[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Dentistry](https://durgical.com/en/dentistry/) › [Dental emergencies and trauma](https://durgical.com/en/dentistry/areas/emergencies/) › Pericoronitis and the wisdom tooth

# Pericoronitis and the wisdom tooth

- Emergency

Inflammation of the gum flap over a partly erupted lower wisdom tooth. It causes pain, swelling and trouble opening, and can spread to deep spaces.

Updated Nov 12, 2026

**See it in 3D:** [Lower left third molar](https://durgical.com/en/anatomy/lower-left-third-molar/) · [Lower right third molar](https://durgical.com/en/anatomy/lower-right-third-molar/)

## Key points

- Swollen flap over a partly erupted lower third molar = pericoronitis.
- Trismus is common; trismus plus dysphagia or fever = deep space risk.
- Recurrent episodes: remove the tooth.

## What it is

Pericoronitis is inflammation of the soft tissue (the operculum) around the crown of a partially erupted tooth, almost always a lower third molar in young adults. Food and bacteria are trapped under the flap, and the upper tooth often bites on it. Symptoms are pain at the back of the mouth, swelling, bad taste, pain on swallowing and limited opening; severe cases have fever, facial swelling and lymph nodes. Because the lower third molar lies close to the masticator, submandibular and parapharyngeal spaces, infection can spread quickly.

## How to recognise it

- Young adult, lower third molar partly erupted, swollen tender flap.
- Trismus and pain on swallowing are common.
- Recurrent episodes are an indication to remove the tooth.
- Local treatment: irrigation under the flap, chlorhexidine or warm saline rinses, analgesia.
- Antibiotics if fever, spreading swelling or trismus with systemic signs.

## What to do at once

- Look for red flags of deep spread: marked trismus, dysphagia, drooling, swelling below the jaw, fever.
- Examine the third molar area with good light; note whether the upper tooth bites on the flap.
- Mild: irrigation, rinses, analgesia and dental review within days.
- With systemic signs: add an antibiotic (metronidazole or amoxicillin per local guidance) and arrange dental care within a day.
- Red flags: emergency referral as for a deep neck infection.

## Costly mistakes

- Severe trismus with fever and sore throat may be a parapharyngeal or masticator space infection, not simple pericoronitis.
- Recurrent pericoronitis in an impacted tooth often leads to extraction once the acute episode settles.
- Pain at the back of the jaw in a teenager is sometimes mistaken for tonsillitis.

## Next step / Initial management

- Refer all cases to the dentist; recurrent episodes for assessment of extraction.
- Spreading infection: antibiotics plus urgent dental care; airway signs: emergency.
- Advise careful cleaning of the area and warm saltwater rinses.

## Test yourself

Think of the answer, then tap the question to see it.

## Which tooth is most often involved in pericoronitis?

A partially erupted lower third molar.

## Why can pericoronitis spread quickly to deep spaces?

Because the lower third molar lies close to the masticator, submandibular and parapharyngeal spaces.

## What is the usual long-term solution for recurrent pericoronitis?

Extraction of the involved third molar after the acute episode settles.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/dentistry/pericoronitis-and-the-wisdom-tooth/)

## Connections

## See it in 3D 2

The structures of Durgical's 3D anatomy where it is found.

- [Lower left third molar](https://durgical.com/en/anatomy/lower-left-third-molar/)
- [Lower right third molar](https://durgical.com/en/anatomy/lower-right-third-molar/)

## Related 4

- [Fascial spaces: where dental infections spread](https://durgical.com/en/dentistry/fascial-spaces-where-dental-infections-spread/)
- [Facial swelling from a tooth: when it is dangerous](https://durgical.com/en/dentistry/facial-swelling-from-a-tooth-when-it-is-dangerous/)
- [Dry socket (alveolar osteitis)](https://durgical.com/en/dentistry/dry-socket/)
- [Tooth eruption: when the teeth come in](https://durgical.com/en/dentistry/tooth-eruption-when-the-teeth-come-in/)

## In Pharmacology 3

- [Chlorhexidine](https://durgical.com/en/pharmacology/chlorhexidine/)
- [Metronidazole](https://durgical.com/en/pharmacology/metronidazole/)
- [Amoxicillin](https://durgical.com/en/pharmacology/amoxicillin/)

[← All of dentistry](https://durgical.com/en/dentistry/)

Educational content; it does not replace assessment by a dentist or doctor and is not a clinical instruction. For facial or neck swelling with difficulty swallowing or breathing, a knocked-out tooth or bleeding that will not stop, go to an emergency department at once.

Sources: [Pericoronitis](https://www.ncbi.nlm.nih.gov/books/NBK576411/) (StatPearls Publishing (NCBI Bookshelf), 2022); [Oral Surgery, Extraction of Mandibular Third Molars](https://www.ncbi.nlm.nih.gov/books/NBK587405/) (StatPearls Publishing (NCBI Bookshelf), 2023); [Odontogenic Orofacial Space Infections](https://www.ncbi.nlm.nih.gov/books/NBK589648/) (StatPearls Publishing (NCBI Bookshelf), 2023).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/dentistry/pericoronitis-and-the-wisdom-tooth/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/dentistry/pericoronitis-and-the-wisdom-tooth/