Back gum swelling
Swelling behind a back tooth can come from irritation, gum infection, or an erupting wisdom tooth and needs triage by symptoms.
The short answer
Swelling behind a back tooth commonly comes from trapped food, gum inflammation, an erupting wisdom tooth, or infection around a tooth. The cause is distinguished by an examination of the gum and tooth, with dental X-rays when the tooth or bone cannot be assessed directly.
What is the direct answer?
What does this question mean?
The area behind the last molar is the retromolar or wisdom-tooth region. A flap of gum over a partly erupted tooth can trap plaque and debris, while a cavity, cracked tooth, periodontal pocket, or dental abscess can also produce local swelling.
What can you do next?
Rinse gently with warm salt water, clean the area with a soft brush, and avoid squeezing or puncturing the swelling. Use pain medicine only according to its label and your clinician’s advice, and arrange an examination rather than relying on home treatment.
When should you seek dental care?
Seek prompt dental care if swelling persists, recurs, or is accompanied by toothache, pus, fever, a bad taste, or difficulty opening the mouth. Emergency assessment is needed for swelling that spreads into the face or neck, or causes trouble breathing or swallowing.
What should you ask the dentist?
Ask whether the swelling is related to a wisdom tooth, gum pocket, cavity, crack, or abscess, and whether an X-ray is needed. Ask which treatment addresses the cause and what warning signs should prompt urgent review.
Frequently asked questions
Can a wisdom tooth cause swelling behind the molar?
Yes. A partly erupted wisdom tooth can leave a gum flap where plaque and food collect, causing inflammation around the tooth.
Should I pop a gum swelling?
No. Puncturing it can injure tissue and does not treat a dental infection or the tooth causing it.