Have you ever seen someone with dark horizontal lines in their teeth? Chances are this person took an antibiotic called tetracycline as a child. While in the bloodstream, this drug is incorporated into developing teeth, where it leaves a dark stain.
Physicians no longer prescribe tetracycline for children, but specialists like Dr. Tanya Smith know how to find the telltale signs of the chemicals we ingest and the stresses our bodies endure in the structural makeup of our teeth.
The lines in the teeth that Dr. Smith studies are very small and can’t be seen without a powerful microscope. They’re created by daily, weekly, and annual cycles in tooth formation. Disruption of these natural cycles by starvation, stress, or disease leaves a noticeable and permanent record in the teeth—one that’s usually too small to see with the naked eye.
Patterns of tooth growth are examples of biorhythms, natural cycles that occur in living organisms. Cyclic growth also produces tree rings and the ridges in the shells of marine organisms.