Meth increases the desire to eat foods and beverages that provide energy. Sipping and nibbling junk food and pop creates an oral environment of constant saturation with carbohydrates and acid that cause aggressive tooth decay.

Consider this -

1) each sip or nibble of sugar, and carbohydrates in general, feeds the bacteria in your mouth that cause tooth decay and gum disease. Normally, saliva helps to wash away the food, the bacteria, and the acid produced by the bacteria as a waste product, and the processes that cause decay subside in about 30 minutes.

2) You could have a large meal, full of sugar and acid, and expect your decay risk to subside within 30 minutes. But if you sip or nibble even a small amount of carbohydrates every 30 minutes, you are effectively traumatizing your teeth with acid all day! Your teeth never get a break.

3) Toothpastes and some mouth rinses include fluoride and other ingredients that help to restore the minerals that make teeth so "hard", more specifically, acid resistant. Ideally, we eat three meals a day, and no more than one short snack. We brush after every meal, floss at least once a day to remove bacteria trapped between teeth, rinse our mouths out, and maintain good salivary flow to "rinse" our teeth continuously. You can never get rid of all the bacteria in your mouth, and would not want to, you just need to disrupt the bacteria often enough to keep them from forming nasty colonies I call "science projects."

4) Meth users often suffer from anorexia, and diets so poor that essential vitamins and nutrients are absent. Healing ability and immune response are subpar, increasing vulnerability to gum disease and tooth decay, which are both chronic infectious diseases.

In summary, meth fosters dietary habits that are devastating to teeth. Coupled with dry mouth, poor oral hygiene, poor nutrition, and severe bruxing, it is no wonder that teeth decay and break off at the gums.