Impacted Tooth: Types, Causes, Complications & Treatment Options

What is an Impacted Tooth?

During the infancy years, primary teeth begin to emerge through the gums. Around age 6, these teeth start to shed and permanent teeth grow in. In some cases, teeth erupt abnormally, which can result in complications later on. For example, when a tooth does not emerge or only grows in partially, it is an impacted tooth. Surgical removal or exposure of the tooth is typically necessary to reduce the chance of dental crowding and other issues in the future.

Primary Causes of Impacted Teeth

The primary cause of an impacted tooth is due to overcrowded teeth in the dental arch. In other words, if your jaw is too small, teeth may grow in crooked and overlap because there is not enough room. Other possible causes of impaction or disturbed tooth eruption include:

  • Dental Trauma — a traumatic dental injury can delay eruption and eventually cause an impacted tooth. Incisors in the upper jaw are most commonly affected.
  • Over-Retained Baby Teeth — this condition refers to teeth that loosen, but then tighten back into the gums, preventing the eruption of permanent teeth. A dentist or oral surgeon typically extract the teeth to allow for the proper eruption of permanent teeth. If a dentist does not remove them, dental crowding commonly develops, which can result in impacted teeth.
  • Irregular Tooth Growth — sometimes, a tooth grows in at an angle, which can result in an impacted tooth. This most commonly affects wisdom teeth (third molars).
  • Supernumerary Teeth this condition refers to people who have an excessive number of teeth. Having extra teeth can result in impacted maxillary incisors (the front teeth in the upper jaw).

Which Teeth Are Mostly Commonly Impacted?

Impaction most commonly affects the wisdom teeth (third molars) and canines in the upper jaw (maxillary canines).

Wisdom Teeth (Third Molars)

Wisdom teeth, also referred to as third molars, erupt behind the 12-year-molars (second molars) about five to nine years later. Between 16 and 20 years of age, most people get their wisdom teeth removed because they don’t grow in properly. For example, third molars can grow in at various angles, even horizontally, because the jaw isn’t large enough for them to erupt normally.

If you have a small jaw, you are more likely to have impacted third molars. If impacted wisdom teeth aren’t removed, serious oral infections and cysts can form.

Maxillary Canines (Upper Jaw)

Canines in the upper jaw are the second most common teeth to become impacted. These teeth are essential because they help you rip and tear food. Because of this, dentists do not typically extract them. Instead, they use treatments that help them erupt normally.


Many times, impacted teeth do not cause any obvious symptoms. However, the longer a tooth is impacted, the more likely these following symptoms may arise:

  • Bad breath (halitosis) that remains even after brushing your teeth
  • Tender, red, and swollen gums
  • Difficulty opening the mouth
  • Pain when opening or closing the jaw
  • Persistent headaches that come on suddenly
  • Occasionally, lymph nodes in the neck may swell
  • A gap between teeth where the tooth should emerge
  • Bad taste in the mouth (typically near the tooth)


Serious complications are not likely if your dentist removes an impacted tooth. Although, if it isn't removed, serious dental infections, chronic mouth discomfort, plaque buildup, and nerve damage are possible. Other potential complications include:

receding gums
Tooth Abscess

A tooth abscess forms due to a bacterial infection from the long-term buildup of pus inside the gums and teeth. Throbbing and pain near the affected tooth often accompany an abscess.

loose tooth
Malocclusion (Teeth Misalignment)

Malocclusion refers to the misalignment of teeth. Impacted teeth, teeth lost prematurely, and extra teeth can result in misalignment, such as dental crowding.

gingivitis gum disease
Gingivitis or Periodontal Disease

Gingivitis is a mild form of gum disease that causes inflammation in the gingival tissues without bone loss. This form of gum disease is reversible and treated during professional teeth cleanings. If it is left untreated, periodontal disease can form, which is a nonreversible gum disease that causes permanent bone loss.

Treatment Options for Impacted Teeth

Treatment may not be necessary if an impacted tooth is not causing problems. Although, in most cases, a dentist or oral surgeon should remove impacted wisdom teeth by age 20 if they are not growing in properly. If the impacted tooth is in the front of the mouth, orthodontists may recommend braces to help move the tooth into the correct position. In some cases, the teeth need to be surgically exposed. There are two common times of exposure treatment, including:

Open Eruption

During this procedure, a dentist or oral surgeon surgically uncovers the crown of the impacted tooth under the gums. The tooth is left exposed to the oral cavity and is surrounded by the soft tissue of the palate or labial mucosa (inside lining of the lips). The orthodontist can also directly visualize the tooth following exposure, which allows for the proper eruption of the tooth.

Closed Eruption

During this procedure, an orthodontist surgically exposes the tooth crown under the gums. Then they place an orthodontic attachment and replace the overlying mucosa. Lastly, a chain extends from the attachment through the mucosa, allowing the dentist to place traction on the tooth and simulate normal tooth eruption. This procedure is lengthy but may be necessary for impacted incisors and anterior teeth.

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

Gupta, Seema, and Nikhil Marwah. “Impacted Supernumerary Teeth-Early or Delayed Intervention: Decision Making Dilemma?” International Journal of Clinical Pediatric Dentistry, Jaypee Brothers Medical Publishers, Sept. 2012,

“Impacted Tooth: MedlinePlus Medical Encyclopedia.” MedlinePlus, U.S. National Library of Medicine,

Updated on: June 29, 2020
Alyssa Hill
Medically Reviewed: November 15, 2019
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Lara Coseo