Abstract: A disposable attachment for reciprocably mounting a dental tool and being mounted to a conventional handpiece which provides the drive for the tool. The attachment includes a plastic housing having a neck and sleeve to rotatably mount a shaft which is driven by a dental handpiece and a head which mounts a plastic socket to be reciprocated by a shaft eccentric extended into an annular groove in the socket. A rotational restrainer is provided in the socket groove to permit rotation of the tool which is friction fitted in the socket while a force external to the attachment is exerted on the tool but otherwise retain the tool in a fixed angular relationship relative to the head as the socket is reciprocated. The attachment housing, socket and rotational restrainer are made of plastic while in one embodiment the attachment shaft is also made of plastic.