The electric toothbrush has a motor in the handle driving a shaft (3) through a gearbox. The driving mode is oscillatory. The head (8) containing the bristles has a hollow stem that fits over a collar (12) around the driving shaft. The stem contains its own shaft that mates with the driving shaft and drives the disk in the head upon which the bristles are mounted. To do this, there is a peg at the head end of the second shaft, at right angles to the shaft axis, which protrudes into a radial slot in the disk. As the shaft oscillates, the peg swings the disk back and forth.
