Why is my gum swelling around one tooth after root canal?

Inflammed or infect: Inflammation can be just that (red, swollen, tender to touch, warm). And will heal with time. Or there could be abnormal pressure from adjacent tissue/structure or infection. Check with the dentist. Swelling around tooth that just had root canal work is not unusual. However, if very swollen, or painful, or pus coming from area, or anything beyond little swelling, check w dentist.

Infection: How long ago was root canal done. If just a day or two after, than it may be a remnant of infection. Please contact dentist as he may need to open tooth to allow infection to drain or place you on antibiotics.

Possible: The swelling could be due to the irrigation solution that is used for the root canal or the clamp that is placed on the tooth to stabilize the rubber covering that is placed around the root canal tooth. Sometimes you can have a persistent infection causing the swelling.

Contact DDS: There are many variables- see your dentist. There may be an infection evident and antibiotic therapy is needed. The area may be sore from the rubber dam clamp or there may be a fracture in the tooth. See DDS for a definitive diagnosis.

Infection, see DDS: The dentists can do their best trying to avoid the complications, however, they are not always preventable. See your dentist for root canal complication treatment.