DE20303177U1 - Manually operated tool to be used in dental surgery, comprising rotating shaft with tip suitable for tightening or loosening screw - Google Patents

Abstract

A cylindrical element (2), bent in an obtuse angle at the front, is provided with a tool clamping area at one end and can be attached to a rotating handle (1) with the opposite end by engaging a spring supported bolt (5) with a matching opening. The tool, which can be a screw driver (9) or an Allen screw, clamped to the front of the device is moved by a rotating shaft accommodated inside the cylindrical element (2) and manually operated with the handle (1).

Description

■ ^v - ^: -'··"'-■-'■ Koblenz, February 26, 2003

Utility model application

Dental equipment

Registrant: Mrs Angela Merth

Ringstrasse 14 56179 Vallendar

and

Dr. Nikolaus Michael Walter Kirsten

100 m from the main square,

8600-754 Lagos

Portugal

Description:

The invention relates to a dental tool with a rotary tool that is inserted into a handpiece with an internal shaft, which preferably sits removably on a rotary drive for driving the shaft. The invention also relates in the same way to the novel part of this rotary tool.

In implantation dental treatments, an implant is inserted into the jaw with a hole closed by a screw for attaching dentures. Once the implant has healed, the screw is removed and the dentures can be screwed in place.

To loosen or tighten the screws, short surgical screwdrivers are used, which are difficult to handle in the oral cavity and often fall off, after which they have to be removed again with tweezers. Loosening this screw is particularly difficult if it is stuck due to deposits or an accident.

To alleviate these difficulties, dental drills with a handpiece have been used.

A so-called "handpiece" is a tube, one end of which is placed on the drive shaft of a dental drill and the other, angled end of which has a tool connection. Inside, the handpiece is passed through a shaft with multiple bearings, which is guided over angles, e.g. by means of gears. When a dentist wants to drill a tooth, he puts the handpiece on

the drive shaft, inserts a drill or similar into the angled end and begins drilling. The angle creates access to the tooth from above or below and gives the dentist a clear view of the treatment site.

Such handpieces are known from US-3 815 240, US-3 936 940, CH-651 745, CH-679 272, CH-681 504, CH-682 074, CH-682 and EP-O 896 811 Al.

Basically, such a handpiece is ideal for clamping a screwdriver and using it to gain access to the treatment site. Since the screwdriver is clamped firmly, it cannot fall down, even if it should slip.

However, the drive mechanisms of such dentist drills run much too fast to be able to screw in cleanly: in the best case, the screw is screwed in quickly and jams itself at the end, so that it is under longitudinal tension and can later break off, for example when biting. In the worst case, the screw is screwed in crookedly and breaks off. In between there are many possibilities of a partially damaged thread that gives way after a while. Damage to the engagement between the screw and the screwdriver (slot, hexagon, etc. in the screw) is also possible.

Therefore, it is the object of the invention to find a device by means of which the operation of the screws in implants or similar manipulations (e.g. in the

Endodontics (root canal treatment) can be made easier and improved.

This object is achieved according to the invention in that a hand-operated rotary handle is provided as the rotary drive, and that the rotary tool is designed as a screwdriver or screwdriver insert. In a completely surprising way, this is a return to a rotary drive that has been out of use for more than 150 years (tooth breakers): the direct hand-held rotary drive. But in contrast to the tooth breaker, it is less the high torque that is important here and more the sensitive turning, whereby the turning hand feels every resistance and every yielding as it develops, so that damage to the extremely sensitive fine threads in particular can be avoided. By slowly turning backwards, the thread can be brought to collapse and then turned carefully, but if necessary forcefully. The hand holding the handpiece feels every movement of the rotary tool, while the hand turning the rotary handle feels all fluctuations in the torque.

Furthermore, alternating forward and backward rotations of 45 - 90 degrees can be carried out with ease, which is a great advantage especially when preparing root canals.

Overall, better results can be achieved with an extremely cost-effective tool than could ever be achieved with a correspondingly reduced motor drive together with the handpiece.

The device can be used in many areas of dentistry (e.g. surgery, implantology, endodontics, prosthetics, pediatric dentistry) to improve quality and reduce costs.

The rotary handle could, for example, be led out of the handpiece at the side; according to a further development of the invention, however, the rotary handle is designed as a handle that is rotatably seated in the handpiece and can be connected to the shaft in a rotationally fixed manner. The rotary handle thus continues the handpiece in a straight line, which in particular results in structural simplifications, but is particularly advantageous when using a commercially available handpiece, as this is usually driven at the end. The rotation of the handle is also immediately visible, as the handle is in the dentist's immediate field of vision. This provides yet another monitoring option.

The handpiece and the handle can be firmly assembled. A special aspect of the invention, however, is the development that the handle can be locked into the handpiece or released from the lock, and it can be connected to or separated from the shaft in a rotationally fixed manner. The rotating handle can therefore be supplied to match each handpiece. The handpiece itself is used in the dental practice as before. It is therefore sufficient to purchase a relatively inexpensive additional device, the handle, in order to be well equipped for work of the type mentioned above, together with the standard equipment of a dental practice.

The invention therefore relates not only to the dental tool mentioned at the beginning, but also to a handle for rotatable connection to a handpiece, but for rotationally fixed connection to its shaft, with the aforementioned features, for driving a rotary tool, preferably a screwdriver or screwdriver bit. Of course, another rotary tool or treatment tool can also be used, for example for treating the root canal. In this case, the success of the treatment depends to a large extent on the sensitive use of the treatment tool, for example whether the tooth can be saved or whether it breaks due to too energetic intervention of the power-driven treatment tool and then has to be removed.

The known handpiece has a shaft that can be coupled to a counterpart that is attached to the handle according to the invention. In the simplest case, this counterpart is inserted into the handle in a rotationally fixed manner. However, since it is possible to apply a considerable torque to the handle by hand by mistake, which can potentially lead to damage when working on the implant, a further embodiment of the invention proposes that the handle has a torque limiter that limits the torque that can be applied to the tool via the handle to a harmless value. This means that the counterpart in the handle can be rotated when a certain torque threshold is exceeded. It is essential that the torque limiter is attached to the handle and not to the

Handpiece is assigned, since the handpiece is a commercially available, unmodified part.

The torque limiter can be set so low when the handle is manufactured that even in extreme cases there is no risk of the tool causing damage. The disadvantage, however, is that the handle may not be suitable for all applications because the threshold torque of the torque limiter is quite low.

According to a further embodiment of the invention, it is therefore proposed that an adjustment device be provided by means of which the value of the torque that can still be applied can be adjusted. This allows the dentist to select an appropriate torque before working on an implant that is safe for his work but sufficiently high.

The subject matter of the invention will become clearer from the attached schematic drawing and its explanation. In this drawing:

Fig. 1 a dental tool according to the invention in disassembled state,

Fig. 2 the handle of the device of Fig. 1, along the line

II - II in Fig. 1 cut,

Fig. 3 the handpiece of the device of Fig. 1, along the line

III - III cut, and

♦ ·

·

Fig. 4 shows a detail of the handle of Fig. 2, enlarged and in longitudinal section.

Fig. 1 shows a conventional handpiece 2, which is standard in every dental practice. This handpiece 2 is angled and has a clamping device at one end in which a screwdriver attachment (for screws with a transverse slot) or screwdriver attachment 9 (for other screws, for example with a male or female hexagon) is seated.

The other end of the handpiece 2 is bell-shaped and has a continuous annular groove 7 inside it (Fig. 3). A rotatable shaft 6 (shown in Fig. 3, but only partially) runs inside the handpiece 2, the end of which is designed as a coupling piece 4b (Fig. 4). This coupling piece 4b is designed for rotationally fixed plug-in engagement in a counterpart 4a, which will be described later.

The handpiece 2 also has, at the end where the coupling piece 4b is located, a section of a cylindrical fitting bore, within which the shaft 6 runs. Behind this section there are bearings, gear arrangements for deflection and the like. These elements are known and are therefore not shown here for the sake of simplicity.

The handle 1 is a handle that can resemble a screwdriver handle. At its end facing the handle 2, it has a tube 3 (Fig. 4) that projects in the direction of the handle and fits exactly into the

cylindrical portion of the bore of the handpiece 2.

The tube 3 is pierced by a transverse bore through which a pin 5 passes (Fig. 4) which is pressed outwards by a leaf spring 8. Coaxially to the tube 3, the counter-formation 4a is firmly screwed into the handle 1.

If the handpiece 2 is placed on the handle 1, the tube 3 guides itself into the hole in the handpiece. A further push while slightly turning the handle 1 brings the coupling piece 4a into engagement with the counter-formation 4b. At the same time, the pin 5 is pressed in from the end of the handpiece 2. The final push of the handpiece 2 onto the handle 1 causes the pin 5 to snap radially outwards again, where it engages in the annular groove 7. Finally, the coupling piece 4b can grip under the leaf spring 8, so that the catch can only be released again when the handpiece 2 is pulled off the handle 1.

Due to its engagement in the circumferential annular groove 7, the pin 5 does not hinder the relative rotation of the handpiece 2 and the handle 1. During this rotation, however, the shaft 6 and thus the tool are rotated together with the handle 1 and relative to the handpiece 2 via the rotationally fixed engagement of the coupling piece 4b and the counter-formation 4a.

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List of reference symbols

1 - Handle

2 - Handpiece

3 - Pipe

4a - Counterpart (counter-formation) to the coupling piece 4b 4b - Coupling piece

5 - spring-loaded pin (bolt)

6 - Wave

7 - Ring groove

8 - Spring (e.g. leaf spring)

9 - Screwdriver bit or screwdriver bit

Claims (6)

1. Dental implement with a rotary tool which is inserted into a handpiece with an internal shaft, which preferably sits removably on a rotary drive for driving the shaft, characterized in that a manually operable rotary handle ( 1 ) is provided as the rotary drive, and that the rotary tool is designed as a screwdriver or screwdriver insert ( 9 ). 2. Dental tool according to claim 1, characterized in that the rotary handle is designed as a handle ( 1 ) which is rotatably mounted on the handpiece ( 2 ) and can be connected in a rotationally fixed manner to the shaft ( 6 ). 3. Dental tool according to claim 2, characterized in that the handle ( 1 ) can be latched into the handpiece ( 2 ) or released from the latch ( 5 , 7 ), wherein it can be connected to the shaft ( 6 ) in a rotationally fixed manner or can be separated from it. 4. Handle ( 1 ) for rotatable connection to a handpiece ( 2 ), but for rotationally fixed connection to its shaft ( 6 ), with the features according to one of claims 1 to 3, for driving a rotary tool, preferably a screwdriver or screwdriver bit ( 9 ). 5. Rotary handle according to one of claims 1 to 4, characterized in that the handle ( 1 ) has a torque limiter which limits the torque that can be applied to the tool ( 9 ) via the handle ( 1 ) to a harmless value. 6. Rotary handle according to claim 5, characterized in that an adjustment device is provided by means of which the value of the torque that can still be applied can be adjusted.