Water flossers are useful for people who have braces, dental implants, those with periodontal disease, and for anyone who has difficulty with accessing areas in between the teeth. The more plaque bacteria that is removed from the teeth, the less is the chance of developing tooth decay, gingivitis and periodontal disease, because all dental disease is caused by the build up of bacteria in our mouths, sitting against the tooth surfaces for periods of time. It makes sense that anything that can increase our ability to keep the teeth clean, and motivate us to do this, is a good thing.
In the fine print for use of these devices, it says that the water flosser does not replace manual flossing, so it would be best to use the water flosser along with manual flossing. However for some people who are not able to regularly floss, it can be an excellent way to cleanse the teeth and remove food debris and bacteria, with bursts of a small stream of high pressure water and air.
The two that stand out for purchase are the Waterpik Cordless Plus Water Flosser, and the Philips Sonicare AirFloss Ultra. Both are rechargeable, portable, have reservoirs to fill with water, and guidance tips to blast a small stream of water and air to dislodge plaque from the teeth, and both come with warranties.
It is far better to use a water flosser than no flossing at all, especially in the hard to reach areas in between the teeth where so many incidences of tooth decay and gum disease start.