A mouthpiece appliance includes an assembly for receiving teeth which includes cleansing portions, such as two opposing side portions and an intermediate center portion. The brushing portions include bristle sections which are adapted to clean teeth. The appliance also includes at least one DC motor assembly with an output shaft with an eccentric mass of crankshaft. The appliance further includes a mechanical motor cover including arm members which are arranged to connect the DC motor assembly to the cleansing portions of the appliance so that as the unbalanced weight on the output shaft rotates, movement of the cleansing portions, toward and away from the teeth or along the surfaces of the teeth occurs, producing cleansing of the teeth.