A replaceable head part for an electric powered toothbrush comprising an elongate sleeve including a flexible portion, and containing a longitudinal drive shaft rotatable in oscillatory rotary motion. The drive shaft has a spherical bearing part received in a cavity in the sleeve. The head part incorporates a transmission system to convert the rotation of the head drive shaft into rotation of the bristle carrier comprising an eccentric pin extending from the head drive shaft to move the bristle carrier in oscillatory rotary motion, and having a spherical pin bearing part received in a receiving cavity in the bristle carrier.