A dental treatment appliance 10 includes a drive mechanism for driving movement of a bristle carrier, and a dental treatment system which transmits signals towards the oral cavity and receives signals returned from the oral cavity. A controller actuates the treatment of the oral cavity depending on a received signal. A transmission path for received signals extends along part of the drive mechanism. The drive mechanism comprises a transmission unit and a drive motor unit for driving the transmission unit to move the bristle carrier relative to the handle, wherein the transmission unit comprises a shaft and wherein the transmission path extends along an external surface of the shaft. The bristle carrier is detachable from the handle, and the shaft comprises a handle contact 94, 96 and a bristle carrier contact 104 for engaging the handle contact when the bristle carrier is attached to the handle.
