Have a mouth full of cavities? You can maybe blame those teachers who wouldn't let you chew gum in class. Gum gets some scientific analysis in a study titled "Quantification and Qualification of Bacteria Trapped in Chewed Gum" published in PLOS ONE yesterday (and, it should be noted, funded in part by the Wm.
Wrigley Jr. Co). Researchers confirmed that the "chewing of gum can trap bacteria," which can cause cavities, and then remove that bacteria when you spit it out.