Using a water pick is not a substitute for daily brushing and flossing. Think of it as an adjunct to your daily care. You must first dislodge the sticky plaque. It is wonderful for rinsing out loose food particals and things stuck around the gumline like popcorn husks. Food particals left in the mouth can be a major source of bad breath.
Water picks use powerful tiny bursts of water to blast away food particles and other loose debris in hard-to-reach areas of your mouth.
People with gum disease may find water picks beneficial for supplementing their brushing regimen. In this case, it's very important to not use it on a powerful setting...that may do more damage to the gums than good.
Other reasons to use a water pick are crowded teeth, braces or food trap areas.
We stock the original "Waterpik" in our office sell it for our cost.