Most don’t get them until around the age of eighteen, while they get through much earlier with our closest relative the chimpanzee. What’s up with that?

Scientists have long wondered how and why people change teeth at specific ages (see box). But that’s not the only mystery. For example, it appears that the wisdom teeth in humans come through remarkably late in comparison to chimpanzees. In a new study researchers decided to delve into this subject. And now they claim to have finally solved this puzzling case.

change teeth
Most children start changing teeth from the age of six. This happens according to a fixed pattern, with the last teeth changing around the age of 12. We then get wisdom teeth around our 18th birthday. Remarkably enough, these teeth come in much later than in our closest living relative: the chimpanzee, which changes the respective teeth around the age of 3, 6 and 12, respectively.

Not only changing teeth, but actually everything takes a little longer with humans. For example, look at the speed at which we grow up, how long we remain dependent on mothers, how long it takes for us to be sexually mature and how old we can live to be. The human pace is therefore always a bit slower. And as a result, our wisdom teeth also emerge very late, later than any other living or extinct primate.

Study

To pinpoint the exact causes, the researchers built 3D models of skulls — including the attachment positions of each major chewing muscle — during the growth period of nearly two dozen different primate species, ranging from small lemurs to gorillas. They then compared this information to the rate at which the jaws of these species grow. And so they got a good idea of ​​the time when each tooth comes through.

Declaration

Thanks to these models, the researchers have now discovered why wisdom teeth are taking so long. According to them, it is the interplay between facial growth and the mechanics of the masticatory muscles that determine not only where, but also when molars come through. This means that they will only get through if there is enough space. If these teeth were to come through earlier by accident, it could result in a malfunctioning chewing system. In addition, this could even cause damage to the temporomandibular joint.

jaws

In short, the combination of how fast our jaws grow and how big they eventually get determines when molars come through. And that takes a little longer in humans than in great apes. “It turns out that our jaws grow very slowly, probably as a result of our overall slow life course,” said study researcher Gary Schwartz. “That, combined with our short, flat faces, means it takes longer to get enough space for the wisdom teeth. And so we only get it at a late age.”

Ancestors

The researchers plan to apply their model to fossil human skulls. And that’s interesting, as it may answer questions about when the retarded jaw growth and delayed emergence of wisdom teeth first appeared in our distant ancestors.

In addition, the results also have implications for dentistry. Because although this study has shown that molars only appear when the face has grown enough and there is enough space, the model may also provide insight into why our species often suffers from ingrown wisdom teeth that eventually have to be extracted. turn into.