I learned about this many years ago and the difference after I started using only SLS-free toothpaste was night and day. I used to get canker sores any time I would bite the inside of my cheek, hit my gums with the hard parts of my toothbrush, etc., and this completely stopped a while after I switched to SLS-free.
SLS is Sodium Lauryl Sulfate, by the way, and it’s a detergent. From what I understand, the only reason why it’s added to toothpaste is to make more foam when you brush. But the SLS-free toothpaste I use makes plenty of foam, so I have no idea why they add it. It’s one of those things about the modern world that makes absolutely no sense. The ads and packaging should say in big letters: “now with even more canker sores!”
Unfortunately, the vast majority of toothpastes on the market (at least in the US) have SLS. I can only seem to find SLS-free toothpaste in natural food/supplement stores. It’s extra difficult to find toothpastes that are SLS-free but that keep fluoride too. The difficulty (and price? I haven’t compared) is completely worth it to me though.
TL;DR: The SLS (Sodium Lauryl Sulfate) in most toothpastes is unnecessary and causes canker sores (painful sores in your mouth and gums). If you have this problem, you will likely benefit from SLS-free toothpaste (some still include fluoride) that you can usually find at natural food stores.
I hate these sores with a passion. You can fix them instantly with Oralmedic from the internet (possibly currently undergoing supply chain issues but that is temporary). It is agonizing— you are cauterizing the sore— but provides immediate and permanent relief. You can also get a laser for it, which does not hurt but is way higher effort and costs a ton more. I am passionate about my sore hatred so I have done this.
If you don’t want to do either, Canker Shield is available on Amazon and reduces sore lifespan to around 24-48hr. Also painful to use but nothing is as bad as Oralmedic or debacterol. Combine that with supplements (not one size fits all, lysine seems to have high success rate though) and you can deal with these while away from home.
Anyway this tip actually reminded me to check my travel toothpastes which naturally do have SLS. So thank you. I had noticed an uptick to a sore every couple months since Covid “ended” but that cause slipped my mind
I used to leave aspirin on the canker, that burned it away.