While the majority of human teeth grow in infancy, wisdom teeth usually do not appear until adulthood. For a long time, scientists have tried to determine the reason, and by studying the dentition of various species of primates, they finally have an answer to this riddle.
A question of coordination between facial growth and the muscle mechanics of the jaw
From infancy to early adolescence, humans develop their first dentition, then lose it to grow permanent teeth. Then there is a brief pause, and then in early adulthood the last set of teeth emerge. Between the ages of 17 and 21, most adults will indeed develop their third set of molars. These molars are more commonly referred to as the wisdom teeth. They are called that for an obvious reason: they are the last to come out, and this, at an age when one is supposed to settle down when entering adult life. But a less obvious question arises regarding wisdom teeth: scientifically, how do we explain their late appearance?
Thanks to a new study by researchers at Arizona State University and Arizona University, we finally have an answer to this question. According to their research, it is the coordination between facial growth and masticatory muscle mechanics that determines not only where, but also when wisdom teeth emerge. In other words, it is only towards adulthood that a mechanically safe space is created to allow the appearance of the last molars in humans. It should indeed be known that in the majority of great apes, wisdom teeth appear much earlier. In chimpanzees, for example, they appear between the ages of 6 and 12.
Thus, if the appearance of wisdom teeth is late in humans, it is related to the fact that they have shorter jaws, retracted faces and a slower body development compared to other primates. ” It turns out that our jaws grow very slowly, possibly due to our generally slow life histories, and in combination with our short faces, delays in the availability of a mechanically safe space – or a great place if you are. want – result in very late emergence of molars ”, Explained Halszka Glowacka, lead author of the study, in a statement.
A better understanding of the development of the jaw
In fact, if the last molars appeared too early in humans, it would be in an inappropriate space and could disrupt the functioning of the chewing apparatus by damaging the jaw joint, the researchers said in their report. study published in the journal Science Advances. To reach these various conclusions, the researchers put together the skulls of 21 different primate species and created 3D biomechanical models for comparison. These models also included the attachment positions of each major masticator muscle, throughout the growth period in these primates.
By simulating the growth of the jaw at different rates for each species of primates, scientists were able to understand how each of the wisdom teeth synchronized with the growing and changing chewing system of the jaw. Far beyond solving this biological conundrum, scientists believe this study could help advance not only the clinical understanding of wisdom teeth, but also their anthropological understanding, as well as that of the jawbone. ” This study provides a powerful new lens through which the long-known links between tooth development, skull growth and maturation patterns can be visualized », Concluded Glowacka.