An open bite occurs when the front teeth do not touch each other while contact occurs on the back teeth; there is a gap between the upper teeth and lower teeth. The upper and lower teeth may be positioned outward. An open bite may be caused by thumb sucking that results in tongue thrusting while swallowing. Some experts believe that prolonged use of bottles and pacifiers can also lead to the development of an open bite due to the development of a tongue thrust while swallowing. Treatment may include braces and the use of a special appliance to retrain the tongue position while swallowing however the best treatment is prevention by stopping thumb sucking and pacifier use before the age of 3.