Remember when your dentist put that sour gel stuff in a giant foam tray put a straw suction tip in your outh and let you sit like that for 5 minutes? That flouride treatment was to help prevent tooth decay. Now there are some better options than that aweful gel. Fluoride Varnish is the most elegant version of office applied Fluoride.
Now there are a hundred different kinds of fluoride and many ways to apply fluoride. There is the fluoride in the drinking water, which you might drink every day which has been statistically proven to prevent tooth decay in large academic studies. That concentration is about one part per million of fluoride ion (ppm). The oral rinses you get in the grocery store are about 200 ppm. Toothpaste has about 1000 ppm. Once you get into those kinds of ranges you really don't want to swallow large amounts of fluoride. That's why we do not recommend regular toothpaste for very young children (under two) and we ask older children and adults to rinse and spit after brushing. The kinds of fluoride we apply in the office are much higher concentrations, usually of a version called APF or Acidualted Phosphate Fluoride (the sour stuff) or sodium fluoride. There has always been a concern for children that you don't want them to swallow too much fluoride during an in office delivery-those concentrations can be around 22,600 ppm! Foam systems were developed and we use that from time to time as you can get the fluoride on the teeth more easily without such a large total dosage.
Now there is an even better way-especially for children-Fluoride Varnish. It's sort of a thick liquid you paint on the teeth coating a concentrated dose of fluoride right up against the teeth, but in total dosage it is quite small. Better yet, long after the patient has left the office, it bathes the teeth in fluoride. It lasts for a few hours or until the patient brushes. It actually tastes pretty good, kind of like bananas I think. The first version thay had was called Duraphat. It was good, but was yellow colored and although very good, it always bothered patients to leave the dental office with goopy yellow looking teeth even if it was just for a few hours. Now they have improved the color. It's a sort of clear/white colored material. It is painted on and once it gets wet, it hardens up a little. Pretty cool, huh.
ADA on Fluoride
More info and video:
Vanish brand varnish from 3M
CDC on fluoride products