A dental malposition or incorrect relation between the teeth of the two dental arches. The term malocclusion comprises both minor anomalies (such as a crooked or inclined tooth, an overcrowding or a small space) and those which alter the aesthetic appearance, the masticatory function or the articulation.

Most malocclusions do not have a specific cause, but they are the result of the influence of genetic or environmental factors, which disrupt the normal development. Long-term incorrect habits (such as an inappropriate position of the tongue, sucking habits or mouth breathing) might alter the normal function and the balance between teeth and the maxillary bones.

Other genetic factors, for instance a disproportionate growth of the maxillary bones, might result in an incorrect relation between the upper and the lower jaw bones, stopping the teeth from properly fitting.

These are corrected through orthodontic treatments and dento-facial orthopaedics. Treatments can be interceptive (those that prevent a severe issue) or corrective (which involve functional, removable or fixed appliances).

The recommended age for treatment of malocclusions depends on the type and seriousness of the problem. The Spanish Society of Orthodontics (SEDO) recommends attending check-up examinations from the age of 6.