Represents abnormal bite relationships in which the upper jaw and teeth project ahead of the lower jaw called “overjet”. Class II patients usually exhibit a convex facial profile with deficient chin prominence. Typically, a Class II patient displays a shorter than normal lower jaw. Other factors, such as persistent thumb sucking can aggravate these problems. Correction of this disorder generally requires influencing facial growth to bring the upper and lower jaws and teeth into their proper position.
An individual with a crossbite will have teeth that are out of place when the mouth is closed. In most cases, this means that one set of teeth will either fall inside or outside of the opposite set. Many of the causes of crossbite are apparent in childhood or early adulthood. Two of the biggest causes of crossbite are hereditary and delayed loss of baby teeth. Both of these situations could cause the teeth to be out of proper position.
May occur when teeth are crooked, turned, or overlapped. Virtually 90% of the population has an orthodontic condition known as crowding. Generally caused by genetics (i.e., a relatively small jaw or relatively large teeth) or by habits such as nail biting and thumb sucking. Aside from aesthetic considerations, poor alignment of teeth may be associated with periodontal problems and increased risk of cavities due to difficulty in maintaining proper oral hygiene.
Excessive vertical overlapping of incisor teeth called “overbite” is generally found in association with a discrepancy between the length of the upper and lower jaws. It usually results in excessive eruption of either the upper or lower incisors or both. Problems include excessive display of gum tissue, lip protrusion or entrapment, biting the roof of the mouth and incisor wear.
A lack of vertical overlap of the incisor teeth can usually be traced to jaw disharmony of persistent (i.e. finger sucking habits and posturing of the tongue between the front teeth) or excessive vertical growth of one or both jaws. Early assessment and intervention of these disorders is critical to the overall success.
Spaces between teeth is another common problem associated with the need for orthodontic care. Like crowding, spacing may be related to tooth-to-jaw size disharmony. Gum tissue attachment called “frenae” are also a common cause of spacing between the front teeth. Excessive vertical overlap of the front teeth as well as incisor protrusion may lead to spacing. Other contributing factors include atypical or usually narrow teeth, and missing or impacted teeth.