In a healthy bite, the jaws are well matched in size, and the size of the teeth is proportionate to the size of the jaws. The upper and lower jaws should fit together properly and not affect the shape of the face.
Ideally the teeth should be regularly aligned. Straight teeth are easier to clean reducing the risk of decay and gum disease. In addition, the smile is more aesthetically pleasing.
When you bite, all the teeth should meet at the same time and with equal pressure. The upper jaw is slightly larger than the lower jaw and overlaps the lower teeth just a little bit. The front teeth will also have slight overlap and the middle of the face will correspond with the midline of the two front teeth. Everything is nice and balanced. The chewing process is straightforward.
In Class I malocclusion is the most common dental problem. The bite is normal with both jaws in a good position to each other but the upper teeth slightly overlap the lower teeth. It is not usually serious enough to require treatment but orthodontic correction of malocclusion may reduce the risk of tooth decay and help relieve excessive pressure on the jaw joints. Orthodontic treatment may also be used to align teeth for aesthetic reasons.
In Class II dental problems an overbite typically occurs when the upper jaw and teeth severely overlap the bottom jaw and teeth. Class II patients usually exhibit a convex facial profile as a result.
Class III dental problems are primarily genetic in origin. In this instance, the lower jaw and teeth are displaced to the front of the upper jaw structures. The facial appearance may give the impression that the lower jaw is excessively large, but in many cases the lack of upper jaw is at fault. Class III patients usually exhibit a concave facial profile as a result.
Crowding of the teeth occurs if there is too little space in the jaw for the teeth. The teeth move or rotate or get stuck in the jawbone. Aside from aesthetic considerations, poor alignment of teeth may be associated with periodontal problems and an increased risk of dental decay due to difficulty in maintaining proper oral hygiene.
Visible from a distance, there are gaps of different sizes between the individual teeth. Excessive vertical overlap of the front teeth as well as incisor protrusion may lead to spacing. Other contributing factors include atypical or unusually narrow teeth, and missing or impacted teeth.
In an open bite, the incisor teeth are not in contact with each other, a problem which can usually be traced to jaw disharmony, persistent habits (i.e. thumb sucking and posturing of the tongue between the front teeth) or excessive vertical growth of one or both jaws. Early assessment and intervention is critical to the overall success of treating these disorders.
Excessive vertical overlapping of incisor teeth called deepbite or “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. Associated problems include: 1) excessive display of gum tissue, 2) lip protrusion or entrapment, 3) biting the roof of the mouth and 4) incisor wear.
A crossbite usually results from a constricted upper jaw or unusually wide lower jaw and will often force a patient to move their lower jaw forward or to the side when closing into a stable bite. This can lead to a functionally incorrect chewing process.