A:  On the subject of tooth decay, one factor that every scientific article cites is carbohydrate intake.  ‘Carbs’ are consumed by every normal person in the world except for those Atkins-diet zealots and probably some isolated primitive meat-eating tribes.  Refined starches, and their building blocks, glucose, fructose, sucrose fuel the bacteria that cause decay.  The microbes arrive at the site where the sugar is stuck to the tooth, then secrete lactic acid after they have their power lunch.  That acid dissolve the innocent tooth underneath and the hole forms.  That hole can now collect more carbs that are now harder to remove.  If you eat things that contain carbs that stick to your teeth (candy, breads, dried fruit, cakes etc) or drink sugary things (pop, fruit juice, milk, sugary coffee, sports drinks etc), then you have conditions for decay.  This is the important bit:  The longer the contact, the greater the risk. So clean it off right away or chug that surgary drink quickly and rinse with water.  Or even better, reduce your refined carbohydrate intake altogether and substitute for healthier unprocessed food and water.  Those primitive tribes people have beautiful smiles and very few fillings.