Q: can you tell where a person comes from by a single tooth?
A: yes, and that’s the isotope analysis we are talking about. Everything in our daily life has varies amount of elements, such as oxygen deposited in it. These isotopes are usually collected by our bones and enamel(the hardest inorganic substance of the outermost layer of a tooth). These collected isotopes are formed in stages of life. For children, the enamel formed will not change for the first few years, which provides a safe storage of isotopes. The most favorite geological isotope analysis is by using the variation of strontium levels in the environment. In other words, if the strontium isotope collected from the enamel matches a specific isotope rating/reading from a geological area, it is more likely the person( the owner of the tooth) spent some time in that area.Likewise, the humidity of an area will also affect the level of oxygen isotope. This may also give us some clues on the atmospheric condition of the person lives/lived in. Other than location, it is also possible to collect info about diets, may be lifestyle too!
Read more: http://archive.archaeology.org/0705/abstracts/isotopes.html