Atlanta, GA (CNN) -- Remember "The Big Book of British Smiles" from "The Simpsons"? The dentist used it to scare children into proper dental hygiene. And let's be honest, it was funny! Because though British tea and good manners have an excellent international reputation, British teeth are mostly used as a punch line. But tooth decay is far from only a British problem -- in fact, it's one of the most common chronic disease worldwide. Scientists say the health of your teeth depends on a combination of genetics and dental hygiene.