Why? Because You're Eating the Wrong Foods!
Artificial foods, chemicals and sugars, fats and other foods which are wrong for your blood type, they all cause issues with teeth.
Eat Clean, Natural Foods for Your Blood Type
and guess what? No bad breath, no plaque build up, no 'film' on your teeth, no tooth aches or cavities.
My teeth rotted out of my head for decades, and then I changed what I eat. ;)