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It’s the Tooth: Dental Remains & Archaeology

§ April 12th, 2009 § Filed under Special Finds § Tagged Archaeology, ASOR, bioarchaeology § 6 Comments

Contributed by Jaime Ullinger, Ohio State University

Dental anthropology is a vital part of bioarchaeology, which is the study of human remains in archaeological contexts. Dental enamel (the hard, white outer covering of the tooth) is the hardest material in the human body, and teeth are often preserved even when bones are not. Not only are they durable, but they are also a treasure trove of information. Using teeth, we can reconstruct age-at-death, diet, health, and ancestry. This information greatly increases our knowledge of people and society in ancient times.

Teeth are particularly useful in identifying the age at which subadults died. Teeth are very stable in evolutionary terms, and therefore erupt in a consistent pattern at predictable ages. Even in adulthood, relative age can be estimated by examining the amount of wear on teeth. Dental wear occurs as we chew our food, slowly removing that hard outer enamel.

Upper right maxilla from Byzantine St. Stephen's (Jerusalem) showing little dental wear and moderate/heavy calculus (photo courtesy of Sue Sheridan).

Upper right maxilla from Byzantine St. Stephen's (Jerusalem) showing little dental wear and moderate/heavy calculus (photo courtesy of Sue Sheridan).

Examining patterns of dental wear can also indicate the types of food people were eating. Foragers tend to have a lot of wear at a young age, while later agriculturalists have less wear. Although farmers do not wear away their enamel, they eat soft, carbohydrate-rich foods that promote bacterial growth. These bacteria destroy enamel, resulting in cavities. Prehistorically, cavities could be quite dangerous. If bacteria erode enamel all the way to the interior of the tooth, an infectious abscess can form at the tip of the tooth root. This infection could ultimately result in the death of the individual.

Tartar builds up on teeth over time, eventually calcifying if not removed. This photo from Byzantine St. Stephen’s (a monastery in Jerusalem dating from 438-614 AD) illustrates an upper jaw that has a good deal of calculus on the teeth. Interestingly, this group of individuals had fairly low levels of calculus and dental caries (cavities) although they are a very urban group that should be consuming a fairly soft diet.

Teeth also reflect general health, particularly in childhood. Enamel is very expensive for the body to generate. If a child is stressed, such as during weaning, when food is scarce, or after contracting a serious disease, the body may stop producing enamel for some time. This results in small furrows on the teeth called hypoplastic defects. The exact position of the defect can tell us what age the child was when the stress occurred.

Teeth also hold clues to ancestry. By examining certain features on the tooth’s surface, we can estimate how closely two (or more) groups are related. These features may include having extra cusps on the teeth, fewer cusps, or extra roots. For example, I have an additional cusp on my first upper molars – it sits on the tongue side of my tooth and is called a “Carabelli’s cusp”. Mine is quite large, and can be seen on the first molars of everyone in my family!

Some of the most interesting dental finds are teeth that have been intentionally modified by their owner during his or her life. Yes, people in prehistory chipped away at their teeth, filed them into points, incised cross-hatched lines on their surfaces, and inserted precious stones into drilled holes on their front teeth. Lest we think this practice barbaric, it would be wise to remember that we subject our own adolescents to painful practices, such as breaking their palates, filing their teeth, and slowly changing their bony tooth sockets by placing pressure on their jaws with braces – all in the name of “beauty”.

This is a quick introduction to what teeth can tell us. They are one of the most informative parts of the human body, and are incredibly well preserved archaeologically. They provide insight into numerous issues archaeologists and historians are concerned with, including diet changes, general stress, how closely groups were related, and markers of social identity. So in the end, the question is – can you handle the tooth?