An interesting article titled “Why We Have So Many Problems with Our Teeth” appeared in Scientific America written by By Peter S. Ungar (paleontologist and dental anthropologist) on April 1, 2020 (322, 4, 44-49). The article discusses how human jaws today are very different than that of our ancestors. In fact today our jaws can be consider underdeveloped due to less chewing that occurs and has kept our teeth from fitting properly into our mouths. The author states
” Nine in 10 people have teeth that are at least slightly misaligned, or maloccluded, and three quarters of us have wisdom teeth that do not have enough room to emerge properly. Simply put, our teeth do not fit in our jaws.”
The author says that teeth no longer fit into jaws because human diets have changed over the years to use softer more processed foods that require less chewing. He says that jaw length was preprogrammed by evolution and that the softer diet of today has created an imbalance between tooth size and jaw size. He feels that jaw length gets created when people had to do a lot of chewing that resulted in straining their chews, without this chewing jaws are short like today. Dr. Unger has studied hundreds of thousands of teeth of fossil species and living animals, and from this research has found that most animals and our ancestors did not have overbites or lower teeth that were crowded or misaligned. He says that jaws are just not growing long enough to accommodate the normal-sized teeth that we have.
According to Dr. Ungar, the jaw bone isn’t getting the stimulation it needs the first 18 years of a person’s life. Jaws become stimulated when people chew vigorously and today a diet that consists of soft foods like peas or potatoes just does not provide enough stimulation. This he says makes it so that the osteoblasts are not secreting the bone that needed to make jaws long. Dr. Ungar says that underdeveloped jaws have led to misaligned teeth and impacted wisdom teeth. He says that today modern day hunter gatherers in norther Tanzania more eat diets closer to those of our ancestors have longer jaws. He also says that even rural Kentuckians from around 100 years ago who grew their own food had longer jaws. It is tough to pin down exactly when our jaws stopped growing to the size they are intended to be. Dr. Ungar thinks that our jaws grow up until 18 years of age and thus during childhood kids need to start eating tougher foods to lengthen their jaws. The author states
“Dentists and orthodontists are realizing that highly processed, softened foods can change the mechanical strains on the face and jaws. Chewing stresses stimulate normal growth of the jaw and the middle of the face in children. Subsisting on such foods leaves these parts of the body chronically underdeveloped.”
It is not clear exactly what kind of chewing and how much chewing is needed during childhood to properly stimulate the jaw to grow long. Dr. Ungar doesn’t think chewing gum would be sufficient. This might instead involve hard food and a lot of vigorous chewing and eating of tough food. Additional research is need to better understand the optimal amount of strain and intensity needed for the jaw to stimulate long growth.