Topical fluoride helps to prevent tooth decay by strengthening the enamel that covers the outer surface of the tooth. We routinely use topical fluoride on our most susceptible patients, those under the age of 15. We use a fluoride varnish that is painted on the teeth, hardens into a sticky material upon contact with saliva, and remains on the teeth until brushing. This allows the fluoride to stay on the teeth for a longer period of time than other types of topical applications and prevents the patient from accidentally ingesting the fluoride.