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Dental Anthropology

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DOI: 10.1007/978-3-319-51726-1_138-2

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D

Dental Anthropology chamber that contains blood vessels and nerves.

Cementum anchors the tooth roots in the sockets
G. Richard Scott of the upper and lower jaws. Enamel, the hardest
Department of Anthropology, University of substance in the human body (97% inorganic),
Nevada Reno, Reno, NV, USA interfaces directly with the external environment.
This basic observation has many ramifications.
For example, teeth are used to process food so
Introduction their shape and size are strongly influenced by
diet. Because teeth come together while masticat-
In some respects, the dentition is a battleground. ing food objects, the enamel eventually wears
For organisms that use teeth to process food, tooth down, exposing the dentine, and finally the pulp.
loss is directly related to survival – lose your teeth, If wear is not too rapid, secondary dentine forms
lose your life (Lucas 2004). Cultural buffering to protect the pulp from exposure to environmen-
during the later stages of human evolution tal variables, including oral microbiota that lead to
removed this dramatic relationship, but dental infection.
conditions are nonetheless dictated by long-term Another plus to the hardness of enamel is pre-
evolution, not recent cultural advances. For that servability. Teeth are often the most abundant
reason, human teeth, along with the teeth of all remnant of the skeletal system in the archaeolog-
vertebrates, were formed under the influence of ical and fossil record.
natural selection. For animals that eat meat, the Because tooth size and shape are linked to
dentition has slicing, dicing, and piercing ele- diet and survival, the dentition is under strong
ments with minimal emphasis on crushing and genetic control. Minor variations are tolerated,
grinding teeth. Conversely, browsers and grazers such as accessory cusps, styles, ridges, and roots
process large quantities of plant foods and thereby (Fig. 1), but pronounced changes are pruned by
have teeth devoted primarily to crushing and the shears of natural selection. Still, minor
grinding, with little need for slicing and dicing. changes that accrue over broad spans of time
For omnivores, including most primates, the den- ultimately lead to major changes, providing a
tition processes a more varied assortment of foods classic example of the relationship between
so their teeth are not as specialized as those of microevolution and macroevolution emphasized
carnivores or herbivores (Ungar 2010). by the modern synthetic theory of evolution.
Teeth are comprised of four different tissues: While dramatic changes occur over millions of
enamel, dentine, cementum, and pulp. Enamel years, as seen for example in the dentition of
covers the dentine which in turn covers the pulp horses as they shifted from browsing to grazing
# Springer International Publishing AG 2018
C. Smith (ed.), Encyclopedia of Global Archaeology,
https://doi.org/10.1007/978-3-319-51726-1_138-2
2 Dental Anthropology

Dental Anthropology, Fig. 1 Examples of minor vari- on upper central incisors, with moderate shoveling; (c)
ants of human tooth crowns and roots. (a) Large Carabelli’s two-rooted lower canine; (d) five-cusped lower first
cusp with dentine involvement; (b) large dental tubercles molar and four-cusped lower second and third molars

(Peyer 1968), other changes are remarkably con- same types of teeth (incisors, canines, premolars,
servative. For example, the adaptive zone of felids molars), along with many commonalities in mor-
is defined broadly by the elements of hunting phological details. Beyond that, human teeth are
strategy (ambush and pursuit), activity period like hominoid teeth, making it obvious that the
(nocturnal), and sociality (solitary), but the subdi- great apes are our closest biological relatives
vision of this zone by prey size resulted in a wide (Swindler 2005). However, human teeth are dis-
variation in felid body size (4 kg to over 200 kg). tinguished from hominoid teeth in several ways.
Despite variation in body size, including tooth The most important difference is in the size of the
size, the teeth of a small cat are basically identical canines. The general primate dental pattern
to those of a lion or tiger from a morphological includes large, projecting canines that are primar-
standpoint. One can see the same pattern in canids ily used in male-male competition for access to
where body and tooth size vary considerably but valued resources. These canines form a shearing
tooth number and morphology are identical in complex with the lower first premolar which
most respects (Hillson 2005). The point is this: if assumes a sectorial shape (elongated front to
you maintain the same diet (e.g., meat eating) but back, or mesiodistally). For proper articulation
vary that diet by prey size (e.g., mice to water of the two jaws, there is a space, or diastema,
buffaloes), your teeth ultimately change in size between the upper lateral incisors and canines to
but not in shape or morphological details. accommodate the lower canine. Paleoanthropolo-
Human teeth are remarkably similar through- gists often note canine reduction, homomorphic
out the world. A dentist who works on “normal lower premolars, and lack of a diastema as hall-
human teeth” could ply his trade in Australia, marks of early hominids. These traits are all linked
Asia, Europe, Africa, or the Americas. With few to a single trait – canine size.
exceptions, humans have the same number of Hominoids and many other primates also differ
deciduous teeth (20) and adult teeth (32) and the from hominins in the form and relative size of the
Dental Anthropology 3

incisors. Humans have relatively small anterior Key Issues

teeth (incisors and canines) that are vertically
implanted in the jaws. Monkeys and apes, by Population History
contrast, have broad, spatulate incisors that are For the past 100 years, dental researchers have
disproportionately large compared to the cheek known human populations from different geo-
teeth (premolars, molars), and these are set graphic regions varied in tooth size, crown and
obliquely in the jaw rather than vertically root morphology, and tooth number. By 1960, we
(Agrawal et al. 2008). This difference revolves knew that Australian aboriginals had the largest
around the degree to which different organisms teeth in the world while the San (Bushmen) and
manipulate food with their anterior teeth. Animals Saami (Lapps) had the smallest. For morphology,
who emphasize incisal preparation of foodstuffs Asian and Asian-derived groups were character-
have broad incisors that jut out from the upper jaw ized by shovel-shaped incisors while Europeans
at an angle. Hominoids also show variation in were distinguished by Carabelli’s cusp. After
enamel thickness on individual cusps, along with 1970, the number of papers using dental charac-
better developed cingula; orangs and some ters to assess population affinity grew exponen-
chimps also exhibit crenulations (small ridges) tially. With the advent of computers, distance
on the premolars and molars. Despite differences, statistics, and new scoring standards, researchers
the overall similarity in morphology is striking. started to examine many populations for multiple
traits and worldwide patterns of variation emerged
(Scott and Turner 1997). C.G. Turner II developed
many of the ranked standards for making obser-
Definition
vations (Turner et al. 1991; Scott and Irish 2017).
He also examined thousands of Asian and Asian-
Dental anthropology is a subdiscipline of physical
derived samples to develop the Sinodont-
anthropology that focuses on the use of teeth to
Sundadont dichotomy in Asia and the three-
resolve anthropological problems. Teeth exhibit a
wave migration model for the peopling of the
wide array of variables, ranging from those
Americas from a northeast Asian Sinodont ances-
largely controlled by genes to those largely dic-
tor (Greenberg et al. 1986). Other researchers are
tated by environment. Dental variables under
using dental morphology to address issues rang-
genetic control include crown and root morphol-
ing from regional microdifferentiation to global
ogy and size, along with tooth number (i.e.,
patterns of variation.
missing and extra teeth, or hypodontia and hyper-
dontia). Dental variables that reflect environmen-
Genetics and Development
tal factors include tooth crown wear and chipping,
For teeth to be useful in the evaluation of phylog-
caries, abscesses, periodontal disease, calculus,
eny and population relationships, dental variables
and linear enamel hypoplasia. Anthropological
should be under strong genetic control. Although
questions focusing on teeth include issues of pop-
normal dental variation cannot be reduced to gene
ulation origins and relationships (tooth morphol-
frequencies, twin and family studies show that
ogy, size, number), diet and behavior (attrition,
traits defined by size or morphology are highly
crown chipping, tooth-tool use), health (caries,
heritable (Fig. 2). The environment contributes to
abscesses, periodontal disease, calculus), and
dental development but genes play a stronger role.
developmental stress (hypoplasia, asymmetry).
Morphological traits, which are present or absent
Fields that involve significant elements of dental
with variable degrees of expression when present,
anthropology include bioarchaeology, forensic
are quasicontinuous variants with polygenic
anthropology, human biology, paleoanthropol-
modes of inheritance. Missing third molars, at
ogy, primatology, and primate paleontology.
one time thought to be a simple Mendelian trait,
are also quasicontinuous. Over the course of the
past two decades, research in evo-devo (evolution
4 Dental Anthropology

Dental Anthropology,
Fig. 2 Two pairs of
monozygotic twin
dentitions with emphasis on
upper left cheek teeth. Note
symmetry of expression of
Carabelli’s cusp for A1-A2
twins but contrast between
this cusp on B1-B2 twins

and development) has advanced our understand- Diet and Behavior

ing of the genetic-developmental basis of tooth Because teeth process food, dental variables pro-
size and shape. Going beyond the identification of vide several types of information on the diet of
individual variables associated with tooth size and earlier human populations. With use, teeth wear
shape, Jernvall and Jung (2000) describe four down. Patterns of wear are used to infer both diet
types of characters based on developmental prin- and dietary behavior. Hunter-gatherers often use
ciples; that is, characters of initiation, termination, their anterior teeth to process hides, so the incisors
cusp shape, and configuration. These different wear down more rapidly than the molars and pre-
developmental patterns are tied provisionally to molars. This is less evident in early agricultural-
size and presence of the hypocone and short cusps ists that show less wear on the anterior teeth but
along with crown diameters, crown relief, and more wear on the cheek teeth because of abrasives
relative cusp size, etc. The patterning cascade introduced by grinding stones in processing
model that ties crown and root traits to regulatory grains. Agriculturalists also exhibit a steeper
genes has further advanced the analysis of tooth wear plane on the cheek teeth compared to
characters in hominin fossils and recent human hunter-gatherers, a pattern that may reflect a
populations (cf. Hunter et al. 2010). reduction in food toughness tied to the use of
grinding stones and cooking (Smith 1984).
Dental Anthropology 5

In addition to attrition and abrasion which are Oral Health

characterized by incremental change and a Some of the most common diseases in earlier
smooth polished surface, teeth can also fracture. human populations were those that impacted the
As a brittle material with limited plasticity, enamel oral cavity. The most widely studied of these
can be chipped when subjected to excessive force. pathologies is dental caries (Fig. 3). Because car-
Such chipping is common in Inuit populations ious lesions are closely linked to the consumption
where individuals generate powerful vertical of refined sugars, they were not common in earlier
occlusal forces and consume a diet of frozen hominin populations who consumed protein and
or dried flesh that is often contaminated with fat along with complex carbohydrates, including
grit (Turner and Cadien 1969). However, all foliage and tubers. One exception is Kabwe
populations chip their teeth to some degree, and (Rhodesian Man) who suffered from multiple car-
this may be patterned relative to tooth-tool use and ious lesions and associated abscesses over
dietary behavior (Scott and Winn 2011). 100,000 years ago. Caries remained in relatively
Dental calculus, often an obstacle to those low frequencies in recent hunting/gathering
measuring teeth and making morphological populations, partially attributable to the rapid
observations, contains dietary information long and pronounced tooth wear that eliminated the
under-appreciated by the anthropological commu- pits and fissures that served as safe harbors for
nity. The DNA of oral microbes shows how major oral bacteria. Even during medieval times in
dietary shifts in human evolution are reflected in Europe, caries occurred primarily between the
changing compositions of bacterial communities teeth (interstitial) rather than on the crown sur-
(Adler et al. 2013). Calculus provides further die- faces (coronal). With the spread of refined sugars
tary insights as it absorbs and preserves starch after CE 1500, caries became a major health
granules (Hardy et al. 2009) and phytoliths scourge. Recent studies show females usually
(Henry et al. 2010). Even though it is primarily a exceed males in caries rates, perhaps due to
mineral, calculus often preserves sufficient male-female differences in snacking habits but
organic material in its calcified matrix to allow also to differences in the oral environment of the
for stable carbon and nitrogen isotope analysis two sexes influenced by female hormones associ-
(Scott and Poulson 2012). ated with reproduction (Lukacs and Largaespada
2006).

Dental Anthropology, Fig. 3 Carious lesions noted by arrows. (a) Coronal; (b) interstitial
6 Dental Anthropology

Another oral pathology that crosscuts all geo- expression and number. Because teeth develop
graphic areas and subsistence practices is dental within relatively limited time periods, some
abscessing, or periapical osteitis. An abscess authors evaluate timing in terms of the biological
almost invariably develops at the root apex when age of the subjects. In Midwest Native Americans,
the pulp chamber is exposed to the oral environ- these lines often occurred between the ages of two
ment. This exposure can be the result of extremely and four, leading researchers to conclude they
rapid crown wear, coronal or interstitial caries, were coincident with weaning infants off breast
significant crown fractures, or periodontal dis- milk and transitioning them to a maize gruel
ease. When oral bacteria invade the bloodstream, lacking essential proteins (Goodman et al. 1984).
an individual is subject to a generalized infection. As the major triggers for LEH are nutritional
Many individuals in the archaeological record had deprivation or disease, interpretation of the lines
active abscesses at death. To what extent such always depends on context. Populations can
abscesses are implicated in mortality is difficult exhibit the same frequency and severity of lines
to assess. Caries and abscesses can lead to ante- but for altogether different reasons. In northern
mortem tooth loss. Individuals who retain their hunting populations, living in small, scattered
teeth throughout life live at least a decade longer communities with few endemic diseases, the trig-
than those who lose one or more teeth. ger for LEH development is primarily seasonal
food shortage. By contrast, in agricultural com-
Developmental Stress munities, periodic food shortages are less of an
Teeth are the calcified product of an original pro- issue than diseases associated with crowding,
tein template. As environmental and genetic exi- including cholera, diphtheria, and typhus.
gencies can impact the calcification of this
template, there are markers that leave an imprint
on teeth that researchers use to evaluate stress- Forensic Odontology
related growth disturbances (Hillson 2014). The
most commonly used marker is linear enamel One branch of forensic science involves teeth.
hypoplasia (LEH) that takes the form of circum- Focus is primarily on bite marks left on the skin
ferential lines around a tooth (Fig. 4). Although all of victims of violent crimes. Most bite mark
teeth can exhibit LEH, the anterior teeth show it experts come from the field of dentistry, not
most clearly. Hypoplastic lines vary in degree of anthropology. Dental anthropologists nonetheless

Dental Anthropology, Fig. 4 Well-developed linear enamel hypoplasia on upper and lower anterior teeth
Dental Anthropology 7

have much to contribute in forensic contexts. With Hardy, K., T. Blakeney, L. Copeland, J. Kirkham,
isolated teeth, one can estimate minimum number R. Wrangham, and M. Collins. 2009. Starch granules,
dental calculus and new perspectives on ancient diet.
of individuals at a commingled grave site and Journal of Archaeological Science 36: 248–255.
provide reasonable age estimates based on tooth Henry, A.G., A.S. Brooks, and D.R. Piperno. 2010. Micro-
development and wear. Individual identification fossils in dental calculus demonstrate consumption of
can sometimes be made based on unusual if not plants and cooked foods in Neanderthal diets (Shanidar
III, Iraq; Spy I and II, Belgium). Proceedings of the
unique patterns of occlusion, especially those evi- National Academy of Sciences 108: 486–491.
dent on the anterior teeth. Although tooth size is Hillson, S. 2005. Teeth. 2nd ed. Cambridge: Cambridge
not a sensitive indicator of ancestry, tooth crown University Press.
and root morphology exhibit sufficient differences Hillson, S. 2014. Tooth development in human evolution
and bioarchaeology. Cambridge: Cambridge Univer-
among the major groups of humankind to allow sity Press.
discrimination at the level of European, African, Hunter, J.P., D. Guatelli-Steinberg, T.C. Weston,
Asian, and derived populations (Scott et al. 2018). R. Durner, and T.K. Betsinger. 2010. Model of tooth
A web-based application (rASUDAS) based on morphogenesis predicts Carabelli cusp expression,
size, and symmetry in humans. PLoS One 5: e0011844.
Bayes theorem has been developed to estimate Jernvall, J., and H.-S. Jung. 2000. Genotype, phenotype,
the probability that an individual can be assigned and developmental biology of molar tooth characters.
to one of seven major geno-geographic groups. Yearbook of Physical Anthropology 43: 171–190.
Lucas, P.W. 2004. Dental functional morphology: How
teeth work. Cambridge: Cambridge University Press.
Lukacs, J.R., and L.L. Largaespada. 2006. Explaining sex
Cross-References differences in dental caries prevalence: Saliva, hor-
mones, and ‘life-history’ etiologies. American Journal
▶ Bioarchaeology, Human Osteology, and Foren- of Human Biology 18: 540–555.
Peyer, B. 1968. Comparative odontology. Chicago: Uni-
sic Anthropology: Definitions and versity of Chicago Press.
Developments Scott, G.R., and J.D. Irish. 2017. Tooth crown and root
▶ Human Skeletal Remains: Identification of morphology: The Arizona State University Dental
Individuals Anthropology System. Cambridge: Cambridge Univer-
sity Press.
▶ Plant Domestication and Cultivation in Scott, G.R., and S.R. Poulson. 2012. Stable carbon and
Archaeology nitrogen isotopes of human dental calculus:
A potentially new non-destructive proxy for
paleodietary analysis. Journal of Archaeological Sci-
ence 39: 1388–1393.
References Scott, G.R., and C.G. Turner II. 1997. The anthropology of
modern human teeth: Dental morphology and its var-
Adler, C.J., K. Dobney, L.S. Weyrich, J. Kaidonis, iation in recent human populations. Cambridge: Cam-
A.W. Walker, W. Haak, C.J. Bradshaw, G. Townsend, bridge University Press.
A. Sołtysiak, K.W. Alt, J. Parkhill, and A. Cooper. Scott, G.R., and J. Winn. 2011. Dental chipping:
2013. Sequencing ancient calcified dental plaque Contrasting patterns of microtrauma in Inuit and
shows changes in oral microbiota with dietary shifts European populations. International Journal of
of the Neolithic and Industrial revolutions. Nature Osteoarchaeology 21: 723–731.
Genetics 45: 450–455. Scott, G.R., C.G. Turner II, G.C. Townsend, and
Agrawal, K.R., K.Y. Ang, Z. Sui, H.T.W. Tan, and M. Martinon-Torres. 2018. The anthropology of mod-
P.W. Lucas. 2008. Methods of ingestion an incisal ern human teeth: Dental morphology and its variation
design. In Technique and application in dental in fossil and recent Homo sapiens. 2nd ed. Cambridge:
anthropology, ed. J.D. Irish and G.C. Nelson, Cambridge University Press.
349–363. Cambridge: Cambridge University Press. Smith, H.B. 1984. Patterns of molar wear in hunter-
Goodman, A.H., G.J. Armelagos, and J.C. Rose. 1984. The gatherers and agriculturalists. American Journal of
chronological distribution of enamel hypoplasias from Physical Anthropology 63: 39–56.
prehistoric Dickson Mounds populations. American Swindler, D.R. 2005. Primate dentition: An introduction to
Journal of Physical Anthropology 65: 259–265. the teeth of non-human primates. Cambridge: Cam-
Greenberg, J.H., C.G. Turner II, and S. Zegura. 1986. The bridge University Press.
settlement of the Americas: A comparison of the lin-
guistic, dental, and genetic evidence. Current Anthro-
pology 24: 477–497.
8 Dental Anthropology

Turner II, C.G., and J.D. Cadien. 1969. Dental chipping in Hrdlička, A. 1920. Shovel-shaped teeth. American Journal
Aleuts, Eskimos and Indians. American Journal of of Physical Anthropology 3: 429–465.
Physical Anthropology 31: 303–310. Irish, J.D., and G.C. Nelson, eds. 2008. Technique and
Turner II, C.G., C.R. Nichol, and G.R. Scott. 1991. The application in dental anthropology. Cambridge: Cam-
Arizona State University Dental Anthropology System: bridge University Press.
Scoring procedures for key morphological traits of the Irish, J.D., and G.R. Scott, eds. 2016. A companion to
permanent dentition. In Advances in dental dental anthropology. Chichester: Wiley-Blackwell.
anthropology, ed. M.A. Kelley and C.S. Larson, Kieser, J.A. 1990. Human adult odontometrics. Cam-
13–31. New York: Wiley-Liss. bridge: Cambridge University Press.
Ungar, P.S. 2010. Mammal teeth: Origin, evolution, and Kurten, B., ed. 1982. Teeth: Form, function, and evolution.
diversity. Baltimore: The Johns Hopkins University New York: Columbia University Press.
Press. Moorrees, C.F.A. 1956. The Aleut dentition. Cambridge:
Harvard University Press.
Pedersen, P.O. 1949. The East Greenland Eskimo denti-
Further Reading
tion. Meddelelser om Grønland 142: 1–244.
Bailey, S.E., and J.-J. Hublin, eds. 2007. Dental perspec-
Scott, G.R., and C.G. Turner II. 1988. Dental anthropol-
tives on human evolution: State-of-the-art research in
ogy. Annual Review of Anthropology 17: 99–126.
dental paleoanthropology. Dordrecht: Springer.
Teaford, M.F., M.M. Smith, and M.W.J. Ferguson, eds.
Brothwell, D.R., ed. 1963. Dental anthropology.
2000. Development, function and evolution of teeth.
New York: Pergamon Press.
Cambridge: Cambridge University Press.
Dahlberg, A.A. 1945. The changing dentition of man.
Ungar, P.S. 2011. Dental evidence for the diets of Plio-
Journal of the American Dental Association 32:
Pleistocene hominins. Yearbook of Physical Anthropol-
676–690.
ogy 54: 47–62.
Dahlberg, A.A., ed. 1971. Dental morphology and evolu-
Weiss, K.M. 1990. Duplication with variation: Metameric
tion. Chicago: University of Chicago Press.
logic in evolution from genes to morphology. Yearbook
Gregory, W.K. 1922. The origin and evolution of the
of Physical Anthropology 33: 1–23.
human dentition. Baltimore: Williams and Wilkins.
Hillson, S. 1996. Dental anthropology. Cambridge: Cam-
bridge University Press.

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