A dynamic seal for use in a dental handpiece is disclosed. The dynamic seal includes a seal carrier including a first portion having a first feature for receiving a first compliant member and a second portion having a second feature for receiving a second compliant member, and a flange disposed between the first feature and the second feature.

When the compressed air is not applied, an inclined surface, which is positioned at an upstream side with respect to the supply direction of the compressed air, of the lip part is in contact with the inclined surface of the inner ring. When the compressed air is applied, a contact area between the inclined surface, which is positioned at the upstream side with respect to the supply direction of the compressed air, of the lip part and the inclined surface of the inner ring becomes smaller, as compared to when the compressed air is not applied.

When the compressed air is not applied, an inclined surface, which is positioned at an upstream side with respect to the supply direction of the compressed air, of the lip part is in contact with the inclined surface of the inner ring. When the compressed air is applied, a contact area between the inclined surface, which is positioned at the upstream side with respect to the supply direction of the compressed air, of the lip part and the inclined surface of the inner ring becomes smaller, as compared to when the compressed air is not applied.

A curved handpiece for dental root canal treatment forms an overall scheme of a dental curved handpiece, which is internally conductive, surface insulated, compact in structure, small in height and size and convenient to repair. A dental root canal length measuring function can be realized accurately, safely and stably, and a stable two-in-one function of combining root canal preparation and dental root canal length measurement is further realized. The structure is compact as a whole, and a good visual field is provided. The risk of instrument separation or preparation step generation in the operation process of doctors is reduced, and the safety improvement is greatly guaranteed. According to the scheme, it is convenient to disassemble, repair and clean, the risk of cross infection is reduced, and the use safety and convenience effects of the present invention are further improved. The curved handpiece has great market benefits.

The invention aims to provide a rotation tool enabling work without obstructing a view of an operator and facilitating fine-adjustment for the tool. A rotation tool includes a flexible shaft including a tool portion at one end and a grip portion at the other end; and a cylindrical exterior body including curved portion on at least a part thereof, wherein a spiral protrusion is formed on at least a part of the shaft and a spiral groove is formed on at least a part of the curved portion, and the shaft is configured to be movable inside the exterior body by screwing the spiral protrusion and the spiral groove to each other.

The dental handpiece consists of a housing with a handle and a turbine that can be operated with compressed gas or compressed air. The rotational movement of the turbine driven by compressed gas is transmitted to the dental tool via a rotor shaft and a chuck. The rotor shaft is rotatably supported by at least one axial groove ball bearing. The radial rigidity required for operating a dental handpiece is achieved by axially preloading the ball bearings. Projections on the housing and the shaft disc of the at least one axial groove ball bearing allow the axial groove ball bearing to be used as radial groove ball bearings. The proposed design of the dental handpiece exhibits little power loss or frictional loss in comparison to dental handpieces with radial groove ball bearings, and slip and drilling friction components can be virtually completely prevented in particular.

A handle system for supporting a tool defining a tool axis during the performance of dental procedures comprises a handle defining a handle axis, a rotation sleeve, a head assembly and a gear set comprising first and second gear portions. The rotation sleeve supports the first gear portion. The head assembly supports the second gear portion. The handle supports the rotation sleeve for rotation relative to the handle. The handle supports the head assembly such that the first gear portion engages the second gear portion. With the head assembly supported by the handle, the head assembly engages the tool to support the tool such that the tool axis extends at a first angle relative to the handle axis and rotation of the rotation sleeve relative to the handle causes axial rotation of the tool about the tool axis.

Provided is a dental handpiece capable of rotating a cutting tool at a high speed as compared with a conventional dental handpiece. A dental handpiece including coupling portion, a body, and a neck to be held by a used and a head connected to them, wherein the head includes a tool rotating mechanism that holds a cutting tool for treating a region to be treated, rotates based on rotation of a drive unit that is rotationally driven, and rotates the cutting tool, and the tool rotating mechanism has a rotation speed of at least 5.5 times or more a rotation speed of the drive unit.

The disclosure relates to a head bearing assembly for a dental or surgical handpiece, comprising an outer sleeve, in which at least four radial bearings are arranged, which enclose an axis of rotation and each have their own bearing outer ring or a common bearing outer rings, wherein the bearing outer rings are surrounded radially on the outside by the outer sleeve in the circumferential direction about the axis of rotation, and each radial bearing has at least one or exactly one rolling element row with rolling elements which are arranged one behind the other in the circumferential direction and rolling in the respective bearing outer ring.

The head bearing assembly according to the disclosure is characterized in that the at least four radial bearings have a common, integral bearing inner ring on which the rolling elements are arranged in rolling contact.

An indexed drive system (10) for mechanised tools, in particular an electric toothbrush, for selectively imparting various drive modes to a pair of concentrically-arranged drive shafts (12, 14) thereby imparting various brushing modes to the head (H) of the mechanised tool, in particular an electric toothbrush.