What causes crooked teeth

There are quite a few reasons why some people’s teeth grow in crooked or twisted.Some people's mouths are too small for their teeth, which crowds the teeth and causes them to shift.  While others may have different upper and lower jaw size or  their jaws are malformed, resulting in either an overbite which usually occurs in case of excessive protrusion of the upper jaw, or an under bite, when your lower jaw protrudes forward causing the lower jaw and teeth to extend out beyond the upper teeth. Watch this video to know what causes crooked teeth.