Gums behind back teeth swollen
Swelling behind the last molar can reflect an inflamed wisdom-tooth gum flap, trapped food, trauma, or infection.
The short answer
Swelling behind the back teeth can come from inflammation around a partially erupted wisdom tooth, trapped food, gum infection, trauma, or an abscess involving a tooth nearby. A gum flap over a partially erupted wisdom tooth can trap food and bacteria.
What is the direct answer?
What does this question mean?
The tissue behind the last molar is often the gum flap over an erupting or impacted third molar. Bacteria and food can collect beneath it, causing tenderness, redness, bad taste, pain on opening, or swelling; a neighbouring tooth or gum pocket can produce similar signs.
What can you do next?
Gently clean the area with a soft brush and follow any rinsing or pain-relief instructions given for you. Do not cut the gum, press on the swelling, or place aspirin directly on tissue; an examination and dental imaging may be needed to identify the source.
When should you seek dental care?
Arrange urgent care for fever, facial swelling, pus, worsening pain, difficulty opening the mouth, swallowing, or breathing. These features can indicate infection spreading beyond the local gum.
What should you ask the dentist?
Is a wisdom tooth erupting or impacted? Is there a gum flap, pocket, cavity, or abscess, and would cleaning, drainage, medication, or removal address the cause?
Frequently asked questions
Can swollen gum behind a molar go away by itself?
It may settle temporarily, but an erupting, impacted, or infected tooth can keep causing the problem and needs assessment.
Why might imaging be needed?
An image can show the wisdom tooth position, roots, bone, and nearby teeth.