Abstract: A dental prophylactic device has a handle section containing a drive member and a driven section at a substantial angle to the handle section containing a driven member also at an angle to the driving member. The handle section includes a longitudinally oscillatable cam follower supported parallel to the handle axis. When the cam follower is translated around the axis by the rotation of the drive shaft, it is caused to oscillate by one end contacting the stationary cam follower track. The other end engages a slot parallel to the axis of a cam at an angle to the cam follower thereby causing the cam to oscillate back and forth over an arc of at least 50.degree. to approximately 150.degree., maintaining the connection between the cam follower and the cam by the use of the slot which permits the cam follower, in effect, to move up and down with respect to the cam as it oscillates.