A sonic toothbrush system including an electric motor, a brush shaft, a drive assembly, a fluid conduit connected to a pressurized, pulsed water source, and a water jet nozzle positioned on the brush head and connected to the fluid conduit. The electric motor includes a drive shaft. When the electric motor is caused to operate, the drive shaft continuously rotates until the motor is caused to stop. The drive assembly is coupled between the drive shaft and brush shaft. The drive assembly is configured to convert the rotation of the drive shaft into sonic oscillation of a toothbrush supported on an end of the brush shaft. The drive assembly further forms part of the fluid conduit to deliver a pulsed water stream to the jet nozzle.