A malocclusion refers to the misalignment of teeth and or incorrect relation between the teeth of the two dental arches.
Most people have some degree of malocclusion, although it isn't usually serious enough to require treatment. Those who have more severe malocclusions may require orthodontic treatment to correct the problem. Correction of malocclusion reduces risk of tooth decay and may help relieve excessive pressure on the temporomandibular joint.
Malocclusions may be coupled with skeletal disarmony of the face, where the relations between the upper and lower jaws are not appropriate. In these cases the dental problem is, most of the time, derived by the skeletal disarmony.
Malocclusions can be divided into three types, depending on the sagittal relations of teeth and jaws:
Class I: The patient's bite is normal but their teeth are mispositioned or crowded.
Class II: ( retrognathism or Excessive overjet) is when the upper front teeth are 3mm or more prominent than the lower front teeth. In this case the patient has very often a short mandible.
Class III: (prognathism or negative overjet) is when the lower front teeth are more prominent than the upper front teeth. In this case the patient has very often a large mandible or a short maxillary bone.
Other kind of malocclusions are due to vertical discrepancies. Long faces may lead to open bite, while short faces can be coupled to a deep bite.
Malocclusions can also be secondary to transversal skeletal discrepancy or to a skeletal asymmetry.