Malocclusion of the Teeth: Types, Causes & Treatment

Evidence Based
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What Is Malocclusion & What Causes It?

Malocclusion simply refers to the misalignment of teeth, which ranges from minor dental crowding to severe overbites or underbites. Teeth misalignment is commonly passed down through genetics.

Most people aren’t born with normal occlusion (a perfect bite) and turn to orthodontic treatment for long-term solutions.

Crowded teeth, gaps, and other forms of misalignment are all caused by the difference in teeth and jaw size. There is usually not enough room for permanent teeth to grow in properly.

Other common causes of malocclusion include:

  • Birth Defects — such as a cleft lip and palate
  • Childhood Habits — tongue thrusting, thumb sucking, excessive pacifier use, and prolonged bottle-feeding
  • Teeth Abnormalities — impacted, lost, and extra teeth
  • Failed Procedures — improper placement of crowns, fillings, retainers, and braces
  • Jaw Injuries and Problems — jaw fractures, cancers, tumors, dislocations, temporomandibular joint dysfunction, and osteonecrosis

Symptoms of Malocclusion

The symptoms of malocclusion are usually obvious, but some are subtle, and may include:

  • Crooked, crowded, or irregularly aligned teeth
  • Change in facial appearance and profile
  • Jaw or teeth discomfort when biting and/or chewing
  • Mouth breathing
  • Developing a lisp or other speech problems
  • Biting your cheeks, tongue, or lips often

Different Types of Malocclusions

There are three different classes of malocclusion, referred to as class I, II, and III:

  • Class I — in this form of malocclusion, the molars align but there is minor crowding in the anterior teeth. It is the most common malocclusion.
  • Class II — in this form of malocclusion, the upper teeth overlap the lower teeth and jaw.
  • Class III — in this form of malocclusion, the lower jaw is pushed forward. Unlike a class II malocclusion, the lower teeth overlap the upper teeth and jaw.

Within these three classes, there are seven different types of misalignment a patient can have. Treatment options also vary depending on age and the type of malocclusion:


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Overbite

An overbite is a class II malocclusion that occurs when the lower jaw is in an improper position. As a result, the upper teeth and jaw have too much overlap with the lower teeth and jaw. It can be attributed to genetics (skeletal), childhood sucking habits (dental), or a combination of the two.

overbite malocclusion scaled 1

An overbite should be treated as soon as possible. If it is left untreated, there is a higher risk of developing a jaw disorder, gum disease, or tooth decay over time.

Common overbite treatment options include:

  • Baby tooth extractions (for children only)
  • Dental braces, clear aligners & retainers (for both children and some adults)
  • Cervical pull headgear (for children only)
  • Jaw surgery (typically only for adults with fully developed jaws and teeth)

Underbite

An underbite is a class III malocclusion that occurs when the lower jaw is pushed forward. As a result, the lower teeth and jaw overlap the front teeth and jaw. There are two different types of underbites, including dental or skeletal.

underbite malocclusion scaled 1

A dental underbite is usually caused by a crossbite, while a skeletal underbite is caused by a malformation of the jawbone (genetics). Similar to an overbite, an underbite should be treated as early as possible to prevent the development of other dental conditions.

Common underbite treatment options include:

  • Baby tooth extractions (for children only)
  • Dental braces, clear aligners, and retainers (for both children and some adults)
  • Reverse-pull face mask (for children only)
  • Upper jaw expander (for children or young adults with developing jaws)
  • Jaw surgery (typically only for adults with fully developed jaws and teeth)

Crossbite

A crossbite is a class II malocclusion that occurs when a few bottom teeth are located outside the upper teeth when the mouth is closed. Genetics, mouth breathing, delayed permanent teeth eruption, and childhood habits (e.g. thumb sucking) can cause this form of malocclusion.

crossbite malocclusion scaled 1

Many people confuse crossbites and underbites, but they are completely different forms of malocclusion. Although, someone with an underbite typically has a crossbite. This form of malocclusion can either affect the anterior teeth, posterior teeth, or both.

Common crossbite treatment options include:

  • Dental braces, clear aligners & retainers (for both children and adults)
  • Reverse-pull face mask (for children only)
  • Rapid palate expander (for children or young adults with developing jaws)
  • Jaw surgery (typically only for adults with fully developed jaws and teeth)

Open Bite

An open bite is the rarest form of malocclusion. It occurs when the upper and lower teeth slant outwards and do not touch when the mouth is closed. An open bite can either affect the anterior teeth or posterior teeth.

open bite malocclusion scaled 1

Skeletal (genetic) or dental (irregular tooth eruption) factors can cause this condition. Additionally, untreated open bites typically result in speaking problems and issues tearing and chewing food.

Common treatment options for open bites include:

  • High pull headgear (for children only)
  • Vertical chin cup (for children only)
  • Roller appliance (for children only)
  • Bite block (for children only)
  • Jaw surgery (typically only for adults with fully developed jaws and teeth)

Overjet

An overjet (upper front teeth protrusion) is usually caused by a class II malocclusion, which is when the upper teeth are ahead of the lower teeth.

overjet malocclussion scaled 1

Overjets can be attributed to genetic factors, childhood habits, and/or irregular skeletal development. Untreated overjets can result in temporomandibular joint disorder (TMD).

Common treatment options for overjets include:

  • Dental braces, clear aligners & retainers (for both children and adults)
  • Carriere appliance (for children or young adults with developing jaws)
  • Cervical pull headgear (for children only)

Crowded Teeth

Dental crowding, also referred to as crowded teeth, occurs when there is not enough space in the mouth for permanent teeth to grow in straight. Crowding is a class I malocclusion that typically only affects the anterior teeth.

crowded teeth scaled 1

This form of malocclusion can be due to abnormal jaw development (genetics), irregular tooth eruption or loss, and normal aging.

Common treatment options for dental crowding include:

  • Dental braces, clear aligners & retainers (for both children and adults)
  • Veneers (for adults only)
  • Dentofacial orthopedics (for both children and adults)

Diastema (Gapped Teeth)

Diastema is when there is a space or gap between two or more teeth. Gaps can range from barely noticeable to large. Midline diastema, which appears as a gap between the two upper front teeth, is the most common.

midline diastema scaled 1

Common treatment options for spaced teeth and diastema include:

  • No treatment
  • Braces, clear aligners & retainers (for both children and adults)
  • Dental bonding (for both children and adults)
  • Restorations (typically for adults only)
  • Veneers (for adults only)
Invisible dental teeth brackets tooth aligners on blue background, plastic braces dentistry retainers to straighten teeth. Orthodontic temporary removable straighteners in dentist office dental

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Resources

Cobourne, Martyn T., and Andrew T. DiBiase. Handbook of Orthodontics. Elsevier, 2016.

Recognizing and Correcting Developing Malocclusions: a Problem-Oriented Approaches to Orthodontics. Wiley, 2015.

Sterling, Evelina Weidman. Your Childs Teeth: a Complete Guide for Parents. Johns Hopkins University Press, 2013.

Updated on: September 4, 2020
Author
Alyssa Hill
About
Medically Reviewed: November 13, 2019
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Lara Coseo
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