Abstract: The invention relates to an improved bur for use in handpieces having a rotatable chuck with a tool bore for receiving the bur, a friction grip member for frictionally retaining the bur in the chuck and a torque lock seat of non-circular cross-section and permitting length adjustment of the bur in the drive head by concentrically supporting the bur in the drive head at any position from a fully inserted position to a maximum retracted position. The bur includes a tool body having an axis of rotation, a working end for projecting from the handpiece and a driven end for insertion into the tool bore of the chuck. The driven end is a generally cylindrical shaft with a preselected outer circumference for fittingly engaging in the tool bore for concentric rotation of the driven end with the chuck. The shaft including a torque lock portion for fittingly and non-rotatably engaging the torque lock seat of the chuck.

Abstract: The invention relates to an improved dental tool drive arrangement for a handpiece with a drive head, the tool drive arrangement permitting length adjustment of the tool in the drive head by concentrically supporting the tool in the drive head at any position from a fully inserted position to a maximum retracted position. The tool drive arrangement preferably includes a tool and a rotatable tool supporting element for concentrically supporting the tool from the fully inserted to the maximum retracted position, the tool preferably including a maximum retraction indicator for indicating to a user when the tool has been retracted to the maximum retraction position. This provides a significant advantage over the prior art by allowing a user to adjust the exposed length of a rotatable tool, preferably a dental bur, without exceeding safe operating limits.

Abstract: The invention relates to an improved dental tool drive arrangement for a handpiece with a drive head, the tool drive arrangement permitting length adjustment of the tool in the drive head by concentrically supporting the tool in the drive head at any position from a fully inserted position to a maximum retracted position. The tool drive arrangement preferably includes a tool and a rotatable tool supporting element for concentrically supporting the tool from the fully inserted to the maximum retracted position, the tool preferably including a maximum retraction indicator for indicating to a user when the tool has been retracted to the maximum retraction position. This provides a significant advantage over the prior art by allowing a user to adjust the exposed length of a rotatable tool, preferably a dental bur, without exceeding safe operating limits.

Abstract: A dental handpiece is disclosed including a turbine construction creating a radial in flow of air onto the impeller blades about the whole circumference of the turbine. This generates additional torque and avoids asymmetrical thrust on the impeller wheel. A pair of axially spaced air bearings support the turbine. Air supply to the bearings is controlled in such a way that the air bearings are floated before drive air is supplied to the turbine and after drive air to the turbine has been shut off. This ensures that the air bearings are always operational irrespective of the operational state of the turbine. The handpiece has an improved ergonomic shape, especially the shape and configuration of the front or drive head, which provides additional tooth clearance and a better field of view. An angled swivel connection to the umbilical cord is provided which reduces physical strain on the dentist's wrist.

Abstract: The invention relates to an improved dental tool drive arrangement for a handpiece with a drive head, the tool drive arrangement permitting length adjustment of the tool in the drive head by concentrically supporting the tool in the drive head at any position from a fully inserted position to a maximum retracted position. The tool drive arrangement preferably includes a tool and a rotatable tool supporting element for concentrically supporting the tool from the fully inserted to the maximum retracted position, the tool preferably including a maximum retraction indicator for indicating to a user when the tool has been retracted to the maximum retraction position. This provides a significant advantage over the prior art by allowing a user to adjust the exposed length of a rotatable tool, preferably a dental bur, without exceeding safe operating limits.