"Incorporation [of fluoride] into the tooth enamel makes it more resistant to the acids produced by bacteria, helping prevent tooth decay in the first place," Morris said. "The presence of fluoride ...

A cavity is the result of tooth decay, which begins when bacteria in your mouth make acids that attack the tooth's surface ...

Over time, the acid makes a cavity (hole) in the tooth. Your risk of tooth decay is increased by how often you have sugary or acidic foods or drinks, so it is best to limit them to mealtimes.