Article

Enamel Hypoplasia Provides New Insights into Early Systemic Stress in Wild and Captive Giraffes (Giraffa camelopardalis)

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Abstract

Enamel hypoplasia, a developmental tooth defect, provides a permanent record of systemic stress during early life. The incidence and distribution of linear enamel hypoplasia has been used by anthropologists and palaeontologists to assess the health status of past populations but has not been applied by wildlife biologists studying extant animals. This study investigates enamel hypoplasia in 23 Giraffa camelopardalis skulls from wild and captive animals of various ages and sex to determine whether any systemic stress events are unique to life in captivity. Results indicate that wild giraffes are relatively stress-free as they do not have linear defects. Based on the distribution of linear defects in other giraffes, three key stress periods during the first 6 years of giraffe life were identified. The first stress event occurs during weaning, the second at about 3 years of age and the third, which is the least common, at 4–5 years of age. All three stress events were observed in both male and female giraffes. This study highlights the usefulness of assessing enamel hypoplasia in both wild and captive animals as well as the need for further research on tooth developmental timings in many wild ungulates. Some left–right asymmetry was observed in the development of linear and non-linear defects, which has implications for the aetiology of these defects.

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... Knowledge about the differences in the frequency of hypoplastic defects between upper-lower and left-right teeth is still scarce (Franz-Odendaal 2004). Hall-Martin (1976) related asymmetrical enamel defects in Giraffa camelopardalis Linnaeus 1758 to different patterns of eruption of the teeth, or to tooth-specific susceptibility to systemic stress, as has been reported for humans (Goodman & Rose 1990). ...
... Palaeopathology studies concerning EH have generally involved determining the age of the individual at the time the defects occurred to help pinpoint the trigger event (Corruccini et al. 1985;Hillson 1992;Dobney & Ervynck 2000;Lukacs 2001;Dobney et al. 2004;Franz-Odendaal 2004;Guatelli-Steinberg 2004). However, this approach is not possible in cases of continuously growing teeth as is the case of Toxodon, because the chronology of tooth eruption and amelogenesis for this taxon has not yet been established. ...
... As has been shown in previous studies, enamel defects are widely recorded in fossils, such as rhinoceros (Mead 1999;Franz-Odendaal et al. 2003), hippos and cattle (Franz-Odendaal et al. 2003), pigs (Dobney & Ervynck 2000) and giraffes (Franz-Odendaal 2004). According to Niven et al. (2004), a variety of diseases such as anthrax (Dragon et al. 1999) and tuberculosis (Rothschild et al. 2001) can affect living populations of large ungulates and may cause defective enamel formation. ...
Article
Enamel hypoplasia is characterized by reduction in the enamel thickness, resulting from a disruption of ameloblast activity due to systemic physiological stress. The euhypsodont teeth of Toxodon, a notoungulate from the Pleistocene of South America, often exhibit signs of enamel hypoplasia, in the form of continuous grooves or a series of pits where the enamel is thinner than in normal areas. These defects alternate with areas of normal enamel, and sometimes more than one form of enamel hypoplasia is present on the same tooth. This study analysed teeth of Toxodon from the Pleistocene Touro Passo Formation and the coastal plain of State of Rio Grande do Sul, Southern Brazil. Six types of enamel hypoplasia were observed. Upper teeth present mainly superficial grooves on the buccal surface, and the defects are less severe than those observed in the lower teeth. In the lower incisors, deep grooves with mesiodistal rows of pits were observed, showing clearly cyclical changes, which to a lesser degree, exist in all teeth. These changes are likely related to the continuous growth of euhypsodont teeth. Seven specimens were analysed under scanning electron microscopy and optical microscopy, which showed the occurrence of microstructural changes associated with the macroscopic enamel defects. Enamel underlying in the vicinity of hypoplastic defects was aprismatic and associated with prominent pathologic striae. These pathological findings might indicate that toxodonts were exposed to some stressing conditions or that their teeth were more easily abraded due to a change in diet items, related to shifting climatic conditions.
... The first method recommended by Hillson (1996) employs the most stringent criterion to examine the effect of stress on hypoplasias by limiting defect prevalence to antimeric pairs of teeth that are forming at the same time. This method considers the nature of stress as Bsystemic^ (Berten 1895;Hillson 1996) and evaluates defects on unmatched pairs as Blocal^ (Franz-Odendaal 2004;Goodman and Rose 1990). Limiting the assessment of hypoplasia prevalence to only those individuals with bilateral defects reduced the sample size to 16 specimens with hypoplasias, reducing the statistical power of our analyses. ...
... Blocal^stress, but includes all incidents as indicative of enamel growth disruption. It is also consistent with other studies examining the relationship between hypoplasias and stress events (e.g., Franz-Odendaal 2004). ...
... In addition, it is possible that if left and right teeth of antimeric pairs initiate and/or complete formation at slightly different times, only one tooth may record the growth disruption as a linear defect. It is also conceivable that the disruption might have occurred on one side only, consistent with Blocal^stress, or that one side was better able to buffer against stressors than its antimere (Franz-Odendaal 2004). Environmental stress has an adverse effect on the physiological mechanisms that maintain this buffering capacity (i.e., developmental stability), resulting in asymmetrical manifestation of bilateral traits (reviewed in Benderlioglu 2010). ...
Article
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Linear enamel hypoplasias are developmental defects ranging in appearance from microscopic to macroscopic furrows in enamel that encircle the tooth crown. Environmental stressors, including lack of food and infectious diseases during early periods of development, are known to induce hypoplasias in human and nonhuman primates. Social correlates of hypoplasias have not been extensively studied, however. Here, we examined the relationship between matriline dominance rank and linear enamel hypoplasia prevalence (i.e., absence or presence) and count (the total number of hypoplasias observed) in free-ranging rhesus monkeys (Macacca mulatta) in Cayo Santiago, Puerto Rico. We sampled 86 female offspring from low-, mid-, and high-ranking matrilines. Our results show that although hypoplasia prevalence and count were numerically higher in the combined group of low-and mid-ranking matrilines than in high-ranking matrilines, this effect was not statistically significant. There was, however, a significant negative relationship between age and hypoplasia prevalence, as well as between age and mean number of enamel defects, likely due to the attrition and abrasion of enamel that wear away shallow defects as individuals age. Future studies would benefit from using large sample sizes and collecting detailed behavioral data to determine if and when social status mediates enamel defect formation.
... Stress episodes that leave their trace in the dentition can be caused by a variety of factors such as pregnancy, birth, weaning, malnutrition, disruption of social bonds, disease or intoxication (e.g. Goodman and Rose, 1990;Hillson, 1996;Mead, 1999;Dobney et al., 2004;Franz-Odendaal, 2004;Niven et al., 2004;Skinner and Hopwood, 2004;Schwartz et al., 2006). ...
... Previous studies in primates (e.g. Guatelli-Steinberg, 2000;Skinner and Hopwood, 2004;Schwartz et al., 2006), domestic pigs (Dobney and Ervynck, 2000;Dobney et al., 2004), giraffes (Franz-Odendaal, 2004), bison (Niven et al., 2004) and fossil rhinoceroses (Mead, 1999) have shown that by recording enamel hypoplasia, the timing of key stress episodes during tooth crown formation can be assessed. As the enamel changes are permanent and teeth are the most durable structures of the mammalian body, a retrospective assessment of the timing of stress episodes occurring during dental development is possible in both recent and fossil species. ...
Article
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The study describes crown and root formation of the permanent mandibular cheek teeth of fallow deer from a gestational age of 22-23 weeks up to a post-natal age of 33 months. Tooth development was recorded using a scoring scheme based on morphological criteria ranging from crypt formation to completion of root growth. The morphological appearance of the enamel surface during three different stages (secretory-stage enamel, maturation-stage enamel and mature enamel) was described, and the approximate age at termination of the secretory stage of amelogenesis in the deciduous and permanent mandibular cheek teeth was determined. The data enable an age estimation of fallow deer up to 3 years of age and provide a basis for assessing the timing of stress episodes that affect tooth crown formation. This information is useful for the management of the species as well as in bioarchaeological and bioindication studies.
... DEHs are among the most conspicuous, manifesting as a visible localized thinning or absence of enamel (Goodman and Rose, 1990;Guatelli-Steinberg, 2001). DEHs are caused by impaired enamel secretion, a symptom of severe nutritional (Ablett and McCance, 1969;Dobney and Ervynck, 2000), pathological (Suckling et al., 1983;Hillson, 1986;Rose, 1990, 1991) or environmental stress (Mead, 1999;Franz-Odendaal, 2004;Franz-Odendaal et al., 2004;Niven et al., 2004;Byerly, 2007;Wu et al., 2012). The morphology of DEH can vary with the degree of metabolic stress (Witzel et al., 2006), but DEH are easily identified in ungulates with exposed enamel surfaces, such as moose. ...
... The morphology of DEH can vary with the degree of metabolic stress (Witzel et al., 2006), but DEH are easily identified in ungulates with exposed enamel surfaces, such as moose. In wild ungulates, hypoplasias have been attributed to weaning and seasonal stressors in extant and extinct giraffids (Giraffa, Sivatherium) (Franz-Odendaal, 2004;Franz-Odendaal et al., 2004); bison (Bison bison) (Wilson, 1988;Niven et al., 2004;Byerly, 2007;Barrón-Ortiz et al., 2019); horses (Equus spp.) (Barrón-Ortiz et al., 2019); white deer (Odocoileus virginianus) (Davis, 2013); and caribou (Rangifer tarandus groenlandicus) (Wu et al., 2012). ...
Article
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Food shortages can leave diagnostic, and in the case of the dentition, irreversible changes in mineralized tissue that persist into historical and fossil records. Consequently, developmental defects of tooth enamel might be used to track ungulate population irruptions or declines in resource availability, but dental tissue’s capacity for preserving historical population density changes has yet to be investigated in wild populations. We test the ability of macroscopic enamel defects, mandible, and metapodial lengths to track changes in the well-known insular moose population of Isle Royale National Park. Our study demonstrates that (1) a moose density threshold exists on the island above for which there is a significant decrease in mandible and metatarsus length and a concomitant increase in enamel hypoplasias; (2) food limitation has a more pronounced effect on male than female skeletal and dental growth; and (3) combined data from tooth enamel hypoplasias and bone lengths reflect the relative density of this ungulate population and should be broadly applicable to other ungulate osteological samples. Developmental defects in dental enamel were among the highest recorded in a wild population, and even during low-density intervals the population density of Isle Royale moose has been high enough to negatively impact skeletal and dental growth, indicating the comparatively poor health of this isolated century-old ecosystem.
... Therefore we propose a set of working hypotheses based on bison biology and ethology, Great Plains paleoecology (past and present), and hypoplasia studies on other mammals. Most of what is known about DEH comes from extensive research on modern and fossil human and non-human primate dentition [e.g., 26–28,35,37,46,54], though it has also been identified in suids [13,14], Miocene and Pleistocene rhinoceros [5,39] and Pliocene and modern giraffe [20,21]. While documented cases are rare in bison, notable amounts have been observed on a small number of archaeological bison assemblages from the Northwestern Plains region, including Casper, Wyoming [63], Ayers-Frazier, Montana [8] and Henry Smith, Montana [64]. ...
... 5 ). DEH has been frequently associated with weaning in humans [28,42,46; but see 51] as well as in pigs [14], giraffe [20,21], and fossil rhinoceros [39]. ...
Article
Bison bison mandibular molars from the Late Plains Archaic kill/butchery sites of Buffalo Creek (Wyoming) and Kaplan-Hoover (Colorado) exhibit significant frequencies of dental enamel hypoplasia (DEH), a defect believed to reflect information about physiological status of individual animals. This study provides a methodology to estimate the ontogenetic and seasonal timing of DEH formation in bison dentition. Integration of these estimates with data from bison life history and grassland ecology allows inferences on age- and season-specific factors exacerbating periodic physiological declines that were recorded in the form of enamel hypoplasias. Differences between assemblages indicate regional variability in grassland conditions, with data from Buffalo Creek pointing to recurrent drought that reduced forage capacity and contributed to physiological stress in bison over two consecutive years. Seasons of physiological stress reflected in the DEH correspond to each of the three kill events at the locality, suggesting that predictability of bison behavior in this location was a critical factor in influencing the seasonal timing and location of repeated hunting episodes. Unlike Buffalo Creek, timings of stress episodes are not consistent with season of death in the Kaplan-Hoover bison assemblage, suggesting that favorable grassland conditions were the primary factor influencing timing of this large single-kill event in order to provision for the upcoming winter. DEH analysis represents a developing approach in the construction of models addressing key aspects of local grassland and bison ecology as well as offers unique insights into the hunting strategies and subsistence decisions of Late Plains Archaic foragers.
... Building on this work, Arbuckle (Unpublished) and Balasse et al. (2010) provided the first evidence that enamel hypoplasia may occur frequently on the teeth of modern and archaeological caprine populations and can easily be identified. Enamel hypoplasia has also been investigated in other high-crowned species (such as giraffe and other African fossil large herbivores: Franz-Odendaal, et al., 2003;Franz-Odendaal 2004;and bison: Niven, et al. 2004;Byerly, 2007, see Kierdorf, et al. 2006 for a critique of this work) using methods based on the Fédération Dentaire Internationale (FDI, 1982), Ensor and Irish (1995) and Dobney and Ervynck (1998). However, none of the above studies addresses problems of dental wear and coronal cementum or uses a systematic strategy for recording of enamel hypoplasia in highcrowned species. ...
... Work by one of us (Arbuckle, unpublished), on caprines from the Neolithic central Anatolian sites of Çatalhöyük and Erbaba, demonstrated very low numbers of hypoplasia recorded in deciduous teeth (as well as on the permanent pre-molars). This pattern was also found in studies of modern and extinct populations of Giraffidae (Franz-Odendaal, et al. 2003;Franz-Odendaal, 2004). ...
Article
This paper outlines the first methodology for recording dental enamel hypoplasia in the high‐crowned dentition of modern and archaeological caprine teeth. The method has been developed and trialed on five caprine populations from Orkney (UK); two modern populations (Shetland and North Ronaldsay breeds) and three Neolithic assemblages from the archaeological sites of Knap of Howar, Skara Brae and Holm of Papa Westray. Problems associated with differential tooth wear, as well as the presence of coronal cementum, are discussed, and recommendations are given on the identification and recording of hypoplastic dental defects in caprines. Copyright © 2012 John Wiley & Sons, Ltd.
... Enamel hypoplasia is a developmental defect that is caused by a disturbance of enamel matrix formation and presents as a deficiency in the thickness of the enamel (Zsigmondy, 1893; Goodman & Rose, 1990;Moggi-Cecchi & Crovella, 1991;Hillson, 1996Hillson, , 2005Kierdorf & Kierdorf, 1997;Guatelli-Steinberg, 2000, 2003Witzel et al. 2008). Enamel hypoplasia is widely considered a good indicator of systemic stress during the period of tooth crown formation, and has been used in numerous studies to retrospectively assess the occurrence of stress episodes during dental development in primates (Goodman & Rose, 1990;Moggi-Cecchi & Crovella, 1991;Hillson, 1996Hillson, , 2005Guatelli-Steinberg, 2000, 2003Skinner & Hopwood, 2004;King et al. 2005;Schwartz et al. 2006;Witzel et al. 2008), as well as in other mammals possessing low-crowned cheek teeth, such as pigs (Dobney & Ervynck, 2000;Dobney et al. 2004;Witzel et al. 2006) and giraffes (Franz-Odendaal, 2004). More recently, the study of enamel hypoplasia as a stress marker has been extended to mammals with high-crowned cheek teeth, such as American bison (Niven et al. 2004) and domestic sheep and goats (Upex, 2010). ...
... In some studies, the location of hypoplastic enamel defects along the vertical axis of the tooth crown was used to reconstruct the timing of stress episodes in relation to dental development (Dobney & Ervynck, 2000;Dobney et al. 2004;Franz-Odendaal, 2004;Niven et al. 2004). These authors divided the tooth crown into vertical stretches of equal length, considered to reflect equal fractions of the crown formation period. ...
Article
Enamel is the most highly mineralized and durable tissue of the mammalian body. As enamel does not undergo remodeling or repair, disturbances of enamel formation leave a permanent record in the tissue that can be used for life history reconstruction. This study reports light and scanning electron microscope findings on hypoplastic enamel defects, and on the chronology of crown growth in the molars of sheep and goats. A marked reduction of enamel extension rates in cervical compared with more cuspal crown portions of sheep and goat molars was recorded, with formation of the cervical 25% of the crown taking about the same time as that of the upper 75% of the crown. This explains the more frequent occurrence of enamel hypoplasia in cervical compared with upper and middle crown portions. Regarding the identification of hypoplastic enamel defects by external inspection, our results suggest a dependence on the type of defect and the associated presence of smaller or larger amounts of coronal cementum. Defects considered to reflect a slight to moderate impairment of secretory ameloblast function can normally be correctly diagnosed as they are not occluded by thick layers of cementum. In contrast, defects denoting a severe impairment of enamel matrix secretion can typically not be correctly identified because they are occluded by large amounts of cementum, so that neither depth nor extension of the defects can be assessed on external inspection. In these cases, microscopic analysis of tooth sections is required for a correct diagnosis of the hypoplastic enamel defects.
... While free-ranging individuals spend a large part of the day browsing, captive giraffes can more easily access food and need less time to consume it (Pellew, 1984). Reported diseases and conditions related to the oral cavity in giraffes are enamel hypoplasia due to systemic or nutritional stress (Franz-Odendaal, 2004) and changes in tooth wear pattern (Clauss et al, 2007) because of food structure and oral stereotypic behaviour (Fernandez et al, 2008). Oral proliferative lesions, including neoplastic as well as hamartomatous lesions, occur rarely in nondomestic artiodactyls (Fecchio et al, 2018;Jones et al, 2018). ...
Article
Complex odontoma is a rare odontogenic lesion reported in rodents (order: Rodentia) and odd-toed ungulates (order: Perissodactyla), to name a few, and only in bovine animals of the order Artiodactyla. A 3-year-old female giraffe presented with a steadily proliferating, firm mass in the rostral mandible. With further expansion and ulceration of the mass, the general condition of the giraffe deteriorated and it was euthanized. Post-mortem examination revealed greyish-white tissue with an irregular arrangement of yellowish hard tissue arranged in thin plates and intermingled areas of greyish soft tissue. Histologically, irregular proliferated odontogenic epithelium and mesenchyme, dentin, cementum and empty spaces, suggestive of decalcified enamel, were present. These findings are consistent with a diagnosis of complex odontoma, which should be added to the differential diagnoses of oral tissue proliferations in giraffes. To our knowledge, this is the first description of a complex odontoma in a giraffe.
... [2,7,14,15,16,24]). One type of hypoplastic defect, mostly termed linear enamel hypoplasia (LEH), has been widely used as an indicator of periods of generalized physiological stress during tooth development in hominid and non-hominid primates [7e10, 22,24,29,33,34], domestic pigs and wild boar [3,4] and other extinct or extant ungulate species [5,6,26,30]. These studies demonstrated that the analysis of LEH is a useful means for retrospective assessment of the timing and intensity of systemic stress events during the period in which an individual's dentition is formed, and can thereby contribute to the understanding of past ecological and health conditions. ...
Article
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Prevalence and intensity of enamel hypoplasia have been used as markers of generalized physiological stress during dental development in a wide range of mammalian taxa. We studied cattle (Bos taurus) cheek teeth exhibiting morphological characteristics that are of relevance to the diagnosis of enamel hypoplasia in this and other bovid species. These characteristics were multiple, more or less horizontally arranged (waveform) lines or grooves in the cementum of the tooth crown and the adjacent root area, leading to an imbricated appearance of the cementum. On macroscopic examination of tooth surfaces, these lines resembled linear enamel hypoplasia (LEH). Microscopic analysis of tooth sections, however, revealed that the lines occurred in the cementum only, and that the underlying enamel did not exhibit morphological irregularities. In cheek teeth of older cattle, a thick cementum layer is regularly found in the cervical crown portion and the adjacent root area. Apposition of this cementum is related to the uplifting of the teeth from their alveoli, a process that compensates for the shortening of the tooth crowns due to occlusal wear. In the studied specimens, a pronounced periodic nature of tooth uplifting and the related deposition of cementum is the likely cause for the observed imbricated appearance of the cementum. While this phenomenon may be misinterpreted as representing a case of LEH, presence of enamel hypoplasia in bovid teeth may be overlooked when the defects become filled with coronal cementum and are therefore not apparent on external inspection. This was the case in one of the cattle teeth analyzed by us, in which the hypoplastic enamel defects were, however, clearly discernible in ground sections. Microscopic analysis of tooth sections is recommended for recording of LEH in bovid teeth in cases where macroscopic examination of tooth surfaces alone does not produce unequivocal results.
... Imbalances of calcium (Ca), phosphorus (P) and/or vitamin D3 have also been shown to affect tooth growth and wear rates (McRoberts et al., 1965;Harcourt-Brown, 1996). Low serum Ca and imbalanced Ca:P ratios have been reported in captive ruminants, with enamel hypoplasia and urolithiasis in captive giraffes (Miller et al., 2003;Franz-Odendaal, 2004). By contrast, hypophosphatemia has been reported in captive D. bicornis (Dennis et al., 2007). ...
Article
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Tooth wear can affect body condition, reproductive success and life expectancy. Poor dental health is frequently reported in the zoo literature, and abrasion-dominated tooth wear, which is typical for grazers, has been reported in captive browsing ruminants. The aim of this study was to test if a similar effect is evident in captive rhinoceros species. Dental casts of maxillary cheek teeth of museum specimens of captive black (Diceros bicornis; browser), greater one-horned (Rhinoceros unicornis; intermediate feeder) and white rhinoceroses (Ceratotherium simum; grazer) were analysed using the recently developed extended mesowear method for rhinoceroses. Captive D. bicornis exhibited significantly more abrasion-dominated tooth wear than their free-ranging conspecifics (p<0.001), whereas captive C. simum exhibited significantly less abrasion-dominated tooth wear, particularly in the posterior cusp of the second molar (p=0.005). In R. unicornis, fewer differences were exhibited between free-ranging and captive animals, but tooth wear was highly variable in this species. In both free-ranging and captive D. bicornis, anterior cusps were significantly more abrasiondominated than posterior cusps (p<0.05), which indicates morphological differences between cusps that may represent functional adaptations. By contrast, tooth wear gradients between free-ranging and captive animals differed, which indicates ingesta-specific influences responsible for inter-tooth wear differences. Captive D. bicornis exhibited more homogenous tooth wear than their free-ranging conspecifics, which may be caused by an increase in the absolute dietary abrasiveness and a decrease in relative environmental abrasiveness compared to their freeranging conspecifics. The opposite occurred in C. simum. The results of this study suggest that diets fed to captive browsers are too abrasive, which could result in the premature loss of tooth functionality, leading to reduced food acquisition and processing ability and, consequently, malnourishment.
... The timing of hypoplastic defects occurring on deciduous and permanent teeth can show how diff erent phases of life history may be more or less stressful and how that might vary across time. Enamel hypoplasia has been studied in the teeth of numerous animals, from giraff es to opossums (Cornay and Mead, 2012 ;Franz-Odendaal, 2004 ). Despite mammals experiencing the same stages of dental development (von Koenigswald, 2000 ), diff erences in tooth morphology and the pace of dental development, in addition to the timing of life-history events, mean that while it is valid to compare changes in the pattern and frequency of hypoplasia within a species over time, between-species comparisons of absolute frequencies are probably inappropriate. ...
Chapter
Historically animals have played an important role in archaeological research as analogues of or surrogates for humans. However, many bioarchaeological signatures used to examine the effect of environmental change on humans also occur on other animals. These common indicators when studied on domesticates and commensals can serve as different lenses on past environmental conditions and can provide a detailed insight into the interplay between humans and other animals. Overlap and variability between species in diet or developmental stresses can be indicative of general conditions that may have affected all species, as well as the specific ecological interactions and consequences for individual species. Thus multiple species analysis is useful for identifying major environmental stressors that affected all species versus cases where humans offset stresses through modifications to environments such as changes in husbandry. In this paper we outline this particular multi-species approach and review its use in Oceania focussing upon analyses of stable isotopes, dental pathology and enamel hypoplasia. Interpretative difficulties can arise from the nature of animal and human assemblages and variability in animal life histories and physiological responses to stressors. Yet the studies discussed here reveal how the multispecies approach can aid understanding of the evolving human niche, and environmental change more broadly.
... This approach is consistent with a recent study examining the relationship between systemic stress and LEH (Franz-Odendaal, 2004). As Franz-Odendaal (2004) noted, the causes of asymmetry in LEH expression are not well-understood. This author suggested that antimeric differences in the timing of eruption may be one cause of asymmetry in the manifestation of LEH. ...
Article
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This study investigates changes in the prevalence of linear enamel hypoplasia (LEH) before and after the shift from irregular to regular provisioning in the Cayo Santiago rhesus monkey population. Prior to 1956, monkeys on this island colony did not receive consistent provisions, and were reported to be in poor health (Rawlins and Kessler [1986] The Cayo Santiago Macaques; Albany: State University of New York Press). A regular provisioning program, instituted in August 1956, resulted in the improved health of individuals and the growth of the population (Rawlins and Kessler [1986] The Cayo Santiago Macaques; Albany: State University of New York Press). LEH, a developmental defect of enamel, is a sensitive indicator of systemic physiological stress (Goodman and Rose [1990] Yrbk. Phys. Anthropol. 33:59-110). It was therefore hypothesized that the prevalence of LEH would be higher in monkeys who were irregularly provisioned than in monkeys who experienced regular provisioning. To test this hypothesis, teeth were examined for LEH in a sample of 181 female rhesus monkeys. The results support the hypothesis: the mean number of defects was statistically significantly higher in the preprovisioned group than it was in the postprovisioned one. When LEH prevalence was assessed using only defects occurring on antimeric pairs, the preprovisioned group again had a higher prevalence than the postprovisioned one, although the difference was not statistically significant, most likely because of the reduced sample size. The results of this study indicate that changes in LEH prevalence, at least in this population of rhesus monkeys, are associated with changes in nutritional status.
... In a study of wild and captive primates, Molnar & Ward (1975) found that all animals had some level of microstruc-tural tooth defects, including hypoplasia, but their incidences were higher in captive individuals. Recently, Franz-Odendaal (2004) has studied the incidence of hypoplasia in the teeth of wild and captive giraffes Giraffa camelopardalis and found that those of wild giraffes lacked defects, while those of captive animals showed lines that corresponded with periods of stress such as weaning. Fagan et al . ...
Article
ABSTRACT The effects of captivity on the behaviour of wild and domestic animals have been relatively well studied, but little has been published on morphological changes in wild animals in captivity. We review the evidence for changes in a wide variety of mammalian taxa, with non-mammalian examples where relevant. We consider the morphological effects of the process of domestication, and compare changes in both hard and soft tissues in captive and domestic animals with those in their wild counterparts. These include skull shape differences, brain size reduction, postcranial adaptations and digestive tract changes. We also summarize studies that have looked at morphological change in feral animals in comparison with their wild and domestic ancestors, and consider their use as an analogue for morphological change in captive-bred animals that have been released into the wild. We then discuss the importance of this work for the wider aims of conservation of endangered species and captive breeding over many generations, and emphasize the importance of studying these changes now, while for many species, the process is just beginning rather than many generations down the line, or immediately prior to release, where survival of captive-bred animals may be severely compromised.
... In a study of wild and captive primates, Molnar and Ward found that all animals had some level of microstructural tooth defects, including hypoplasia, but their incidences were higher in captive individuals [23]. Franz-Odendaal has studied the incidence of hypoplasia in the teeth of wild and captive giraffes Giraffa camelopardalis and found that those of wild giraffes lacked defects, while those of captive animals showed lines that corresponded with periods of stress such as weaning [24]. Fagan et al. [25] discussed the incidence of traumatic breakages of elephant Loxodonta africana and Elephas maximus tusks caused by the captive environment, and noted similar occurrences in walruses Odobenus rosmarus and babirusas Babyrousa babyrussa. ...
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Objective: To investigate wildlife diseases in Nigeria spanning across 20 years, highlighting various conditions diagnosed in zoo/wild animals using conventional and ancillary pathological techniques. Methods: The animals were closely examined for signs of illness by the attending veterinarian and clinical samples were taken as appropriate. Carcasses were submitted for detailed necropsy by the experienced pathologists and diagnostic samples were taken for cytological, microbial isolation, parasitic identification and histopathology. Results: Between 1991 and 2014 about 262 carcasses of zoo animals were presented for postmortem comprising ruminants (12.2%), primates (16.8%), carnivores (11.5%), reptiles (20.6%), Equidae (4.2%), rodents (5%) and aviary (29.7%). Pasteurellosis and other forms of respiratory diseases were common in ruminants; pneumonia, trichuriasis and dndocarditis were common in primates; tuberculosis and helminthiasis (ancylostomiasis) were common in carnivores; enteritis and impaction were common in reptiles; cholera, salmonellosis and Newcastle diseases were common in aviary. Conclusions: It is important to know the causes of death in zoo animals and wildlife for purposes of preservation and conservation.
... While DEH has the potential to provide insight into patterns of physiological disruption during development in non-human mammals, the study of enamel defects in zooarchaeological research is limited with the exception of a few notable examples that focused on suids ( Dobney et al., 2002Dobney et al., , 2004Ervynck, 1998, 2000;Ervynck and Dobney, 1999;Upex et al., 2014;Wang et al., 2012) and bovids ( Byerly, 2007;Kierdorf et al., 2006;Niven, 2000;Niven et al., 2004); paleontological studies have also been conducted on a few fossil species ( Franz-Odendaal et al., 2003;Mead, 1999). More varied studies have been done on a range of living mammals ( Franz-Odendaal, 2004;Kierdorf et al., 1991Kierdorf et al., , 2006Kierdorf et al., , 2012Kierdorf et al., , 2016Mellanby, 1929Mellanby, , 1930Suckling, 1980;Suckling et al., 1983Suckling et al., , 1986Suckling and Purdell-Lewis, 1982;Upex and Dobney, 2012). A species of particular interest for the study of human adaptation in the Arctic is the caribou (Rangifer tarandus groenlandicus). ...
Article
Bioarchaeology as a field of study can contribute important insights to our understanding of how stress-related phenomena experienced in childhood influence later life conditions. One area that is especially effective is looking at the dental enamel surface microstructures reflecting patterns of growth and growth disruption. Since dental enamel grows incrementally, and because it does not remodel once formed, a record of growth disruption (formed during childhood) is preserved for the rest of an individuals' life. Enamel surface defects are commonly observed macroscopically as enamel hypoplasia. However, this method does not capture the smaller defects reflecting a disruption in only a few of the growth lines visible on the tooth surface. Previous approaches to the assessment of these structures have included scanning electron microscopes and polarized light microscopes with photomontaging and z-stacking capacity. This paper presents the application of the Olympus LEXT 3D Laser Measuring Microscope OLS4000 and Olympus LEXT analytical software to capture and examine dental enamel surface microstructures. The use of the LEXT for these purposes is critically assessed, and the strengths and challenges discussed. Recommendations are made for future application of this instrument to bioarchaeological research.
... The studies about EH in extinct and extant species of ungulates have been carried out by different researchers in order to trace out the environmental conditions these species faced during their developmental and growth period (Franz-Odendaal, 2004;Franz-Odendaal et al., ...
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Studies on dental enamel hypoplasia have been used by different paleontologists as stress indicator in evaluation of palaeo-environments. The present study involves the analysis of enamel hypoplasia in seven extinct giraffid species to determine and compare stress periods during the early Miocene to Pleistocene ages of the Siwaliks of Pakistan. Enamel hypoplasia is a tooth malady which is caused by the deficiency of food/nutrients. The feeding deficiency is directly linked to the physiological or environmental stress. In this study occurrence of enamel hypoplasia in giraffids has been observed in species of all time intervals between 18.3-0.6 Ma except the time 11.2-9.0 (late Miocene) that has no giraffids with this dental defect. The comparative percentage for occurrence of enamel hypoplasia in giraffids of these Siwalik deposits is early Miocene-early middle Miocene (29%), middle Miocene (20%), late Miocene-early Pliocene (15%), early Pliocene-late Pliocene (26%) and late Pliocene-early Pleistocene (10%). Prevalence of enamel hypoplasia indicates the existence of stress episodes and percentage displays the comparative intensity of these stresses in the Neogene and Quaternary period of the Siwalik region. These stress episodes are due to the climatic, vegetational, ecological and faunal changes during these time spans. These early Miocene to Pleistocene stress events may have played a key role in evolution and speciation of the Siwalik fauna especially the mammals.
... 96 While DEH has the potential to provide insight into patterns of physiological disruption 97 during development in non-human mammals, the study of enamel defects in zooarchaeological 98 research is limited with the exception of a few notable examples that focused on suids ( Dobney 99 et al., 2002, Dobney and Ervynck, 1998, 2000Ervynck and Dobney, 1999;Upex et al., 100 2014;Wang et al., 2012) and bovids ( Byerly, 2007;Kierdorf et al., 2006;Niven, 2000;Niven et 101 al., 2004); paleontological studies have also been conducted on a few fossil species ( Franz102 Odendaal et al., 2003;Mead, 1999). More varied studies have been done on a range of living 103 mammals ( Franz-Odendaal, 2004;Kierdorf et al., 1991, 2006, 2012, Mellanby, 1929, 104 robust data collection can proceed, yielding quantifiable results that will provide insights on 140 caribou herd dynamics over time. 141 ...
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Dental enamel defects have been used extensively in past human populations to elucidate patterns of health and physiological disruption (often simply referred to as stress). These defects are most commonly assessed through visual examination and used to infer such information as the frequency and age at occurrence of stress events. However, a microscopic approach makes it possible to more consistently identify patterns of growth and growth disruption in greater detail than that possible with traditional macroscopic techniques. Such microscopic studies are being increasingly explored in bioarchaeology, but this area of investigation has not seen extensive application to zooarchaeological material. Consequently, enamel defects in general have not been integrated as heavily in this field. A species of particular importance within the modern context of climate change is the barren-ground caribou (Rangifer tarandus groenlandicus). This species has been a crucial species to the human populations throughout the Arctic for thousands of years, and herd fluctuations have in the past shaped the human experience. The study of past stress in these populations could provide significant historical insight into herd patterns, which would have impacted subsistence and mobility patterns, and traditional use of these animals among both past and contemporary human populations. This paper presents the results of a pilot study using the Olympus LEXT Laser-Scanning Confocal Microscope OLS4000 to evaluate enamel growth in an archaeological caribou tooth from the LdFa-1 site (a large caribou hunting site located in the deep interior of southern Baffin Island). Our study demonstrates the potential of this technology to capture enamel surface microstructures and to provide greater insight into the fine patterns of growth arrest within this zooarchaeological context.
... Modern specimens of eastern grey kangaroo (Macropus giganteus Shaw, 1790) (Kierdorf et al. 2016), North American opossums (Didelphis virginiana Kerr, 1792) (Cornay and Mead 2012), several non-human primate species (e.g., Moggi-Cecchi and Crovella 1991;Guatelli-Steinberg 2000;Skinner and Hopwood 2004), giraffe (Giraffa camelopardalis Linnaeus, 1758) (Franz-Odendaal 2004), pigs (Suidae) (Kierdorf et al. 2000;Dobney et al. 2004), white-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) (Davis and Mead 2013), red deer (Cervus elaphus Linnaeus, 1758) (Kierdorf and Kierdorf 1997), western roe deer (Capreolus capreolus (Linnaeus, 1758)) (Kierdorf and Kierdorf 1997), and Old World domestic sheep (Ovis aries Linnaeus, 1758) and goats (Capra hircus Linnaeus, 1758) (Balasse et al. 2010;Kierdorf et al. 2012Kierdorf et al. , 2013Upex and Dobney 2012;Upex et al. 2014) have been documented as having DEHs. Paleozoologists have reported DEHs among ancient remains of Old World domestic sheep and goats (Gifford-Gonzalez 1985), pigs Ervynck 1998, 2000), North American bison (genus Bison C.H. Smith, 1827) (Wilson 1988;Niven et al. 2004), North American horses (genus Equus Linnaeus, 1758) (Timperley and Lundelius 2008), and North American rhinoceroses (genus Teleoceras Hatcher, 1894) (Mead 1999). ...
Article
Dental enamel hypoplasias have been documented in extant and fossil mammal species and attributed to several kinds of physiological stress. They have not previously been reported among bighorn sheep (Ovis canadensis Shaw, 1804). Forty-six (36.8%) of 125 mandibular molars (m1, m2, m3) of bighorn recovered from disturbed Holocene archaeological deposits in eastern Washington state display several kinds of hypoplasias. The exact ontogenetic age of the individual animals when hypoplasias formed cannot be determined. The majority of the hypoplasias occur near the root-enamel junction of the m3, suggesting that most individuals were young adults when the defect formed. Physiological stress associated with reproductive costs, winter nutritional deficits, or both seems likely.
... Imbalances of calcium (Ca), phosphorus (P) and/or vitamin D3 have also been shown to affect tooth growth and wear rates (McRoberts et al., 1965;Harcourt-Brown, 1996). Low serum Ca and imbalanced Ca:P ratios have been reported in captive ruminants, with enamel hypoplasia and urolithiasis in captive giraffes (Miller et al., 2003;Franz-Odendaal, 2004). By contrast, hypophosphatemia has been reported in captive D. bicornis (Dennis et al., 2007). ...
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Tooth wear can affect body condition, reproductive success and life expectancy. Poor dental health is frequently reported in the zoo literature, and abrasion-dominated tooth wear, which is typical for grazers, has been reported in captive browsing ruminants. The aim of this study was to test if a similar effect is evident in captive rhinoceros species. Dental casts of maxillary cheek teeth of museum specimens of captive black ( Diceros bicornis ; browser), greater one-horned ( Rhinoceros unicornis ; intermediate feeder) and white rhinoceroses ( Ceratotherium simum ; grazer) were analysed using the recently developed extended mesowear method for rhinoceroses. Captive D . bicornis exhibited significantly more abrasion-dominated tooth wear than their free-ranging conspecifics ( p <0.001), whereas captive C . simum exhibited significantly less abrasion-dominated tooth wear, particularly in the posterior cusp of the second molar ( p =0.005). In R . unicornis , fewer differences were exhibited between free-ranging and captive animals, but tooth wear was highly variable in this species. In both free-ranging and captive D . bicornis , anterior cusps were significantly more abrasiondominated than posterior cusps ( p <0.05), which indicates morphological differences between cusps that may represent functional adaptations. By contrast, tooth wear gradients between free-ranging and captive animals differed, which indicates ingesta- specific influences responsible for inter-tooth wear differences. Captive D . bicornis exhibited more homogenous tooth wear than their free-ranging conspecifics, which may be caused by an increase in the absolute dietary abrasiveness and a decrease in relative environmental abrasiveness compared to their freeranging conspecifics. The opposite occurred in C . simum . The results of this study suggest that diets fed to captive browsers are too abrasive, which could result in the premature loss of tooth functionality, leading to reduced food acquisition and processing ability and, consequently, malnourishment.
... Small horizontal linear pits and horizontal linear grooves are known as linear enamel hypoplasia. Linear defects have been associated with different systemic stressors (e.g., weaning, parturition, nutritional stress, and illness) at the time of tooth formation (Franz-Odendaal 2004;Franz-Odendaal et al. 2004). Some researchers consider that the width and depth of linear enamel hypoplasia correspond, respectively, to the duration of the stress episode and its severity (Goodman et al. 1980;Suckling 1989). ...
Article
Approximately 50,000–11,000 years ago many species around the world became extinct or were extirpated at a continental scale. The causes of the late Pleistocene extinctions have been extensively debated and continue to be poorly understood. Several extinction models have been proposed, including two nutritionally based extinction models: the coevolutionary disequilibrium and mosaic-nutrient models. These models draw upon the individualistic response of plant species to climate change to present a plausible scenario in which nutritional stress is considered one of the primary causes for the late Pleistocene extinctions. In this study, we tested predictions of the coevolutionary disequilibrium and mosaic-nutrient extinction models through the study of dental wear and enamel hypoplasia of Equus and Bison from various North American localities. The analysis of the dental wear (microwear and mesowear) of the samples yielded results that are consistent with predictions established for the coevolutionary disequilibrium model, but not for the mosaic-nutrient model. These ungulate species show statistically different dental wear patterns (suggesting dietary resource partitioning) during preglacial and full-glacial time intervals, but not during the postglacial in accordance with predictions of the coevolutionary disequilibrium model. In addition to changes in diet, these ungulates, specifically the equid species, show increased levels of enamel hypoplasia during the postglacial, indicating higher levels of systemic stress, a result that is consistent with the models tested and with other climate-based extinction models. The extent to which the increase in systemic stress was detrimental to equid populations remains to be further investigated, but suggests that environmental changes during the late Pleistocene significantly impacted North American equids.
... Ahmad et al. (2018) studied enamel hypoplasia (EH) in six jaw fragments and noted that EH is more prevalent in the members of the family Giraffidae than in other animals. He observed that it was due to environmental or nutritional stress during the development and growth period, specifying that environmental alteration in different regions would cause comparatively more stress to giraffids (Hall-Martin 1976;Franz-Odendaal 2004;Franz-Odendaal et al. 2004). In current study, PUPC 15/423 (M1) [ Fig. 4a] represents an enamel hypoplasic line (24.05 ...
Article
Giraffokeryx punjabiensis is reported from Dhok Bun Amir Khatoon (DBAK), district Chakwal, Punjab, Pakistan. The newly recovered material includes two maxillary fragments, three mandibular rami, and seven isolated teeth. The well-preserved specimens enhance our knowledge about G. punjabiensis and can be used as a reference material in the future. The existence of G. punjabiensis along with Dorcatherium and suids suggests the presence of wet meadows, floodplain, and open woodland at the time of the early Middle Miocene deposition in Dhok Bun Amir Khatoon, Lower Siwalik Subgroup. A few studied specimens clearly showed signs of enamel hypoplasia as a nutritional and ecological stress indicator for the late Middle Miocene giraffids of Dhok Bun Amir Khatoon.
... Such morphology of enamel hypoplasia (in contrast with the morphology of adjacent lines within the same tooth), suggests a greater intensity of the stressor, or the interaction of two or more factors (Goodman and Rose, 1990). That might be consistent with the long dietary and behavioral transition of the weaning, known to be one of the most stressful periods in various large-bodied mammals (Mead, 1999;Dobney and Ervynck, 2000;Franz-Odendaal, 2003;Franz-Odendaal et al., 2004;Niven et al., 2004;Witzel et al., 2006). ...
Article
The Coc Muoi fauna provides a good example of the type of tropical mammalian communities that existed in northern Vietnam during the late Middle Pleistocene. The first results of the analysis of hypoplasia indicated that rhinoceroses and wild cattle were exposed to multiple physiological and psychological stress events specific to age [Bacon et al., 2018. A rhinocerotid-dominated megafauna at the MIS6-5 transition: The late Middle Pleistocene Coc Muoi assemblage, Lang Son province, Vietnam. Quat. Sci. Rev. 186, 123–141]. In this paper, we aim to supplement the study of hypoplasia in the orangutans (Pongo) from Coc Muoi and, more widely, from different Pleistocene faunas. To address this issue, we conducted a macroscopic analysis of linear enamel hypoplasia [LEH] on Pongo from three collections: Coc Muoi (148–117 ka), Duoi U'Oi (70–60 ka), and Tham Khuyen (>475 ka). Such comparative analysis based on isolated teeth is constrained by numerous biases including: the small datasets; the differential representation of tooth types; the difficulty in distinguishing first from second molars; the small number of individuals [MNI]; the differential representation of males versus females. The data analysis has been divided into two parts: (1) an analysis of the frequency and expression of LEH on incisors, premolars, and molars (three sites), and (2) an analysis of the frequency and expression of LEH on a set of canines (Tham Khuyen). We used a reference sample composed of 17 adult and 10 immature Pongo individuals to determine the age range of fossil Pongo individuals, at the time of the defects. Results show that hypoplasia was a common phenomenon in Pleistocene Pongo: two individuals at Coc Muoi; 2 out of 3 individuals at Duoi U’Oi; and 4 out of 6 individuals at Tham Khuyen. They experienced multiple stresses between ∼2 and 5 years of age, a period of great vulnerability for immature individuals. The occurrence of accentuated lines of hypoplasia on canine crowns of Tham Khuyen suggests a greater intensity of the stressor, in a time range consistent with the long dietary and behavioral transition of the weaning. In terms of paleoecology, Pleistocene orangutans from the Asian mainland could survive in different environmental conditions than those they occupy today. Various sources (archaeozoology, geological context, and ecology of wild populations), suggest that they might have been larger apes than extant orangutans, living in limestone forests on hills and tower karsts.
Article
Analysis of mammalian teeth can provide information regarding local environmental conditions. For example, a high incidence of breakage and wear within a population may indicate poor food quality. Individuals consuming a diet causing high mechanical stress on their teeth, and/or lacking the appropriate minerals for proper development, could experience degradation of tooth condition. Previously, we documented a high rate of incisor tooth breakage, with age, in two genetically distinct moose populations in Atlantic Canada. In this study, multi-element (11B, 63Cu, 64Zn, 75As, 85Rb, 88Sr, 111Cd, 118Sn, 137Ba, 208Pb, 232Th, and 238U) analyses using laser ablation ICP-MS were performed on moose incisors from multiple North American regions. The purpose was to determine whether the elemental composition of moose incisors varies among regions, and whether that variation is related to tooth degradation among Atlantic Canadian populations. A principal components analysis revealed that nearly 50% of the elemental variation in the inner enamel matrix of moose teeth was explained by three groupings of elements. The element groupings revealed differences among geographic regions, but did not explain the variation between incisors that were broken and those that were not. Regression models indicate that the elemental group which includes Cu, Pb, and Zn is related to decreases in incisal integrity. It is likely that other environmental factors contribute to the occurrence of increased incisor breakage in affected populations. The relationship between food resource quantity and quality, as a function of moose density, is hypothesized to explain loss of tooth integrity.
Article
We studied the relationship between the macroscopic appearance of hypoplastic defects in the dental enamel of wild boar and domestic pigs, and microstructural enamel changes, at both the light and the scanning electron microscopic levels. Deviations from normal enamel microstructure were used to reconstruct the functional and related morphological changes of the secretory ameloblasts caused by the action of stress factors during amelogenesis. The deduced reaction pattern of the secretory ameloblasts can be grouped in a sequence of increasingly severe impairments of cell function. The reactions ranged from a slight enhancement of the periodicity of enamel matrix secretion, over a temporary reduction in the amount of secreted enamel matrix, with reduction of the distal portion of the Tomes' process, to either a temporary or a definite cessation of matrix formation. The results demonstrate that analysis of structural changes in dental enamel allows a detailed reconstruction of the reaction of secretory ameloblasts to stress events, enabling an assessment of duration and intensity of these events. Analysing the deviations from normal enamel microstructure provides a deeper insight into the cellular changes underlying the formation of hypoplastic enamel defects than can be achieved by mere inspection of tooth surface characteristics alone.
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The developmental or usage patterns experienced in the dentition by certain mammals during their growth or later in life often are preserved in their fossilized remains and have extensively been used in reconstructing life-history or the habitat in which the animals lived. One such, though lesser emphasized, feature is the enamel hypoplasia (EH), which is a failure for the enamel to form properly leaving distinct linear or curved marking(s) on the teeth. EH is caused by environmental or physiological stresses in an animal's life at that particular time when the growth was taking place. Hence, the EH analysis in a faunal accumulation has been used for providing a unique perspective into environmental conditions present during the growing years of an extinct animal's life. The present study on EH of Siwalik Rhinocerotids has proved to be an important tool for not only understanding their past life-history but also in reconstructing local palaeoenvironment and regional palaeoclimate of the region.
Article
We describe a developmental defect that manifests as a mild constricted "waist" in anterior teeth from seven of nine chimpanzee individuals from Taï National Park, Côte D'Ivoire. The sample consists of 21 canine teeth and one incisor, imaged in profile with a digital microscope. Twelve teeth are affected. The waist develops during tooth formation as an external, encircling depression in the contour of the outer enamel surface, more easily seen labially. It is not a thinning of enamel per se, but rather a slight decrement in dentinal crown volume, shown in microCT scans as a change in contour of the enamel-dentin junction, spanning between 3 and 6 years of age, varying among individuals, with maximum expression at about age 4.3 years. The timing and duration of coronal waisting are consistent with descriptions of the weaning process at Taï and other chimpanzee study sites. We propose that coronal waisting records variation in the individual infant chimpanzee's physiological experiences during the process of attaining independence, increased foraging efficiency, and lactational weaning. Am J Phys Anthropol 149:272-282, 2012. © 2012 Wiley Periodicals, Inc.
Article
We studied the presence of linear enamel hypoplasias (LEHs; tooth defects associated with physiological stress) in caribou (Rangifer tarandus). A timeline of tooth enamel development was determined by radiographic examination of 48 mandibles from caribou aged 3–24 months old. We examined mandibles from the Bluenose East (n = 56) and Bluenose West (n = 15) caribou herds in the Northwest Territories and Nunavut, Canada, for LEHs and 21.1% (15/71) were affected. We concluded that LEHs do occur in caribou and tracking these over time may provide a tool to track population dynamics in extant wildlife. © 2012 The Wildlife Society.
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IntroductionAnimal Paleopathology: A Brief HistoryProblemsWhat can we Learn from Animal Paleopathology?Human Exploitation of AnimalsAnimal Husbandry PracticesCultural Attidudes to AnimalsClimate and EnvironmentThe Future of Animal PaleopathologyReferences
A skull of Anchisaurus polyzelus (YPM 1883) has been misinterpreted for over 120 years as a result of deformation during preservation and loss of a small piece of the skull block shortly after collection in 1884. The only other skull of this taxon (YPM 209), from a smaller individual, has been largely ignored in previous studies owing to distortion and incomplete preparation. Additional preparation of the latter specimen has exposed several new elements, including the nearly complete parabasisphenoid, a region that is damaged and incomplete in YPM 1883. Based on this new information, a phylogenetic analysis supports the recent hypothesis that Anchisaurus was a basal sauropod. However, the strength of this hypothesis has been greatly reduced, and is also undermined further by the possibility that the specimens of Anchisaurus are skeletally immature. In general, the skull and braincase of Anchisaurus resembles those of 'prosauropods' more closely than those of derived sauropods.
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Captive giraffe (Giraffa camelopardalis) mostly do not attain the longevity possible for this species and frequently have problems associated with low energy intake and fat storage mobilization. Abnormal tooth wear has been among the causes suggested as an underlying problem. This study utilizes a tooth wear scoring method ("mesowear") primarily used in paleobiology. This scoring method was applied to museum specimens of free-ranging (n=20) and captive (n=41) giraffes. The scoring system allows for the differentiation between attrition--(typical for browsers, as browse contains little abrasive silica) and abrasion--(typical for grazers, as grass contains abrasive silica) dominated tooth wear. The dental wear pattern of the free-ranging population is dominated by attrition, resembles that previously published for free-ranging giraffe, and clusters within browsing herbivores in comparative analysis. In contrast, the wear pattern of the captive population is dominated by abrasion and clusters among grazing herbivores in comparative analyses. A potential explanation for this difference in tooth wear is likely related to the content of abrasive elements in zoo diets. Silica content (measured as acid insoluble ash) is low in browse and alfalfa. However, grass hay and the majority of pelleted compound feeds contain higher amounts of silica. It can be speculated that the abnormal wear pattern in captivity compromises tooth function in captive giraffe, with deleterious long-term consequences.
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A method is proposed for recording linear enamel hypoplasia (LEH) present on archaeological pig teeth. The methods described have been developed and tested on material from five archaeological sites of a wide range of periods; Durrington Walls (UK), Wellin, Ename, Sugny and Londerzeel (Belgium). Recommendations are made on what teeth, surface, cusp, and side to record, as well as on details of the visibility, the identification and the measurement of LEH lines. Problems encountered with the application of the recording protocol to the five case studies are detailed, and possible interpretative drawbacks are discussed. © 1998 John Wiley & Sons, Ltd.
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The dentition of 27 enslaved African Americans from archaeological sites in Maryland and Virginia were examined. All 17 males and 7 of the 10 females in this study exhibited enamel hypoplastic defects indicative of systemic nutritional and disease stresses interfering with amelogenesis. Estimates of the ages of occurrence of these defects show that most occur between 1.5 and 4.5 years of age, 0.5-3.75 years later than historically documented weaning age (9-12 months of age) in similar plantation populations. Comparisons are made with studies of dental enamel hypoplasia in contemporaneous enslaved and free African American populations, including our data on 75 individuals from the First African Baptist Church cemetery in Philadelphia. These populations were highly stressed. While there appears to be a modest effect of early weaning stress, no direct relationship of peak frequencies to weaning age can be shown. These data raise questions about the attribution of peak hypoplasia frequencies to age at weaning or "post-weaning" stresses in previous paleopathological studies. High hypoplasia frequencies during the middle years of enamel development are more likely the result of a combination of 1) multiple environmental stresses, 2) differences in hypoplastic susceptibility in enamel, and 3) random factors.
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A high prevalence of enamel hypoplasia in several herbivores from the early Pliocene Langebaanweg locality, South Africa, indicates general systemic stress during the growing years of life. The presence of several linear enamel hypoplasias per tooth crown in many teeth further suggest that these stress events may be episodic. The delta18O values along tooth crowns of mandibular second molars of Sivatherium hendeyi (Artiodactyla, Giraffidae) were used to investigate the cause of the stress events in this tooth type. Results show that weaning in this fossil giraffid occurred at a similar ontogenetic age to that in extant giraffes, and that the observed enamel hypoplasia towards the base of this tooth type manifested post-weaning. Further, high-resolution oxygen isotope analyses across S. hendeyi third molars suggest that the entire development of defective tooth crowns occurred under conditions of increased aridity in which the cool, rainy part of the seasonal cycle was missing. The high prevalence of this defect in many herbivores suggests that climatic conditions were not favourable. This study reiterates the value of stable isotope analyses in determining both the behaviour of fossil animals and the environmental conditions that prevailed during tooth development.
Article
Deals mainly with fossils from late Tertiary strata along the W coastal margin of the subcontinent ranging in age from early Miocene to late Pliocene. Terrestrial vertebrates are rare and most of the finds are in marine strata. Changes during the late Tertiary are summarised and there are notes on environmental changes and sea level fluctuations. -K.Clayton
Article
Harris lines are osteological markers of recovery from an episode of growth arrest that have been utilized primarily to track fluctuations in the health of prehistoric human communities. The transverse lines are visible in radiographs of long bones and should be visible in well-preserved fossil material. Here, we test their utility for non-hominid fossils in an analysis of late Pleistocene mammals from the extensive collections of the Rancho La Brea tar seeps. The species examined include dire wolf (Canis dims), coyote (C. latrans), sabertooth cat (Smilodon fatalis), bison (Bison antiquus), camel (Camelops hesternus), and horse (Equus laurentius). The tar pits range in age from about 33,000 years ago to near the time of last appearance of all these species but the coyote, about 11,000 years ago. The frequency of Harris lines in the bones of the fossil mammals ranged from less than one percent to nearly seven percent. These frequencies were compared with those found in samples of presumed healthy and possibly food-stressed populations of modern mammalian herbivores and carnivores. Harris line frequencies in the Pleistocene mammals did not differ significantly from those of the presumed healthy modern populations but were significantly lower than that of one of the possibly stressed populations, the highly endangered Florida panther (Puma concolor coryi). This suggests that the late Pleistocene species were not suffering from unusual levels of poor health, even as they approached the extinction horizon. This study of Harris line incidence in both modern and fossil mammal populations demonstrates their utility for future studies of paleofaunas.
Article
Quarry samples of lower cheek teeth of the Miocene rhinoceros Teleoceras are analyzed for the presence of enamel hypoplasia using macroscopic, thin-section, and scanning electron microscopic techniques. The presence of enamel pits, furrows, and grooves is noted predominantly on, but not limited to, the buccal side of dp4s. The enamel defect is not as common on permanent teeth, but does occur with decreasing frequency on p4s, mls, m2s, and m3s.Analysis of the formative sequence of deciduous cheek teeth in Teleoceras and the extant rhinoceros Diceros bicornis suggests that the Teleoceras dp4 was developing in the alveolus at the time of birth. Varying degrees of wear on the dp4s exhibiting enamel hypoplasia imply that the defect-producing stress did not result in immediate death. Isolation of the enamel hypoplasia to distinct bands on the Teleoceras dp4s suggests causes linked to non-lethal severe physiological stress due to metabolic disruption or nutritional deficiency occurring at or very near birth. The Teleoceras p4 was probably developing in the alveolus between three and five years of age. The observed p4-hypoplasias appear to reflect physiological stresses not related to weaning, but to some other stressful period such as cow-calf separation prior to the birth of the next offspring.
Article
Almost two thousand mandibular teeth of the short-necked giraffid, Sivatherium hendeyi, from Lange-baanweg, South Africa, were examined for dental pathologies. Enamel hypoplasia is present in 0 to 34 percent of deciduous teeth and 40 to 75 percent of permanent teeth. No linear enamel hypoplasias were found in the deciduous teeth, while 20 to 35 percent of the permanent teeth have this defect. The linear defects at the base of the first molar are thought to relate to stress associated with weaning. The defects in the later erupting permanent teeth are, however, widely distributed over tooth crowns. Several linear defects are present on some teeth suggesting that these stress episodes were periodic. We propose that poor environmental conditions, possibly seasonal nutritional stress, are responsible for the observed enamel hypoplasia in the permanent dentition of S. hendeyi. This study provides new insight into the current understanding of the paleoenvironment at Langebaanweg, South Africa.
Article
Thirteen tooth eruption stages and their corresponding chronological ages are descri bed from a series of giraffe jaws. These can be used for age determination in giraffes with immature dentition. Significant correlations of the lingual crown height (r=0-957; P < 0001) and lingual occlusal surface width (r=0-959; P < 0001) with the number of dark staining incremental lines in the cementum of thin decalcified sections of the maxillary first molar were found. The regression equations derived from these relationships provide a further method for determining the age of a giraffe. A composite plate showing maxillary first molar wear patterns provides a means of roughly assigning an age to a particular specimen. Thin sections of undecalcified teeth, mandible measurements, various other indices of tooth wear and eye lens mass were investigated and found unsuitable for age determination in this
Article
Dental enamel hypoplasias are deficiencies in enamel thickness resulting from physiological perturbations (stress) during the secretory phase of amelogenesis. The results of a wide variety of experimental, clinical, and epidemiological studies strongly suggest that these defects and their associated histological abnormalities (such as accentuated stria of Retzius and Wilson bands) are relatively sensitive and nonspecific indicators of stress. Because of the inability of enamel to remodel, and the regular and ring-like nature of their development, these defects can provide an indelible, chronological record of stress during tooth crown formation. For these reasons, along with the ease with which they are studied, enamel hypoplasias have been increasingly employed as indicators of nutritional and disease status in paleopathology, and their study has begun to extend into other subdisciplines of physical anthropology.
Article
Frequencies and morphological and chronological distributions of enamel hypoplasias are presented by tooth type (permanent I1 to M2s), based on a sample of 30 prehistoric Amerindians with complete and unworn dentitions. There is nearly a tenfold variation in frequency of defects by tooth, ranging from 0.13 per mandibular second molar to 1.27 per maxillary central incisor. The six anterior teeth average between 0.70 and 1.27 defects/tooth, whereas the eight posterior teeth average between 0.43 and 0.13 defects/tooth. Earlier developing teeth, such as incisors, have earlier peak frequencies of defects (2.0–2.5 years), while later developing teeth, such as second molars, have subsequent peak frequencies (5.0–6.0 years). These variations are relevant when comparing hypoplasia data based on different teeth. Differences in hypoplasia frequencies among teeth are not solely due to variation in time of crown development, as is usually reported. Rather, there is evidence for biological gradients in susceptibility to ameloblastic disruption. Anterior teeth are more hypoplastic than posterior teeth. More developmentally stable “polar” teeth are more hypoplastic than surrounding teeth. Polar teeth may be more susceptible to hypoplasias because their developmental timing is less easily disrupted. In all teeth, hypoplasias are most common in the middle and cervical thirds. Crown development and morphological factors, such as enamel prism length anddirection, may influence the development and expression of enamel surface defects.
Article
Structural changes resulting from fluoride-induced disturbances of the secretory stage of amelogenesis were studied in fluorosed dental enamel of ten permanent premolars and molars from roe deer (Capreolus capreolus) and red deer (Cervus elaphus). The fluorosed enamel exhibited surface hypoplasias of different depths and extents and an associated loss of its normal prism/interprism structure. The occurrence of such aprismatic enamel either was restricted to grossly accentuated and hypomineralized incremental (calciotraumatic) bands or affected more extended areas to the bottom of the hypoplastic lesions. The fluoride-induced disturbance of the secretory functions of the cells had thus been either temporary or permanent. Layers of aprismatic enamel were regarded as denoting periods of reduced enamel matrix formation by secretory ameloblasts lacking the distal, i.e., the prism-forming, portions of their Tomes processes. Our observations also indicated that the transition from the presecretory to the secretory stage of amelogenesis could be affected by fluoride, thereby preventing the ameloblasts from achieving their normal secretory function and from establishing fully formed Tomes processes. Aprismatic enamel was formed throughout the secretory stage of amelogenesis at these locations. The most severe ameloblast reaction that could be deduced from our findings was an abrupt cessation of enamel matrix secretion. Some of the pathological changes observed in fluorosed deer enamel showed striking similarities to those reported in rodents after acute parenteral fluoride dosing. Thus, periods of especially elevated plasma-fluoride levels in chronically fluoride-stressed deer can cause a disruption in the function of secretory ameloblasts similar to that following acute fluoride dosing in rodents.
Article
The differences between Middle and Upper Palaeolithic cultures from Europe have been likened to the contrast between generalized and complex hunter–gatherers. A test of this model is undertaken by comparing the types, amount, severity and timing of episodes of enamel hypoplasia between the two periods among specimens from western Europe and the circum-Mediterranean area. The earlier sample consists of 59 dentally immature individuals with 128 primary and 154 permanent teeth while the later sample consists of 47 dentally immature individuals with 162 primary and 125 permanent teeth. It was predicted that the Upper Palaeolithic would show more variation in the attributes noted above as a consequence of increased social differentiation. While the prevalence (50% of individuals) and severity of enamel hypoplasia do not differ between the samples, the Upper Palaeolithic component is significantly more variable in the types and timing of enamel defects. Localized hypoplasia of the primary canine is absent from the Middle Palaeolithic but very common among Upper Palaeolithic children. Earlier work has linked this enamel defect to craniofacial osteopenia due to low bioavailability of vitamin A. Linear enamel hypoplasia peaks at age 3·5 years in the Middle Palaeolithic sample but is as common at age 2·0 as 5·0 years in the Upper Palaeolithic sample. The age distribution differs significantly. Peak age at stress, combining all types of enamel hypoplasia, is 3·5 years in the Middle Palaeolithic and 0·5 years in the Upper Palaeolithic. The major contrast between the Middle and Upper Palaeolithic in terms of enamel hypoplasia is the advent of stressful episodes in early infancy in the Upper Palaeolithic. This is attributed to the low bioavailability of vitamin A due to the synergistic effects of malnutrition and infection exacerbated by a net increase in population density among socially competitive family lineages.
Article
By recording abnormal incremental lines, known as linear enamel hypoplasia (LEH), visible on the tooth crowns of numerous archaeological pigs' teeth, it has been possible to construct a chronology of physiological stress for five different archaeological assemblages. The results confirm that LEH is a common occurrence in all the populations investigated. Given the geographical and temporal differences between the sites studied, LEH in pigs is thus likely to be a frequently observable phenomenon. Analysis of the frequency distribution of the height of each LEH lesion on the lingual surface of each cusp of each molar shows that the occurrences of LEH follow clear patterns. Taking into account the published data on tooth crown growth in the modern domestic pig, it is proposed that birth and weaning are the direct causal agents of the two discrete peaks noted on the first permanent molar (M1), whilst a period of under-nutrition encountered during the first winter of the animals' life is thought to be the main causal factor for the occurrence of the single distinct LEH peak noted on the second permanent molar (M2). A broad peak on the third permanent molar (M3) is similarly interpreted. These links between patterns of LEH and the normal developmental physiology of the animal open a number of possibilities for interpretation.
Article
Summary in English. Word processed copy. Thesis (Ph. D.(Archaeology))--University of Cape Town, 2002. Includes bibliographical references (leaves 228-243).
Article
Two hundred black and white adult human skeletons and 200 living black and white children from the greater Cleveland area were examined for evidence of enamel hypoplasia. Enamel hypoplasia, present in varying expressings (pits, lines and grooves), was found to be more prevalent in both skeletal samples, than in the living groups. In the majority of cases, sex differences between white and black males and females through time and space are highly significant for all tooth catagories. Regardless of the mechanisms behind it, prevalence of enamel hypoplasia for both white and black group has significantly declined through time. No evidence suggesting specific etiologies responsible for enamel hypoplasia can be found. In the majority of previously published reports, the etiology is still idiopathic. The reduction in the prevalence of enamel hypoplasia in the groups examined through time may be related to improved nutritional conditions and the elimination or decline of childhood diseases that have been implicated in this condition.
Article
Incisor teeth from 5- to 6-year-old Holstein-Friesian cattle maintained on a ration averaging 40 ppm F annually from 4 months of age were analyzed by a variety of histologic techniques. These techniques included photomicroscopy, microradiography, protein staining, and microhardness testing. The features of fluorotic enamel that were noted were: hypomineralized outer enamel, coronal cementum hyperplasia, disrupted subsurface pigment band, hypoplastic pits, puckered incremental lines, periodic radiolucent regions, positive protein staining, and decreased microhardness of the outer enamel. These results were similar to the lesions of dental fluorosis observed in other species, and explain the external appearance of fluorotic bovine teeth observed under field conditions.
Article
Histological enamel defects have been used as indicators of childhood morbidity and nutritional inadequacy. However, the usefulness of these defects has been hampered by a lack of clear criteria for differentiating normal and defective enamel. This report demonstrates that the criteria of abnormal prism structure can accurately differentiate defective enamel (i.e., pathological bands) from normal enamel. In addition, pathological bands can be divided into three distinct subtypes: distorted structure bands, black spot pathological bands, and structureless pathological bands. It has been assumed that the patterning of pathological bands and enamel hypoplasia is the same for all populations. Comparisons between populations show that each population has its own unique pattern. It has also been assumed that striae of Retzius, pathological bands, and enamel hypoplasias represent three grades of severity of the same phenomenon. Correlations between these three features demonstrate instead that this patterning is possibly influenced by the morphology of the teeth.
Article
Developmental defects of enamel are visible deviations from the normal translucent appearance of tooth enamel resulting from enamel organ dysfunction. In the past, information about the activities of the ameloblasts has determined the terminology used to describe the lesions. Advances in our understanding of the complicated secretory and maturation phases of amelogenesis have required a re-appraisal of the concepts of defect formation. The phase of ameloblast activity, the duration of the disturbance, and its severity leading to temporary or permanent inactivity of the cells determine the appearance of the three common types of lesions--hypoplasia, and diffuse and demarcated opacities.
Article
Recent studies of teeth from prehistoric children have reported a localized, roughly circular patch of deficient enamel on the labial aspect of the primary canine, which reaches its highest prevalence in the Upper Paleolithic of Europe. This study reports social and biological correlates of 33 affected kindergarten-aged children from Vancouver, Canada (2.4% of 1,350 examined). Affected children can be characterized as coming from low-income families often of East Asian or Chinese origin in which there is a degree of milk avoidance and reduced breastfeeding. The defect appears to be due to minor physical trauma to the face approximately 6 months after birth occasioned by normal motor development, involving handling and mouthing objects, which damages the developing tooth crown through deficient cortical bone over the canine crypt. Reduced cortical bone in the face of the infant is attributed to nutritional factors, involving calcium deficiency, of the mother and/or developing infant.
Article
An abnormality of enamel formation, detected only recently in living children, was found in a majority of prehistoric children, some from more than 20,000 years ago. The lesion, roughly a circular area of enamel hypoplasia approximately one millimeter in diameter, occurs on the labial surface of the primary canine tooth. A clinical examination of 2,367 school children in the Vancouver, Canada, area showed the defect occurring in fewer than one percent.
Article
A roughly circular hypoplastic defect restricted to the labial enamel surface of the deciduous canine is described. This pathology is quite common in available samples of Upper Paleolithic and Neolithic children and a cadaver sample of recent Calcuttans, affecting 44% to 70% of individuals. It is rare in a Neanderthal sample and in children from a clinical practice in Vancouver. The lesion occurs twice as commonly in the lower jaw. The defect appears to commence at or after birth owing to localized pressure on thin or nonexistent alveolar bone overlying the bulging crypt of the deciduous canine. Population differences in the incidence of the pathology probably reflect innate and acquired variation in hard and soft tissue thicknesses in this region.
Article
Dental enamel hypoplasia is a putative marker of childhood morbidity (nutritional or infectious stress) which can be analyzed by age-of-occurrence using a calcification standard. We have recorded age-specific occurrence of (a) minor linear hypoplasias, (b) pits, (c) major growth-arrest lines, and (d) combined hypoplasias in 103 specimens of 17-19th century Caribbean slaves. This population is probably unique in terms of environment, nutritional deficiency and other severe environmental stresses, and (especially) association with historical resources that might allow more specific correlation of stresses with hypoplasia chronology. Barbados slaves have a clearly defined central age tendency of 3-4 years at formation of hypoplasias. The lateness of the mode, the percent concentration between 3-4 years, and the residual occurrences at 4+ years are relatively pronounced compared to other reported populations (notwithstanding differences in counting techniques). The age of first hypoplasia occurrence per individual is also probably later in slaves than in other populations. The 3-4 year age range encompasses the year following the historically-documented relatively late time that slave children were weaned (at 2-3 years). Other non-industrial populations show a hypoplasia peak at 2-3 years following a presumed weaning at 1-2 years. Thus the weaning hypothesis and other historical factors (such as periodic food shortages and famine conditions) help explain the mode and the residual distribution of hypoplasia. The historical sources also support the general expectation that the post-weaning period was one of high risk.
Article
To compare the occurrence of chronic fluoride toxicosis in wild and domestic animals in selected areas of Utah, Idaho, Montana, and Wyoming, deer, elk, and bison bones and teeth were collected for evaluation. Vegetation and drinking water samples also were collected, so that potential sources of fluoride could be evaluated. Deer, elk, and bison were found to be susceptible to the adverse effects of ingestion of excessive amounts of fluoride. Teeth and bones were primarily affected with characteristic lesions. Pathognomonic soft tissue changes were not observed. The animals had been exposed to a variety of sources of excessive fluoride, including water high in fluoride, forages contaminated by industrial effluents that were high in fluoride, vegetation contaminated with high fluoride-content soil by rain splash or wind, or a combination of these sources. Waters high in fluoride, especially from geothermal springs and wells, often contained appreciable amounts of various soluble salts. Evidence accumulated from specimens collected throughout the aforementioned states indicated that there are areas where chronic fluoride toxicosis is a problem for wildlife. These areas were where natural sources of fluorine (especially geothermal waters) provided amounts for ingestion that exceed species tolerance limits or were near certain industrial operations.
Article
When aged 8.5 months, 10 sheep born in the same week were given 4 mg fluoride (F)/kg body weight orally for 26 days. Three sheep received no F. Sheep were killed at the end of the treatment period and later at selected stages of tooth development. The macroscopic changes in the enamel of one incisor were related to the cellular changes in the enamel organ of the contralateral tooth. A break in enamel continuity, hypoplasia, was seen on the labial enamel of 9 of the 10 F-treated sheep. Pitting of the enamel was associated with shortening of some ameloblasts and aggregations of cysts affecting cells late in their secretory phase in the first-killed sheep. In sheep killed later, these changes were associated with cells which had progressed into their maturation phase. A more extensive absence of enamel with ledge formation cervically, seen in one sheep, was associated with displacement or death of almost all the cells in their secretory phase during F treatment and consequent retention of the organic matrix. The hypoplastic lesions resulted from secretory-cell reaction during the period of F dosing. Diffuse patchy opacities, characterized by an irregular hypomineralized surface zone, were only apparent in the enamel of the later-killed sheep and were associated in one sheep with abnormal ameloblast regression in the contralateral tooth. These defects possibly resulted from the long-continued release of F stored in the bones during the period of F dosing.
Article
This article discusses the abnormalities of orofacial structures that can occur in association with various congenital disorders and syndromes. The importance of the association between orofacial anomalies and other congenital malformations can be appreciated when one considers that the dysmorphic development of various tissue and organ systems is often associated with craniofacial malformation. Certain specific alterations of craniofacial form, structure, or function are found to be associated with certain syndromes and systemic disturbances to an extent that they may be classified as cardinal features of those conditions. Because of this, it is important for the clinician to be cognizant of dysmorphologic changes of orofacial structures in order to alert him or her to consider certain specific disease entities and to rule out the involvement of other tissues and organ systems that may be syndromically related. Dysmorphic changes of craniofacial structures should be discussed using the same descriptive terminology and nomenclature and the same systems of classification that have been standardized in the field. In this article, we will provide a brief review and discussion of the general principles of dysmorphology; the identification and recognition of craniofacial dysmorphology; dental abnormalities associated with common congenital disorders; and orofacial considerations (other than teeth) in the diagnosis of syndromes.
Article
A sample representing a population of the Florence district of middle 19th century was studied to determine the age of occurrence of enamel hypoplasias. The age interval most affected was that between 1.5 and 3.5 years. Historical sources on weaning habits of 19th-century Italian populations indicate a weaning period between 12 and 18 months. This is in agreement with the data on enamel defects, showing that children of post-weaning age are more subject to stress. Wide "grooves", with prolonged duration, are concentrated between 2 and 2.5 years, whereas "lines" occur primarily between 2.5 and 3 years. We suggest that this distribution could reflect the gradual introduction of dietary supplements until weaning is complete.
Article
Localized enamel hypoplasia of the primary canine (LHPC) is produced by a different mechanism from that causing linear enamel hypoplasia, and yet contributes disproportionately to epidemiological studies of enamel hypoplasia in childhood that do not separate the two etiological types. LHPC results from impact, probably self-inflicted by infants mouthing objects, to the unerupted primary canine crown through abnormally fenestrated cortical bone overlying the crypt. Examination of the primary teeth of ninety-six children whose mothers were enrolled in the Healthiest Babies Possible Program in Vancouver showed an average prevalence of 31 percent with LHPC (ranging from 19 percent in Vietnamese Canadians to 56 percent among Indocanadians). This is much higher than previously reported for unselected samples from Vancouver, but equivalent to studies in the USA. Mean hours of sunshine in the birth month of children with LHPC is 141.7 hours and those without is 169.4 hours; the difference is statistically significant (p = .0383). Seasonal increase in food costs and reduced availability of fresh foods containing vitamin A are thought to contribute to facial osteopenia predisposing the infant to LHPC.
Article
Using macroscopic, microradiographic and scanning electron-microscopic methods, the effects of increased fluoride exposure on enamel and dentine formation were studied in fluorosed mandibular premolars and molars of roe deer from the heavily industrialized Ruhr area, Germany. Macroscopically, fluorosed teeth were characterized by opaque and stained enamel and in more severe cases also by enamel surface lesions, reduction or loss of enamel ridges on their occlusal surfaces and increased wear. Microradiographically, fluorosed enamel exhibited different degrees of subsurface hypomineralization, in part apparently indicating a fluoride effect during enamel maturation. In some specimens, a pronounced but varying enhancement of the pattern of Retzius lines was observed throughout the enamel, denoting strongly intermittent fluoride exposure during enamel matrix secretion. This variation in exposure was also reflected histologically in dentine, by bands of interglobular dentine and marked accentuation of incremental lines. Microradiography of sections through enamel surface hypoplastic lesions showed the enamel forming the bottom and partly also the walls of the lesions to be highly mineralized. Scanning electron microscopy showed that the outer enamel along the more pronounced hypoplastic lesions consisted of stacked, thin layers of 'aprismatic' enamel, indicating that the ameloblasts in these areas had lost the distal (rod-forming) regions of their Tomes' processes. These observations demonstrate that the origin of enamel hypoplasias in deer clearly differs from that in rodents, where fluoride induces the formation of subameloblastic cysts. The differences in the degree of fluorotic alteration between the teeth of a single tooth row could be related to the developmental sequence of the dentition in roe deer. The roe deer is thus considered to be a very sensitive and useful bioindicator of environmental pollution by fluorides.
Article
A macroscopic, microradiographic and scanning electron microscope study was performed on the structure of fluorosed dental enamel in red deer from a fluoride polluted region (North Bohemia, Czech Republic). As was revealed by analysis of mandibular bone fluoride content, the rate of skeletal fluoride accumulation in the fluorotic deer was about 6 times that in controls taken from a region not exposed to excessive fluoride deposition. In all fluorosed mandibles, the 1st molar was consistently less fluorotic than the other permanent teeth. This was related to the fact that crown formation in the M1 takes place prenatally and during the lactation period. Fluorosed teeth exhibited opaque and posteruptively stained enamel, reduction or loss of enamel ridges, moderately to grossly increased wear and, in more severe cases, also enamel surface lesions of partly posteruptive, partly developmental origin. Microradiographically, fluorosed enamel was characterised by subsurface hypomineralisation, interpreted as a result of fluoride interference with the process of enamel maturation. In addition, an accentuation of the incremental pattern due to the occurrence of alternating bands with highly varying mineral content was observed in severely fluorosed teeth, denoting fluoride disturbance during the secretory stage of amelogenesis. A corresponding enhancement of the incremental pattern was also seen in the dentine. The enamel along the more pronounced hypoplasias consisted of stacked, thin layers of crystals arranged in parallel, indicating that the ameloblasts in these locations had lost the distal (prism-forming) portions of their Tomes processes. The findings of the present study indicate that red deer are highly sensitive bioindicators of environmental pollution by fluorides.
Article
Enamel hypoplasia (EH) is a deficiency in enamel thickness due to physiological insults that compromise ameloblast function during the secretory phase of amelogenesis. The prevalence of EH in the deciduous teeth of nonhuman primates is largely unknown. One exception is the recent discovery of EH in the deciduous teeth of extant great apes which exhibit significant differences in prevalence between genera (Lukacs, 1999 a, 2000 a, Am. J. phys. Anthrop.110, 351-363). EH in deciduous teeth of other primates, living and fossil, remain undocumented. This communication describes a "plane form" type of EH known as localized hypoplasia of primary canines (LHPC) (Skinner, 1986 a, Am. J. phys. Anthrop.69, 59-69) in early Miocene catarrhines from Kenya. Specimens were examined macroscopically, with a 10x hand lens and with a variable power (10-30x) binocular microscope. Fédération Dentaire International (FDI)/Defects of Dental Enamel (DDE) standards were employed in recognition and recording of enamel defects (Fédération Dentaire International, 1982, Int. Dent. J.32, 159-167; Clarkson, 1989, Adv. Dental Res.3, 104-109). Size, shape and location of defects were measured and recorded on an outline drawing of the tooth crown. The Kenya National Museum study sample includes six genera of early Miocene catarrhines (n=66 specimens, with n=80 teeth). Seven deciduous teeth were afflicted with EH, yielding an overall prevalence of 8.75%. Two taxa, Kalepithecus (n=1 deciduous canine) and Proconsul (n=3 deciduous canines), were affected with LHPC. Expression of LHPC in fossil catarrhines is consistent with the expression of EH observed in skeletal samples of extant great apes. This report establishes an approximately 17-23 Ma antiquity for EH among early catarrhines and suggests that the neonatal stage of ontogenetic development was sufficiently stressful physiologically to produce disruption in amelogenesis. These physiological stresses impacted neonates of fossil taxa with a wide range of adult body sizes, from large-bodied Proconsul major ( approximately 75 kg) to one of the smaller-bodied catarrhines, Kalepithecus ( approximately 5 kg).
The correspondence of developmental enamel defects between mandibular canine and first premolar
  • Condon K. W.
Condon, K. W. (1981). The correspondence of developmental enamel defects between mandibular canine and first premolar. Am. J. Phys. Anthropol. 54(2): 211.
Enamel hypoplasia in bison: paleoecological implications for modeling hunter‐gatherer procurement and processing on the northwestern plains
  • Niven L. B.
Niven, L. B. (2002). Enamel hypoplasia in bison: paleoecological implications for modeling hunter-gatherer procurement and processing on the northwestern plains. Archaeozoologica 11: 101–112.
  • Franz-Odendaal T. A.