One hears that Bulimia and certain drug addictions (Crack, Meth) are very bad for your teeth. Bulimia because of the strong acid, and drugs because they interfere with the mouth's self-cleaning instinct.
I'd guess the best teeth live in a mouth with:
1. Active high-volume saliva glands
2. A population of healthy bacteria
The reason why amphetamines are bad for your teeth is that they prevent your mouth from making saliva, which allows bacteria to multiply and causes other bad things to happen as well. Obviously it's probably not a good idea to be using meth in the first place, but if you're going to use any sort of drug that causes dry mouth then at the very least you should brush, floss, and use mouthwash and flouride rinse beforehand.
How about encourage them not to become crack heads or bulimics in the first place? It's a strategy that probably has benefits beyond mere dental health.
I'd guess the best teeth live in a mouth with: 1. Active high-volume saliva glands 2. A population of healthy bacteria
How do you encourage that?