A sterile, substantially maintenance free disposable dental handpiece is constructed from two shells and a center core, the center core having a flow deflector on one end. The shells are joined around the core with mating protrusions and/or tapered walls to form the body and head of the handpiece. A base is integrally-formed with the center core. The base has conduits that allow entry of light and pressurized air and/or water into the body. The head at the opposite end of the body from the base rotatably mounts an impeller assembly having an impeller shaft. The impeller shaft includes blades driven by the pressurized air. The blades can have cavities to reduce weight.