Updated on February 7, 2024
7 min read

Impacted Tooth: Causes, Complications, and Treatment

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What is an Impacted Tooth?

An impacted tooth refers to a tooth that hasn’t properly erupted from the gums or can’t erupt. It may have partially broken through the gums but hasn’t come in fully, or it may be blocked from appearing outside the gums.

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This situation is most common with wisdom teeth since many people don’t have sufficiently large jaws to allow these teeth to erupt fully. After wisdom teeth, the upper canines are the most likely to be impacted.

When a tooth is impacted, dental crowding, discomfort, and other issues can result. Because of this, surgery may be necessary to remove or expose the tooth.Clear aligners can save you thousands of dollars compared to braces. Learn about clear aligners

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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 known as third molars, erupt behind the 12-year-molars (second molars) about 4 to 8 years later.

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Between 16 and 20 years of age, most people undergo wisdom tooth removal surgery because the teeth do not grow in properly. Third molars can grow in at various angles, even horizontally, because jawbones usually aren’t large enough for them to erupt normally.

If you have a small jaw, you are more likely to have impacted wisdom teeth. Serious oral infections and cysts can form if an impacted wisdom tooth is not removed.

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 naturally.We recommend at-home clear aligners if you have mild teeth misalignment. View our top recommendations

Symptoms of an Impacted Tooth

In many cases, impacted teeth do not cause any obvious symptoms. However, the longer a tooth is impacted, the more likely the following symptoms will arise:

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

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What Causes an Impacted Tooth?

The primary cause of impacted teeth is the dental arch not having enough room in your jaw to allow the teeth to erupt (dental crowding). If your jaw isn’t large enough to accommodate all of your teeth, they may grow crooked and overlap, and some may become impacted.

Other possible causes of an impacted tooth include:

  • Dental trauma — An injury to the tooth or jaw can delay eruption and eventually cause an impacted tooth. Incisors in the upper jaw are most commonly affected.
  • Over-retained baby teeth — Sometimes, baby teeth don’t fall out when they should. Dentists typically extract these teeth to allow space for permanent teeth. Otherwise, crowding and impaction are likely to occur.
  • Irregular tooth growth — Sometimes a tooth grows in at an angle, which can result in it becoming impacted. This most commonly affects wisdom teeth (third molars).
  • Supernumerary teeth — These are extra teeth that some people are born with. Extra teeth can result in impacted maxillary incisors (the front teeth in the upper jaw).

Complications of Impacted Teeth

While tooth impaction doesn’t always cause serious problems, it can lead to issues like: 

Tooth Decay

If a tooth is impacted, it may be partially exposed but difficult to keep clean. This means that over time, plaque can build up in the area, and bacteria can begin to eat away at the tooth.

If tooth decay is allowed to continue, the impacted tooth may become infected and develop an abscess. This is a buildup of pus around the tooth that can result in throbbing pain and requires immediate attention.

Malocclusion (Teeth Misalignment)

Malocclusion refers to the misalignment of teeth. Impacted teeth are often associated with crowding of the adjacent teeth, which can cause (sometimes severe) misalignment.

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Gum Disease

Because impacted teeth are hard to access for brushing and flossing, bacteria and plaque can build up in the area around them. This can cause not only tooth decay but also gum disease.

This is most commonly seen with impacted third molars, which are often covered by a vulnerable flap of gum tissue. This flap can easily become inflamed and infected, in a condition called pericoronitis.

gingivitis NewMouth


Sometimes the tissue surrounding an impacted tooth can fill with fluid, resulting in a benign (noncancerous) cyst known as a dentigerous cyst. Like tooth decay, if this is left untreated, it can have more severe consequences, including:

  • Expansion of the bone surrounding the teeth
  • Displacement of teeth
  • Root resorption
  • An infection that spreads beyond the tooth
  • The cyst becoming malignant (cancerous)
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Treatment Options for Impacted Teeth

Treatment may not be necessary if an impacted tooth is not causing problems. If treatment is needed, it may take several forms depending on the location and severity of the impaction:


Extraction of impacted teeth may be recommended if your jaw doesn’t have enough room for them to erupt completely. Wisdom teeth, for example, are often removed by around age 20 if they aren’t growing in properly.

For teeth further to the front of the mouth, such as canines or incisors, extraction is less likely to be recommended. Instead, it may be surgically exposed, with orthodontic treatment to bring the adjacent teeth into alignment.

Orthodontic Treatment

If the impacted tooth is in the front of your mouth, you may benefit from orthodontic treatment. This treatment may follow surgery to extract or expose the impacted tooth.


Braces use brackets and wires to bring teeth into alignment. The brackets, which cover each tooth, can be made of metal or ceramic, and the wires are generally made of metal. Together with elastic or metal ligaments, they can exert (and withstand) a great deal of pressure.

For more severe or complex cases of teeth misalignment, braces may be required. This may be the case following extraction or eruption of an impacted tooth.

Clear Aligners

Clear aligners are a popular alternative to braces, since they’re nearly invisible and can offer shorter and more convenient treatment. They vary widely in quality and cost, but in general they work best for milder or less complicated alignment issues. If your teeth aren’t severely displaced by an impacted tooth, clear aligners may be a more cost-effective option than braces.


Once treatment with either braces or aligners is finished, you’ll be given a retainer to wear at night. This device doesn’t move your teeth any further, but it helps to keep them in their new positions.

Your dentist might recommend continuing to wear your retainer at night throughout your life. 

Surgical Exposure

In some cases, an impacted tooth will need to be surgically exposed. There are two types of oral surgery used to expose impacted teeth:

Open Eruption

During an open eruption procedure, your dentist or oral surgeon will surgically uncover 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 buccal gingiva (the portion of the gingiva that covers the front surfaces of the teeth). From here, the dentist can directly visualize the tooth after exposure, allowing for proper eruption.

Closed Eruption

During a closed eruption procedure, your dentist or orthodontist will surgically expose the tooth under the gums. Then, they will place an orthodontic attachment on the tooth and replace the overlying gum tissue (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 other front teeth.


Impacted teeth are teeth that are trapped within the jawbone and can’t erupt properly. They may have erupted partially, or they may remain completely covered by bone or gum tissue. Wisdom teeth (third molars) are the most likely to suffer impaction, followed by the upper canines.

Sometimes, no serious issues result from impacted teeth. But in many cases, they contribute to overcrowding or malocclusion, and they may become infected because they’re hard to clean. Surgery to remove or expose the impacted tooth may be needed to prevent or relieve these issues.

If you have concerns about an impacted tooth, consult your dentist or oral surgeon.

What’s Next?

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Last updated on February 7, 2024
7 Sources Cited
Last updated on February 7, 2024
All NewMouth content is medically reviewed and fact-checked by a licensed dentist or orthodontist to ensure the information is factual, current, and relevant.

We have strict sourcing guidelines and only cite from current scientific research, such as scholarly articles, dentistry textbooks, government agencies, and medical journals. This also includes information provided by the American Dental Association (ADA), the American Association of Orthodontics (AAO), and the American Academy of Pediatrics (AAP).
  1. Cobourne, Martyn T., and Andrew T. DiBiase. Handbook of Orthodontics. Elsevier, 2016.
  2. Gupta, Seema, and Nikhil Marwah. “Impacted Supernumerary Teeth-Early or Delayed Intervention: Decision Making Dilemma?” International Journal of Clinical Pediatric Dentistry, 2012.
  3. Impacted Tooth.” MedlinePlus Medical Encyclopedia, U.S. National Library of Medicine.
  4. Santosh, P. “Impacted Mandibular Third Molars: Review of Literature and a Proposal of a Combined Clinical and Radiological Classification.” Annals of medical and health sciences research, 2015.
  5. Siotou, Kalliopi, et al. “Frequency and Local Etiological Factors of Impaction of Permanent Teeth among 1400 Patients in a Greek Population.” Dentistry Journal, 2022.
  6. Lövgren, Mai Lin, et al. “Dental age in children with impacted maxillary canines.” Acta Odontologica Scandinavica, 2020.
  7. Mohan, Karthik Rajaram, et al. “An infected dentigerous cyst associated with an impacted permanent maxillary canine, inverted mesiodens and impacted supernumerary teeth.” Journal of pharmacy & bioallied sciences, 2013.
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