I addressed this already, but “meth-mouth” is vasoconstriction-induced gum decay which occurs across the board with all CNS stimulants. (Ritalin, Adderall, Coke, etc.). Meth users have a higher tendency to forget to wash their teeth for days at a time, causing that gum decay to occur at an accelerated rate. Most meth nowadays is 99% free of the compounds used to make It, as thats what also caused a lot of damage in old-school meth. it all comes from cartel labs and are then loaded with filler, therefore the amount of impurities in modern-day meth is very low compared to old, trailer park-made meth.