A Publication of the Dental Anthropology Association
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Volume 31, Issue 02, 2018 ISSN 1096-9411 Dental Anthropology A Publication of the Dental Anthropology Association Dental Anthropology 2018 │ Volume 31 │ Issue 02 2 Dental Anthropology Volume 31, Issue 02, 2018 Dental Anthropology is the Official Publication of the Dental Anthropology Association. Editors: Marin A. Pilloud and G. Richard Scott Editor Emeritus: Christopher W. Schmidt Editorial Board (2016-2019) Debbie Guatelli-Steinberg Grant Townsend Simon Hillson Chris Stojanowski Leslea Hlusko Cathy M. Willermet Yuji Mizoguchi Officers of the Dental Anthropology Association Heather J.H. Edgar (University of New Mexico) President (2016-2019) Daniel Antoine (British Museum) President-Elect (2016-2019) Loren R. Lease (Youngstown State University) Secretary-Treasurer (2015-2018) Scott Burnett (Eckerd College) Past President (2012-2016) Contact for Manuscripts Dr. Marin A. Pilloud Dr. G. Richard Scott Department of Anthropology University of Nevada, Reno E-mail addresses: [email protected], [email protected] Website: journal.dentalanthropology.org Address for Book Reviews Dr. Greg C. Nelson Department of Anthropology, University of Oregon Condon Hall, Eugene, Oregon 97403 U.S.A. E-mail address: [email protected] Published at University of Nevada, Reno Reno, Nevada 89509 The University of Nevada, Reno is an EEO/AA/Title IX/Section 504/ADA employer Editorial Assistant Rebecca L. George Production Assistant Daniel E. Ehrlich Dental Anthropology 2018 │ Volume 31 │ Issue 02 3 Linear Enamel Hypoplasia in Permanent Dentition of Children in the Late Archaic and the Late Prehistoric River Valley Emily Moes1* and Samantha H. Blatt2 1University of New Mexico, USA 2Idaho State University, USA Keywords: Linear enamel hypoplasia, Ohio River Valley, perikymata, agriculture ABSTRACT The intensification of agriculture is often correlated with an increase in physiological stress, but this relationship is not always clear and needs to be examined in biocultural context. This project compares the timing and duration of stress events of foragers (4000-3000 B.P.) with those of agriculturalists (A.D. 1000-1500) by analyzing linear enamel hypoplasia (LEH) on the permanent anterior teeth of 40 children from Late Archaic and Late Prehistoric Ohio River Valley. Scanning electron microscopy was used to create photomontages of the tooth surfaces. Prevalence, frequency, and duration of LEH were compared between samples using Fisher’s ex- act tests and pairwise ANOVA. Results indicate that agriculturalist children endured the highest prevalence and frequency of stress events; although, forager children endured longer durations of stress events. Variation in stress experiences may be attributed to the nutritional transition to maize consumption and food storage during the Late Prehistoric period. However, a period of increased conflict, population aggregation, and political shifts from interaction with Mississippians are also discussed as contributing factors. The intensification of agriculture often corresponds to Physiological stress during development results in an increase in skeletal indicators of physiological stress disruption of enamel formation (Hillson, 1992), creating and growth disruption relative to hunter-gatherers in enamel defects that are permanently archived in the similar environments (Cohen and Armelagos, 1984; Co- tooth crown. Bioarchaeologists consider these defects to hen, 1989; Steckel and Rose, 2002; Larsen, 2006; Ungar be non-specific indicators of stress attributable to causes et al., 2017). For example, at Dickson Mounds, Illinois, including psychological factors, fevers, malnutrition, multiple indicators show increasing levels of nutritional infection, and trauma (Armelagos et al., 2009; Roberts stress and infectious disease with the rise of maize agri- and Manchester, 2005). While the crown of a tooth is culture (Goodman and Armelagos, 1988; Kent 1986). forming, enamel matrix is secreted continuously by However, this trend is not universal (e.g. Winterhalder ameloblasts in successive layers starting at the crown of and Kennett, 2006). Hutchinson and Larsen (1988) find the tooth. Successive growth layers are differentiated by that stress experiences among Native Americans of St. striae of Retzius (Hillson, 1996). Striae are temporally Catherines Island, Georgia increase in duration over divided by cross-striations, which represent a circadian time, despite similarities to previous agriculturalists in rhythm of growth, each accounting for 24 hours of maize consumption. The authors argue this is likely due growth (Fitzgerald, 1995; Hillson, 2005; Lacruz et al., to disease and social changes introduced by the arrival 2012; Reid and Dean, 2006). Therefore, when cross stria- of Spanish missionaries. Therefore, generalizations tions are counted between striae of Retzius, the timing about the well-being of archaeological populations are in days, or periodicity of the striae, can be determined. not synonymous with their subsistence strategies. Life Externally, these striae correspond to circumferential course hypotheses regarding response to early life structures that are visible on the surface of the tooth, stressors are dependent on accurate documentation of known as perikymata (Antoine and Hillson, 2016; Hill- duration of stress episodes and the ages at which they son, 1996; Fitzgerald, 1995). Therefore, as enamel is laid occurred in order to better contextualize interpretations down in successive layers, each perikyma represents a (Temple et al., 2013; Temple, 2014). Hutchinson and *Correspondence to: Larsen (1988) showed that information about stress epi- Emily Moes sode duration could alter interpretations of the relation- University of New Mexico ship between subsistence strategy and physiological Albuquerque, New Mexico 87110 stress. [email protected] Dental Anthropology 2018 │ Volume 31 │ Issue 02 4 period of development in days, as reflected by the peri- Frequency reflects the average number of growth dis- odicity, or cross-striation count. ruptions that any one person in the sample is likely to When a systemic stress event occurs, energy is di- have experienced. Lastly, LEH duration is an indication verted away from ameloblasts, causing a deficit in ma- of how long an individual was affected by a single trix secretion and the enamel volume, interrupting the growth disruption. In other words, LEH duration re- normal distribution of perikymata (Hillson, 1992). The flects the amount of time until that person began recov- result is an increased distance between successive ering from such an incident. Therefore, discordance of perikymata. These physiological disruptions during LEH prevalence, frequency, and stress episode dura- growth produce localized defects on the enamel sur- tion is possible, though not always expected. face, which can occur as pits, furrows, or planes With the advent of agriculture in North America, (Hillson, 2005). Linear enamel hypoplasia (LEH) is the maize became an important subsistence staple, alt- most recognizable and commonly reported form of hough it varied regionally in the rate of adoption (e.g. enamel defect (Hillson and Bond, 1997; Ten Cate, 1994), Cassidy, 1984; Cook and Schurr, 2009; Goodman and and takes the form of a horizontal line or linear array of Rose, 1984; Sciulli and Oberly, 2002). Isotopic analysis pits on the enamel surface (Goodman and Rose, 1990; from numerous sites within the Ohio River Valley indi- Hillson, 1996). The width of LEH is the result of the cate rapid incorporation of maize in the diet in the Late number of affected perikymata; therefore, representing Prehistoric period (1100 – 400 B.P.) with intensified ag- a quantification of the duration of stress events riculture (Greenlee, 2002). Although maize meets daily (Antoine and Hillson, 2016; Hubbard et al., 2009). The caloric requirements, it is a poor source of amino acids appearance of LEH is further influenced by its location and protein (Spielmann and Angstadt-Leto, 1996; Whit- on the tooth surface since perikymata are more widely ney and Rolfes, 2011). The phytates and plant proteins spaced near the occlusal/apical surface and more in maize inhibit iron absorption, and niacin in maize densely packed at the cervix. This means that LEH near binds to glucose molecules, decreasing their bioavaila- the crown cervix of an incisor, for example, will appear bility (Baynes and Brothwell, 1990; MacKay et al., narrower compared to its matching defect on a canine, 2012). The nutritive value of maize is also altered dur- which will appear in the middle of the crown. Matched ing food processing further removing important miner- defects will often appear at different locations when als and fiber depending on the processing protocols using two different teeth due to differences in the tim- (Rylander, 1994). If absorption or consumption of iron ing of enamel development. Regardless of their loca- and other nutrients is low, anemia could result, leading tions on two or more teeth, defects that form in re- to susceptibility of disease and infection (Dubos, 1965; sponse to the same systemic stress are composed of the Scrimshaw, 1964; 2003). same number of striae of Retzius and perikymata It is often assumed that maize gruel was introduced (Antoine and Hillson, 2016; Hillson and Bond, 1996). to infants around six months of age in Late Prehistoric The occlusal wall of LEH represents the period dur- populations, when growth needs begin to exceed the ing which the stress event occurred, while the cervical nutrients supplied in