What is a Malocclusion?

Malocclusion is a dental condition that occurs when the teeth of the lower and upper jaws are improperly aligned. Occlusion is a term referring to the manner in which the lower teeth and the upper teeth meet when a person bites down. In ideal conditions, a person’s upper teeth should rest somewhat over his lower teeth. Malocclusion can unevenly distribute force when a person bites down. This can place considerable force on a few teeth, which may result in one or more teeth fracturing or becoming loose.

Dentists generally recognize three different categories, or classes, of this condition. The most common type is Class I. Class I is mild malocclusion in which the upper teeth are slightly extended over the lower teeth. A person with Class I still has a normal bite.

Class II malocclusion is also called overbite, or retrognathism. The bite is abnormal because the upper teeth considerably overlap the lower teeth. Class III malocclusion is also called underbite, or prognathism. In these instances, the lower jaw extends beyond the upper jaw, causing an overlap of the teeth.

There are several possible ways a person might have malocclusion. It is hereditary, which means that it can run in families; it also can occur due to a severe facial injury, such as a jaw fracture. A jaw or mouth tumor may cause it, and a person may also have teeth that are abnormally shaped. It may also be caused by poor dental work, such as fillings, braces, or retainers that do not fit properly. If a child engages in thumb-sucking past the age of three, or uses a bottle or pacifier for an extended time, this may also result in the condition.

Mild malocclusion may not result in conspicuous symptoms. A person with more severe forms of the condition may experience discomfort when he chews food. He may also speak with a lisp, or have problems speaking. The face may appear abnormal. He may also have breathing difficulties and may be unable to close his mouth while breathing.

Patients with this condition are often diagnosed during normal dental check-ups. Dentists will ask the patient to bite down to check the alignment of the teeth. He may also take x-rays. If he suspects a problem, the dentist usually will send the patient to an orthodontist.

An orthodontist specializes in fixing improper tooth alignment. Patients with Class I malocclusion may not even require treatment. For severe cases, the orthodontist may use an appliance such as braces to correct the alignment. If the patient has an overcrowded mouth, he may need to have one or more teeth removed.

Correcting improper teeth alignment in teenagers or young children typically has an excellent prognosis. The teeth of children generally are easier to manipulate into the correct position. Adults may need to keep braces or a retainer in place for longer periods of time.