I've always dreamed of writing a folksong that was good enough for a toothpaste advert

How many tubes of Macleans must you use before your smile is pearly white?
And how many times must you scrub your teeth - morning, dinner time and night?
Yes and how many times must we do oral sex, before you learn not to bite?
The answer is brief, the best thing for your teeth
Is a bottle of green Listerine.