The advice from dental experts for keeping your teeth clean sounds simple enough: Brush twice a day and floss. But choosing among the many products available to help you do this can be daunting.

Dental hygiene aficionados have surely noticed a new format battling for a share of the oral hygiene market. Toothpaste tablets are dry, pressed-powder pills about the size of an aspirin or a pea.

Experts say oral hygiene is shifting from eliminating bacteria to maintaining balance. Overuse of antibacterial products may ...