Gum behind back molar swollen

Swelling behind a back molar can come from trapped food, gum trauma, or an erupting wisdom tooth and needs assessment if persistent.

The tissue behind the last molar is the retromolar or posterior gum area. A partially erupted wisdom tooth can trap plaque beneath a gum flap, causing pericoronitis, while a cavity, periodontal pocket, or cheek-biting injury can produce similar swelling.

Rinse gently, keep the area free of food with careful brushing, and avoid poking or cutting the gum flap. Soft foods can reduce trauma while you arrange an examination; do not squeeze a swelling.

See a dentist if swelling persists, recurs, causes bad taste, pain, limited opening, or discomfort when swallowing. Facial swelling, fever, or breathing difficulty needs urgent care.

Ask whether the wisdom tooth has enough space and whether an X-ray is needed to assess its position. Ask whether cleaning, gum-flap treatment, restoration, or removal addresses the cause.