Getting a recurring mouth ulcer between gums and cheek near root canaled tooth, gums are tender and sore. dentist says x-ray of root canal looks good?

Recurring ulcer: Any sore or lesion in the mouth that does not heal in 10-14 days, or is recurring, needs to be examined and possibly biopsied. If your dentist is unsure why you are have a lesion, Have the root canal evaluated by an endodontist. If the root canal is sound, and no other teeth are involved, see an oral surgeon or periodontist for an exam.

Ulceration: An ulcer should have nothing to do with your root canal therapy. An abscess or fistula would indicate an infection. If your dentist says the root canal tooth appears fine, then the ulceration must not be related.

Contact DDS: Two possibilities, the area is a fistulous tract and the tooth is either infected, has a missing canal not addressed or the tooth is fractured, the second possibility is that it is unrelated to the tooth in question and the origin needs to be evaluated by your dentist. If this is problematic, possibly seek a second opinion.

Root canal and X-ray: How a root canal “looks” on X-ray doesn’t matter. Symptoms like these may imply a “mouth” ulcer—from the procedure and instrumentation, or from an unrelated “Cold sore mouth ulcer” so many patients can experience. It can also be an incomplete or failed root canal, cracked tooth, and draining fistula from it, even with a “good” X-ray. A skilled examiner must ‘look harder”—at more than an X-ray.