The bur includes a shaft to which a bur head is attached. The bur head includes a plurality of flutes. Each flute at least has a rake surface, a cam surface and a cutting edge. The rake surface extends radially outwardly from the longitudinal axis of the head. The rake surfaces define the flute cutting edge (38). The associated cam surface curves away from the rake surface. One or more ribs extend radially outwardly from the cam surface.
