Is it best to leave mouth ulcer alone?

Depends on pain: Oral ulcers happen most frequently from trauma from eating or tooth brushing and usually heal within 5-14 days. Ulcers lasting longer than should be checked to determine the source of the ulceration. Cancer must be considered if the lesion persists.

Yes: Mouth ulcers usually resolve on their own, but you should see your dentist right away to diagnose what type of ulcer it is.

Diagnosis determined: There are many different types of mouth ulcers, namely canker sores (aphthous ulcers), and those caused by trauma, virus, candidia, lichen planus, medications, radiation, and neoplasms just to mention a few. The actual diagnosis determines the treatment, if any. Most resolve on their own and are best left alone. Salt water rinses may help. If it lasts more than 2 weeks, see a dentist to evaluate.