Abstract: An orthodontic expansion screw has two bodies, the mutual distance of which can be changed by a spindle. The spindle has an actuating part with a threaded part engaged in a threaded bore of one of the two bodies. A straight-line guiding means engage both bodies and prevent a relative rotation of the bodies and prevent inadvertent rotation of the spindle. The threaded part of the spindle has one recess. The inner surface of the threaded bore of the body in which the threaded part is inserted has a projection, which is directed against the at least one threaded part and, in a position of the spindle in which it faces the flattened portion or recess, touches the threaded part on the flattened portion or in the recess, whereas in positions of the spindle in which it does not face a flattened portion or recess, presses against the threaded part.

Abstract: The orthodontic expansion screw has two bodies, the mutual distance between which can be changed by a spindle means. The spindle has an activating part with a threaded part and is turned into a threaded hole of one of the two bodies. The bodies have a first end, which faces the activating part of the spindle, and a second end, which faces away from the activating part of the spindle. A linear guiding means engage both bodies and guide them while preventing a relative rotation of the bodies and prevent inadvertent twisting of the spindle relative to the bodies. The spindle's threaded part has a recess in which the at least one threaded part is inserted and has an extension externally that contacts the threaded part on a flattened region or in the recess, whereas it elastically presses against the threaded part.

Abstract: An orthodontic expansion screw including at least two bodies, the mutual distance between which can be changed by means of a spindle, and with one or two guide pins, which engage both bodies and guide them while preventing a relative rotation of the bodies given a change in their distance relative to each other. In order to prevent or impede an inadvertent twisting of the spindle relative to the bodies, the outer periphery of the activating part has a shell surface, whose configuration differs from a shell surface of a circular cylinder in such a way that there is at least one first position of the spindle in which the activating part contacts the guide pins with a pressure that leads to an elastic deformation of a guide pin.

Abstract: An orthodontic expansion screw has two bodies, the mutual distance of which can be changed by a spindle. The spindle has an actuating part with a threaded part engaged in a threaded bore of one of the two bodies. A straight-line guiding means engage both bodies and prevent a relative rotation of the bodies and prevent inadvertent rotation of the spindle. The threaded part of the spindle has one recess. The inner surface of the threaded bore of the body in which the threaded part is inserted has a projection, which is directed against the at least one threaded part and, in a position of the spindle in which it faces the flattened portion or recess, touches the threaded part on the flattened portion or in the recess, whereas in positions of the spindle in which it does not face a flattened portion or recess, presses against the threaded part.

Abstract: The orthodontic expansion screw has two bodies, the mutual distance between which can be changed by a spindle means. The spindle has an activating part with a threaded part and is turned into a threaded hole of one of the two bodies. The bodies have a first end, which faces the activating part of the spindle, and a second end, which faces away from the activating part of the spindle. A linear guiding means engage both bodies and guide them while preventing a relative rotation of the bodies and prevent inadvertent twisting of the spindle relative to the bodies. The spindle's threaded part has a recess in which the at least one threaded part is inserted and has an extension externally that contacts the threaded part on a flattened region or in the recess, whereas it elastically presses against the threaded part.

Abstract: An orthodontic expansion screw including at least two bodies, the mutual distance between which can be changed by means of a spindle, and with one or two guide pins, which engage both bodies and guide them while preventing a relative rotation of the bodies given a change in their distance relative to each other. In order to prevent or impede an inadvertent twisting of the spindle relative to the bodies, the outer periphery of the activating part has a shell surface, whose configuration differs from a shell surface of a circular cylinder in such a way that there is at least one first position of the spindle in which the activating part contacts the guide pins with a pressure that leads to an elastic deformation of a guide pin.

Abstract: The invention relates to a method for producing an orthodontic element with a ceramic main body, which has a base surface for fixing the element to a tooth. In order to develop the method in such a way that the main body can, on the one hand, be fastened to the tooth with a high adhesive force and, on the other hand, can easily be detached from the tooth at the end of an orthodontic treatment, it is proposed according to the invention that a laser beam is guided along the base surface in an impingement area, the base surface in the impingement area is superficially heated locally by means of the laser beam and microscopic particles are broken free from the base surface by means of crack development.