosis. The micro‐CT technique made it possible to verify the presence of enamel hypoplasia and to more precisely quantify defect dimensions, especially in unerupted teeth and shallow hypoplasias that are difficult to detect by binocular microscopy or SEM. Copyright © 2015 John Wiley & Sons, Ltd.     

A dental study comparing age estimations of the human remains from the Swedish warship Vasa

The great Swedish warship Vasa capsized and sank in Stockholm harbour on her maiden voyage in 1628. The ship was raised from the seabed in 1961 and skeletal remains were recovered from at least 25 individuals, with teeth and jaws from 17 of them. The skeletal material was odontologically examined, including dental radiographs. Teeth lost both ante‐mortem and post‐mortem were recorded and variations in tooth anatomy noted. Acquired changes were recorded including enamel hypoplasia, attrition, dental caries and periodontal recession. Age estimations based on a separate odontological study, osteological changes and tooth attrition had been made in 1989. Ages were estimated additionally by three non‐destructive dental methods based on (a) the length of the apical translucent zone, (b) selected measurements both on intact teeth and from ratios on dental radiographs and (c) ratios of the length and width measurements on dental radiographs from selected teeth. Several sources of post‐mortem changes had been observed, among them vivianite in 33 teeth from four individuals. The results of the dental examination showed that few teeth had been lost ante‐mortem, there was a low caries rate and little loss of periodontal attachments. With few exceptions, there is fairly good agreement between the different methods of estimating age. Age estimates based on dental attrition were, however, significantly different from the other dental methods and age estimates calculated from apical translucency ought to be regarded with scepticism due to post‐mortem changes. The chronological ages of the victims will never be known, but age estimates based on all the age‐markers available will probably reach a fairly close approximation. Copyright © 1999 John Wiley & Sons, Ltd.     

Testing the ‘Laacher See hypothesis’: tephra as dental abrasive

In a series of recent studies, changes in material culture and settlement pattern in the Late Glacial of Northern Europe have been linked to the eruption of the Laacher See volcano. This eruption occurred c. 13,000 years ago towards the end of the Allerød chronozone. It is argued that the tephra fall-out from this eruption set in motion significant demographic fluctuations along the northern periphery of Late Glacial human settlement and that these led to a number of material culture transformations. In particular, the emergence of the regionally distinct techno-complexes with large tanged points – the Bromme culture in southern Scandinavia and the Perstunian culture in northeastern Europe – and the temporary abandonment of central European regions are thought to relate to this eruption. While numerous archaeological datasets are in accord with this ‘Laacher See hypothesis’, the forcing mechanism or mechanisms that brought about these archaeologically visible changes have remained largely unexplored. A particular challenge is to explain how some of the culture-historical effects of the Laacher See eruption seem to change or become more pronounced with distance from the eruptive centre. We here investigate one potential middle-range link between the Laacher See eruption and Late Glacial fauna and foragers: tephra as dental abrasive. We use instrumented nanoindentation to quantitatively investigate tephra from a number of sites covering the medial and distal fall-out zones as well as the dental enamel of Homo sapiens and key prey species of Late Glacial foragers. Our results show that the Laacher See tephra contained particles roughly twice as hard as even the hardest portions of any of the teeth investigated. We also suggest that fluoride-induced weakening of dental enamel may have further aggravated tooth wear. These mechanisms may have acted in concert to produce elevated levels of, in particular, animal mortality, which in turn may have led to an abandonment of the affected landscapes.     

Dental Modifications in a Skeletal Sample of Enslaved Africans Found at Lagos (Portugal)

An archaeological intervention in Valle da Gafaria (Lagos, Portugal) allowed the excavation of a deposit of waste dating from the 15^th to 17^th centuries. Among discarded objects, an important amount of human skeletal remains was exhumed (N = 158 individuals). The archaeological and historical context, as well as the morphometric analysis of the skulls, led us to attribute them an African origin. While historical sources document the trade of slaves by the Portuguese since the 15^th century, so far no slave cemetery was excavated in Portugal. The study of their lives and deaths has been accomplished by historical documents. Therefore, this sample provides a unique opportunity to learn more about captive individuals who were brought to Portugal in the modern period. The present work focuses in the intentional dental modifications presented by several of these individuals. A total of 113 subjects have teeth that can be evaluated for the presence of intentional modifications. Of these, 55.8% individuals present dental modifications on their anterior dentition, 42.9% exhibiting modifications on both upper and lower teeth. The incisors were the most frequently modified teeth, followed by the canines. Both men and women as adults and sub‐adults have dental intentional modifications. In most individuals, dental modifications involved the removal of the mesial and distal angles, which is comparable with sub‐Saharan African practices. However, we cannot infer a more specific origin for these slaves only based on dental modification's type and pattern because several ethnic groups modify teeth in the same way. Copyright © 2015 John Wiley & Sons, Ltd.     

Cultural Changes in Funeral Rites During the Neolithic in the Northeast of the Iberian Peninsula? The Cave of Pantà de Foix (Barcelona)

During the third millennia bc , there is a change in the funerary patterns of the populations in Catalonia. This novelty usually has been usually related to a change in the economical source of the human groups that become less sedentary as the stockbreeding becomes more important. In the present study, we analyse this change, reflected in the mortuary practices, by the study of diet and health markers such as caries, dental calculus or enamel hypoplasias and of biological affinities based on dental non‐metric traits. It has been included a total amount of 317 permanent teeth from Cova del Pantà de Foix sites, a sepulchral cave found at the south‐west of the city of Barcelona and dates from the third millennia bc . The 74.2% of them present dental calculus deposits, which are usually related to a high protein intake. Nevertheless, the high prevalence of carious lesions (15.3% of the teeth) suggests that the main dietary contribution comes from carbohydrates. Furthermore, when this group is compared with one from the Middle Neolithic Age, which presents a lower calculus prevalence, no biological differences are observed. This lack of differences among these groups denote that the origin of the high amount of calculus deposit is environmental, which is consistent with the elevated observation of hypoplasias of the crown enamel. The absence of dietary, biological and economical differences indicates that the population substrate during the Neolithic in Catalonia is the same and that the transition in the funerary rite is related to a substantial change only regarding to mortuary practices. Copyright © 2014 John Wiley & Sons, Ltd.     

A Case of Early Childhood Caries from Late Roman Ancaster,England

This paper presents a differential diagnosis of pathological changes observed in the deciduous dentition of a child aged 3–4 years, recovered from a Late Roman (c. ad 270–410) cemetery at Ancaster, England. The entire maxillary dentition exhibited areas of missing enamel and erosion of the underlying dentine, which was most pronounced at the lingual surfaces of the anterior teeth, and lingual and occlusal surfaces of the molars. Additionally, the mandibular second molars and mandibular right first molar displayed superficial enamel erosion of the buccal surfaces. Radiography indicated normal enamel density, and no further dental pathology was identified. Conditions considered in a differential diagnosis included amelogenesis imperfecta, fluorosis, perimolysis, xerostomia‐related caries and early childhood caries (ECC). The nature and distribution of lesions implicates ECC – also known as ‘nursing caries’ or ‘baby‐bottle caries’ – as the most probable diagnosis. The potential significance of the findings for studies of infant health and feeding practices in past populations is discussed. Copyright © 2015 John Wiley & Sons, Ltd.     

Linear Enamel Hypoplasia and Age‐at‐Death at Medieval (11th–16th Centuries) St. Gregory's Priory and Cemetery,Canterbury, UK

Linear enamel hypoplasia (LEH) is a macroscopically detectable band‐like dental defect, which represents localized decrease in enamel thickness caused by some form of disruption to a child's health. Such dental deformations are utilized in osteoarchaeological research as permanent markers of childhood physiological stress and have been extensively studied in numerous ancient human populations. However, currently there is no such data for medieval populations from Canterbury, UK. Here, LEH is examined in the context of age‐at‐death in human burials from the medieval St. Gregory's Priory and adjacent cemetery (11^th–16^th centuries), Canterbury, UK. The cemetery and Priory burials represented lower (n = 30) and higher status (n = 19) social groups, respectively. Linear enamel hypoplastic defects were counted on mandibular and maxillary anterior permanent teeth (n = 374). The age and sex of each skeleton were estimated using standard methods. Differences in LEH counts, age‐at‐death, and LEH formation ages were sought between the two social groups. Results indicate significantly greater frequencies of LEH in the Cemetery (mean = 17.6) compared to the Priory (mean = 7.9; t = −3.03, df = 46, p = 0.002). Adult age‐at‐death was also significantly lower in the Cemetery (mean = 39.8 years) compared to the Priory burials (mean = 44.1 years; t = 2.275, df = 47, p = 0.013). Hypoplasia formation ages differed significantly between the Priory (mean = 2.49 years) and Cemetery (mean = 3.22 years; t = 2.076; df = 47; p = 0.034) individuals. Results indicate that childhood stress may reflect adult mortality in this sample, and that the wellbeing of individuals from diverse social backgrounds can be successfully assessed using LEH analyses. Results are discussed in terms of the multifactorial etiology of LEH, as well as weaning‐related LEH formation. Copyright © 2012 John Wiley & Sons, Ltd.     

Comparing the Chronological Distribution of Enamel Hypoplasia in Rogowo,Poland (2nd century ad) Using Two Methods of Defect Timing Estimation

The frequency and chronological distribution of enamel hypoplasias were assessed in a Roman Period population of the Wielbark culture from Rogowo, northern Poland, dated to the 2nd century ad . Hypoplasias were recorded on permanent incisors, canines, and premolars of 52 skeletons. The position of linear defects on the crown surface was measured and then converted to the age of occurrence using two methods: a conventional method that employs the chart of enamel development for the permanent teeth, constructed by Massler et al. (1941) in Swärdstedt's (1966) modification, and the method by Goodman & Song (1999), which corrects for hidden cuspal enamel. Hypoplastic defects were found in 48.1% of examined cases. Linear defects [linear enamel hypoplasias (LEH)] were observed in 38.5% of individuals and in 22% of investigated teeth. The chronological distribution of LEH according to the conventional method revealed two peaks of defects: one at 2.6–3.0 years of age and the other at 4.1–4.5 years of age. The method that accounts for hidden cuspal enamel also provided two peaks, but they occurred at later ages: 3.0–4.0 and 4.6–5.0 years of age. The prevalence of hypoplasia in the Rogowo population in comparison with other European populations of the Roman Period seems to be rather low for both individuals and teeth affected. This may indicate advantageous living conditions, which are supported by archaeological data that suggest general well‐being of the Wielbark people. Copyright © 2011 John Wiley & Sons, Ltd.     

Diet and Oral Health of Populations that Inhabited Central Argentina (Córdoba Province) during Late Holocene

The aim of this work is to study, from a bioarchaeological perspective, the diet and oral health of the populations that inhabited Central Argentina in two periods which would reflect changes in subsistence strategies: earlier late Holocene (ca. 2500–1500 years BP) and later late Holocene (ca.1500–400 years BP). The sample is composed by 83 adult individuals from 47 archaeological sites. We considered five non‐specific indicators of stress, infectious and degenerative diseases: hypoplasia of dental enamel, dental caries, abscesses, antemortem teeth loss, and calculus. We also considered hypercementosis, dens in dens, and agenesis. We test intraobserver error by means of intraclass correlation coefficient and analysis of variance of repeated measures. We calculated prevalence by sex, age, geographic subregion, and chronological period. We applied Chi‐square (X²) to test statistical significance of observed differences. Considering the sample as a whole, low prevalence of dental caries (10.27%), abscesses (16.52%), and hypoplasia (10.84%) are coincident with values observed for populations with mixed or hunter‐gathering subsistence strategy. In later late Holocene, high incidence of caries should be considered as indicator of consumption of C4 vegetables or other carbohydrate‐rich vegetables, such as legumes of Prosopis sp. Also, moderate values of dental enamel hypoplasia should be related with metabolic‐systemic stress episodes. Summarizing, these results are coincident with isotopic, archaeological, and ethnohistorical evidences which suggest climatic, social, and demographic pressures that might have affected the lifestyle of these populations before the Spanish conquest. Copyright © 2012 John Wiley & Sons, Ltd.     

Dental Remains from the Middle Paleolithic Layers of Altai Cave Sites*

Two Middle Paleolithic cave sites in the Altai – Okladnikov and Chagyrskaya – have yielded dental remains (mostly isolated teeth) of individuals of various ages. A newly discovered mandibular fragment with teeth from Chagyrskaya Cave reveals a Neanderthal trait combination: anterior fossa and epicristid (midtrigonid crest) on molars, metaconid and crest on premolars. The totality of dental traits support the conclusion previously drawn on the basis of postcranial characters: Altai Neanderthals appear to be intermediate between other Eurasian Neanderthals and anatomically modern humans.     

Identification of Areca catechu (Betel Nut) Residues on the Dentitions of Bronze Age Inhabitants of Nui Nap,Northern Vietnam

The dentitions of 31 individuals excavated from the Bronze Age site Nui Nap, Thanh Hoa province, Vietnam were examined for the presence of Areca catechu (betel nut) residues. The chief investigatory method involved GC/MS analysis of a dark reddish-brown stain commonly observed on the labial aspect of the anterior teeth of individuals from this site. The results of this work indicate that these teeth were stained by way of betel nut. Enamel surface morphology and the distribution of staining suggests purposeful application of betel nut residues to the teeth, perhaps for aesthetic reasons.     

Reconstructing dietary and environmental history from enamel isotopic analysis: time resolution of intra‐tooth sequential sampling

The carbon and oxygen isotopic composition of the mineral phase of tooth enamel is linked to diet and environment. Enamel is not remodelled once formed. Several studies of intra‐tooth isotopic variability in hypsodont mammal teeth have involved sequential sampling of enamel in order to detect changes in diet and environment during tooth formation. The possibility of exploring individual history opens the door to many applications, particularly in palaeoenvironment and herd management reconstruction. However, previous histological investigations have shown that enamel mineralization is a progressive and discontinuous process. The goal of the present study is to determine if this pattern significantly influences the time resolution of an intra‐tooth sequential sampling. Isotopic analyses (δ¹³C) were performed on tooth enamel from steers (Bos taurus) that had changed from a C₃ plant‐based diet to a C₄ plant‐based diet with very different carbon isotopic compositions. The change of diet was reflected in the mineral phase of enamel. The pattern of intra‐tooth isotopic variation suggests that completion of enamel mineralization required six to seven months. Such a lag in enamel mineralization will decrease the time resolution of enamel sequential sampling. The effects of prolonged mineralization of enamel have to be considered when interpreting patterns of intra‐tooth isotopic variations. Copyright © 2002 John Wiley & Sons, Ltd.     

Do silica phytoliths really wear mammalian teeth?

There is considerable literature suggesting that silica (opal) phytoliths cause dental enamel microwear in mammals. Much of this literature cites a single study from 1959 as evidence that silica phytoliths are harder than mammalian tooth enamel and so have the potential to cause dental microwear. No other studies using similar methodology have actually confirmed whether phytoliths are harder than dental enamel.