Occlusion refers to the alignment of teeth and the way that the upper and lower teeth fit together (bite). Ideally, all upper teeth fit slightly over the lower teeth. The points of the molars fit the grooves of the opposite molar.
The upper teeth keep the cheeks and lips from being bitten and the lower teeth protect the tongue.
Malocclusion is most often hereditary, which means the condition is passed down through families. There may be a difference between the size of the upper and lower jaws or between jaw and tooth size, resulting in overcrowding of teeth or in abnormal bite patterns.
Variations in size or structure of either jaw may affect its shape, as can birth defects such as cleft lip and palate.
Other causes of malocclusion include:
- Childhood habits such as thumb sucking, tongue thrusting, pacifier use beyond age 3, and prolonged use of a bottle
- Extra teeth, lost teeth, impacted teeth, or abnormally shaped teeth
- Ill-fitting dental fillings, crowns, appliances, retainers, or braces
- Misalignment of jaw fractures after a severe injury
- Tumors of the mouth and jaw
There are different categories of malocclusion.
- Class 1 malocclusion is the most common. The bite is normal, but the upper teeth slightly overlap the lower teeth.
- Class 2 malocclusion, called retrognathism or overbite, occurs when the upper jaw and teeth severely overlap the bottom jaw and teeth.
- Class 3 malocclusion, called prognathism or underbite, occurs when the lower jaw protrudes or juts forward, causing the lower jaw and teeth to overlap the upper jaw and teeth
- Abnormal alignment of teeth
- Abnormal appearance of the face
- Difficulty or discomfort when biting or chewing
- Speech difficulties (rare) including lisp
- Mouth breathing (breathing through the mouth without closing the lips)
How can I know if my bite is “off”?
During your examination, your doctor will examine your jaw closely and may notice symptoms that your bite may be off. Some symptoms include if the jaw does not open evenly on both sides, if the jaw makes a clicking noise as it opens, if the enamel has been ground away in certain areas, or if there are fractured teeth. Chronic symptoms of bruxism, headaches or neck aches, are also clues that the bite may be off.
How is my bite fixed?
Before the procedure begins, the doctor will have you bite on a very thin piece of mylar paper. The mylar paper transfers color to the areas where contact occurs. The doctor will then smooth the area where the marks have been left removing just enough of the tooth or restoration to eliminate the interference. This process will be done on all areas where the mylar paper left color on the tooth until the jaw is able to get into its normal position.