Abstract: A contra-angle tool holder head notably for dental drills and cutters, for rotatably driving in opposite directions two coaxial dental tools such as drills or cutters comprises a first holding member adapted to drive the first tool and consisting of a claw supporting a first bevel pinion and a second holding member for rotatably driving the second tool in the opposite direction, this second holding member consisting of a second hollow bevel pinion, both holding members being driven simultaneously from a third bevel pinion carried by a shaft driven in turn from the motor and disposed between the first and second bevel pinions, the axis of the drive being disposed at right angles to the common axis of the first and second bevel pinions and of their holding members.

Abstract: A dental handpiece having a head adapted to receive the tool rotatably driven through a central shaft and having a rear end adapted to be coupled to a driving member adapted to rotate freely therein, comprises an internal inlet port for supplying cooling fluid to the tool which communicates with an outlet passage leading to the head of the holder. An external inlet port also communicating with the outlet passage via a chamber is provided; the internal inlet port opens into this chamber and a valve member adapted to close either of these ports is provided for permitting the communication between the open port and the outlet passage. This handpiece is adapted to be coupled to driving members provided or not with an internal passage for delivering cooling fluid to the tool.

Abstract: A centrally-bored cylindrical abutment member is fitted over the shank of a root canal instrument and held against the instrument handle or head by elastic clipping means acting on the instrument handle, or on a handpiece carrying the instrument. The thickness of the abutment member may be adjustable, e.g. by screwing, or several interchangeable devices with abutment members of different thicknesses can be provided to accurately set the effective penetrable length of the instrument.

Abstract: A dental handpiece comprises a rear portion or handle and a front portion or head which are coupled by means of a female member secured to one portion and a male member secured to the other portion, the female member having formed therein a longitudinal slot and a recess shifted angularly in relation to the slot, the male member comprising a projection, one member comprising an elastically deformable portion whereby rotating one member in relation to the other through a predetermined angle permits introducing said projection into the recess, the projection being allowed to expand therein.

Abstract: A dental handpiece comprises two sections, notably in the case of a contra-angle, which are rigidly assembled and both provided with an aligned passage for delivering the liquid to be atomized to the head of the handpiece, said passage being incorporated in the wall of each section and the joint between the two sections comprises an annular seal fitted in a recess surrounding the passage and formed in one section, the length of this seal being slightly greater than the depth of the recess, so that the outer edge of the seal tightly engages the registering face formed in the other section, this arrangement being adaptable to all dental handpieces provided with internal passage means for the liquid intended for cooling the tool.

Abstract: An axially slidable chuck-actuating internal sleeve of a dental handpiece is biased to a chuck-closing position by a spring, but can be displaced to open the chuck by cooperation with radially-movable balls. These balls are biased outwardly by leaf springs to normally rest in contact with the inner surface of an axially slidable or rotatable external actuating sleeve, whereby the balls remain out of contact with the internal sleeve when it is rotated with the handpiece shaft.

Abstract: A package for dental root canal instruments comprises a rectangular base plate of stamped metal having integral resilient protuberances along a marginal edge defining housings for gripping the handles of the instruments, a part of the handle protruding beyond said marginal edge. A cover with U-section slides is slidably mounted on the base plate to cover the instruments and enclose the protruding handles.