Pericoronitis: Infection Around the Erupting Third Molar

Pericoronitis is an acute infection of the soft tissue surrounding a partially erupted tooth, and it most often affects the mandibular third molar. It is a common reason for emergency dental attendance, causing pain, swelling, trismus, and occasionally serious spread of infection into the deep ne...

Pericoronitis is an acute infection of the soft tissue surrounding a partially erupted tooth, and it most often affects the mandibular third molar. It is a common reason for emergency dental attendance, causing pain, swelling, trismus, and occasionally serious spread of infection into the deep neck spaces. This article explains why the condition develops, how it presents, how it is managed in the acute phase, and why removal of the offending tooth is frequently the definitive solution.

Why Pericoronitis Develops

When a wisdom tooth erupts partially, a flap of gingiva known as the operculum remains draped over the crown. The space between the operculum and the tooth creates a deep pocket that traps food debris, plaque, and bacteria. Because this area cannot be cleaned effectively with a toothbrush, a biofilm-rich environment develops that readily becomes infected. Trauma from the opposing tooth biting onto the operculum further aggravates the inflamed tissue.

Pericoronitis is most common in adolescents and young adults, precisely when the third molars are erupting. Contributing factors include poor oral hygiene, previous episodes of pericoronitis, and the presence of a partially erupted tooth with a deep overlying flap. Episodes may be acute and severe, or chronic with recurrent mild discomfort. The condition is predominantly associated with the mandibular third molar, but it can also affect other partially erupted teeth.

Clinical Features and Diagnosis

The cardinal symptom of pericoronitis is pain in the region of the erupting wisdom tooth, which often worsens with chewing and can radiate to the ear, throat, or floor of the mouth. Examination typically reveals an inflamed, tender operculum with surrounding redness and swelling. A thin, purulent discharge may be expressed from beneath the flap, and the patient frequently complains of a bad taste or halitosis. In more severe cases, facial swelling, lymph node enlargement, and limited mouth opening signal the spread of infection.

The diagnosis is clinical and straightforward in most cases. A periapical or panoramic radiograph is useful to assess the position and angulation of the tooth, the state of the surrounding bone, and to rule out caries or periapical pathology of the adjacent second molar. Systemic symptoms such as fever and malaise indicate that the infection is more extensive and that the patient may require broader treatment.

Acute Management of the Episode

Management of an acute episode focuses on relieving pain, controlling infection, and removing the cause. Gentle irrigation of the pocket beneath the operculum with warm saline or chlorhexidine helps dislodge debris and bacteria and provides rapid symptomatic relief. The patient is advised to maintain meticulous oral hygiene and to rinse regularly with chlorhexidine mouthwash during the episode.

If there is significant swelling, systemic symptoms, or evidence of spreading infection, antibiotics are indicated; a penicillin such as amoxicillin, or clindamycin in patients with penicillin allergy, is commonly prescribed. Analgesics such as ibuprofen or paracetamol control pain. The decision to remove the operculum surgically, a procedure called operculectomy, or to extract the tooth is usually deferred until the acute infection has settled, because operating during an acute phase risks poorer anesthesia and wider spread of infection.

Definitive Treatment and Prevention

For many patients, particularly those with recurrent episodes or a poorly positioned tooth, extraction of the third molar is the definitive treatment. Removal eliminates the pocket and the source of infection and prevents future episodes. Teeth that are well positioned, fully functional, and have adequate space may occasionally be retained with operculectomy, but this option is associated with a higher rate of recurrence.

Prevention is directed at maintaining good oral hygiene around partially erupted teeth, including careful brushing and the use of a chlorhexidine rinse during periods of eruption. Patients with a history of pericoronitis should be counseled about the likelihood of recurrence and the potential benefits of extraction. In young adults, removal of third molars before the age of 25 is associated with easier surgery and more rapid healing, and may be recommended before the tooth causes problems.

Complications of Untreated Pericoronitis

When pericoronitis is neglected or inadequately treated, the infection can spread beyond the operculum into the fascial spaces of the head and neck. The mandibular third molar lies adjacent to several potential spaces, and pus may track into the submandibular, buccal, pterygomandibular, or lateral pharyngeal spaces. In severe cases, bilateral involvement of the sublingual and submandibular spaces produces Ludwig's angina, a life-threatening condition characterized by rapidly progressive swelling, elevation of the tongue, and airway compromise. Other serious complications include osteomyelitis of the mandible, septicemia, and rarely spread to distant sites. The presence of significant trismus, dysphagia, fever, or swelling that extends beyond the local area should therefore be treated as an emergency, with prompt referral for hospital care, intravenous antibiotics, and surgical drainage when necessary. Recognizing these warning signs is essential for preventing catastrophic outcomes.

Clinical Key Points

- Pericoronitis is an infection of the operculum over a partially erupted third molar, driven by a biofilm that cannot be cleaned.

- The classic presentation is pain, swelling, and often a purulent discharge beneath the flap, with possible trismus and fever in severe cases.

- Acute management relies on irrigation, chlorhexidine, analgesics, and antibiotics only when infection is spreading.

- Surgery, usually extraction, should be delayed until the acute infection has resolved.

- Recurrent pericoronitis is a strong indication for removal of the tooth.

- Good oral hygiene and early assessment of erupting third molars help prevent episodes and serious complications.

Conclusion

Pericoronitis is a common, painful, and potentially serious infection that dental practitioners encounter regularly. A clear understanding of its cause, a careful clinical assessment, and a stepwise approach to acute and definitive management allow the condition to be controlled safely and effectively. For most patients with recurrent or severe involvement, extraction of the third molar offers the most reliable route to a lasting cure and the prevention of future complications.