Most often crooked teeth, overbites, and underbites are inherited traits just as the color of your eyes or size of your hands. Other causes of misaligned bites are early loss of baby or adult teeth; improper fit of dental restorations (for example, fillings or crowns); gingivitis (gum disease); undue pressure on the teeth and gums; misalignment of the jaw after an injury; tumors of the mouth or jaw; or common oral health problems in children such as thumb sucking, tongue thrusting, pacifier use beyond the age of three, or prolonged use of a bottle.
So, what kind of problems can crooked teeth cause, besides perhaps an unwillingness to smile?
Unhealthy gums: Properly positioned teeth are easier to brush and floss than teeth that are crowded, crooked or spaced too far apart.
More difficult cleanings: Crooked or misaligned teeth can increase the risk of plaque retention, tooth decay or periodontal (gum) disease. This can give way to cavities and gingivitis, as well.
Abnormal wear of your jaw: A crooked set of teeth can put stress on your jaws and increase your chances of breaking a tooth.