A dental tool displacement apparatus for use with a motorized power handle to displace a dental tool includes a tool holder having a receptacle for receiving the dental tool, and a drive arrangement. The drive arrangement defines a transmission from the motorized power handle to the tool holder such that the tool holder undergoes reciprocating motion parallel to the tool axis at a first frequency of oscillations per minute and rotates about the tool axis at a second frequency of rotations per minute. In some cases, the two types of motion are generated by an eccentric drive pin engaging an annular slot which has gear teeth along one side, thereby generating an angular rotation step of the tool holder during each reciprocating stroke. In some cases, the first frequency is at least one order of magnitude greater than the second frequency.
