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Malocclusion of teeth

Show Alternative Names
Crowded teeth
Misaligned teeth
Crossbite
Overbite
Underbite
Open bite

Malocclusion means the teeth are not aligned properly.

Causes

Occlusion refers to the alignment of teeth and the way that the upper and lower teeth fit together (bite). The upper teeth should fit slightly over the lower teeth. The points of the molars should fit the grooves of the opposite molar.

The upper teeth keep you from biting your cheeks and lips, and your lower teeth protect your tongue.

Malocclusion is most often hereditary. This means it is passed down through families. It may be caused by a difference between the size of the upper and lower jaws or between the jaw and tooth size. It causes tooth overcrowding or abnormal bite patterns. The shape of the jaws or birth defects such as cleft lip and palate may also be reasons for malocclusion.

Other causes 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, dental 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.

Symptoms

Symptoms of malocclusion are:

  • 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)
  • Inability to bite into food correctly (open bite)

Exams and Tests

Most problems with teeth alignment are discovered by a dentist during a routine exam. Your dentist may pull your cheek outward and ask you to bite down to check how well your back teeth come together. If there is any problem, your dentist may refer you to an orthodontist for diagnosis and treatment.

You may need to have dental x-rays, head or skull x-rays, or facial x-rays. Diagnostic models of the teeth are often needed to diagnose the problem.

Treatment

Very few people have perfect teeth alignment. However, most problems are minor and do not require treatment.

Malocclusion is the most common reason for referral to an orthodontist.

The goal of treatment is to correct the positioning of the teeth. Correcting moderate or severe malocclusion can:

Treatments may include:

  • Braces or other appliances: Metal bands are placed around some teeth, or metal, ceramic, or plastic bonds are attached to the surface of the teeth. Wires or springs apply force to the teeth. Clear braces (aligners) without wires may be used in some people.
  • Removal of one or more teeth: This may be needed if overcrowding is part of the problem.
  • Repair of rough or irregular teeth: Teeth may be adjusted down, reshaped, and bonded or capped. Misshapen restorations and dental appliances should be repaired.
  • Surgery: Surgical reshaping to lengthen or shorten the jaw is needed in rare cases. Wires, plates, or screws may be used to stabilize the jaw bone.

It is important to brush and floss your teeth every day and have regular visits to a general dentist. Plaque builds up on braces and may permanently mark teeth or cause tooth decay if it is not properly removed.

You will need a retainer to stabilize your teeth after having braces.

Outlook (Prognosis)

Problems with teeth alignment are easier, quicker, and less expensive to treat when they are corrected early. Treatment works best in children and adolescents because their bones are still soft and teeth are moved more easily. Treatment may last 6 months to 2 or more years. The time will depend on how much correction is needed.

Treatment of orthodontic disorders in adults is often successful, but may require longer use of braces or other devices.

Possible Complications

Complications of malocclusion include:

  • Tooth decay
  • Discomfort during treatment
  • Irritation of mouth and gums (gingivitis) caused by appliances
  • Chewing or speaking difficulty during treatment

When to Contact a Medical Professional

Call your dentist if toothache, mouth pain, or other new symptoms develop during orthodontic treatment.

Prevention

Many types of malocclusion are not preventable. It may be necessary to control habits such as thumb sucking or tongue thrusting (pushing your tongue forward between your upper and lower teeth). Finding and treating the problem early allows for quicker results and more success.

Review Date: 1/24/2022

Reviewed By

Michael Kapner, DDS, General Dentistry, Norwalk Medical Center, Norwalk CT. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

References

Dean JA, Walsh JS. Managing the developing occlusion. In: Dean JA, ed. McDonald and Avery's Dentistry for the Child and Adolescent. 11th ed. St Louis, MO: Elsevier; 2022:chap 23.

Dhar V. Malocclusion. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 335.

Hinrichs JE, Thumbigere-Math V. The role of dental calculus and other local predisposing factors. In: Newman MG, Takei HH, Klokkevold PR, Carranza FA, eds. Newman and Carranza's Clinical Periodontology. 13th ed. Philadelphia, PA: Elsevier; 2019:chap 13.

Koroluk LD. Adolescent patients. In: Stefanac SJ, Nesbit SP, eds. Diagnosis and Treatment Planning in Dentistry. 3rd ed. St Louis, MO: Elsevier; 2017:chap 16.

Nesbit SP, Reside J, Moretti A, Gerdts G, Boushell LW, Barrero C. Definitive phase of treatment. In: Stefanac SJ, Nesbit SP, eds. Diagnosis and Treatment Planning in Dentistry. 3rd ed. St Louis, MO: Elsevier; 2017:chap 10.

Disclaimer

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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Prognathism - Illustration Thumbnail

Prognathism

Prognathism is a descriptive term for a jaw (lower or upper) that protrudes forward beyond the plane of the face.

Illustration

Teeth, adult - in the skull - Illustration Thumbnail

Teeth, adult - in the skull

This is a picture of normal teeth with an overjet. Some bone has been cut away to reveal the roots of the teeth.

Illustration

Malocclusion of teeth - Illustration Thumbnail

Malocclusion of teeth

Occlusion refers to the alignment of teeth and the way that the upper and lower teeth fit together (bite). Malocclusion is the most common reason for referral to an orthodontist. Most malocclusion is mild enough not to require treatment. If a severe misalignment is present, orthodontics and/or oral surgery may be required.

Illustration

Dental anatomy - Illustration Thumbnail

Dental anatomy

The appearance of normal teeth varies, especially the molars. Abnormally shaped teeth can result from many different conditions. Specific diseases can have a profound effect on tooth shape, tooth color, time of appearance, or absence of teeth.

Illustration

 
 
Prognathism - Illustration Thumbnail

Prognathism

Prognathism is a descriptive term for a jaw (lower or upper) that protrudes forward beyond the plane of the face.

Illustration

Teeth, adult - in the skull - Illustration Thumbnail

Teeth, adult - in the skull

This is a picture of normal teeth with an overjet. Some bone has been cut away to reveal the roots of the teeth.

Illustration

Malocclusion of teeth - Illustration Thumbnail

Malocclusion of teeth

Occlusion refers to the alignment of teeth and the way that the upper and lower teeth fit together (bite). Malocclusion is the most common reason for referral to an orthodontist. Most malocclusion is mild enough not to require treatment. If a severe misalignment is present, orthodontics and/or oral surgery may be required.

Illustration

Dental anatomy - Illustration Thumbnail

Dental anatomy

The appearance of normal teeth varies, especially the molars. Abnormally shaped teeth can result from many different conditions. Specific diseases can have a profound effect on tooth shape, tooth color, time of appearance, or absence of teeth.

Illustration

 
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