A dental handpiece for root canal treatment comprises an outer sleeve, a connecting device for connecting the handpiece to a control and analyzing unit, a measurement circuit having a power source and to a drive unit, an electrically conducting tool receptacle and an electrically conducting driving device, wherein the tool receptacle and the driving device are mechanically and electrically connected together so that a driving motion generated by the drive unit can be transmitted via the driving device to the tool receptacle and electrical measurement signals can be transmitted between the driving device and the tool receptacle. A first connection is provided for transmitting the driving motion. A second electrically conducting connection, which may comprise sliding contacts, is provided for transmitting the electrical measurement signals. With separate connections, an improved signal transmission and in particular a low loss of measurement signals of the root canal length measurement during the signal transmission are achieved.

A medical or dental handheld element has a rotatably arranged rotary part, at least one roller bearing for bearing support of the rotatably arranged rotary part, the roller bearing having at least one rotatable roller bearing part that is co-rotational with the rotary part and at least one stationary roller bearing part that is stationary in relation to the rotary part, and an anti-twist device or anti-rotation element provided to restrict the stationary roller bearing part from rotating. The anti-twist device comprises a polygonal, generally arc-shaped, open metallic anti-twist device. A handheld element with this anti-twist device is less sensitive to the effects of sterilization or cleaning processes. Also disclosed is a method for manufacturing such a handheld element.

An insertion element that can be inserted into a medical handpiece head and can receive at least one spray medium. The insertion element comprises a bearing seat for a bearing and a lateral surface. The lateral surface has at least one ring groove which is connectable to a media line for transfer of a spray medium. The insertion element is made of resilient or elastically compressible material that can be fit within the handpiece head.

The present invention relates to a seal in the tool side of a straight or contra angle handpiece head for sealing the interior of straight or contra angle handpieces. The seal is characterised by a spring, which prestresses a gasket of compressible elastic material against a fixed component and a rotating disk located in the immediate vicinity of the seal. Moreover, the present invention relates to a straight or contra angle handpiece with such a seal.