Anecdotal +1. I've switched to non-SLS toothpaste and seen a dramatic drop in my frequency and severity of apthous ulcers (and, unfortunately, I get them often enough and badly enough that I can state causality with some certainty).

I used to have a (powerful-to-the-point-of-personal-uneasiness) corticosteroid that I would put on them to dubious effect, but I haven't needed to resort to that at all since I switched away from SLS toothpastes.