Investigating the demographic history of Japan using ancient oral microbiota.

While microbial communities in the human body (microbiota) are now commonly associated with health and disease in industrialised populations, we know very little about how these communities co-evolved and changed with humans throughout history and deep prehistory. We can now examine these communities by sequencing ancient DNA preserved within calcified dental plaque (calculus), providing insights into the origins of disease and their links to human history. Here, we examine ancient DNA preserved within dental calculus samples and their associations with two major cultural periods in Japan: the Jomon period hunter-gatherers approximately 3000 years before present (BP) and the Edo period agriculturalists 400-150 BP. We investigate how human oral microbiomes have changed in Japan through time and explore the presence of microorganisms associated with oral diseases (e.g. periodontal disease, dental caries) in ancient Japanese populations. Finally, we explore oral microbial strain diversity and its potential links to ancient demography in ancient Japan by performing phylogenomic analysis of a widely conserved oral species-Anaerolineaceae oral taxon 439. This research represents, to our knowledge, the first study of ancient oral microbiomes from Japan and demonstrates that the analysis of ancient dental calculus can provide key information about the origin of non-infectious disease and its deep roots with human demography. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.

Assessing subsistence and its relationship to cultural complexity in the late prehistoric upper Midwest: A new perspective provided by dental health.

OBJECTIVE: Previous researchers have assumed that the Late Prehistoric Oneota were less reliant on maize agriculture than their Middle Mississippian neighbors to the south. This assumption is based on the idea that intensive maize agriculture is related to sociopolitical complexity, and that the climate of the Great Lakes region was less conducive to full-scale agriculture than that of the American Bottom. Here, we assess the diet of the Oneota using dental pathology to test the hypothesis that the Oneota in Eastern Wisconsin were highly reliant on maize agriculture. MATERIALS AND METHODS: To test our hypothesis, skeletal remains representing 187 individuals and 1,102 teeth were examined from nine Oneota sites from the Middle Fox and Koshkonong Localities, as well as the Late Woodland/Middle Mississippian site of Aztalan. Dental caries, antemortem tooth loss (AMTL), and dental abscesses were assessed for each individual in the sample. Dental pathologies in the Oneota groups were compared to each other based on Locality and to the Aztalan population using chi-squared tests. RESULTS: Dental caries rates for the Oneota, based on the tooth count approach, were observed at 16.8% for the Middle Fox Locality, and 49% for the Koshkonong Locality. Comparatively, the Late Woodland/Middle Mississippian population from Aztalan had a tooth count rate of 19.5%. AMTL rates were similar across samples. Dental abscessing was universally low. DISCUSSION: The relatively high rate of dental caries among the Oneota is comparable to Middle Mississippian populations from throughout the Midwest, suggesting similar reliance on maize between the groups.

Earliest evidence of caries lesion in hominids reveal sugar-rich diet for a Middle Miocene dryopithecine from Europe.

The formation of dental caries is mainly caused by dietary habits and therefore, may contain information for dietary reconstructions of fossil hominids. This study investigates the caries lesion in the 12.5 Ma old type specimen of Dryopithecus carinthiacus Mottl 1957 (Primates, Hominidae) from St. Stefan (Austria). Potential food sources are identified on associated palynological data, which allow conclusions about food quality, sugar availability and the hominid metabolism during the Middle Miocene. Using micro computed tomography (µCT) and scanning electron microscopy (SEM) we provide a detailed analysis and characterization of the individuals' caries type. Its lesion is compared with a dataset of 311 wild chimpanzees, indicating morphological and etiological differences in caries formation between both species. The affected molar of D. carinthiacus reveals features known from severe dental caries in humans: (1) Cavitation with steep walls and smooth surface; (2) Reparative dentine at the roof of the pulp chamber; (3) Sclerotic dentine below the cavitation; (4) Association with dental calculus and (5) Unilateral usage of the healthy right tooth row. Its advanced primary caries, initiating on the intact enamel surface, indicates a frequent intake of highly cariogenic sugar-rich fruits, which likely exceeds the frugivory of extant chimpanzees. This finding corresponds with the associated palynological record, which infers a habitat with nearly year-round supply (9-10 months/year) of high quality foods (>carbohydrates; < fibers). Our conclusions challenge the model of a step-wise increase in dietary quality during hominid evolution and support the uricase hypothesis, which discusses the hominid autapomorphy of a fructose-based fat accumulation for periods of starvation. This model receives further validation by the identification of soft-tissue preservation, interpreted as fossilized white adipose cells, in the articulated hominid skeleton of Oreopithecus bamboli from Italy.

Exploring sex differences in diets and activity patterns through dental and skeletal studies in populations from ancient Corinth, Greece.

Sex and temporal differences are assessed in relation to dietary habits and activity patterns in three ancient populations from Corinth, Greece. The skeletal sample spans time from the Geometric to the Early Byzantine Period (9th c. BCE-5th c. CE). Dental caries and tooth wear have been proven to be reliable dietary indicators. Similarly, spinal osteoarthritis, spinal facet remodeling and Schmorl's nodes, have been used to infer activity patterns.

The dawn of dentistry in the late upper Paleolithic: An early case of pathological intervention at Riparo Fredian.

OBJECTIVES: Early evidence for the treatment of dental pathology is found primarily among food-producing societies associated with high levels of oral pathology. However, some Late Pleistocene hunter-gatherers show extensive oral pathology, suggesting that experimentation with therapeutic dental interventions may have greater antiquity. Here, we report the second earliest probable evidence for dentistry in a Late Upper Paleolithic hunter-gatherer recovered from Riparo Fredian (Tuscany, Italy). MATERIALS AND METHODS: The Fredian 5 human consists of an associated maxillary anterior dentition with antemortem exposure of both upper first incisor (I1 ) pulp chambers. The pulp chambers present probable antemortem modifications that warrant in-depth analyses and direct dating. Scanning electron microscopy, microCT and residue analyses were used to investigate the purported modifications of external and internal surfaces of each I1 . RESULTS: The direct date places Fredian 5 between 13,000 and 12,740 calendar years ago. Both pulp chambers were circumferentially enlarged prior to the death of this individual. Occlusal dentine flaking on the margin of the cavities and striations on their internal aspects suggest anthropic manipulation. Residue analyses revealed a conglomerate of bitumen, vegetal fibers, and probable hairs adherent to the internal walls of the cavities. DISCUSSION: The results are consistent with tool-assisted manipulation to remove necrotic or infected pulp in vivo and the subsequent use of a composite, organic filling. Fredian 5 confirms the practice of dentistry-specifically, a pathology-induced intervention-among Late Pleistocene hunter-gatherers. As such, it appears that fundamental perceptions of biomedical knowledge and practice were in place long before the socioeconomic changes associated with the transition to food production in the Neolithic.

Dental worm disease.

During human evolution, the period in which groups of humans stopped harvesting fruits and seeds growing wild and introduced the cultivation of cereals as well as the domestication of animals represents a very important event. This circumstance had a considerable impact on human pathocenosis, increasing the risk of infectious diseases of animal origin. The aim of this review was to summarise the archaeological and palaeo-pathological evidence in the literature concerning this topic. Starting from early prehistory (about 1.5 million years ago) up to the historical period, several authors have described the changes in human habits and the consequent changes in food supply, leading to the transition from a protein- to a carbohydrate-rich diet across a broad interval of time. This led to additional problems for human health. The increased accumulation of carbohydrate debris in the odonto-stomatological apparatus, without the appropriate use of hygiene in the oral cavity, increased the risk of infectious disease involving the mouth. Therefore, since the Neolithic period there has been a higher risk of tooth caries, abscesses, deep infection of the teeth roots, reaching also the mandibular and maxillary bone. Several hypotheses have been proposed by the distinct civilizations, which have alternated in the different ages, to explain the cause of these human health problems, including the idea that a "dental worm" could be involved in this process, such as in the Sumerian period. We describe and discuss further modifications of this theory, developed in Egypt, Assyria, Babylon, China, Greece, in Etruscan cities and in Rome in ancient times as well as in the Middle Ages, and the evolution of scientific thought on this topic in the past 300 years. In addition, the results of some palaeo-pathological studies, which were performed on human remains, such as the maxillary bone and teeth, mainly in different geographical areas in Italy, are examined and reported.

Dental health in antique population of Vinkovci - Cibalae in Croatia (3rd-5th century).

Roman city Cibalae (Vinkovci) - the birthplace of Roman emperors Valentinian I and Valens was a very well developed urban ares in the late antique what was evidenced by numerous archaeological findings. The aim of this paper is to get insight in dental health of antique population of Cibalae. One hundred individuals with 2041 teeth dated to 3rd - 5th century AD have been analyzed for caries, antemortem tooth loss, periapical diseases and tooth wear. Prevalence of antemortem tooth loss was 4.3% in males, 5.2% in females. Prevalence of caries per tooth was 8.4% in males, 7.0% in females. Compared to other Croatian antique sites, ancient inhabitants of Roman Cibalae had rather good dental health with low caries prevalence and no gender differences. Statistically significant difference was found between males in females in the prevalence of periapical lesions and degree of tooth wear. Periapical lesions were found only in males.

[The historical materials of stomatology in the All Things, Prescriptions of Fifty-two Diseases and Yinshu].

All Things, Prescriptions of Fifty-two Diseases and Yinshu were three bamboo and silk medical manuscripts which form-time was no later than the late Warring States period. From the visible bamboo and silk, the ancient Chinese knew the relationships between some drugs and the volume of saliva and used compound drugs to treat dental caries. Some oral and maxillofacial diseases, such as inflammation and pain of oromaxillo-facial region, temporomandibular dislocation and the methods of treatment were descriped in these books. Mouth-rinsing and tooth-picking were the more often used methods for maintaining oral hygiene. Kouchi(clicking the tooth)was also used for prevention and/or treatment of caries. Most of these knowledge were the first documents in ancient China.

Biocultural implications of oral pathology in an ancient Central California population.

Bioarchaeologists have long noted two unusual trends in the dentitions of prehistoric Native Californian populations: high rates of wear and low prevalence of caries. The Central California site of CA-CCO-548 offers a unique opportunity to examine the relationship between oral pathology and extreme dental wear in a large (n = 480), ancient (4,300­3,100 BP), and temporally well-defined population sample. This study specifically examines three interrelated processes of the oral cavity in this population: dental wear, dental caries, and periodontal disease. The results show high levels of dental wear (average of 6.1, Smith system), low frequencies of carious lesions (2.5%), low frequencies of periodontal disease (17.8%), and high frequencies of periapical abscesses (10.7%). The pathological processes examined here have complicated multifactorial etiologies. However, they all share the common primary etiological agents of facultative pathogenic bacteria proliferation in the oral biofilm. Integration of the current etiological explanations for infections of the oral cavity, information from the ethnographic record pertaining to subsistence and activity patterns in Native Californian populations, and statistical analysis of specific disease and wear patterns leads to a novel explanation for the observed pattern of oral pathology in this population sample. Specifically, the introduction of antibacterial compounds through dietary items and non-alimentary tooth use is suggested as the most likely explanation for the unusually low prevalence of dental caries and periodontal disease.

The frequency and distribution of caries among the Iron Age population (about 2200 years BP) buried in the Mausoleum of Emperor Qinshihuang.

OBJECTIVES: The purpose of this study was to assess the prevalence, distribution, and intensity of dental caries in the Iron Age population of northern China in order to increase knowledge about the type of food, dietary habit, and social stratification in this Iron Age people. MATERIALS AND METHODS: The samples analyzed were dental remains of 1548 permanent teeth from 69 male individuals unearthed from the Qin archaeological site of Emperor Qinshihuang's Mausoleum in Lintong (northern China). The sex and the age-at-death of the samples were estimated. RESULTS: Overall frequency of antemortem tooth loss in the samples was 0.8%. The proportion of individuals with at least one carious tooth was 65.2%, and the frequency of carious lesions was 9.4%, both showing a trend to rise as age increased. Data obtained on dental caries and antemortem tooth loss provided a corrected rate of 9.5% of teeth with caries. The most frequent carious lesions were occlusal lesions (2.6%), followed by interproximal (2.5%) and buccal/lingual lesions (1.0%). Tooth type analysis showed that molars had the highest percentage of caries (18.6%), followed by premolars (4.5%), canines (3.0%), and incisors (3.0%). The total SRCI was 1.6, increasing with age. CONCLUSIONS: These findings indicate that dental caries may be related, at least in part, to the subsistence and diet of this Iron Age population.

The neolithic demographic transition and oral health: The Southeast Asian experience.

The purpose of this article is to present new oral health data from Neolithic An Son, southern Vietnam, in the context of (1) a reassessment of published data on other Neolithic, Bronze, and Iron Age Southeast Asian dental series, and (2) predictions of the Neolithic Demographic Transition (NDT). To this end, frequencies for three oral conditions (caries, antemortem tooth loss, and alveolar lesions) were investigated for seven Southeast Asian adult dental series from Thailand and Vietnam with respect to time period, age-at-death and sex. A clear pattern of elevated rates for oral disease in the Neolithic followed by a marked improvement in oral health during the Bronze and Iron Ages was observed. Moreover, rates of caries and antemortem tooth loss for females were almost without exception higher than that for males in all samples. The consensus view among Southeast Asian bioarchaeologists that oral health did not decline with the adoption/intensification of agriculture in Southeast Asia, can no longer be supported. In light of evidence for (1) the low cariogenicity of rice; (2) the physiological predisposition of females (particularly when pregnant) to poorer oral health; and (3) health predictions of the NDT model with respect to elevated levels of fertility, the most plausible chief explanation for the observed patterns in oral health in Southeast Asia is increased levels of fertility during the Neolithic, followed by a decline in fertility during the subsequent Bronze and Iron Ages.

Oral pathologies of the Neolithic Iceman, c.3,300 BC.

The famous Iceman 'Ötzi' (South Tyrol Museum of Archaeology, Bolzano, Italy), a Neolithic human ice mummy, offers a unique opportunity to study evolutionary aspects of oral disease. The aim of this study was to assess, for the very first time, his oral cavity, which surprisingly had never been examined systematically. Based on several computed tomography (CT) scans from 1991 onwards and on macroscopic investigation, only a few findings, such as a central maxillary diastema, heavy abrasions, and missing wisdom teeth, were known. We re-evaluated the latest CT scans from 2005 and found various oral pathologies. In line with the increase of tooth decay in the Neolithic - because of diet change in this historic transition phase - several carious lesions were found, one of which penetrated into the dental pulp. In accordance with the Iceman's troubled life, as several injuries on his body and his violent death attest, mechanical trauma of one of his upper front teeth is evident. Finally, the poor periodontal condition of the Iceman's dentition (e.g. loss of alveolar bone), indicative of periodontitis, was assessed. These oral pathological findings in the Iceman's dentition provide a unique glimpse into the evolutionary history of oral conditions.

Dento-alveolar features and diet in an Etruscan population (6th-3rd c. B.C.) from northeast Italy.

OBJECTIVES: The purpose of this study was to assess the prevalence of some dento-alveolar features (caries, dental calculus, tooth wear, enamel hypoplasia, abscesses, retraction of the alveolar bone, chipping, and ante mortem tooth loss) on an Iron Age sample from the Etruscan necropolis of Spina (North-Eastern Italy) and to make a relation with dietary evidence found in the archaeological records. These dental features were used to evaluate the oral health status and dietary habits with the aim of shedding light on the lifestyle and living conditions of this population. MATERIALS AND METHODS: The sample analysed consisted of 680 permanent teeth from 80 burials. RESULTS: Overall, individuals at Spina exhibited a low incidence of caries, abscesses and ante mortem tooth loss, high calculus rates and severe attrition, suggesting a subsistence pattern based on a mixture of fishing, pastoralism and agriculture. The low incidence of hypoplasia was probably related to their good nutritional conditions and weak metabolic stresses during early childhood. CONCLUSIONS: These findings, quite similar to those of Etruscans from other parts of Italy, are very different from those of other populations living in the same territory during the same time. This pattern is indicative of a general good health status in this Iron Age population and may be related, at least in part, to the Etruscan diet.

Dental caries in Rome, 50-100 AD.

Scarce information exists on the clinical features of dental caries in the Imperial Roman population and no structural data on caries lesions from this period have so far been published. We report on the findings of 86 teeth (50-100 AD) found during archaeological excavations of the temple of Castor and Pollux in the Forum Romanum. We found that nearly all teeth had large carious cavities extending into the pulp. The distribution and size of the caries lesions were similar to those found in contemporary adult populations in Africa and China living without access to dental care. Most lesions had a hypermineralized zone in the dentin at the advancing front of the carious cavities as revealed by micro-computed tomography. This biological dentin reaction combined with the morphology of the cavities might indicate that some temporary topical pain relief and intervention treatment slowed down the rate of lesion progression. This is indirectly supported by examination of cavities of similar size and depth from a contemporary population without access to dental health care. In contrast to the lesions in the Roman teeth, these lesions did not exhibit a hypermineralized dentin reaction. We investigated whether the Pb isotopic composition of enamel and/or dentin of a single tooth matched that of a sample of an ancient Forum water lead pipe. The Pb isotopic composition of the tooth did not match that of the tube, suggesting that the subjects were exposed to different Pb sources during their lifetime other than the lead tubes.

Dental caries prevalence as a product of agriculture and subsistence pattern at the Yean-ri site, South Korea.

Yean-ri human skeletal remains from South Korea have been dated to the fourth to seventh century AD. They have morphological similarities to immigrants of the Yayoi period excavated in northern Kyushu and Yamaguchi prefecture in Japan. The overall dental caries prevalence was 8.1% in the Yean-ri skeletal remains, indicating a much lower prevalence than that of most Yayoi immigrant skeletal remains from Japan, although similar to that of the Kofun people (8.3%) in Japan. There was no significant difference in the dental caries prevalence between the males and females of the same age group, but there were differences in the prevalence by age. The late middle age and elderly males and females had significantly higher dental caries prevalence than the early middle age males and females, indicating increased prevalence with age. Root caries prevalence tended to increase in old age. The percentage of root caries increased, accounting for 80% of all caries in Yean-ri human skeletal remains. Agriculture is believed to have arisen approximately 3,000 years ago in Korea. Therefore, agriculture was practiced during this period, but since the Yean-ri tumuli are from coastal areas, their diet may have retained a significant marine component. Additionally, caries prevalence was not very high in Nukdo human remains (ca. 2100-2000 BC) in Korea. We speculate that they maintained subsistence activities suitable for their environment despite their knowledge of agriculture. This hypothesis is supported by differences in the caries prevalence between excavation sites of the Yayoi and Kofun periods in Japan.

Prevalence of dental caries and tooth wear in a Neolithic population (6700-5600 years BP) from northern China.

OBJECTIVES: The purpose of this study was to assess the prevalence, distribution and intensity of dental caries as well as tooth wear in Neolithic population of northern China to increase our knowledge about the type of food, dietary habit and social stratification in this Neolithic population. MATERIALS AND METHODS: The samples analysed were dental remains of 1007 permanent teeth from 79 adult individuals, who were excavated from three Yangshao archaeological sites in the Xi'an district and adjacent Counties (northern China). The sex and the age-at-death of the samples were estimated. RESULTS: The frequency of antemortem tooth loss in the samples was 1.6%. The proportion of individuals with at least one carious tooth reached 41.8%, and the frequency of carious lesion was 5.7%. The most frequent carious lesions were occlusal lesions (4.4%), followed by interproximal (1.4%) and buccal/lingual lesions (0.4%). All 79 individuals were affected by attrition (100%) with various degrees of dental wear observed. The anterior teeth were much more worn than the posterior ones. The frequency of caries in men (3.9%) was significantly lower than that in women (8.1%), but the prevalence of tooth wear in men (99.0%) was significantly higher than that in women (95.2%). CONCLUSIONS: These findings indicate that both caries and tooth wear may be related to the subsistence and diet of this Neolithic population.

St Apollonia's tooth--a relic in the cathedral treasury in Rab (Croatia).

AIM: To anatomically identify and describe the changes on the tooth of St Apollonia which is kept as a relic in Rab (Croatia). SOURCES AND METHODS: Reviewing relevant literature, macroscopic examination of the tooth in the reliquary, photographing and further examining the enlarged photos. RESULTS: The tooth in question is the first upper right premolar. Observed pathological change is type II enamel lesion, i.e. cervical or gingival caries. Other discovered characteristics are enamel fracture on the distoaproximal surface, shallow fracture on the occlusal third of the crown and two enamel formations, a cluster of smooth and shiny enamel surfaces. CONCLUSION: Attention is drawn to a relic that was previously virtually unknown. It is presented how important this relic is for Christian and ethnomedical tradition. Additionally, anatomical determination and the description of pathoanatomical changes are used to affirm the anthropological approach as one of the prerequisites in the attempt to scientifically evaluate the relic phenomenon.