Dental microwear of a basal ankylosaurine dinosaur, Jinyunpelta and its implication on evolution of chewing mechanism in ankylosaurs.

Jinyunpelta sinensis is a basal ankylosaurine dinosaur excavated from the mid Cretaceous Liangtoutang Formation of Jinyun County, Zhejiang Province, China. In the present study, its dental microwear was observed using a confocal laser microscope. Jinyunpelta had steep wear facets that covered most of buccal surfaces of posterior dentary teeth. Observation of dental microwear on the wear facet revealed that scratch orientation varied according to its location within the wear facet: vertically (i.e. apicobasally) oriented scratches were dominant in the upper half of the wear facet, and horizontally (i.e. mesiolaterally) oriented ones were in the bottom of the facet. These findings indicated that Jinyunpelta adopted precise tooth occlusion and biphasal jaw movement (orthal closure and palinal lower jaw movement). The biphasal jaw movement was widely observed among nodosaurids, among ankylosaurids, it was previously only known from the Late Cretaceous North American taxa, and not known among Asian ankylosaurids. The finding of biphasal jaw movement in Jinyunpelta showed sophisticate feeding adaptations emerged among ankylosaurids much earlier (during Albian or Cenomanian) than previously thought (during Campanian). The Evolution of the biphasal jaw mechanism that contemporaneously occurred among two lineages of ankylosaurs, ankylosaurids and nodosaurids, showed high evolutionary plasticity of ankylosaur jaw mechanics.

Exploring late Paleolithic and Mesolithic diet in the Eastern Alpine region of Italy through multiple proxies.

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 (M2 s) 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.

Tooth grooves, occlusal striations, dental calculus, and evidence for fiber processing in an Italian eneolithic/bronze age cemetery.

OBJECTIVES: We conducted a systematic macroscopic and microscopic examination of occlusal and para-occlusal wear in a large dental sample (n = 3,014) from 217 individuals dated to the Early Bronze age site of Gricignano d'Aversa, Italy. We used macroscopic and microscopic techniques to document nondietary occlusal and para-occlusal wear and to analyze calculus inclusions in some of the teeth. In combining an analysis of the wear with the calculus inclusions we linked the specific wear to the likely fiber that was involved in producing it. MATERIALS AND METHODS: Teeth and their high resolution epoxy casts were analyzed through SEM and reflected light microscopes. Nineteen individuals (fifteen with activity induced dental modifications and four as a control sample) were examined for the presence of calculus inclusions. RESULTS: Activity induced dental modifications (AIDMs), notches, grooves and micro-striations, were found in the 62.2% of the adult females, in 21.2% of the adults of unknown sex and in a single male. We found the full spectrum of dental manipulations from very minor nonocclusal wear in some young individuals to severe attrition at the other extreme. The width of the striations and grooves, mostly on the upper incisors, suggests a craft activity involving fibers and thread production and manipulation. From the dental calculus of two females with grooves and striations, we extracted three fragments of fibers, identified as hemp (Cannabis, sp.). Previously from Gricignano woven hemp fibers were found on both surfaces of a metal blade associated with a male burial. DISCUSSION: This study found the co-occurrence of tooth AIDMs and the actual fibers preserved in the dental calculus. As more work is done analyzing dental calculus in a variety of humans, it is apparent that this biological material holds rich resources documenting non-dietary habits.

Transition to agriculture in South-Eastern Arabia: Insights from oral conditions.

OBJECTIVES: In Southeast (SE) Arabia, agriculture is supposed to expand around 3000 BC, but its tempo and its actual role in populations' subsistence is still debated by archaeologists. Here, we compare dental health conditions of 11 skeletal samples from coastal and inland sites, dated from the Late Neolithic (ca. 4500-3100 BC) to the Early Bronze Age (EBA), conventionally divided into Hafit (ca. 3100-2700 BC) and Umm an-Nar period (ca. 2700-2000 BC). The goal is to assess long-term trends in subsistence patterns and regional variability during the local transition to agriculture. METHODS: Seven indicators of oral health and childhood stress were analyzed, including dental wear, calculus, caries, alveolar resorption, periapical lesions, ante-mortem tooth loss (AMTL), and linear enamel hypoplasia (LEH). RESULTS: Neolithic coastal populations are globally characterized by high dental wear, high calculus frequency, high LEH frequency, and frequent periodontal disease, whereas they exhibit low abscesses and AMTL frequencies and a total absence of carious lesions. Samples from the Hafit period present high dental wear, low rates of calculus and LEH, frequent periodontal disease, combined with low abscess and AMTL frequencies and absence of caries. By contrast, samples from the Umm an-Nar period exhibit much lower dental wear, calculus and LEH rates, whereas caries, periapical lesions and AMTL frequencies increase significantly. Marked differences were observed between coastal and inland Umm an-Nar groups, the latter presenting significantly higher frequencies of caries, periapical lesions, alveolar resorption and AMTL. DISCUSSION/CONCLUSION: Oral conditions from the Neolithic coastal populations denote a diet mainly composed of unprocessed and abrasive food, with high protein and low carbohydrate intakes, and frequent stress episodes. Although Hafit populations display some changes in oral pathologies, which indicate modifications in their lifestyle and a diversification of the diet, no markers of high carbohydrate intakes were observed in our samples. The impact of agriculture on oral health appears clearly only from the Umm an-Nar period, and is more intense inland than on the coast, where marine resources are still a main component of the diet.

New methodology to reconstruct in 2-D the cuspal enamel of modern human lower molars.

OBJECTIVES: In the last years different methodologies have been developed to reconstruct worn teeth. In this article, we propose a new 2-D methodology to reconstruct the worn enamel of lower molars. Our main goals are to reconstruct molars with a high level of accuracy when measuring relevant histological variables and to validate the methodology calculating the errors associated with the measurements. METHODS: This methodology is based on polynomial regression equations, and has been validated using two different dental variables: cuspal enamel thickness and crown height of the protoconid. In order to perform the validation process, simulated worn modern human molars were employed. The associated errors of the measurements were also estimated applying methodologies previously proposed by other authors. RESULTS: The mean percentage error estimated in reconstructed molars for these two variables in comparison with their own real values is -2.17% for the cuspal enamel thickness of the protoconid and -3.18% for the crown height of the protoconid. This error significantly improves the results of other methodologies, both in the interobserver error and in the accuracy of the measurements. CONCLUSIONS: The new methodology based on polynomial regressions can be confidently applied to the reconstruction of cuspal enamel of lower molars, as it improves the accuracy of the measurements and reduces the interobserver error. The present study shows that it is important to validate all methodologies in order to know the associated errors. This new methodology can be easily exportable to other modern human populations, the human fossil record and forensic sciences.

Dental wear and age grading at Roonka, South Australia.

OBJECTIVES: In many hunter-gatherer populations, the teeth are used as a third hand or a tool. Much attention has been paid to wear and its relationship to gendered division of labor, but age is also a significant organizing factor in many societies. In this article, I analyze whether the pattern of wear at Roonka, Australia, reflects the age-graded acquisition of tasks. MATERIALS AND METHODS: The remains analyzed come from Roonka and date from c6000 BP to 150 BP. In total 126 adults and juveniles were analyzed. Wear gradients were calculated for each tooth relative to wear on the first molar. Data were compared using nonparametric statistics and cluster analysis to assess the degree of patterning within the sample. RESULTS: Dental wear proceeded rapidly. There is no evidence of sex differences in the pattern of wear. Age differences do occur. While disproportionate anterior wear occurs among juveniles and young adults, by middle adulthood the pattern is less variable and involves the premolars. Old adults have a much flatter pattern of wear. DISCUSSION: The pattern of wear is consistent with ethnographic observations, which suggest a degree of latitude in the activities of juveniles and young adults. By middle age variability between individuals declines reflecting shared tasks and more intensive use of the teeth. The pattern of wear amongst old adults, however, is much flatter presumably due to changes in occlusion. While dental wear is informative about the organization of labor there is a need to take into account both patterns of activity and occlusion.

Dental wear quantity and direction in Chalcolithic and Medieval populations from southwest France.

The aim of this study was to verify if dental wear changed due to the dietary shift between the Chalcolithic and Middle Ages from relatively hard and fibrous foods to soft cooked cereals. This was accomplished by comparing dental wear quantity and direction between people from two archaeological sites, Les Treilles during the Chalcolithic (mixed subsistence farmers) and Marsan from the Middle Ages (agriculturalists) in southwest France. The materials studied include 65 mandibles, 32 from Les Treilles and 33 from Marsan; 549 teeth were studied. The results show statistically significant difference in wear quantity and direction, the Chalcolithic population (Les Treilles) had the greatest levels of wear in a mainly oblique direction, with the anterior teeth heavily affected by wear. Comparatively, the Medieval sample (Marsan) had lesser levels of wear in a mainly horizontal direction, and the most heavily worn teeth were the molars and incisors. The quantity of wear seems to correlate well with changes in diet, the high level of wear on the anterior teeth in the Chalcolithic sample corresponds with the consumption of a mixed diet of fibrous and tough foods. At Marsan, the lower wear quantity was likely due to a diet of soft boiled cereals, requiring less mastication. However, wear direction appears dependent on several factors and may correlate with more mixed subsistence practices. This study demonstrates the need for additional research into the complex actions of mastication and its effect on dental wear, as well as standardised methodology for the examination of dental wear in archaeological samples.

Tooth wear pattern analysis in a sample of Italian Early Bronze Age population. Proposal of a 3-D sampling sequence.

OBJECTIVE: The purpose of this study was to assess the prevalence, distribution and intensity of tooth wear in a sample of an ancient Italian population in order to explain the pattern in terms of dietary habits and/or non-dietary tooth-use behaviors during the Early Bronze Age, with a focus on possible age-group and sex differences. DESIGN: Well-preserved permanent teeth of individuals from the Bronze Age site of Ballabio (Lecco) in northern Italy were examined for tooth wear by different methods. Eight 3D models of teeth at increasing severity of wear were created. RESULTS: In total, 357 permanent teeth belonging to male and female individuals were included in the study. Dental wear was present in 96.6% of the total sample. Males showed significantly greater levels of wear than females in the mandibular teeth. Both sexes exhibited a significantly different wear direction between the anterior (oblique and flat) and posterior (oblique and concave) teeth. Significant age differences were observed in the direction and level of wear in the incisors, canines and premolars, with higher wear in the older group. Complete and rotatable virtual 3D images of different wear patterns are proposed. CONCLUSIONS: The findings of the present study confirm the data from archaeological studies on this site and on northern Italian habits during the Early Bronze Age suggesting a diet rich in vegetables. The observed wear patterns can be related both to the diet of this Bronze age population, based on hard and abrasive food requiring vigorous mastication, and to sex differences in cultural practices.

Reconstructing diet and behaviour of Neanderthals from Central Italy through dental macrowear analysis.

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.

Supernumerary fourth molar and dental pathologies in a Chalcolithic individual from the El Mirador Cave site (Sierra de Atapuerca, Burgos, Spain).

We present a middle-aged Chalcolithic male with a supernumerary distomolar in the mandible. The prevalence of supernumerary teeth in present-day populations is low, ranging from 0.1% to 3.4%; most supernumerary teeth are documented in the anterior and molar regions of the maxilla in present populations. However, the prevalence of supernumerary molars in past populations is still unknown. Moreover, a complete pathological study has been done of this individual. Maxilla, mandible and teeth have been analyzed searching for dental pathologies. A cone-beam computed tomography (CBCT) analysis of mandibular and maxillary fragments was performed to check the evidence of hyperdontia. Dental wear and maxillary alveolar bone have been analyzed with environmental scanning electron microscope (ESEM) to improve the diagnosis of an abscess and evidence of tooth picking. This individual shows a left distomolar in the mandible without any evidence of other supernumerary teeth. The fourth molar is not associated with any congenital disease. However, this individual suffered severe dental wear and a variety of oral pathologies such as, dental decay, abscesses, pulpitis, periodontal disease, toothpicking marks in an upper molar, arthritis of the temporomandibular joint and malocclusion associated with high masticatory loads. To our knowledge, this individual from El Mirador Cave (Sierra de Atapuerca, Spain) shows the most ancient case of a fourth molar documented. The poor oral health of this individual corresponds to the general dental health of Chalcolithic populations.

Brief communication: Comparative patterns of enamel thickness topography and oblique molar wear in two Early Neolithic and medieval population samples.

Enamel thickness has been linked to functional aspects of masticatory biomechanics and has been demonstrated to be an evolutionary plastic trait, selectively responsive to dietary changes, wear and tooth fracture. European Late Paleolithic and Mesolithic hunter-gatherers mainly show a flat wear pattern, while oblique molar wear has been reported as characteristic of Neolithic agriculturalists. We investigate the relationships between enamel thickness distribution and molar wear pattern in two Neolithic and medieval populations. Under the assumption that dietary and/or non-dietary constraints result in directional selective pressure leading to variations in enamel thickness, we test the hypothesis that these two populations will exhibit significant differences in wear and enamel thickness patterns. Occlusal wear patterns were scored in upper permanent second molars (UM2) of 64 Neolithic and 311 medieval subadult and adult individuals. Enamel thickness was evaluated by microtomography in subsamples of 17 Neolithic and 25 medieval individuals. Eight variables describing enamel thickness were assessed. The results show that oblique molar wear is dominant in the Neolithic sample (87%), while oblique wear affects only a minority (42%) of the medieval sample. Moreover, in the Neolithic molars, where buccolingually directed oblique wear is dominant and greatest enamel lost occurs in the distolingual quadrant, thickest enamel is found where occlusal stresses are the most important-on the distolingual cusp. These results reveal a correlation between molar wear pattern and enamel thickness that has been associated to dietary changes. In particular, relatively thicker molar enamel may have evolved as a plastic response to resist wear.

Bizarre tooth surface loss and the Miswak stick.

Tooth surface loss can present in a variety of ways, some of which can appear rather strange on first examination. This case report demonstrates an unusual presentation of tooth surface loss (TSL) and its subsequent treatment. This loss of hard dental tissue appeared to be affecting the whole of the patient's remaining dentition, both lingually and buccally. Detailed questioning revealed the origins of this problem which turned out to be due to excessive use of an intra-oral Miswak chewing stick. Cinical Relevance: This article will enable clinicians to understand the importance of specific, targeted history-taking, involving a rare case of tooth surface loss as well as the use of minimally destructive restoration composites and a fibre-reinforced composite bridge.

Assessing change in diet and biological affinity between the 4th and 3rd millennia cal BCE in the Portuguese Estremadura: a preliminary dental comparison of Feteira II and Bolores.

Although the social and political changes accompanying the transition from the Neolithic through Copper Age, between the 4th and 3rd millennia cal BCE, in southwestern Iberia are reasonably well understood, much less is known about whether population movements and dietary changes accompanied these transformations. To address this question, human dental remains from the Middle through Late Neolithic site of Feteira II (3600-2900 cal BCE) and the Late Neolithic site of Bolores (2800-2600 cal BCE) in the Portuguese Estremadura were used to examine diet (microwear) and affinity (dental non-metrics). Microwear features were not found to be significantly different between Feteira II and Bolores, suggesting that the emergence of social complexity during this period did not result in large-scale changes in subsistence practices during the period of use at these sites. Using the Arizona State University Dental Anthropology System and supporting statistics, no significant difference between the samples from Feteira II and Bolores was observed, suggesting that no population replacement occurred between the Middle Neolithic and Late Neolithic/Copper Age. However, at Bolores there is some indication that there may have been demographic exchanges between southern Iberian and North African populations during the Late Neolithic/Copper Age.

Avaliação das alterações odontológicas em sincrânios de Cerdocyon thous oriundos de atropelamentos na rodovia ES-060, Espírito Santo / Evaluation of dental changes in sincranium of Cerdocyon thous from running over in the ES-060 road, Espirito Santo

Os cachorros-do-mato (Cerdocyon thous Linnaeus, 1766) são animais amplamente encontrados em países da América do Sul. Apesar de não ser uma espécie ameaçada de extinção, é possível que muitas populações sofram impactos decorrentes de atropelamentos de indivíduos nas rodovias do país, pois, trata-se de uma das espécies de carnívoros com elevada ocorrência de mortes deste tipo. Foram avaliados 32 sincrânios de C. thous, oriundos de vida livre, armazenados na coleção osteológica do Laboratório de Anatomia Veterinária da Universidade Vila Velha (Vila Velha/ES), a fim de diagnosticar doenças que acometeram estes indivíduos enquanto vivos. As lesões macroscópicas identificadas foram: apinhamento dentário, ausência dentária, cálculo dentário, dentina terciária, desgaste, escurecimento dentário, exposição de polpa, fenestração óssea, fratura dentária, fratura de esmalte, giroversão, pigmentação e reabsorção da crista alveolar. Os achados mais comumente observados foram: ausência dentária, desgaste dentário e fratura dentária. Ausências dentárias anteriores à morte, alterações ósseas, cálculos dentários, apinhamento e giroversão aparentemente não causaram quaisquer prejuízos aos animais enquanto vivos.

The crab-eating foxes (Cerdocyon thous Linnaeus, 1766) are animals widely found in South American countries. Although it is not an endangered species, it is possible that many of them suffer impacts from being hit by car on the highways of the country, and this is the reason why it is one of the carnivores' species with high frequency of deaths. 32 free living sincranium stored in the osteological collection in the Laboratory of Veterinary Anatomy of Vila Velha University (Vila Velha/ES) were studied in order to diagnose diseases suffered by these individuals while alive. The main lesions identified were: crowding, no dental, dental calculus, tertiary dentin, detrition, darkening tooth, exposure of pulp, bone fenestration, fractured tooth, enamel fracture, giroversion, pigmentation and resorption of the alveolar crest. The most common findings were: no dental, dental detrition and fractured tooth. No dental before death, bone changes, dental calculus, crowding and giroversion apparently did not cause any harm to the animals while alive.

Topical laser application enhances enamel fluoride uptake and tribological properties.

Topical fluoride treatment prevents dental caries. However, the resulting calcium-fluoride-like deposits are soft and have poor wear resistance; therefore, frequent treatment is required. Lasers quickly heat surfaces and can be made portable and suitable for oral remedies. We examined the morphology, nanohardness, elastic modulus, nanowear, and fluoride uptake of fluoride-treated enamel followed by CO2 laser irradiation for 5 and 10 sec, respectively. We found that laser treatments significantly increased the mechanical properties of the calcium-fluoride-like deposits. The wear resistance of the calcium-fluoride-like deposits improved about 34% after laser irradiation for 5 sec and about 40% following irradiation for 10 sec. We also found that laser treatments increased fluoride uptake by at least 23%. Overall, laser treatment significantly improved fluoride incorporation into dental tissue and the wear resistance of the protective calcium-fluoride layer.

Nonalimentary tooth use in the neolithic population of the Lengyel culture in central Poland (4600-4000 BC).

One hundred and four skeletons of adult individuals representing Neolithic populations of the Brzesc Kujawski group of the Lengyel Culture (Kuyavia, central Poland, 4600-4000 BC) were analyzed with regard to evidence of nonalimentary tooth use, periapical lesions and antemortem tooth loss (AMTL). Instances of nonalimentary behaviors were found in 47.1% of females and 27.5% of males. Females were primarily characterized by occlusal grooves on the incisors and canines, most probably resulting from yarn production or weaving. The most frequent defect in males was severe tooth wear extending from the incisors to first molars, caused by some hard-to-identify nonalimentary activities. Occlusal grooves were also found in males, but their morphology indicates processing of some coarser material. The occupational nature of the tooth defects has been confirmed by archaeological data. The only two burials with grave goods indicative of craft specialization at the sites studied contain the remains of individuals with marks of nonalimentary tooth use. Moreover, the sites provide unequivocal evidence of weaving and basketry production in the form of loom weights and imprints of cloth and mats. Periapical lesions have been found in 40.4% of males and 35.6% of females, and AMTL in 32.1% of males and 36.7% of females. Individuals with evidence of nonalimentary tooth wear are characterized both by a higher incidence of these lesions in general, and by their more frequent location in the anterior part of the alveolar arch.

Tooth wear and dental pathology of the Bronze-Iron Age people in Xinjiang, Northwest China: Implications for their diet and lifestyle.

Tooth wear and dental pathology related to diet and lifestyle were investigated in the human dental remains unearthed from three archaeological sites of Bronze Age and Iron Age in Xinjiang of northwest China, and in comparative samples from two Neolithic sites in Henan and Shanxi in central China along the Yellow River. Our results indicate that the average tooth wear on most tooth types in the three Xinjiang sites was close to those of the Neolithic samples from central China. The variation within the Xinjiang samples was also explored. Some special wear patterns such as severe wear on the first molar and relatively heavy wear of anterior teeth were observed on the specimens from the Xinjiang sites. Obvious differences in caries and antemortem tooth loss were found between Xinjiang and comparative samples with higher frequencies of caries observed in samples from central China and higher antemortem tooth loss in samples from the Xinjiang sites. Strongly developed exostoses (tori) were also identified on mandibles and maxillae of the specimens from Xinjiang. The authors believe that the differences in tooth wear and dental pathology between Xinjiang and central China were caused by differences in diet and lifestyle. Food of a harder texture was consumed by the people who lived in Xinjiang than by the people in Henan and Shanxi of central China. The higher occurrence of heavily worn anterior teeth and some other special wear patterns, antemortem tooth loss and presence of exostoses on jaw bones in Xinjiang suggest that the people in Xinjiang lived in a relatively harsh environment, frequently gnawing hard objects, or using teeth as some kind of tools. All these activities put masticatory organs under a heavy load. The differences in caries frequencies between the frontier and central areas of China indicate that food richer in carbohydrates was consumed by the people in the central areas. It is proposed that about 3000-2000 years BP in many areas of frontier Xinjiang, people mainly relied on the type of hunter-gatherer economy with agriculture playing a smaller role in their lifestyle.

On the relationship of dental microwear to dental macrowear.

Dental microwear analysts have demonstrated that hard diets leave numerous microscopic pits on occlusal surfaces. The relationship between occlusal pitting and gross macrowear, however, is not well known. The current study seeks to elucidate the relationship between dental microwear and macrowear by determining if microscopically pitted teeth are associated with greater expressions of macrowear. This study examined microwear and macrowear on mandibular second molars from 60 prehistoric adult Native Americans representing three dietary regimes (foraging, mixed economy, and agriculture). Initially, two dental microwear feature variables were studied: percentage of pits and mean scratch width. Standard macrowear scores ranged from 4 to 40. ANOVAs suggested that neither of the microwear variables was affected by age or sex, but age affected macrowear scores. Because of this, the sample had a balanced number of young and old adults (i.e., those below and above skeletal age 35). A Pearson's correlation showed no covariation between scratch width and the percentage of pits. Regression analysis indicated that macrowear was not a function of the percentage of pits. However, a significant positive relationship was found between dental macrowear and scratch width. A post priori test found a significant negative relationship between macrowear and the total number of scratches. It is concluded, then, that wide scratches remove more enamel and dentin than do numerous pits, although both cause dental wear. It is suggested here that the term "abrasive" be used to describe those microwear profiles that lead to heavy macrowear and have relatively wide scratches.