I work in a dentist office and whenever I get a horrible canker sore I use Silver Nitrate Sticks. It burns for a little bit but then forms a wet scab over the area. I asked one of the Dentist at the office I work in why this works; and he said he had heard at in a CE class that it's because the canker sore is cause by a virus and the body does not heal the virus it just runs its course, so the Silver Nitrate injures the area, causing the body to heal itself. Although it stings and makes your mouth taste a little like an ashtray for about five minutes, it's totally worth it.
Silver Nitrate Sticks
When I underwent chemotherapy, I would also get mouth ulcers. The doctor gave me a prescription for a mouthwash, but it was useless. Rather than suffer for days with mouth ulcers, I decided to cauterize them using silver nitrate sticks. Yes, this is painful but only for seconds as compared to 10 days of daily suffering with mouth ulcers.