Why are we born with two sets of teeth, baby and adult?

Almost all mammals have two sets of teeth (this is called diphyodonty). One of the hypothesis to explain the existance of these two dental generations is related to the way our teeth work.


The teeth of adult mammals occlude (=come together) in very precise patterns that are related to the type of food and the way this food is chewed, and are very important for feeding efficiency. If the definitive teeth were to erupt in a young individual that is still growing, the growth of the skull and jaw bone could make the upper and lower teeth lose their occlusion, with negative consequences.


So the hypothesis proposes that the first generation or milk teeth appear during the first years (in humans, much earlier in other mammals), when the young one is feeding on breast milk, and then it is not so important that they become separated when the child keeps growing.


Only then they%26#039;re replaced by the definitive ones. And remember, only incisors, canines and premolars have two generations. The molars (the most important for mastication) only erupt once, and they do so later, when the person is much more grown. In fact, the last molars or %26quot;wisdom teeth%26quot; sometimes do not erupt at all in humans.





More about mammalian teeth, jaws, and milk, at the Animal Diversity Web:


http://animaldiversity.ummz.umich.edu/si...

Why are we born with two sets of teeth, baby and adult?
Because our face and jaw grow as we go through childhood.





Adult sized teeth wouldn%26#039;t fit in a baby%26#039;s mouth, and baby teeth would look silly in an adult%26#039;s mouth.
Reply:HOW MANY SETS DO U WANT 2 HAVE
Reply:The first set of teeth are the deciduous teeth, 20 small teeth also known as baby teeth or milk teeth. Deciduous teeth start developing about two months after conception and typically begin to erupt above the gumline when a baby is six or seven months old. Occasionally a baby may be born with one or more deciduous teeth at birth, known as natal teeth. By the time a child is six years old, a second set of 32 larger teeth, called permanent teeth, start to erupt, or push out of the gums, eventually replacing the deciduous teeth.
Reply:if we we grew our adult teeth only, they would be too big for our skull. if we only had baby teeth they would not serve our greater food consumption when we grow.
Reply:Sean is right. I was going to say that but he said it fine. Some of us wish that we had a spare pair after the adult teeth (not dentures). LOL The adult teeth are growing beneath the gum and when ready push out the baby teeth.


E-hah!! Money under the pillow time. $$$$$$$$$
Reply:its believed that in the ancient past we were diverge from another species of humanoid that had such teeth. that particular species died out. excellent question and conundrum to all evolutionist..
Reply:because when people had poor dental health in the olden days, we NEEDED two sets of teeth. plus our mouth gets bigger. and we need bigger teeth to chew bigger pieces of meat.



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