Dental hand piece, comprising a housing and a drive train with a coupling element for a drive, wherein the housing radially surrounds the drive train and wherein the housing has a first and a second housing end, and wherein the housing is held on the drive train on the first and on the second housing end. Between the first housing end and the coupling element is arranged a decoupling element, which is strictly springy or springy and damping in the axial direction, whereas the second housing end is braced rigidly against the drive train and the housing is braced with respect to the coupling element in the axial direction by means of the decoupling element.

A dental hand piece or angle piece including a rotating tool, which is driven via a rotating drive element disposed in a housing, wherein the rotating drive element is mounted in the housing by a radial rolling bearing, wherein the rolling bearing comprises an axial abutment surface and the housing comprises an axial countersurface, and wherein the rolling bearing is axially preloaded with respect to the housing by a spring element 11 and has a coefficient of friction for the static friction of the abutment surface to the countersurface or the abutment surface and the countersurface to the spring element that is at least 0.16 in the lubricated state and at least 0.25 in the unlubricated state.

A dental hand piece or angle piece including a rotating tool, which is driven via a rotating drive element disposed in a housing, wherein the rotating drive element is mounted in the housing by a radial rolling bearing, wherein the rolling bearing comprises an axial abutment surface and the housing comprises an axial countersurface, and wherein the rolling bearing is axially preloaded with respect to the housing by a spring element 11 and has a coefficient of friction for the static friction of the abutment surface to the countersurface or the abutment surface and the countersurface to the spring element that is at least 0.16 in the lubricated state and at least 0.25 in the unlubricated state.

A head assembly for a dental contra-angle hand-piece and a dental contra-angle hand-piece are provided. The head assembly includes a hand-piece main body, a reversing valve movably connected to the hand-piece main body, and an inner water tube connected to the hand-piece main body, wherein the hand-piece main body is provided with a first flow channel and a second flow channel independent from each other, the first flow channel is configured to be in communication with a liquid outlet of a motor, and the second flow channel is configured to be in communication with an external pipeline; the reversing valve is provided with a confluence channel, the reversing valve is configured to enable, when moving relative to the hand-piece main body, the first flow channel and the second flow channel to alternatively be in communication with the inner water pipe through the confluence channel.

A head assembly for a dental contra-angle hand-piece and a dental contra-angle hand-piece are provided. The head assembly includes a hand-piece main body, a reversing valve movably connected to the hand-piece main body, and an inner water tube connected to the hand-piece main body, wherein the hand-piece main body is provided with a first flow channel and a second flow channel independent from each other, the first flow channel is configured to be in communication with a liquid outlet of a motor, and the second flow channel is configured to be in communication with an external pipeline; the reversing valve is provided with a confluence channel, the reversing valve is configured to enable, when moving relative to the hand-piece main body, the first flow channel and the second flow channel to alternatively be in communication with the inner water pipe through the confluence channel.

A fixing structure of a dental handpiece has a transmission assembly for connecting a handpiece head, a positioning sleeve sleeved onto the transmission assembly and having a positioning member thereon, and a casing composed of a front casing and a rear casing. The front casing is sleeved onto the positioning sleeve. The rear casing is detachably connected to one end of the front casing. The front casing is provided with a push member. The push member is inserted inwardly to lean against the positioning member for the positioning member to be tightly pressed against an outer circumferential surface of the transmission assembly so that the front casing, the positioning sleeve and the transmission assembly are fixed and connected together.

The invention relates to a dental handpiece with a manually operable push button for actuating the trigger mechanism, wherein the push button is double-walled with an outer cover plate and an inner contact element, wherein for actuating the push button an upper side of the outer cover plate is pressable by a user against a bias, thereby actuating an actuator by an underside of the inner contact element to actuate the trigger mechanism, wherein a thermal insulation layer extends between the outer cover plate and the inner contact element which causes a thermal decoupling of the outer cover plate from the inner contact element.

A dental treatment apparatus according to the present invention includes a drive unit that includes a micromotor, a motor driver, and the like, a controller, and a root canal length measurement circuit. The controller controls the cutting tool to be held at a head forward driven in a direction of cutting of an object to be cut. The controller also controls the cutting tool to be reverse driven in a direction reverse to forward rotation drive when the cutting tool is forward driven and the root canal length measurement circuit detects a tip end of the cutting tool reaching a reference position. The controller further carries out a fail-safe control when the cutting tool is reverse driven and the root canal length measurement circuit detects movement of the tip end of the cutting tool toward a root apex position.

A dental treatment apparatus according to the present invention includes a drive unit that includes a micromotor, a motor driver, and the like, a controller, and a root canal length measurement circuit. The controller controls the cutting tool to be held at a head forward driven in a direction of cutting of an object to be cut. The controller also controls the cutting tool to be reverse driven in a direction reverse to forward rotation drive when the cutting tool is forward driven and the root canal length measurement circuit detects a tip end of the cutting tool reaching a reference position. The controller further carries out a fail-safe control when the cutting tool is reverse driven and the root canal length measurement circuit detects movement of the tip end of the cutting tool toward a root apex position.

A fluid-driven medical or dental handheld device includes a head, the head including a housing and a impeller rotatably mounted in the housing. The housing defines a receiving chamber for receiving the impeller, a main air inlet and an air outlet being defined in the housing and communicating with the receiving chamber. An inner surface of the housing surrounding the receiving chamber defines a plurality of grooves, the grooves being arranged at intervals along a circumferential direction of the housing. The grooves reflect rotating airflows directed to the grooves to change directions and speeds of the airflows to form interference airflows, which can effectively reduce the rotation speed of the head at idling, while ensuring the torque output of the head during grinding teeth.