I haven't personally noticed any effect, but I'm sure it does affect your teeth in a similar way to drinking tea and coffee in the long run. Beyond that, it creates temporary irritation on your gums (temporary meaning it goes away if you stop and doesn't damage your gums permanently), and over a long period of time it can cause a permanent effect of receding your gum line, which of course isn't great. I'm no authority on how serious these effects are, how common they are etc. but I would imagine that they would require some pretty heavy usage under a long period of time, and that "loose" (un-portioned) snus probably affects your gums much harder than the more popular portioned variant in small bags, since the un-portioned variant is pure tobacco with no material in between it and your gums.

(And, on the topic, I am quite sure that in addition to the comparably low health risks of snus in contrast to e/cigarettes, the trust in the origin and the quality of the raw material used is rightfully so higher than that of the materials used in after market vape juice.)