Why are we born with two sets of teeth, baby and adult?
374150
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.\nThe 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.\nSo 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. \nOnly then they'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 "wisdom teeth" sometimes do not erupt at all in humans.\n\nMore about mammalian teeth, jaws, and milk, at the Animal Diversity Web:\nhttp://animaldiversity.ummz.umich.edu/site/topics/mammal_anatomy/tooth_replacement.html
916447
A lot of people have multiple sets of wisdom teeth.  That, in and of itself, means very little.
700969
some, like our skull, which starts in 4 plates I think, grow together into one or fuse. That's why we have a "soft spot" as newborns. Others must be the same.
558128
Some people don't get them at all. One of mine didn't come in until I was in my 20's. I don't have dental insurance, so it is still there just hanging around with the rest of my teeth.  \nI think way back humans had them because of the food that they ate, but now that humans don't have to eat the rough food, our mouths have adapted to not needing these teeth to eat.
352803
Because we are not yet an independently human being during this period of 9 months. Our body is bounded at our mother's body and the 2 bodies function like a system. When our fetus body is complete, so that we can use our own digestive system for the nutrition, comes the moment of the birth when we naturally break the connection. In this moment is beginning our own life as an independent human body (but of course we are independent only from the body-perspective, otherwise we depend of other people in the point nutrition, care etc.).\nThis theory of calculating the age is guilty only for the natural birth.I don't know how it shows in other situations : the clones, for example.
329942
There's no connection b/w being a twin and having a cleft palate. A cleft palate occurs when the right and left sides of your palate fail to join/fuse. Identical twins are born when a fertilized egg and sperm splits into two.
62243
because man has incisors, canines and molars..\n\ncanines to rip and shred.. incisors to slice and bite off ...and molars to chew.
493660
BABY?  Did you say Baby?\n\nYou can't extrapolate your babies teeth to your adult dentition.  In fact that's what you want.  GAPS\n\nLot's of gaps, the more gaps the better.  \n\nGaps signify a growing maxilla and mandible.  Growth? you ask?\n\nYes growth.  The adult teeth are way bigger than the baby teeth.  Dentists look for gaps as an indicator that your child will have fewer problems moving into their adult dentitions.  For now,  Don't sweat the gaps\nGaps are good.\n\nHope it puts your mind at ease about gaps.
226295
There are 32 teeth in the adult dentition.  4 quadrants consisting of 8 teeth:  Central Incisor, Lateral Incisor, Cuspid, 1st Bicuspid (1st Premolar), 2nd Bicuspid (2nd Premolar), 1st Molar, 2nd Molar, 3rd Molar (Wisdom Tooth).  There are instances where people have an 'extra' tooth or teeth and these are known as supernumerary teeth.  Also, in some cases, certain teeth never develop.  So it's possible for a person to have more or less than the 'normal' 32.
30613
because we were born that way
355407
Babies skulls are made up multiple bones that fuse as they get older.  This is why babies heads have "soft spots"
51559
As an infant, you're born with around 300 bones.  As you grow, many fuse together and you're left with 206 as an adult.  And more than half of your bones are contained in your hands and feet.  That's a lot of bones!
933425
I'VE SEEN THIS MANY, MANY TIMES. THIS MEANS THAT THOSE OTHER TEETH ARE THE ADULT TEETH ERUPTING, AND  THERE IS NOTHING WRONG WITH THAT. THE BABY TEETH OUGHT TO LOOSEN ON THEIR OWN. IF THE ADULT TEETH KEEP GROWING, AND THE BABY TEETH ARE STILL THERE, THEY SHOULD BE REMOVED TO ALLOW THE ADULT TEETH TO GROW FREELY. =O)
74220
From birth to adult?  Yes.
464826
A good "Jumble" sort of question\n\nThe word is "teething"!\n\n(I guess no one here has ever had kids?)
773358
Hi yes this has happened to my friends daughter recently.She still had her baby tooth but behind it the new tooth had started to grow.My friend was worried that the baby tooth wouldn't come out or that the new tooth would stay further back on the gum. However it was all ok , the baby tooth came out on its own in the end and the new tooth moved forward to fill the gap.
174238
Adult Dentition:\nStarting with the front and going back:  Central Incisor, Lateral Incisor, Cuspid (Canine), 1st .Bicuspid (1st Premolar), 2nd Bicuspid (2nd Premolar), 1st Molar, 2nd Molar, 3rd Molar (Wisdom Tooth).  There are 4 quadrants with 8 teeth in each quadrant for a total of 32 teeth.\n\nChild's Dentition:\nStarting with the front going to the back:  Central Incisor, Lateral Incisor, Cuspid (Canine), 1st Molar, 2nd Molar.  There are 4 quadrants with 5 teeth in each quadrant for a total of 20 teeth.