Abstract: A motorized surgical handpiece comprises a housing enclosing an interior containing a motor and an output shaft for being driven in rotation by the motor. The output shaft has a central longitudinal axis, a bore extending therethrough for receiving a shank of a surgical tool to be rotatably driven by the output shaft, a forward end portion extending forwardly beyond the motor and a rearward end portion extending rearwardly beyond the motor. The housing has a continuous lumen extending entirely therethrough formed in part by the output shaft bore for insertion of a bore brush through the lumen for cleaning when the surgical tool is removed from the handpiece.