There are several speculations about why shark teeth occur. Some dentists believe that this is because the roots of infant teeth are not dissolved as they should be. Permanent teeth have nowhere to go, so they just enter the mouth with the least resistance.
Other dentists believe that the permanent teeth start to grow behind the baby's teeth because the jaw is crowded too much.
Another theory holds that because permanent teeth develop behind the baby's teeth, this is slightly different from normal and they are not as forward as they should be.
I think all this is to explain why this phenomenon occurs. I personally think that all three are possible explanations, any of which may apply to a particular individual.
