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Restoring the correct masticatory function of broken teeth is the basis of dental crown prosthesis rehabilitation. However, it is a challenging task primarily due to the complex and personalized morphology of the occlusal surface. In this article, we address this problem by designing a new two-stage generative adversarial network (GAN) to reconstruct a dental crown surface in the data-driven perspective. Specifically, in the first stage, a conditional GAN (CGAN) is designed to learn the inherent relationship between the defective tooth and the target crown, which can solve the problem of the occlusal relationship restoration. In the second stage, an improved CGAN is further devised by considering an occlusal groove parsing network (GroNet) and an occlusal fingerprint constraint to enforce the generator to enrich the functional characteristics of the occlusal surface. Experimental results demonstrate that the proposed framework significantly outperforms the state-of-the-art deep learning methods in functional occlusal surface reconstruction using a real-world patient database. Moreover, the standard deviation (SD) and root mean square (RMS) between the generated occlusal surface and the target crown calculated by our method are both less than 0.161 mm. Importantly, the designed dental crown have enough anatomical morphology and higher clinical applicability.

Objectives Carabelli is a nonmetric dental trait variably expressed as a small pit to a prominent cusp in the maxillary molars of modern humans. Investigations on the occurrence and expression rates of this trait have been conducted extensively, tracing its origin to genetic sources. However, there remains a lack of understanding about its potential role in chewing. In this study, we examine molar macrowear with the aim of reconstructing Carabelli trait occlusal dynamics occurring during chewing. Methods We have examined 96 deciduous and permanent maxillary molars of children and young adults from Yuendumu, an Australian Aboriginal population that was at an early stage of transition from a nomadic and hunter-gatherer way of life to a more settled existence. We apply a well-established method, called Occlusal Fingerprint Analysis, which is a digital approach for analyzing dental macrowear allowing the reconstruction of jaw movements required to produce wear pattern specific to each tooth. Results Carabelli trait slightly enlarges the surface functional area, especially in those molars where this feature is expressed in its cuspal form and it is closer to the occlusal plane. Moreover, the highly steep contact planes would also indicate that Carabelli wear areas contribute to increasing the shearing abilities of the occluded teeth, which are particularly important when processing fibrous and tough foods. Conclusions The macrowear analysis suggests that Carabelli trait in the Aboriginal people from Yuendumu slightly enhanced occlusion and probably played some functional role during mastication. Future biomechanical and microwear analyses could provide additional information on the mechanical adaptation of Carabelli trait in modern human dentition.

[Objectives] Dietary diversity in primates is reflected in their dental morphology, with differences in size and shape of teeth. The objective of this study is to investigate the relationship between molar morphology and macrowear patterns in Pongo, Gorilla, and Pan to obtain dietary information., [Methods] We have examined 68 second lower molars using the Occlusal Fingerprint Analysis method including 18 chimpanzees, 28 gorillas, and 22 orangutans. We selected only molars from wildshot specimens characterized by a moderate degree of wear. High-resolution digital models of teeth were created using a white scanning light system with a resolution of 45 μm., [Results] The macrowear patterns of Pan were significantly different from those of Gorilla and of Pongo, differences that are mostly due to shearing wear. Gorilla and Pongo macrowear patterns are dominated by phase II areas, followed by lingual phase I facets, while in Pan we observe a significant increase in buccal phase I facets. The latter group also displays the highest macrowear variation across the sample examined in this study., [Conclusions] The molar macrowear patterns of the great apes analyzed in this study did not confirm our initial hypothesis of finding larger crushing and grinding areas in Pongo and more shearing wear in Gorilla. Pan shows the most variable macrowear, which is probably associated with their more flexible diet. The similarity between Pongo and Gorilla macrowear patterns may be due to a larger intake of mechanically challenging foods that could obfuscate dietary wear signals generated by softer foods., Australian Research Council Discovery Program, Grant/Award Number: DP190100465; Deutsche Forschungsgemeinschaft, Grant/Award Number: DFG Research Unit 771; H2020 European Research Council, Grant/Award Number: 724046; Max Planck Society

Objective. Restoring the correct masticatory function of partially edentulous patient is a challenging task primarily due to the complex tooth morphology between individuals. Although some deep learning-based approaches have been proposed for dental restorations, most of them do not consider the influence of dental biological characteristics for the occlusal surface reconstruction. Description. In this article, we propose a novel dual discriminator adversarial learning network to address these challenges. In particular, this network architecture integrates two models: a dilated convolutional-based generative model and a dual global-local discriminative model. While the generative model adopts dilated convolution layers to generate a feature representation that preserves clear tissue structure, the dual discriminative model makes use of two discriminators to jointly distinguish whether the input is real or fake. While the global discriminator focuses on the missing teeth and adjacent teeth to assess whether it is coherent as a whole, the local discriminator aims only at the defective teeth to ensure the local consistency of the generated dental crown. Results. Experiments on 1000 real-world patient dental samples demonstrate the effectiveness of our method. For quantitative comparison, the image quality metrics are used to measure the similarity of the generated occlusal surface, and the root mean square between the generated result and the target crown calculated by our method is 0.114 mm. In qualitative analysis, the proposed approach can generate more reasonable dental biological morphology. Conclusion. The results demonstrate that our method significantly outperforms the state-of-the-art methods in occlusal surface reconstruction. Importantly, the designed occlusal surface has enough anatomical morphology of natural teeth and superior clinical application value.

Human dentin consists of a primary layer produced during tooth formation in early childhood and a second layer which first forms upon tooth eruption and continues throughout life, termed secondary dentin (SD). The effect of attrition on SD formation was considered to be confined to the area subjacent to attrition facets. However, due to a lack of three-dimensional methodologies to demonstrate the structure of the SD, this association could not be determined. Therefore, in the current study, we aimed to explore the thickening pattern of the SD in relation to the amount of occlusal and interproximal attrition. A total of 30 premolars (50–60 years of age) with varying attrition rates were evaluated using micro-computerized tomography. The results revealed thickening of the SD below the cementoenamel junction (CEJ), mostly in the mesial and distal aspects of the root (p &lt, 0.05). The pattern of thickening under the tooth cervix, rather than in proximity to attrition facets, was consistent regardless of the attrition level. The amount of SD thickening mildly correlated with occlusal attrition (r = 0.577, p &lt, 0.05) and not with interproximal attrition. The thickening of the SD below the CEJ coincided with previous finite element models, suggesting that this area is mostly subjected to stress due to occlusal loadings. Therefore, we suggest that the SD formation might serve as a compensatory mechanism aimed to strengthen tooth structure against deflection caused by mechanical loading. Our study suggests that occlusal forces may play a significant role in SD formation.

Before the end of the Last Glacial Maximum (LGM, ∼16.5 ka ago) set in motion major shifts in human culture and population structure, a consistent change in lithic technology, material culture, settlement pattern, and adaptive strategies is recorded in Southern Europe at ∼18–17 ka ago. In this time frame, the landscape of Northeastern Italy changed considerably, and the retreat of glaciers allowed hunter-gatherers to gradually recolonize the Alps. Change within this renewed cultural frame (i.e., during the Late Epigravettian phase) is currently associated with migrations favored by warmer climate linked to the Bølling-Allerød onset (14.7 ka ago), which replaced earlier genetic lineages with ancestry found in an individual who lived ∼14 ka ago at Riparo Villabruna, Italy, and shared among different contexts (Villabruna Cluster). Nevertheless, these dynamics and their chronology are still far from being disentangled due to fragmentary evidence for long-distance interactions across Europe. Here, we generate new genomic data from a human mandible uncovered at Riparo Tagliente (Veneto, Italy), which we directly dated to 16,980–16,510 cal BP (2σ). This individual, affected by focal osseous dysplasia, is genetically affine to the Villabruna Cluster. Our results therefore backdate by at least 3 ka the diffusion in Southern Europe of a genetic component linked to Balkan/Anatolian refugia, previously believed to have spread during the later Bølling/Allerød event. In light of the new genetic evidence, this population replacement chronologically coincides with the very emergence of major cultural transitions in Southern and Western Europe., The research was supported by the European Union through the European Research Council under the European Union’s Horizon 2020 Research and Innovation Programme (grant agreement no. 724046 – Success awarded to S.B., http://www.erc-success.eu; grant agreement no. 803147 Resolution awarded to S.T., https://site.unibo.it/resolution-erc/en) as well as through the European Regional Development Fund (project no. 2014–2020.4.01.16–0030 to C.L.S. and T.S.) and projects no. 2014-2020.4.01.16-0024 and MOBTT53 (L.P.), by the Estonian Research Council personal research grant (PRG243; C.L.S.), and by UniPd PRID 2019 (L.P.).

OBJECTIVES The primate talus is known to have a shape that varies according to differences in locomotion and substrate use. While the modern human talus is morphologically specialized for bipedal walking, relatively little is known on how its morphology varies in relation to cultural and environmental differences across time. Here we compare tali of modern human populations with different subsistence economies and lifestyles to explore how cultural practices and environmental factors influence external talar shape. MATERIALS AND METHODS The sample consists of digital models of 142 tali from 11 archaeological and post-industrial modern human groups. Talar morphology was investigated through 3D (semi)landmark based geometric morphometric methods. RESULTS Our results show distinct differences between highly mobile hunter-gatherers and more sedentary groups belonging to a mixed post-agricultural/industrial background. Hunter-gatherers exhibit a more "flexible" talar shape, everted posture, and a more robust and medially oriented talar neck/head, which we interpret as reflecting long-distance walking strictly performed barefoot, or wearing minimalistic footwear, along uneven ground. The talus of the post-industrial population exhibits a "stable" profile, neutral posture, and a less robust and orthogonally oriented talar neck/head, which we interpret as a consequence of sedentary lifestyle and use of stiff footwear. DISCUSSION We suggest that talar morphological variation is related to the adoption of constraining footwear in post-industrial society, which reduces ankle range of motion. This contrasts with hunter-gatherers, where talar shape shows a more flexible profile, likely resulting from a lack of footwear while traversing uneven terrain. We conclude that modern human tali vary with differences in locomotor and cultural behavior.

Objectives Palate morphology is constantly changing throughout an individual's lifespan, yet its asymmetry during growth is still little understood. In this research, we focus on the study of palate morphology by using 3D geometric morphometric approaches to observe changes at different stages of life, and to quantify the impact of directional and fluctuating asymmetry on different areas at different growth stages. Materials and Methods The sample consists of 183 individuals (1–72 years) from two identified human skeletal collections of 19th and early 20th Century Italian contexts. A 3D‐template of 41 (semi)landmarks was applied on digital palate models to observe morphological variation during growth. Results Asymmetrical components of the morphological structure appears multidirectional on the entire palate surface in individuals, Directional and fluctuating asymmetry of human palate.

The analysis of dental wear, at both the microscopic and macroscopic scale, is one of the most widely used tools in archeology and anthropology to reconstruct the diet and lifestyle of past human populations. Biomechanical studies have indicated that tooth wear helps to dissipate the mechanical load over the crown surface, thus reducing the risk of tooth fracture. To date, there are only a few studies that have examined functional tooth wear variation in modern humans. Here we propose to study masticatory efficiency through the use of the Occlusal Fingerprint Analysis method, a well-developed digital approach that allows the reconstruction of the occlusal dynamics occurring during mastication. The aim of this study is to provide the first longitudinal quantitative data of molar and premolar macrowear patterns within a functional context. We examined the mixed and permanent dentition of one Australian Aboriginal child (from ages 8 to 17) from Yuendumu, using high-resolution surface scans of dental casts including both upper and lower arches. Our results suggest that the occlusal macrowear patterns of this individual did not significantly change through time. Occlusal contact parameters such as functional area, inclination and direction remain relatively unaltered throughout childhood and adolescence, indicating little change in the masticatory function of this individual. The functional tooth wear pattern in this individual did not change longitudinally indicating the degree of masticatory efficiency has most probably remained unaltered.

Reconstructing the detailed dietary behaviour of extinct hominins is challenging1—particularly for a species such as Australopithecus africanus, which has a highly variable dental morphology that suggests a broad diet2,3. The dietary responses of extinct hominins to seasonal fluctuations in food availability are poorly understood, and nursing behaviours even less so; most of the direct information currently available has been obtained from high-resolution trace-element geochemical analysis of Homo sapiens (both modern and fossil), Homo neanderthalensis4 and living apes5. Here we apply high-resolution trace-element analysis to two A. africanus specimens from Sterkfontein Member 4 (South Africa), dated to 2.6–2.1 million years ago. Elemental signals indicate that A. africanus infants predominantly consumed breast milk for the first year after birth. A cyclical elemental pattern observed following the nursing sequence—comparable to the seasonal dietary signal that is seen in contemporary wild primates and other mammals—indicates irregular food availability. These results are supported by isotopic evidence for a geographical range that was dominated by nutritionally depauperate areas. Cyclical accumulation of lithium in A. africanus teeth also corroborates the idea that their range was characterized by fluctuating resources, and that they possessed physiological adaptations to this instability. This study provides insights into the dietary cycles and ecological behaviours of A. africanus in response to food availability, including the potential cyclical resurgence of milk intake during times of nutritional challenge (as observed in modern wild orangutans5). The geochemical findings for these teeth reinforce the unique place of A. africanus in the fossil record, and indicate dietary stress in specimens that date to shortly before the extinction of Australopithecus in South Africa about two million years ago.

Many aspects of diet and behaviour can be gleaned from dental wear, including environmental conditions, food-fracture properties, food processing techniques, and cultural habits. Specifically, the angulation (flat vs. steep) of molar wear has been used as an indicator of food toughness and has also been implicated in the use of grinding stones and pottery in food processing. In this work, we focus on the sequential phases of the power stroke of mastication in a functional way, measuring the inclination of molar wear facets through the occlusal fingerprint analysis method. Specifically, we have calculated the angulation of wear facets in upper and lower molars of Palaeolithic humans, extant hunter-gatherers, and proto-farmers to discern differences between groups with different diets. Contrary to previous analyses, our study shows that the molars of Late Pleistocene specimens are characterized by significantly steeper angles than those of modern hunter-gatherers. The flat molar wear found in the latter group could be related to the excessive mixture of exogenous materials accidentally introduced into their foods, as indicated by ethnographic evidence. On the contrary, the steep wear angles characterizing the Palaeolithic group are probably associated with the consumption of a less abrasive diet, which could be ultimately due to food preparation techniques that incorporated less dust and grit into their diets.

Objectives The analysis of prehistoric human dietary habits is key for understanding the effects of paleoenvironmental changes on the evolution of cultural and social human behaviors. In this study, we compare results from zooarchaeological, stable isotope and dental calculus analyses as well as lower second molar macrowear patterns to gain a broader understanding of the diet of three individuals who lived between the end of the Late Pleistocene and the Early Holocene (ca., 17–8 ky cal BP) in the Eastern Alpine region of Italy. Materials and methods We analyze individuals buried at the sites of Riparo Tagliente (Verona), Riparo Villabruna, and Mondeval de Sora (Belluno). The three burials provide a unique dataset for diachronically exploring the influence of climatic changes on human subsistence strategies. Results Isotopic results indicate that all individuals likely relied on both terrestrial and freshwater animal proteins. Even though dental calculus analysis was, in part, hindered by the amount of mineral deposit available on the teeth, tooth macrowear study suggests that the dietary habits of the individuals included plant foods. Moreover, differences in macrowear patterns of lower second molars have been documented between Neanderthals and modern humans in the present sample, due to a prevalence of Buccal wear among the former as opposed to higher values of Lingual wear in modern human teeth. Discussion Isotopic analyses have emphasized the contribution of animal proteins in the diet of the three foragers from the Eastern Alpine region. The possible intake of carbohydrate-rich plant foods, suggested by the retrieval of plant remains in dental calculus, is supported by the signal of macrowear analysis. Moreover, the latter method indicates that the distribution of macrowear in lower second molars (M2s) allows us to discriminate between Neanderthals and modern humans within the present reference sample. Overall, our results show these three prehistoric hunter-gatherers were well adapted to the environment in which they lived exploiting many natural resources.

The adoption of bipedalism is a key benchmark in human evolution that has impacted talar morphology. Here, we investigate talar morphological variability in extinct and extant hominins using a 3D geometric morphometric approach. The evolutionary timing and appearance of modern human-like features and their contributions to bipedal locomotion were evaluated on the talus as a whole, each articular facet separately, and multiple combinations of facets. Distinctive suites of features are consistently present in all fossil hominins, despite the presence of substantial interspecific variation, suggesting a potential connection of these suites to bipedal gait. A modern human-like condition evolved in navicular and lateral malleolar facets early in the hominin lineage compared with other facets, which demonstrate more complex morphological variation within Homininae. Interestingly, navicular facet morphology of Australopithecus afarensis is derived in the direction of Homo, whereas more recent hominin species such as Australopithecus africanus and Australopithecus sediba retain more primitive states in this facet. Combining the navicular facet with the trochlea and the posterior calcaneal facet as a functional suite, however, distinguishes Australopithecus from Homo in that the medial longitudinal arch had not fully developed in the former. Our results suggest that a more everted foot and stiffer medial midtarsal region are adaptations that coincide with the emergence of bipedalism, whereas a high medial longitudinal arch emerges later in time, within Homo. This study provides novel insights into the emergence of talar morphological traits linked to bipedalism and its transition from a facultative to an obligate condition.

International audience; Tooth wear is an important feature for reconstructing diet, food processing and cultural habits of past human populations. In particular, occlusal wear facets can be extremely useful for detecting information about diet and non-masticatory behaviors. The aim of this study is to reconstruct the diet and cultural behavior of the Neanderthal specimen Regourdou 1 (Dordogne, Southern France) from the analysis of the macrowear pattern, using the occlusal fingerprint analysis method. In addition, we have also examined whether there is any association between the observed dental macrowear and mandibular bone distribution and root dentine thickness. The posterior dentition of Regourdou 1 is characterized by an asymmetric wear pattern, with the right side significantly more worn than the left. In contrast, the left lower P3 shows a more advanced wear than the right premolar, with unusual semicircular enamel wear facets. The results from occlusal fingerprint analysis of this unique pattern suggest tooth-tool uses for daily task activities. Moreover, the left buccal aspect of the mandibular cortical bone is thicker than its right counterpart, and the left P3 has a thicker radicular dentine layer its antimere. These results show a certain degree of asymmetry in cortical bone topography and dentine tissue that could be associated with the observed dental macrowear pattern. The molar macrowear pattern also suggests that Regourdou 1 had a mixed diet typical of those populations living in temperate deciduous woodlands and Mediterranean habitats, including animal and plant foods. Although this study is limited to one Neanderthal individual, future analyses based on a larger sample may further assist us to better understand the existing relationship between mandibular architecture, occlusal wear and the masticatory apparatus in humans.

International audience

Since the first discovery of Pithecanthropus (Homo) erectus by E. Dubois at Trinil in 1891, over 200 hominid dentognathic remains have been collected from the Early to Middle Pleistocene deposits of Java, Indonesia, forming the largest palaeoanthropological collection in South East Asia. Most of these fossils are currently attributed to H. erectus. However, because of the substantial morphological and metric variation in the Indonesian assemblage, some robust specimens, such as the partial mandibles Sangiran 5 and Sangiran 6a, were formerly variably allocated to other taxa (Meganthropus palaeojavanicus, Pithecanthropus dubius, Pongo sp.). To resolve the taxonomic uncertainty surrounding these and other contentious Indonesian hominid specimens, we used occlusal fingerprint analysis (OFA) to reconstruct their chewing kinematics; we also used various morphometric approaches based on microtomography to examine the internal dental structures. Our results confirm the presence of Meganthropus as a Pleistocene Indonesian hominid distinct from Pongo, Gigantopithecus and Homo, and further reveal that Dubois’s H. erectus paratype molars from 1891 are not hominin (human lineage), but instead are more likely to belong to Meganthropus. Morphometric analyses of hominid teeth from Early to Middle Pleistocene Java reveal that Meganthropus was a Pleistocene Indonesian hominid distinct from Pongo, Gigantopithecus and Homo, and that molars previously assigned to Homo erectus are more likely to belong to Meganthropus.

Supernumerary teeth, or teeth that develop in addition to the normal number of deciduous and permanent dentition, have been widely described in human and nonhuman primates. Most studies have focused on the morphology and on the etiology of supernumerary teeth, and little is known about their occlusal relationships with adjacent and antagonistic teeth, and their effects on individuals’ masticatory efficiency. We analyzed the occlusal wear pattern of an adult male Western lowland gorilla (Gorilla gorilla gorilla) with a fully erupted extra maxillary right premolar. We used a virtual method, occlusal fingerprint analysis, to reconstruct the major mandibular occlusal pathways responsible for the creation of wear facets on the tooth crowns. This approach is based on analysis of facet parameters such as inclination, directions, and areas, all measured using high-resolution 3-D virtual models of dental crowns. The results show unusual wear patterns in the supernumerary premolar and on its antagonist contacts (lower P4 and M1) that cannot be associated with a normal masticatory behavior. Occlusal simulation and kinematic analyses reveal a high level of directional overlapping combined with the absence of common occlusal contacts. This indicates a case of malocclusion that must have caused discomfort in this gorilla when biting or chewing, and may represent the first evidence of bruxism (grinding the teeth and clenching the jaw) in wild great apes.

Reconstructing the detailed dietary behaviour of extinct hominins is challenging1—particularly for a species such as Australopithecus africanus, which has a highly variable dental morphology that suggests a broad diet2,3. The dietary responses of extinct hominins to seasonal fluctuations in food availability are poorly understood, and nursing behaviours even less so; most of the direct information currently available has been obtained from high-resolution trace-element geochemical analysis of Homo sapiens (both modern and fossil), Homo neanderthalensis4 and living apes5. Here we apply high-resolution trace-element analysis to two A. africanus specimens from Sterkfontein Member 4 (South Africa), dated to 2.6–2.1 million years ago. Elemental signals indicate that A. africanus infants predominantly consumed breast milk for the first year after birth. A cyclical elemental pattern observed following the nursing sequence—comparable to the seasonal dietary signal that is seen in contemporary wild primates and other mammals—indicates irregular food availability. These results are supported by isotopic evidence for a geographical range that was dominated by nutritionally depauperate areas. Cyclical accumulation of lithium in A. africanus teeth also corroborates the idea that their range was characterized by fluctuating resources, and that they possessed physiological adaptations to this instability. This study provides insights into the dietary cycles and ecological behaviours of A. africanus in response to food availability, including the potential cyclical resurgence of milk intake during times of nutritional challenge (as observed in modern wild orangutans5). The geochemical findings for these teeth reinforce the unique place of A. africanus in the fossil record, and indicate dietary stress in specimens that date to shortly before the extinction of Australopithecus in South Africa about two million years ago. Trace-element analysis of teeth from the hominin Australopithecus africanus, dated to 2.6–2.1 million years ago, sheds light on the weaning sequence of this species and its responses to seasonal food scarcity

Since the first discovery of Pithecanthropus (Homo) erectus by E. Dubois at Trinil in 1891, over 200 hominid dentognathic remains have been collected from the Early to Middle Pleistocene deposits of Java, Indonesia, forming the largest palaeoanthropological collection in South East Asia. Most of these fossils are currently attributed to H. erectus. However, because of the substantial morphological and metric variation in the Indonesian assemblage, some robust specimens, such as the partial mandibles Sangiran 5 and Sangiran 6a, were formerly variably allocated to other taxa (Meganthropus palaeojavanicus, Pithecanthropus dubius, Pongo sp.). To resolve the taxonomic uncertainty surrounding these and other contentious Indonesian hominid specimens, we used occlusal fingerprint analysis (OFA) to reconstruct their chewing kinematics; we also used various morphometric approaches based on microtomography to examine the internal dental structures. Our results confirm the presence of Meganthropus as a Pleistocene Indonesian hominid distinct from Pongo, Gigantopithecus and Homo, and further reveal that Dubois's H. erectus paratype molars from 1891 are not hominin (human lineage), but instead are more likely to belong to Meganthropus.

Three adaptive hypotheses have been forwarded to explain the distinctive Neanderthal face: (i) an improved ability to accommodate high anterior bite forces, (ii) more effective conditioning of cold and/or dry air and, (iii) adaptation to facilitate greater ventilatory demands. We test these hypotheses using three-dimensional models of Neanderthals, modern humans, and a close outgroup ( Homo heidelbergensis ), applying finite-element analysis (FEA) and computational fluid dynamics (CFD). This is the most comprehensive application of either approach applied to date and the first to include both. FEA reveals few differences between H. heidelbergensis , modern humans, and Neanderthals in their capacities to sustain high anterior tooth loadings. CFD shows that the nasal cavities of Neanderthals and especially modern humans condition air more efficiently than does that of H. heidelbergensis , suggesting that both evolved to better withstand cold and/or dry climates than less derived Homo . We further find that Neanderthals could move considerably more air through the nasal pathway than could H. heidelbergensis or modern humans, consistent with the propositions that, relative to our outgroup Homo , Neanderthal facial morphology evolved to reflect improved capacities to better condition cold, dry air, and, to move greater air volumes in response to higher energetic requirements.

The use of teeth as tools for manipulating objects and simple food-processing methods was common among prehistoric and modern hunter-gatherer human populations. Paramasticatory uses of teeth frequently produce enamel chipping and distinctive types of dental wear that can readily be related to specific tool functions. In particular, the presence of unusual occlusal wear areas (named para-facets) on maxillary teeth of prehistoric, historic and modern hunter-gatherers has been associated with cultural habits involving extensive use of teeth (Fiorenza et al., 2011; Fiorenza and Kullmer, 2013). However, Sarig and Tillier (2014) believe that this wear had been caused by pathological occlusal relationships rather than by the use of teeth as tools. In this contribution, we show how occlusal contacts are created and how it is possible to distinguish between masticatory and non-masticatory wear facets by using an innovative digital approach called Occlusal Fingerprint Analysis. Statistical results from the analysis of comparative modern samples clearly demonstrate that described para-facets in Skhul and Qafzeh could not have been produced by dental occlusal anomalies such as malocclusions and crossbites. Moreover, dental pathologies in prehistoric humans were extremely rare. Only with the adoption of the modern lifestyle between 18th and 19th centuries, did the emergence of malocclusions become significantly more common. Because more than 50% of the Skhul and Qafzeh individuals analysed in our study are characterised by this distinctive type of wear, it is highly unlikely that their para-facets occurred as a result of dental pathologies.

The mastication of tough and hard foods combined with the extensive use of teeth as tools, have been considered possible antemortem causes in determining enamel microfractures of the tooth crown. This phenomenon, known as dental chipping, has been found in different fossil hominins and in several pre-historic and historic human populations who adopted different subsistence strategies. However, little is understood of the mechanism, function and the formation of dental chipping. In this study we analyze the maxillary molar wear areas associated with dental chipping (and named para-facets) of several hunter–gatherer specimens, using the Occlusal Fingerprint Analysis method. We employ three-dimensional digital models of tooth crowns created by surface scanning of dental replicas, to analyze the dip and dip directions of normal occlusal wear areas and para-facets. This allows us to reconstruct the jaw movements responsible for the creation of para-facets, and investigate whether they are produced during normal mastication or not. Vectors of the para-facets do not show any preferred direction and are distributed randomly as visualized by the occlusal compass, displaying significant differences with the major jaw movements in action during the normal chewing cycle. More importantly, no antagonist contacts in the lower teeth are associated with the para-facets of the upper teeth. This excludes the possibility that the para-facets are created during normal mastication. We therefore suggest that this unusual type of tooth wear is mainly due to attritional and abrasive contacts generated through daily task activities for foods processing and/or manufacturing of objects.

Objectives Exact symmetry and perfect balance between opposite jaw halves, as well as between antagonistic teeth, is not frequently observed in natural masticatory systems. Research results show that asymmetry in our body, skull, and jaws is often related to genetic, epigenetic, environmental and individual ontogenetic factors. Our study aims to provide evidence for a significant link between masticatory asymmetry and occlusal contact between antagonist teeth by testing the hypothesis that tooth inclination is one of the mechanisms driving distribution of wear in masticatory phases in addition to dietary and cultural habits. Materials and Methods The present work investigates the relationship between dental macrowear patterns and tooth inclinations on a sample of complete maxillary and mandibular 3D models of dental arches from 19 young and adult Yuendumu Aboriginal individuals. The analysis was carried out on first molars (M1) from all quadrants. Occlusal Fingerprint Analysis was used for the quantification of macrowear patterns, and 2D cross‐sectional geometric analysis was carried out to investigate asymmetry in dental arches. Results The asymmetry is highly variable on both arches, and it is associated with differences in the inclination of upper M1 crowns. Each molar has variable inclination (buccal/lingual) which influence tooth to tooth contact, producing greater or lesser variation in wear pattern. Interindividual variability of morphological variation of the occlusal relationship has to be considered in macrowear analysis. Discussion Our results suggest that overall asymmetry in the masticatory apparatus in modern humans affects occlusal contact areas between antagonist teeth influencing macrowear and chewing efficiency during ontogeny.

Morphometrics of the molar crown is based traditionally on diameter measurements but is nowadays more often based on 2D image analysis of crown outlines. An alternative approach involves measurements at the level of the cervical line. We compare the information content of the two options in a three-dimensional (3D) digital sample of lower and upper first molars (M(1) and M(1) ) of modern human and Neanderthal teeth. The cervical outline for each tooth was created by digitizing the cervical line and then sectioning the tooth with a best fit plane. The crown outline was projected onto this same plane. The curves were analyzed by direct extraction of diameters, diagonals, and area and also by principal component analysis either of the residuals obtained by regressing out these measurements from the radii (shape information) or directly by the radii (size and shape information). For M(1) , the crown and cervical outline radii allow us to discriminate between Neanderthals and modern humans with 90% and 95% accuracy, respectively. Fairly good discrimination between the groups (80-82.5%) was also obtained using cervical measurements. With respect to M(1) , general overlap of the two groups was obtained by both crown and cervical measurements; however, the two taxa were differentiable by crown outline residuals (90-97%). Accordingly, while crown diameters or crown radii should be used for taxonomic analysis of unworn or slightly worn M(1) s, the crown outline, after regressing out size information, could be promising for taxonomic assignment of lower M1s.

Information about food ingestion and mastication behavior during the lifespan of an individual is encoded in the dental occlusal wear pattern. To decode this information, we describe a new method called occlusal fingerprint analysis (OFA). Structural parameters of wear facets on the occlusal surface of teeth are quantified from digitized casts for the interpretation of occlusal aspects. The OFA provides an individual three-dimensional dental occlusal compass that indicates the major pathways of interaction between antagonists, revealing information about development, spatial position, and enlargement of wear facets. Humans develop a very similar overall pattern of crown contacts, although specific characteristics of wear facets reflect an individual's occlusal relationships and masticatory behavior. We hypothesize that the wear pattern is a unique character and therefore valuable for individual identification. Furthermore we suggest that OFA, when further developed, may be useful for identification of behavioral, biological, and chemical factors affecting crown morphology.

Neanderthals have been commonly depicted as top predators who met their nutritional needs by focusing entirely on meat. This information mostly derives from faunal assemblage analyses and sta- ble isotope studies: methods that tend to underestimate plant consumption and overestimate the intake of ani- mal proteins. Several studies in fact demonstrate that there is a physiological limit to the amount of animal proteins that can be consumed: exceeding these values causes protein toxicity that can be particularly danger- ous to pregnant women and newborns. Consequently, to avoid food poisoning from meat-based diets, Neander- thals must have incorporated alternative food sources in their daily diets, including plant materials as well. Yrbk Phys Anthropol 156:43-71, 2015. V C 2014 American Association

Department of Palaeoanthropology and Messel Research, Senckenberg Research Institute, D-60325 Frankfurt amMain, GermanyKEY WORDS Neanderthals; anatomically modern humans; occlusal compass; Levant;para-facetsABSTRACT Neanderthals and anatomically modernhumans (AMHs) may have lived in close proximity inthe Near East region during Middle Paleolithic times.Although functional morphological analyses suggest amarked behavioral contrast between these two humangroups, new dental micro- and macro-wear studies,together with new archaeological data, have revealedsome similarities in ecology and dietary habits. In thisstudy, we analyze the tooth wear patterns of Neander-thals and AMH from Middle Paleolithic sites of Israeland Northern Iraq, using the Occlusal Fingerprint Anal-ysis (OFA) method to virtually reconstruct the jaw move-ments responsible for the creation of the occlusal wearareas. We particularly focus on para-facets, a distinctivetype of wear which has been previously described in thedentition of historic and modern hunter-gatherers. Theanalysis reveals a similarity in para-facet frequencybetween early Near Eastern Neanderthals and AMH,and a significant difference with other Pleistocenehuman groups. The absence of antagonist occlusal con-tacts in the lower teeth and the occlusal compass analy-sis suggest that para-facet formation is not related tonormal mastication but to nonmasticatory activities.Thus, the identification of these nonmasticatory wearareas on the molars of early Near Eastern Neanderthalsand AMH may indicate analogous tooth-tool uses fordaily task activities. These may have emerged independ-ently or could be interpreted as indirect evidence of cul-tural interactions between these two groups. Am J PhysAnthropol 152:107-117, 2013.

Howler monkeys (genus Alouatta) display a distinctive cranial architecture characterized by airorhynchy (or retroflexion of the facial skeleton on the cranial base), a small braincase, and a posteriorly oriented foramen magnum. This configuration has been associated with distinct factors including a high folivory diet, locomotion, and the presence of a specialized vocal tract characterized by large hyoid bone. However, the morphological relationships between the facial and neurocranial blocks in Alouatta have been scarcely investigated. In this study we quantitatively analyzed the cranial shape variation in Alouatta seniculus, to evaluate possible influences and constraints in face and braincase associated with airorhynchy. We also considered the structural role of the pteric area within the cranial functional matrix. We applied landmark-based analysis and multivariate statistics to 31 adult crania, computing shape analyses based on 3D coordinates registration as well as the analysis of the Euclidean distance matrix to investigate patterns of intraspecific morphological variability. Our results suggest that allometry is the main source of variation involved in shaping cranial morphology in howlers, influencing the degree of facial proportions and braincase flattening, and generating the main sexual differences. Larger individuals are characterized by a higher degree of airorhynchy, neurocranial flattening, and expansion of the zygomatic arch. Allometric variations influence the skull as a whole, without distinct patterns for face and braincase, which behave as an integrated morphological unit. A preliminary survey on the pteric pattern suggests that the morphology of this area may be the result of variations in the vertical growth rates between face and braincase. Future studies should be dedicated to the ontogenetic series and focus on airorhynchy in terms of differential growth among distinct cranial districts.

In genere l’uomo di Neanderthal è visto come un cacciatore, vissuto in climi freddi, che si nutriva quasi esclusivamente di carne. Ma recenti scoperte archeologiche e nuovi studi, tra cui quello degli autori sull’usura dei denti di Neanderthal, indicano una dieta più flessibile. I neandertaliani si nutrivano di quello che offriva l’ambiente, e l’analisi dell’usura dentale di Neanderthal dell’Europa centro-settentrionale conferma una dieta carnivora. Quella di Neanderthal vissuti in luoghi più caldi indica invece una dieta che comprende anche risorse vegetali. Questa flessibilità è simile a quella rilevata per H. sapiens nel periodo di coesistenza tra le due specie, e suggerisce una competizione alimentare tra uomini moderni e Neanderthal, la cui scomparsa però è ancora un mistero.

Tooth wear studies in mammals have highlighted the relationship between wear facets (attritional areas produced during occlusion by the contact between opposing teeth) and physical properties of the ingested food. However, little is known about the influence of tooth morphology on the formation of occlusal wear facets. We analyzed the occlusal wear patterns of first maxillary molars (M1s) in Neanderthals, early Homo sapiens, and contemporary modern humans. We applied a virtual method to analyze wear facets on the crown surface of three-dimensional digital models. Absolute and relative wear facet areas are compared with cusp area and cusp height. Although the development of wear facets partially follows the cusp pattern, the results obtained from the between-group comparisons do not reflect the cusp size differences characterizing these groups. In particular, the wear facets developed along the slopes of the most discriminate cusp between Neanderthals and Homo sapiens (hypocone) do not display any significant difference. Moreover, no correlations have been found between cusp size and wear facet areas (with the exception of the modern sample) and between cusp height and wear facet areas. Our results suggest that cusp size is only weakly related to the formation of the occlusal wear facets. Other factors, such as, diet, food processing, environmental abrasiveness, and nondietary habits are probably more important for the development and enlargement of wear facets, corroborating the hypotheses suggested from previous dental wear studies. Anat Rec, 2011. © 2010 Wiley-Liss, Inc.

Reconstruction of fractured, distorted, or missing parts in human skeleton presents an equal challenge in the fields of paleoanthropology, bioarcheology, forensics, and medicine. This is particularly important within the disciplines such as orthodontics and surgery, when dealing with mandibular defects due to tumors, developmental abnormalities, or trauma. In such cases, proper restorations of both form (for esthetic purposes) and function (restoration of articulation, occlusion, and mastication) are required. Several digital approaches based on three-dimensional (3D) digital modeling, computer-aided design (CAD)/computer-aided manufacturing techniques, and more recently geometric morphometric methods have been used to solve this problem. Nevertheless, comparisons among their outcomes are rarely provided. In this contribution, three methods for hemimandibular body reconstruction have been tested. Two bone defects were virtually simulated in a 3D digital model of a human hemimandible. Accordingly, 3D digital scaffolds were obtained using the mirror copy of the unaffected hemimandible (Method 1), the thin plate spline (TPS) interpolation (Method 2), and the combination between TPS and CAD techniques (Method 3). The mirror copy of the unaffected hemimandible does not provide a suitable solution for bone restoration. The combination between TPS interpolation and CAD techniques (Method 3) produces an almost perfect-fitting 3D digital model that can be used for biocompatible custom-made scaffolds generated by rapid prototyping technologies.

The determination of the minimum number of individuals can be very challenging, especially in an assemblage of fragmentary bones and isolated teeth. Similarities in tooth morphology, degree of wear, and interproximal wear facets (IPWF) are generally used to associate isolated teeth qualitatively. However, no quantitative method has yet been established for an objective identification and matching of isolated tooth crowns. In this study, we analyze the IPWF morphology of adjacent mandibular molars (17 M(1)/M(2) pairs), applying both qualitative and quantitative methods to test a reproducible approach for crown association. The surfaces of distal (for M(1)) and mesial (for M(2)) IPWF were surface-scanned and digitally selected. Three-dimensional (3D) and two-dimensional (2D) outlines of IPWF were analyzed using elliptic Fourier analysis (EFA) and geometric morphometrics methods (GMM). Additionally, teeth were qualitatively associated by visual evaluation of the IPWF outline and by physical matching. Unsatisfactory results with less than 50% of tooth pairs correctly associated were obtained by using both methods, shape analysis (digital approach) and the visual evaluation (qualitative assessment) of the IPWF outline. The physical matching of the crowns showed highly variable accuracy ranging between 53% and 77%. The quantitative form-space analysis of 2D IPWF outlines provided the best results (82% of correctly associated teeth), but no statistically significant differences were recorded when compared with the manual matching. Since three tooth pairs out of 17 could not be quantitatively associated, we suggest that the quantitative analysis of IPWF should be used only in addition with other approaches.

High variability in the dentition of Homo can create uncertainties in the correct identification of isolated teeth. For instance, standard tooth identification criteria cannot determine with absolute certainty if an isolated tooth is a second or third maxillary molar. In this contribution, using occlusal fingerprint analysis, we reassess the identification of Krapina D58 (Homo neanderthalensis), which is catalogued as a third maxillary molar. We have hypothesized that the presence/absence of the distal occlusal wear facets can be used to differentiate second from third maxillary molars. The results obtained confirm our hypothesis, showing a significant difference between second and third maxillary molars. In particular we note the complete absence of Facets 7 and 10 in all third molars included in this analysis. The presence of these facets in Krapina D58 eliminates the possibility that it is a third maxillary molar. Consequently it should be reclassified as a second molar. Although this method is limited by the degree of dental wear (i.e., unworn teeth cannot be analyzed) and to individual molars in full occlusion, it can be used for tooth identification when other common criteria are not sufficient to discriminate between second and third maxillary molars.

Prehistoric dental treatments have been known from the Neolithic 9,000-7,500 years before present (BP) [1], when the adoption of early farming culture caused an increase of carious lesions [2]. Only a few early cases have been documented [3], some were characterized by in vivo perforation of the crown surface made by a drilling tool [1]. Here we document the earliest evidence of proto-dental therapeutic intervention on a Late Upper Paleolithic modern human lower right third molar (RM3) from a burial in Northern Italy [4]. The RM3 belongs to a young male individual (ca. 25 years old) unearthed in 1988 from the Epigravettian deposit of Riparo Villabruna (Sovramonte – Belluno, Italy), and dated around 14,160-13,820 BP. This tooth presents a large occlusal cavity, with a polished internal surface and extensive enamel chipping traces on the steep mesial wall. Within the cavity four caries are present. The cavity is sub-squared on the lingual and mesial sides but rounded on the buccal and distal sides. Using Scanning Electron Microscopy (SEM) we show the presence of striations within the cavity, which fade out towards the occlusal surface probably as a consequence of tooth wear. The striations have a ”V” shaped transverse section and microstriations at the bottom, sharply defined, with a high apex, steep sides, narrow cross-sections and well-defined parallel ancillary ridging, as typically displayed by cutmarks on teeth [5]. Based on in vitro experimental replication and a complete functional reconstruction of the Villabruna dental arches, we confirm that the identified striations and the associated extensive enamel chipping on the mesial wall of the cavity were produced ante-mortem by pointed flint tools during scratching and chiseling activities. The Villabruna specimen is therefore the oldest known evidence of dental caries intervention, suggesting rudimentary knowledge of disease treatment well before the Neolithic. This study also suggests that primitive forms of carious treatment in human evolution entail an adaptation of the well-known toothpickings for levering and scratching rather than drilling practices.

Neanderthals have been traditionally considered at the top of the food chain with a diet mostly consisting of animal proteins. New findings challenged this view and suggested that Neanderthals living in areas with more favourable climatic conditions exploited various food sources, including plant materials. In this study, the attention is focused on dental macrowear of Neanderthals from Central Italy, whose diet has been largely unexplored. Three-dimensional digital models of teeth have been examined through occlusal fingerprint analysis (OFA), a method used to understand how wear facets are formed. The results show a close similarity between the specimens of Saccopastore 1 and 2, with a wear pattern that indicates the use of diverse sources of food, but with a predominance of animal proteins. On the other hand, the specimens of Guattari 2 and 3 display a slightly different dental wear from each other, which probably reflects the chronological sequence of the Guattari Cave. It appears that at the end of the marine isotope stage (MIS)5 the occupants of this cave consumed marginally more plant foods, while during MIS 3 they relied more on animal proteins. Finally, a close look at the Saccopastore maxillary molars reveals the presence of a distinct type of wear that has been previously described in some Neanderthals and early Homo sapiens from Near East, and it provides additional information about the culture and lifestyle of these Pleistocene human populations.

Neanderthals and anatomically modern humans (AMHs) may have lived in close proximity in the Near East region during Middle Paleolithic times. Although functional morphological analyses suggest a marked behavioral contrast between these two human groups, new dental micro- and macro-wear studies, together with new archaeological data, have revealed some similarities in ecology and dietary habits. In this study, we analyze the tooth wear patterns of Neanderthals and AMH from Middle Paleolithic sites of Israel and Northern Iraq, using the Occlusal Fingerprint Analysis (OFA) method to virtually reconstruct the jaw movements responsible for the creation of the occlusal wear areas. We particularly focus on para-facets, a distinctive type of wear which has been previously described in the dentition of historic and modern hunter-gatherers. The analysis reveals a similarity in para-facet frequency between early Near Eastern Neanderthals and AMH, and a significant difference with other Pleistocene human groups. The absence of antagonist occlusal contacts in the lower teeth and the occlusal compass analysis suggest that para-facet formation is not related to normal mastication but to nonmasticatory activities. Thus, the identification of these nonmasticatory wear areas on the molars of early Near Eastern Neanderthals and AMH may indicate analogous tooth-tool uses for daily task activities. These may have emerged independently or could be interpreted as indirect evidence of cultural interactions between these two groups.

The Kalamakia cave, a Middle Paleolithic site on the western coast of the Mani peninsula, Greece, was excavated in 1993–2006 by an interdisciplinary team from the Ephoreia of Paleoanthropology and Speleology (Greek Ministry of Culture) and the Museum national d'Histoire naturelle (Paris). The site is dated to between ca. 100,000 and >39,000 years BP (Before Present) and has yielded Mousterian lithics, a rich fauna, and human remains from several layers. The latter include 10 isolated teeth, a cranial fragment and three postcranial elements. The remains represent at least eight individuals, two of them subadults, and show both carnivore and anthropogenic modifications. They can be identified as Neanderthal on the basis of diagnostic morphology on most specimens. A diet similar to that of Neanderthals from mixed habitat is suggested by our analysis of dental wear (occlusal fingerprint analysis) and microwear (occlusal texture microwear analysis), in agreement with the faunal and palynological analyses of the site. These new fossils significantly expand the Neanderthal sample known from Greece. Together with the human specimens from Lakonis and Apidima, the Kalamakia human remains add to the growing evidence of a strong Neanderthal presence in the Mani region during the Late Pleistocene.

The Middle Paleolithic fossil human teeth from Taddeo cave in southwestern Italy were discovered in 1967, but to date only scanty and partially incorrect information has been published about them. The teeth were recovered in a reddish sandy layer from the cave’s floor, which is attributed either to an early phase of Wurm I (OIS 5c or 5d) or a transition phase between Wurm I and Wurm II (OIS 5a). In this paper, we present a revised morphological description and morphometric comparisons of the four dental remains discovered. Apart from a classic morphometric comparison, we also provide a qualitative and quantitative assessment of the internal morphology with the aid of micro-CT imaging. In addition, virtual restoration and matching of adjacent teeth were performed with 3D digital modeling and Computer-Aided Design techniques. Occlusal Fingerprint Analysis was also employed to help correctly identify each tooth. While in the previous studies, Taddeo 1 was considered either an upper right canine or a lower right canine, in the present work it has been definitely identified as lower left canine. Taddeo 2 has been reclassified as a right P 4 instead of a right P 3 . Based on the occlusal and interproximal wear, we have also shown that Taddeo 2 and Taddeo 3 (right M 1 ) belong to the same individual. All of the teeth show characteristic Neanderthal features in crown morphology and fissure pattern. However, although Taddeo 4 shows morphological features typical of Neanderthal M 1 s, some morphometric results (large enamel thickness, low dentine volume) recall more modern humans than Neanderthals. This result might suggest that, at least for lower first molars, the Neanderthal range of variation is large and still not clearly understood.

The issue of reconstructing lost or deformed bone presents an equal challenge in the fields of paleoanthropology, bioarchaeology, forensics, and medicine. Particularly, within the disciplines of orthodontics and surgery, the main goal of reconstruction is to restore or create ex novo the proper form and function. The reconstruction of the mandibular condyle requires restoration of articulation, occlusion, and mastication from the functional side as well as the correct shape of the mandible from the esthetic point of view. Meeting all these demands is still problematic for surgeons. It is unfortunate that the collaboration between anthropologists and medical professionals is still limited. Nowadays, geometric morphometric methods (GMM) are routinely applied in shape analysis and increasingly in the reconstruction of missing data in skeletal material in paleoanthropology. Together with methods for three-dimensional (3D) digital model construction and reverse engineering, these methods could prove to be useful in surgical fields for virtual planning of operations and the production of customized biocompatible scaffolds. In this contribution, we have reconstructed the missing left condylar process of the mandible belonging to a famous Italian humanist of the 15th century, Pico della Mirandola (1463–1494) by means of 3D digital models and GMM, having first compared two methods (a simple reflection of the opposite side and the mathematical–statistical GMM approach) in a complete human mandible on which loss of the left condyle was virtually simulated. Finally, stereolithographic models of Pico’s skull were prototyped providing the physical assembly of the bony skull structures with a high fitting accuracy. Anat Rec, 292:1088–1097, 2009. V C 2009 Wiley-Liss, Inc.

Neanderthals have been traditionally described to be at the very top of the food chain, with a diet consisting almost exclusively of meat. On the other hand, anatomically modern humans (AMH) are thought to be a more flexible species with the exploitation of various food sources. Here we analyze dental macrowear of a large sample of Neanderthal and AMH postcanine teeth from different chronological and geographical areas of Europe and the Near East, applying a well-established method called Occlusal Fingerprint Analysis (OFA). This digital approach is based on the identification and analysis of attrition and abrasive occlusal wear facets (defined as polished homologous areas with well-defined borders) with the aim to reconstruct the jaw movements responsible for their formation. Thus, it enables to obtain information on dietary and non-dietary habits of these populations. Wear facet size and distribution seem to correlate well with diet, showing a large variation within Neanderthals and AMH, which mostly depends on the habitats they inhabited. We found ecomorphological signals distinguishing populations who lived in cold habitats from those who inhabited warm climatic conditions, suggesting an increase in meat consumption at the northern latitudes. In contrast, wear facet inclination is strongly influenced by the environmental abrasiveness accidentally introduced in the mouth through food preparation methods. In addition, we have also identified non-dietary wear on the postcanine dentition in Mediterranean populations that suggests the use of teeth as tools for daily task activities.