Yellow stains aside, brewed coffee or tea may not be the worst thing you could swish past your pearly whites.

Other drinks tested in a recent study produced much more wear and tear on tooth enamel, especially bubbly soft drinks. But here's the surprise: It didn't matter if the sodas were diet or not.

Erosion Explosion
When your tooth enamel starts to erode, you've got major problems on your hands. And certain foods like sweets and sodas may hasten this process. All carbonated drinks in a recent study had some impact on tooth enamel (with the one possible exception being root beer -- its impact on tooth enamel was slight). Citrus-flavored sodas hit teeth hardest, but colas caused problems, too. And it didn't matter if the drinks were diet or full-sugar.

It's the Acids
Contrary to what you might think, it's not only the sugars in bubbly beverages that erode tooth enamel. It's also the acids. The total acid content and acid type -- look for names like phosphoric, citric, malic, and tartaric -- in a beverage affect how strong the attack is on your choppers. Rinsing after sipping a soda may hasten the acids out of your mouth.