January 8, 2018 in News
Impacted third molars, also known as wisdom teeth, can cause a lot of suffering. However, some people are free of this curse – in fact, certain ethnic groups, like the Inuit, have remarkably low rates of wisdom teeth. But why do some people have wisdom teeth while others do not? New research may provide the answer.
According to Alan Mann, a Princeton University researcher, a random mutation took place thousands of years ago resulting in the suppression of wisdom teeth formation. This trait has spread and is the cause in certain people and groups of the total or partial lack of wisdom teeth.
The oldest fossil to be found missing the third molar comes from China and is about 300,000 years old, suggesting the date of the first mutation. Humans, like other mammals, originally had four sets of three molars for a total of 12 teeth to help in chewing food. According to Mann, when humans underwent an evolution that resulted in a significant brain expansion, there was an architectural problem; the jaw had to become narrower to be able to connect to the lower end of the skull.
During this period, and even after, the genes controlling brain size developed differently from those controlling dental quantity. Narrower jaws left little room for the wisdom teeth to erupt from the jaw, leading to a mismatch. This is a familiar problem for most people. Wisdom teeth often don’t fit, and if they don’t make it through the gum (become impacted), they can become infected, potentially leading to real health problems. Even when not infected, impacted wisdom teeth can still cause pain.
These reasons may partly explain the mutation causing a lack of wisdom teeth in certain people and groups. Following basic evolutionary theory, we can assume that the pain could have made humans less likely to reproduce, therefore favoring those with the mutation.
About 10 to 25 percent of Americans who descended from European ancestry miss at least one third molar in their dentistry; however, 45 percent of the Inuit who live in the Arctic regions of Alaska, Greenland and Canada lack at least one of their third molars.
One reason for this disparity is that this group had its origins in Asia, which is where this mutation began. And, like Asians, the Inuits have flatter faces and, hence, narrower jaws, making it even harder for the wisdom teeth to grow.
As years go by and people continue to marry across races, this mutation will continue to spread until, one day, most of the global population will have no third set of the molar in their dentistry. This will be a relief, cutting down on dental problems and visits to the dentist to extract wisdom teeth due to infections or chronic pain at the end of the jaw and ears.
If you have any questions or concerns about your family’s dental care, give Dr. Mott a call. We can schedule a cleaning or checkup for you and answer any questions you may have.