Baby teeth are cute, aren’t they? For some reason, I’ve always thought that baby teeth appear whiter and more adorable than permanent teeth. They also seem to be squarer and much more prettily made than permanent teeth. However, why do we need primary or deciduous teeth? Is there any particular reason for losing one set of teeth and getting another? Moreover, if there is a reason, why don’t we keep replacing our teeth as we age just like alligators? Why are we just limited to two sets of teeth?
All very interesting questions and why don’t we find the answers right away!
Evolutionary Explanation for Two Sets of Teeth
The reasoning for these two sets of teeth is pretty simple. According to researchers, the baby mammalian skull is small and it cannot accommodate too many teeth. As a result, evolution granted children smaller, much cuter teeth that could fit into those adorable baby-talking jaws. Once the bones of the face and cranium developed into adult size, the tooth fairy removes the old teeth much to the satisfaction of money-hungry children who are paid for those lovely teeth. As these baby teeth are los, they are referred to by many names like ‘deciduous’ which means annual shedding. Baby teeth are also referred to as milk teeth, primary teeth, etc. After a certain period, a temporary trigger activates the formation and movement of permanent teeth that are located under the milk teeth. When the trigger activates, the permanent teeth push their way out into the mouth and literally displace the milk teeth. For some reason, the teeth are synced with age and skull size. That means permanent teeth are geared to start pushing themselves into the mouth only when the jaws are grown enough to accommodate these teeth. It is an interesting process but researchers still do not understand how it works. They have been able to find genetic triggers like Pa-9, which does causes milk teeth to soften and breakdown and aid the growth and eruption of permanent teeth.
So what is The Function of Milk Teeth?
Essentially, milk teeth are placeholders in the oral real estate. They hold the space for permanent teeth and guide them into the position they will occupy for the rest of their life. Most milk teeth also hold the bud of evolving permanent teeth under their roots and they guide the permanent teeth into the correct position in the oral cavity. If milk teeth are lost early due to damage, caries or injury, the permanent teeth tend to wander here and there in the mouth and eventually pop out where ever they want to in the mouth. This leads to a whole set of complications like overcrowding, misaligned teeth and dental problems that will require expensive treatment in the future. As a result, even if the child does experience dental problems like cavities, they have to be treated immediately to prevent tooth loss. In case the has to be removed, a good dentist will make placeholders that will ensure that permanent teeth erupt into the right place at the right time.
Could we evolve to have an endless supply of teeth?
Well, evolution is tricky that way. It usually tries to fulfill essential needs and do away with unnecessary body parts. We lost several unessential body parts along the path to being what we are at present and we are still evolving. There is a very good chance that an increased life span and good diet may cause human physiology to evolve to create new teeth for us in the long run. Researchers like Dr Fraser at the University of Sheffield also state that millions of years may be required, but evolution and a little push in the form of research could result in the ability to regrow teeth past those two sets nature has granted us.