Have to agree with DerZniker on this one, it does very much depend on how look after yourself in generally, and not just the substance taken ;-).
I'm sure they're are plenty of people out there, who drink, take H, Coke
and look worse than the "Meth
Mouth" type pictures. I think it comes down to the individual efforts maintained to try and ensure that look after themselves well, and try to counter balance the effects of their lifestyle to positive ones.
Can't help thinking that Whilst Meth Mouth does, and can happen, the proportions of serious Meth Mouth amoungst users would be pretty low, and not this Dead-Cert guarantee that many government bodies have produced rldwide.
Most of it it just common sense, like if you can't eat...drink supplement drinks to try and help your body get some of the nutrients it needs; chew-gum (i've heard that it's the lack of saliva that actually compounds the issue; cBrush, floss and use mouthwash twice a day like you would normally (even though you might have not slept, you're mouth still wants that morning bursh
Oh...and Never, Never rub it into your gums, try bombing it instead