According to the American Journal of Public Health, an estimated 10 million wisdom teeth are removed annually form an estimated 5 million Americans. Extracting impacted wisdom teeth is such a commonly performed restorative dental procedure that it has almost become a rite of passage for many American teens and young adults. Your dentist will always have the best advice regarding the wisdom tooth extraction, but it’s still pretty interesting to know about these three surprising facts about these problematic teeth.
Most people have four wisdom teeth. However, somewhere between .1% and 3.8% of the world’s population have an extra set of wisdom teeth. This situation, known as hyperdontia (from the Greek words for “excessive teeth”), is obviously pretty rare. Still, the extra set of wisdom teeth are impacted in nearly all cases of hyperdontia and must be removed to avoid infection and promote better oral hygiene.
The better question may be, “Why do we grow a third set of molars when our jaws are only big enough to accommodate only two sets?” Indications from our evolutionary history might hold the key to these problematic teeth. Scientists speculate that early man wore down their teeth at a much faster pace because they lived on a diet of mostly fibrous grains and vegetation and raw meat. If an early man lost a tooth to excessive wear, a third set of “backup” molars would be there to move forward and take over. As we have evolved and developed a diet of easier to chew foods, our jaws have narrowed but the number of teeth has remained the same.
At Japan’s National Institute of Advanced Industrial Science and Technology, scientists discovered that cells from the pulp of an extracted wisdom teeth strongly resembled a type of adult stem cells (as opposed to controversial embryonic stem cells) extracted from bone marrow. These molar-derived stem cells have shown promise in lab testing and, in the future, we may find ourselves storing our extracted wisdom teeth away for therapeutic use later on.