Did you realize that you typically spend about 24 hours every year brushing your teeth. In all that time have you ever wondered what was in your toothpaste? The answer varies from brand to brand but here are 5 ingredients that are the most common. Fluoride This mineral is key to fighting tooth decay. Fluoride makes the enamel of your teeth harder and more resistant to acid wear. To make sure your toothpaste contains fluoride, check the list of active ingredients for sodium fluoride, sodium monofluorophosphate or stannous fluoride. Only these three forms of fluoride are recognized by the Food and Drug Administration for cavity prevention. And a little fluoride goes a long way: Most toothpastes contain only 0.15% fluoride ion, or 1500 …