Water flossers (also known as oral irrigators) cost a lot more up-front than string floss does. And they can also be pretty uncomfortable to use — get ready to drool.The evidence isn’t clear that water flossers are superior to traditional floss. And you need to thoroughly clean them every so often to keep mold and mineral deposits at bay.Yet some people really like the way the water jets feel between their teeth, and others find it’s easier to work with a wand than with a piece of string.Since 2018, we’ve tested 21 models. The Waterpik Ion Professional — a corded, countertop water flosser with a cordless charging base — is our top pick. Compared with most of its competitors, this model cleans mouths more thoroughly and takes up less counter space.