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Teeth Include Clues to the Evolution of Man
Teeth contain a wealth of information and provide clues to the history of life on earth, says Harold Slavkin, D.D.S.
"You can trace the genesis of teeth back at least 460 million years according to fossils found in the Canadian Rockies," Dr. Slavkin wrote in the Journal of the American Dental Association. "What scientists have found is how creatures adapted to their environment and how the evolution of vertebrates required changes in dentition."
Dr. Slavkin says researchers have been able to discover the actual genes associated with tooth and enamel formation. Scientists are using the genetic information to study how to provide treatment for a variety of oral health problems, including advanced periodontal diseases.
Dr. Slavkin points out that the actual composition of teeth changed over time to accommodate the environment. Structural changes were needed for function, and size and shapes changed as well, so teeth could work more efficiently.
"What we've found is that over these 460 million years, the way teeth are formed in fish and people is rather similar," Dr. Slavkin says. For example, a number of the structural genes in the teeth's outer coverings are remarkably similar to those of an agnathous (jawless) fish of almost 500 million years ago.
Genetic coding determines tooth position, size and shape in the tooth-making cells during gestation. "These fossils are evidence of the transition of teeth over the centuries or millenniums from simple vertebrates to primates," says Dr. Slavkin. "It is one of the best-documented transitions in the fossil record."
Looking at the past may actually help dental patients in the future, Dr. Slavkin notes. He says the genetic information and the evolution of the teeth may lead researchers to discover better methods for restoration of the teeth and improving treatment of other oral diseases.
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