Genetics - thank your parents. For instance, you may have inherited your mother's small bone structure and your father's large teeth.

Habits - thumb-sucking, tongue-thrusting, and other para-functional habits can shift your teeth rapidly out of alignment.

Trauma - teeth are constantly trying to move, but are held in place by numerous opposing forces. When you loose a tooth and it's not replaced, the adjacent and opposing teeth will begin to shift into the open space.

Disease - cavities and gum disease are two of the major causes for tooth loss. Once again, if the space occupied by the lost tooth is not restored, your teeth will shift.

Malnutrition - nutritional deficiencies can alter the growth rate of the jaws and teeth, resulting in misaligned teeth.

Why Undergo Treatment?

Though orthodontics can dramatically improve your appearance, it's not the only reason you should undergo treatment.
 
Long-term effects of misaligned teeth :

• abnormal facial muscle function
• abnormal swallowing
• increased susceptibility to cavities due to the difficulty of removing plaque from misaligned teeth
• increased vulnerability to trauma or fractured teeth (front teeth which stick out are usually more likely to become injured)
• increased difficulty chewing
• problems with speech