Until dental vaccines are available, tooth decay can still be battled successfully with a combination of dental weapons. Yet surveys suggest that "the general public simply does not know the best way to protect against tooth decay," says Alice Horowitz of the National Institute of Dental Research.

Among the steps recommended for prevention:

*Fluoride, which Horowitz calls "the first line of defense against tooth decay." Fluoride is available in topical solutions, but the best way to get adequate fluoride protection, she says, is by drinking fluoridated water. Fluoride protects teeth by making them tougher and more resistant to erosion by the acid that bacteria produce in the mouth.

In the metropolitan area, fluoridated water is widely available, according to surveys by the federal government. The District ranks No. 1 in the country for fluoride water consumption. More than 98 percent of the population here drinks fluoridated water. Maryland is seventh with 68 percent, and Virginia comes in 20th with slightly more than 50 percent.

*Dental sealants are "second only to fluoride" in offering protection from cavities, Horowitz says. Unlike fluoride, sealants must be applied to the teeth by a dentist or a dental hygienist. A fairly recent arrival on the dental scene, sealants are generally used to seal pits and fissures in the upper tooth surface.

*Diet. The most potent cavity promoters are foods high in sugar. Particular problems are sweet, sticky foods -- like raisins and chewy candy -- that cling to the teeth. Dentists recommend limiting consumption of these foods to meals and encourage brushing immediately afterward.

*Toothpaste. The American Dental Association evaluates toothpaste upon request by manufacturers. Based on tests of safety and effectiveness, the ADA allows manufacturers to put a seal of approval on the label. Five fluoride-containing toothpastes -- Aim, Aquafresh, Colgate, Crest and Macleans -- carry the ADA seal, as do three toothpastes for sensitive teeth -- Denquel, Protect and Sensodyne.