Abstract: A tooth brush includes a handle, a shank attached to the handle and having a housing, a casing disposed in the housing, and a paddle wheel rotatably received in the casing and having a shaft extended out of the casing. A rotary brush device is attached to the shaft of the paddle wheel, and includes a number of brush members for teeth brushing purposes. A water supplying device may be used to supply water into the casing, to drive and to rotate the paddle wheel relative to the casing, and to drive the brush members of the rotary brush device to brush teeth. The casing includes a cover having one or more orifices for allowing water to flow out through the orifices of the cover of the casing.