Malocclusion literally means bad bite. Some children's jaws and teeth do not develop properly. Malocclusion refers to crooked, misaligned teeth and a fault in the relation between the bottom and top set of teeth (the two dental arches). This may develop because of injury to the teeth or facial bones, frequent thumb sucking, or for reasons unknown.

Thumb sucking (or finger sucking) can result in localized deformation of the teeth and supporting bone. In order to restore a natural improvement, the thumb sucking habit has to be stopped.

Generally, malocclusions do not affect physical health, malocclusion is not a disease, it is a variation in the normal position of teeth. However, it may impact on the shape of the person's face and the appearance of their teeth, which can lead to embarrassment, a lack of self-confidence, and even depression.

Severe malocclusion may affect eating, speech and keeping the teeth clean.