Commercials...

One set of commercials that comes to mind are the Orbit gum commercials. In every commercial, there is usually some ridiculous scene going on where people are getting dirty / their mouths are dirty, such as the ones where people are being splashed with mud, dirt, and even fish. Orbit uses the British Orbit girl, who comes across as very "clean" (she is usually wearing a light color, has light skin and hair, and a sparkling smile), and the dirty people in the commercial smile with a crisp white smile. The commercials usually say "Dirty mouth? Clean it up with Orbit", or something that goes along those lines. The use of that phrase and the image of a clean mouth among a bunch of dirt helps us connect these two images to the gum.