Abstract: A dental instrument is provided with a pivotally arranged shaft and a head mounted to the shaft. The head is equipped with a plurality of cutting blades. The cutting blades have a clearance angle of 0° and a negative cutting angle. The areas of the blades that trail the cutting edges are either planar surfaces or a partially cylindrical shape. In some embodiments, the front area of head is provided with a circumferential groove that is open at the front side, into which an annular contact element (O-ring) is inserted. The contact element can have the shape of an elastic ring.