I have been a crack addict for 13 years and the only teeth problems I have had are the one's where they were knocked out in a robbery attempt on me. But I got all that fixed and it does help the self esteem ALOT!!!
I only have a flipper right now but it does the job. I can smile again!!
For me being too caught up in getting high to brush my teeth is the only thing that really would affect my teeth. But thats just me.
Also I use to hold quite a bit of that crap in my mouth between my lips and gums. Never did anything except numb my mouth.
I have a healthy mouth from what my dentist says.