Pericoronitis refers to inflammation around the crown of an unerupted tooth. It most commonly occurs with the mandibular third molar and can be acute, subacute, or chronic. Acute pericoronitis presents as a red, swollen, painful lesion that may cause fever and lymphadenitis. Treatment involves antibiotics and flushing the area for mild cases or flap removal for persistent symptoms to prevent recurrence. The decision to retain or extract the tooth depends on its stage of eruption, position, and likelihood of further eruption without complications.