The upper teeth keep the cheeks and lips from being bitten and the lower teeth protect the tongue. Very few people have perfect occlusion. However, most occlusion abnormalities are so minor that they do not require treatment. Benefits of treatment of moderate or severe malocclusion include improved oral health and the cosmetic and psychologic benefits of improved appearance. Treatment eliminates strain on the teeth and jaws, which lessens the risk of breaking a tooth and reduces symptoms of temporomandibular joint disorders.
Malocclusion is most often hereditary.
There may be a disproportion between the size of the upper and lower jaws or between jaw and tooth size resulting in overcrowding of teeth or in abnormal bite patterns. Extra teeth, malformed teeth, impacted or lost teeth, and teeth that erupt in an abnormal direction may contribute to malocclusion. Less frequent causes include habits such as thumb sucking or tongue thrusting. Type 1 malocclusion is the most common. It occurs when the bite is normal but there are crowded or malpositioned teeth.