“giudizio Tooth”, “queixal the seny”, “do Siso dente” or “dent de sagesse”. They are the names Italian, Catalan, Portuguese or French have traditionally given to popular (and annoying) wisdom teeth . Structures that usually appear between 17 and 20 years when teething is already final and maturity begins to characterize our personality. But its existence has for decades been a mystery to science. Why are they there? What is the famous third molar ? A new study, published today in Nature , finally reveals the mystery of the wisdom teeth, symbolic representatives of the pain-in its apparition and maturity-for the time when nacen-. The small size of the wisdom teeth in humans was unknown to science
And in the case of our ancestors, the third molar had a size four times that our and a flat surface, two optimal characteristics for chewing. Something that does not happen, unfortunately, in humans where wisdom teeth have become a real nuisance that causes many times we should go to the dentist for removal.
The evolutionary changes occurred in the wisdom teeth have traditionally explained by factors related to diet and culture. However, the study published in Nature shows that the reduction of the third molar is not a single modern human feature , but actually responds to basic mechanisms of development shared with most mammals.
Alistair Evans, Matt Skinner, Kierstin Catlett and Susanne E. Daly.
the development is also in the teeth
in 2007, the group Kathryn Kavanagh proposed theoretical model of “inhibition cascade”. Under this approach, the time when a tooth sends signals activation or repression of their “neighbors” develops. The ratio of both signals will determine the size of the adjacent teeth. This model was based on data obtained from tests in mice, but had not yet been applied in other mammals. So far. When you leave a new tooth, trigger signals or repression of its neighbors, which in turn will determine the size of adjacent teeth
research Alistair Evans has allowed to extend the idea of ”inhibition cascade” to the human species. In particular, the scientists note that the model could explain the reduction in size of the third molar from the australopithecines to the present. In Ardipithecus or ancestors as Australopithecus own, wisdom teeth have considerable size, since other teeth also tend to grow in this area of the mouth.
By contrast, the proportion varied with the emergence of the genus Homo . The size of each tooth was not constant, but began to change depending on the total size of the teeth . Decreasing the size of our teeth turn caused a reduction third molar, as a result of inhibition cascade mechanism. In other words, we are not as special as we thought, despite having a “nuisance” as wisdom teeth.
Dr Alistair Evans examining some of the samples used in the workplace. . Image: David Hocking
The initially proposed by Kavanagh model is as simple as attractive. Knowing the size of the teeth and the species to which belongs a hominid, scientists can now infer the size of baby teeth and permanent molars in the back of the mouth. This conclusion, which might seem anecdotal, can also be used in studies of the evolution human.
To demonstrate this, the team of Evans was able to predict the large reduction in size third molar remains found in the Sima de los Bones Atapuerca . This is undoubtedly a clear proof that our history is also written in the teeth. Although they are so heavy and annoying as the trial.
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