Use mouthwashes for dry mouth -- bacteria love to play in a dry mouth.

Also, what is your diet like? Do you eat tons of whole grains, drink/eat highly acidic stuff? Do you get enough calcium/Vitamin D3/Magnesium (not just in supplements but food as well)? These kinds of things can affect your teeth. Whole grains can be good, but too much can rob your body of certain nutrients, because they can bind to things like calcium before you can absorb it.