Malocclusion means the teeth aren’t aligned properly, or the upper and lower teeth don’t fit together well. MedlinePlus notes very few people have perfect alignment and most problems are minor, but malocclusion is the most common reason for referral to an orthodontist. This guide covers the types, causes and treatment options.
What a normal bite looks like
MedlinePlus explains the upper teeth should fit slightly over the lower teeth, and the points of the molars should fit the grooves of the opposite molars. Upper teeth keep you from biting your cheeks and lips, and lower teeth protect your tongue.
Types
- Class 1: the most common. The bite is normal, but the upper teeth slightly overlap the lower teeth.
- Class 2 (overbite, retrognathism): the upper jaw and teeth severely overlap the lower.
- Class 3 (underbite, prognathism): the lower jaw juts forward, so lower teeth overlap the upper.
Other terms you may hear include crowded teeth, crossbite and open bite.
Causes
MedlinePlus says malocclusion is most often hereditary, from a mismatch between upper and lower jaw size or between jaw and tooth size. Other causes include:
- childhood habits such as thumb sucking, tongue thrusting, pacifier use beyond age 3 and prolonged bottle use. See thumb sucking and pacifiers.
- extra, lost, impacted or abnormally shaped teeth
- ill-fitting fillings, crowns, appliances, retainers or braces
- misaligned jaw fractures after severe injury
- birth differences such as cleft lip and palate, and tumors of the mouth and jaw
Symptoms
MedlinePlus lists abnormal tooth alignment or facial appearance, difficulty or discomfort biting or chewing, mouth breathing, inability to bite into food correctly (open bite) and, rarely, speech difficulties such as a lisp.
Diagnosis
Most problems are found by a dentist at a routine exam. The dentist may pull your cheek outward and ask you to bite to check how your back teeth meet. MedlinePlus says you may be referred to an orthodontist, and X-rays and models of the teeth are often used.
Why treat it
MedlinePlus says correcting moderate or severe malocclusion can make teeth easier to clean, lowering the risk of decay and gum disease. It can also relieve strain on teeth, jaws and muscles, reducing the risk of breaking a tooth and possibly TMJ symptoms, and improve facial appearance.
Treatment options
- Braces or other appliances, including clear aligners for some people. See aligners vs braces.
- Removing teeth when overcrowding is part of the problem.
- Repairing rough or irregular teeth by reshaping, bonding or capping, and fixing misshapen restorations.
- Jaw surgery to lengthen or shorten the jaw, needed only in rare cases.
Brush and floss every day during treatment. MedlinePlus warns plaque on braces can permanently mark teeth or cause decay. See cleaning teeth with braces. A retainer is needed afterward. See retainers after braces.
What to expect
MedlinePlus says problems are easier, quicker and less expensive to fix early. Treatment works best in children and teens because bones are softer. It may last 6 months to 2 or more years. Adult treatment often succeeds but may take longer. See when kids should see an orthodontist.
Possible issues during treatment
Tooth decay, discomfort, gum irritation from appliances and temporary chewing or speaking difficulty. Contact your dentist if a toothache, mouth pain or other new symptoms develop.
Frequently asked questions
Can malocclusion be prevented?
MedlinePlus says many types can’t be, but controlling habits like thumb sucking or tongue thrusting may help, and early treatment gets quicker results.
Is an overbite the same as malocclusion?
A severe overbite is Class 2 malocclusion.
Sources
By the Dentist Review Editorial Team.
This article is for general information only and is not medical advice. Talk to a licensed dentist about your own situation. See our disclaimer.
Featured image: “Teeth Braces (1)” by Suyash Dwivedi, via Wikimedia Commons, licensed CC BY-SA 4.0. Resized and compressed for the web.
Our guides are written and reviewed by the Dentist Review editorial team. We research each topic using public, authoritative sources such as the CDC, the National Institutes of Health (NIH/NIDCR), the American Dental Association (ADA) and CMS, and we update guides when guidance changes. Guides are for general information only and are not dental or medical advice; please read our disclaimer and learn more about us.