Meth poisons you from the inside out, so I would think that meth slows down saliva production which increases the amount of live bacteria, and rots the gums. You can brush your teeth as often as you want and can have pearly whites, but if your gums are decayed, your teeth will fall out. You're just like me! I would have no choice but to show very tough love to a family member or friend that became addicted to meth. Some people sugarcoat and baby their addicted friends way too much and it often makes the situation worse! I saw one case where a father knew his daughter was on meth and still gave her the money to buy it because he just couldn't say no!