As someone who occasionally suffers from canker sores, I wish it were true that they'd heal faster than say a paper cut.
Give it a try. Can't hurt.
SLS is only used to make foam when you brush your teeth. I promise I won't think any less of your toothpaste if it doesn't foam!
And, I live in a water district with fluoride in the water.
My personal armchair doctor explanation is that the inside of the mouth experiences a lot of small cuts, but our immune system takes care of those before they turn into larger wounds. When your immune system is weaker, or your mouth is drier, then those small wounds open into larger ones.
(I didn't actually notice that they had disappeared until I returned to milk-land, and they came back. Took another month or so to establish the link clearly, since there was 3-4 day delay between drinking milk and appearance of canker sores. Then it took another couple of years to alter my habits ...)
It seems likely, although you could test the theory by eating some raw papaya.
To talk about canker sores, I first have to talk about dental plaque. Plaque appears when both of these conditions are true:
1. your mucous membranes are saturated with nutrients (such as those in milk, or juice, or soda, or "saucy" foods) amenable to the growth of bacterial biofilms; and
2. you are dehydrated enough—or under the chronic effects of diuretics such as caffeine—such that you don't consistently produce enough saliva to reach the mucous membrane and battle the nascent bacterial colony.
(That's right: plaque may live on your teeth, but the food those bacteria consume mostly isn't food stuck to/between your teeth; it's food "in" the mucous membranes of your lips. This is why the regrowth speed of plaque seems to have no correlation to how well you've brushed your teeth—the factor is how much food they have access to, and brushing your teeth has no effect on the nutritive content of your mucous membranes.)
Canker sores, then, happen when an established plaque (bacterial biofilm) colony is pressed into a dehydrated mucous membrane, further isolating it from the reach of saliva, for an extended period. Picture, say, a dirty tooth pressed against your lower/upper lip as you sleep, with your face laying to squeeze that part of your lip around the tooth, such that saliva can't get in.
So, ways to avoid the problem:
1. brush your teeth at night (i.e. after you stop eating food.) It's more important than brushing in the morning, if you want to prevent canker sores.
2. If you're dehydrated, drink water or another substance that contains few bacteria-promoting nutrients (like unsweetened flavoured carbonated water, or even hard liquor.) If you can't—if only milk/juice/soda/beer/coolers are being served—then try to "chase" your drink with water as soon as possible. When you do, swish some of the water in your mouth as if it was a mouthwash. Ensure your mucous membranes themselves are getting hydrated.
3. Get enough vitamin C. Subclinical hypovitaminosis C ("pre-scurvy") causes the linings of your mucous membranes to weaken, making it easier for rough spots on your teeth to cause micro-abrasions in them, which is where bacterial biofilms get in. But make sure you're not "getting enough vitamin C" by drinking orange juice when you're dehydrated!
I've been reading about xylitol lately, a sweetener found in sugar free gum. From what I can tell, it could potentially help with cavities because it can help regenerate dentin. Not to mention gum seems to be generally helpful for removing waste from teeth. Is this something you've heard about?
Which reminds me of a rant:
You know what doesn't do either of those things? Any mouthwash you can buy in the mouthwash aisle.
Ask a dentist about mouthwash. They'll recommend it—but only because the alcohol temporarily shrinks your gums, which allows a toothbrush and/or floss to scrape plaque out that was embedded deeper between the gum and the tooth. Mouthwash doesn't kill bacteria. (Or, it does, but only for the 30 seconds it's in your mouth—meaning that you'll have just created a power-vacuum that other, worse bacteria from e.g. the back of your throat can intrude into. And now the alcohol has also dried out your mucous membranes!)
If a dentist needs to prescribe you a mouthwash, on the other hand—for example, to keep a wound inside your mouth clean post-surgery—they'll prescribe something with ingredients completely unlike that in "regular" mouthwash. Here's (https://www.amazon.ca/Chlorhexidine-Gluconate-Antiseptic-Pep...) an example of one.
The primary ingredient of "mouthwash that actually works" is chlorhexidine—that's a chemical more commonly used as a surgical antiseptic (i.e. a "scrub" doctors will sanitize their hands with before putting them inside your body.) Conveniently, the fact that it's safe to touch your internal organs with, also means that it's safe to touch your mucous membranes with. (Though it's not entirely safe; it says stringently on such mouthwashes not to swallow any—but not because it'd harm you per se, just that it'd likely kill your intestinal flora in much the same way an antibiotic would.)
Interestingly, chlorhexidine and xylitol work in similar ways—they're both things bacteria intentionally take up into themselves, that then destroy the bacteria from the inside. Xylitol just stalls the bacteria's metabolism, starving it to death; while, IIRC, chlorhexidine throws off the bacteria's osmotic regulation until it pops, much like highly-saline environments do—but without doing the same to animal cells. Unlike xylitol, though, chlorhexidine will stick around in the mucous membranes (until you do any of the stuff I mentioned in the previous post) for eight hours, protecting you all the while. It's great. Everyone should use it, at least at night.
It's kind of weird, given all this, that it's not well-known, and not used in regular mouthwashes, no? Well, much like you just can't convince some people that a HWRNG-seeded CSPRNG is a valid source of OS entropy, you just can't convince some people that long-term chlorhexidine use wouldn't result in bacterial resistance—even though, in both cases, if there was any potential for it to fail in "normal" use (OS entropy; mouth-washing), it would have failed a long time ago in the "heavy-duty" use-case where it's already being used (cryptography; surgery.)
Or, to put that another way: if doctors will put chlorhexidine on their hands every day without worrying about growing MRSA under their fingernails, you can put it in your mouth every day without worrying about growing MRSA in your throat.
(Bonus pleasant fact: most prepared chlorhexidine mouthwash solutions are sweetened with xylitol. So you're getting a double-effect from that.)
On the other hand, prepared chlorhexidine mouthwash isn't very cheap (the one I linked above was $15 for a bottle that'll last less than a month), and preparing such a mouthwash yourself from concentrate is really a hassle (pure 2-4% chlorhexidine gluconate is much cheaper, but just diluting it with water/alcohol would create a solution that only retains potency for ~1 day; you'd need to add other chemicals to make it shelf-stable.)
But, if you can't (or just don't want to) get chlorhexidine mouthwash, I still wouldn't recommend using alcohol-based mouthwash. For battling gingivitis or a canker sore or whatever else, Xylitol actually works pretty well as a "quick-fix" alternative. That is, it works well if you exploit the very property I mentioned before—increased mucous-membrane absorption and retention under dehydration. So, here's a "life hack":
• Go buy a box of xylitol sweetener packets (the kind you'd pour into coffee. You can probably find them sorted into the "nutrition products for diabetics" area of a drug store.)
• Before you sleep, brush your teeth, floss, swish with water, spit. And then...
• Dump one of those xylitol sweetener packets directly into your mouth, not dissolved in liquid or anything. Spread it around; get it onto the insides of your lips, onto your teeth, etc.
• Let it absorb. Don't swallow it; just let it sit.
• Go to sleep, just like that.
That will protect your mouth, at least a little. Far more than Listerine ever would.
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Oh, and as a separate thought: if you have recurring canker sores, oral thrush, throat/sinus infections, ear infections, etc., despite good oral hygiene—there's likely a "hidden fortress" of bacterial biofilm somewhere out of reach, probably your maxillary sinuses or adenoids or Eustachian tubes. These areas are "safe" for bacteria because they're damp from breathing, but few actual fluids reach them.
Want a permanent solution? Flush them out. For the nose, I see people trying nasal lavage ("neti pots" et al), and for the ears, I see people going to an ENT to get microsuction. Neither of these are really needed. The biofilms aren't invincible; they're just dry—too dry for your body's natural defences to loosen them. Drip a few drops of mineral oil down your nose/into your ears, once per day. After two days, you should start to feel the need to clear your sinus passages by snorting, inwards. Just keep doing that. And voila, the hidden fortress has been destroyed.
Mouthwash, specifically Listerine. As long as I use it everyday I never get canker sores anymore.
Personally I found my worst heartburn was at night, so sleeping with a wedge pillow stopped me from needing pills.
(Disclaimer: I am not a doctor.)