Abstract: A tooth brush is disclosed in which parallell bristles extend in opposite directions from a central plate-like stem connected to a shaft or a handle. The tooth brush is used for cleaning teeth interspaces and comprises a base plate which abuts the gum and protects the same when the bristles work upon opposite teeth faces. The bristles are longer next to the base plate and gradually shorter as the distance therefrom increases. Also in the length direction of the stem the length of the bristles varies, and the minimum bristle lengths are found either at the tip or at the middle of the length of the active part of the brush.