Archive for September 7th, 2010

The Stories Teeth Tell

by Treloar Bower, Curator of Education

Teeth can tell incredible stories about their “owners.”  Recently, the museum received a donation from a local dentist that included casts of teeth.  Two museum volunteers are creating an inventory of these casts, which they anticipated would been a very tedious process (there are a lot of casts) until I introduced them to the stories to look for on the teeth of those casts.

As an undergraduate, I concentrated my anthropology major on the study of human osteology and forensics and continued this focus during graduate school, interning in the Physical Anthropology Department at the National Museum of Natural History.  A forensic anthropologist goes where a coroner doesn’t: when human remains lack soft tissue, a forensic anthropologist is called in to examine the bones that do remain (and teeth are bones).  I think of bones as the hangers of a body, but unlike the hangers used for clothes, these hangers reflect certain characteristics of the “clothes” that hang on them: age, height, and gender of the individual, plus much more.  Bones are living things and can be changed by injury (bruises and breaks) and illness (Rickets impacts the lower leg bones, while syphilis leaves bones looking like sponge).

Frontal cranium, syphilis infection

Muscles attach to bones; high levels of muscle development, such as in weightlifters, can actually “pull” on the bone, creating well-defined ridges at the muscle attachment sites. Sometimes this pulling can indicate handedness: when one side of the body is obviously more muscularly developed than the other, particularly in the upper arm, shoulder and clavicle region, it indicates the preference of use, left vs. right.  One bone, the hyoid, is located in the throat and when broken perimortem (at the time of death, and, yes, it is possible to determine if a bone was broken before, at or after the time of death) is an indication of death by strangulation.

Several diagnostic characteristics are visible on teeth. Two teeth can indicate ancestry: molars and central incisors. People of Asian and Native American ancestry can have molars with 5 cusps and y-shaped groove, and shovel-shaped incisors (the lingual, or tongue side, of the tooth is “scooped out”), while people of European ancestry have molars with 4 cusps and incisors that are straight and smooth on the lingual side.

Comparing the lingual sides of teeth from different ancestries

Behavior can also leave information on teeth.  One obvious behavior – or lack thereof – is poor hygiene, which can be easily seen by even a novice “tooth-watcher”.  Other behaviors impacting teeth are the habitual use of pipes and toothpicks, both of which over the course of many years of use can wear away enamel and leave “impressions” of their presence in one’s teeth.  In prehistoric populations, one behavior seen on teeth is the use of stone manos and matates to grind corn for flour.  Tiny bits of stone ended up in the flour and over years of eating the flour, those tiny stone fragments would wear down the teeth.  Older individuals would end up with completely smooth molars.

Teeth worn from diet containing grit- Late prehistoric approx. 1500 B.P. (seen in-situ at exhumation)

Once I suggested that our volunteers look for these stories on the teeth casts, their whole approach to the inventory process changed.  Now they seem excited to see what the next box will hold.  And if you ever catch me looking at your mouth and not your eyes while we are speaking, it’s because I’m looking for stories on your teeth.

September 2010

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