It’s a no-brainer fact that the sugar in regular sodas (you know, Coke, Pepsi, 7 Up, etc) causes tooth decay, just like sugar in any other form can cause tooth decay.
But what about diet sodas? There’s no actual sugar, only artificial sweeteners, so no danger of tooth decay, right? Actually, the reason that real sugar causes decay is that the natural bacteria in our mouths feed on the sugar and deposit acid on our enamel surfaces. The acid itself eats through our teeth, making cavities. So, yes, eliminating the bacterial food source (sugar) definitely decreases the acid level in the oral cavity.
Unfortunately, the thing that makes most sodas bubbly is phosphoric acid, which is added specifically to carbonate the liquid. When drinking any soda containing this ingredient, the teeth are bathed in acid…bummer. The only drink that is non-cariogenic is plain water.
It is unrealistic to believe that people can be satisfied with drinking only plain water for the balance of their lives, so when you do reach for a soda of some sort, try using a straw to reduce the flow onto the teeth and chase it with a swig of water if you don’t have a brush and floss handy. Then enjoy what you’ll be missing—no extra cavities!