Abstract: A dental handpiece has a head housing having a turbine chamber and an annular channel. First and second bearings are provided on opposite sides of the turbine chamber in the head housing. An air-driven turbine rotor is arranged in the turbine chamber and supported on the first and second bearings. A rotor spindle is driven by the air-driven turbine and drives, in turn, a tool. The first bearing is positioned proximal to the tool and the second bearing is positioned distal to the tool. The head housing has a drive air channel guiding drive air to the air-driven turbine rotor and a return channel for the drive air. A hollow space is provided in the head housing in which an actuator for the tool holder of the tool is arranged. Several air-permeable connecting channels connect a radially outer area of the turbine chamber to the hollow space or the annular channel or both.

Abstract: A dental handpiece includes a turbine arranged in a handpiece head for rotating a tool, wherein the turbine is supported by slide bearings or roller bearings arranged on the side of the rotor or turbine facing the tool and on the side of the rotor or turbine facing away from the tool. The handpiece head includes an air duct for the propulsion air and a return duct for the returned or used air. At least one opening in the turbine chamber wall in the area near the axis is connected through a connecting duct to the return duct.