oh shi*!!! you dudes are freaking me out...I hate those things...my 4yr old got one of these recently and i had her do the warm salt water rinse...she got over it pretty quick... later dudes.
Biotene mouthwash works VERY well for canker sores...
Up until about 4-5 years ago I would get canker sores all the time. Sometimes as many and 5 at a time. I started using Biotene and it definately helped them heal faster, especially using it before bedtime.
I actually went to see a doctor for these because I was getting them frequently, twice a month or so if I lacerated my mouth with my toothbrush or a tortilla chip, taco shell,etc. He told me they start as cuts in the mouth and the bacteria in your mouth makes it become a canker sore. The ONLY documented "cure" for these things believe it or not is either live (acidopholus bulgaris) culture yogurt or acidopholus milk. The reason is that these other bacteria (beneficial)when eaten or drunk in yougurt or milk actually overwhelm the bacteria that causes the canker and allows it to heal. I tried it and by God it works. Try it and the sore begins to heal in a day or two after you ingest the other bacteria! By the way, ever since I went to an electric toothbrush, I don't get canker sores as much. Doc said I was brushing too hard and lacerating the inside of my cheek with the toothbrush.
I used to get apthous ulcers on a regular basis, but like some others here they have lessened with age. I have gotten them on most of the soft tissue in my mouth, including my tongue, and have on rare occasions gotten them on the roof of my mouth or on the gum. The worst ones I've ever had were on my uvula. Talk about pain. And that time I had a margarita with one on my uvula, well I don't want to think about it. The other ones that can be real bad are the ones that form on the tip of my tongue. You'd be amazed at how important the tip of your tongue is in eating until you find you can't use it for a while.
Many of mine have come from injuries. Biting the inside of my cheek, or the tip of my tongue, can cause one to form. Often times if one pops up, others will follow. I've heard this is caused by an overreaction of the immune system, but I'm not sure if that's true or not.
Stress may or may not be a factor for me. I've recently gone through some stressful times without any appearing, but then again as I've mentioned they've become rarer as I've gotten older. As a child I had them a lot, and never really was stressed back then.
My mom recently had an allergic reaction to an anesthesia her dentist used, and had 13 open up in her mouth. She apoligized to me for not being more sympathetic when I had them.
One strange thing I've found is that Coke actually soothes mine. You'd think the opposite because of the acid, but it works for me.