The following excerpt was obtained from the American Dental Association on www.mouthhealthy.org
Fluoride hails from the planet Earth. It’s found naturally in rocks, soil and water, but fluoride doesn’t exist on its own. Like so many superheroes, it’s created through a scientific process.
When you eat things like candy, crackers or noodles, cavity-causing bacteria starts feasting on the carbohydrates in these foods. This produces acids that attack your enamel. It causes calcium and phosphate to be stripped from the tooth enamel, leaving you more vulnerable to decay and cavities. However, saliva disrupts the attack as it coats your teeth and adds back calcium and phosphate to replace what had been stripped away.
Now, here’s where fluoride is the superhero. When your saliva has fluoride in it from sources like toothpaste or water, your teeth are able to take it in. Once in your enamel, fluoride teams up with calcium and phosphate there to create the most powerful defense system your teeth can have to prevent cavities from forming: fluoroapatite. It’s much stronger, more resistant to decay and fights to protect your teeth.
There are many ways to get fluoride fighting for you. Fluoride is found in community water systems. It is also found in some mouth rinses, and your dentist can apply it to your teeth in the dental office.