Control method of a device for extracting a tooth root and device

Abstract

In a control method for a device, in particular for the extraction of tooth roots, the device (10) has an anterior oral-side support (12), a tensioning element (15) guided in the anterior oral-side support, and a tensioning mechanism (20) connectable with the tensioning element (15). The tensioning element (15) is deflected at the front at approximately right angles to the longitudinal extent of the support (12) and is connected with a pin which can be fastened in the tooth root. The tensioning element (15) is pulled into its stretched state by a controllable motor with low force consumption or is connected with the pin in this stretched state. The stretching force (F) is then increased manually or automatically to a predetermined fixed or variable value by preferably increasing the electrical output of the motor of the tensioning mechanism (20), and thereafter, when the tooth root has been loosened, the output of the motor is reduced to a limiting value or to zero. The extraction of tooth roots can thus be carried out very easily and extremely safely, in particular by a dentist.

Description

[0001] The invention relates to a control method for a device, in particular for the extraction of tooth roots, and to such a device.

[0002] According to the known device for the extraction of tooth roots from the printed publication EP-A-1 578 296, a tensioning device is provided which can be partially introduced into the oral cavity and supported therein in order to generate the extraction force required for the extraction, which tensioning device comprises an adjustable extraction element which can be connected with a pin which can be fixed in the tooth root. To this end, the tensioning device comprises a longitudinally extending base body and a longitudinally adjustable tensioning support opposite this, which tensioning support is functionally connected with an engagement extraction element provided with a bolt which passes through a support sleeve fixed to the base body and has a knurled nut screwed thereon which is in contact with the support sleeve.

[0003] With this device and depending on the case, the extraction of a tooth root can be carried out relatively effortlessly, wherein the pin fixed in the tooth root and connected with the extraction element of the tensioning device can be subjected to the extraction force by means of the tensioning device which is partially introduced into the oral cavity and supported therein by means of the manual rotation of the knurled nut, whereupon the tooth root is extracted with the pin. As a result, the reliable extraction of a tooth root can be achieved by means of manual actuation.

[0004] Starting from this general device, it is the object of the invention to provide such a device and a method for controlling the device, with the aid of which the extraction of such a tooth root is possible in an at least partially automated manner, without the dentist generally having to manually participate in the extraction procedure.

[0005] This object is solved according to the invention by the following features.

[0006] According to the invention, the extraction element can provide this extraction force by means of a controllable motor assigned to the extraction mechanism, in order to be able to extract, in particular, a tooth root.

[0007] A device comprises a front oral cavity side support, an extraction element guided in this support and an extraction mechanism which can be connected with this support, wherein the extraction element is deflected in the front portion at approximately right angles to the longitudinal extension of the support and can be connected with a pin or similar element which can be fixed in a tooth root.

[0008] It is very advantageous to use a method for controlling this device, in which the extraction force of the extraction element is increased manually or automatically, preferably by increasing the electrical output of the motor of the extraction mechanism to a predetermined fixed or variable value, and after this, when the tooth root has been detached, the output of the motor is reduced to a certain value or to zero.

[0009] Thus, the person skilled in the art, in particular a dentist, can perform a tooth root extraction very easily and extremely reliably with little manual intervention. This surgical intervention is also extremely comfortable for the patient, and the entire procedure can be performed in a better controlled sequence without the risk of complications. The dentist can apply this control of the device according to the application and thus perform the extraction with a fast learning curve.

[0010] Since the electrical output of the motor of the pulling mechanism is automatically adjusted to the maximum pulling force, and this output is correspondingly reduced when the tooth root has been detached, this extraction can be performed in an extremely simple manner, and the activity of the dentist can be limited to monitoring the course of the operation without any disruption of the sequence.

[0011] It is very advantageous to use a controllable electric rotary motor for the pulling mechanism as the motor, with which, by detecting the speed of rotation per unit of time, the adjustment path and the adjustment speed of the pulling element can be determined.

[0012] Furthermore, with the device according to the application, the pulling mechanism with controllable motor is arranged in a housing with a front-side support, and is actuated and controlled by a control device in such a way that this tooth root extraction can be performed without manual intervention.

[0013] The application and its further advantages are explained in more detail below according to exemplary embodiments and by referring to the drawings. Shown in the drawings are:

[0014] Figure 1 a longitudinal section of the device according to the application,

[0015] Figure 2 in accordance with Figure 1 a perspective side view of the device according to the application, in which the rotary motor and the reduction gear are shown separately from the support as a modular unit each, and

[0016] Figure 3 a diagram of the pulling force exerted by the motor on the pulling element and a diagram of the adjustment path of the pulling element, each based on time.

[0017] Figure 1 and Figure 2 A device 10 for extracting tooth roots, among other things, is shown, further details of which are not shown, which is used in particular in dental technology. With regard to tooth roots, teeth can be partially or completely broken or have been extracted, and this can also relate to natural or artificial roots or roots with artificial parts.

[0018] The device 10 comprises a multi-part housing 11 and a front support 12 connected thereto, each having a longitudinal configuration. Guided longitudinally in the support 12 are a pulling element 15 and a carrier 19 connected thereto, the latter being guided in a guide path 12' of the support 12 substantially without play and being connectable at the rear end with a pulling mechanism 20. The pulling element 15 is deflected at the front side around an angular guide element 14 substantially at right angles to the longitudinal extension of the support 12 and comprises at the front end a connecting element 15' which can be connected with a pin or similar element which is fixed in the tooth root by hanging into the tooth root, by screwing into the tooth root or in some other way.

[0019] At the front side and behind the deflected pulling element 15, the support 12 is provided with support jaws 16, 18, at least one of which can be adjusted by means of an adjusting screw 17 with a nut 17' also at right angles to the support 12 in order to adjust the alignment of the device 10 in the mouth of the patient in such a way that the pulling direction of the pulling element 15 is effectively in the direction of the tooth root, so that if the direction of the pulling deviates from the axial direction of the gap, no disturbing lateral frictional forces occur during the extraction. The configuration and the size of the front support 12 with the guide of the pulling element 15 can of course be different depending on the requirements.

[0020] According to the invention, the pulling mechanism 20 in the housing 11 is provided with a controllable electric motor 21 for generating a pulling force for the pulling element 15, which is actuated and controlled by a control device in such a way that with this electric motor 21 it is possible to exert such a pulling force on the pulling element 15 that it is possible to extract the tooth root without manual intervention.

[0021] Very advantageously, this electric motor is configured as a rotary electric motor 21 which is arranged at the rear side in the housing 11 and from which a connection cable 31 with a connection plug 32 leads to the rear. A reduction gear 22 is arranged coaxially with this rotary electric motor 21 in the housing 11, a drive shaft is rotatably connected thereto and a conversion element 23 for converting a rotary movement into a linear movement for adjusting the carrier 19 and thus the pulling element 15 in the support.

[0022] The conversion element 23 is formed by a threaded sleeve 26 which is rotatably connected with the drive shaft 24 of the reduction gear 22 and a threaded spindle 19' of the carrier 19. The drive shaft 24 can be connected coaxially with the threaded sleeve 26 via a coupling element 27, wherein the latter is supported circumferentially in the housing by a plain bearing 28 and by at least one axial bearing 29 in such a way that the pulling force generated thereby, which during the extraction is mainly along the axis A, is reliably absorbed.

[0023] For control purposes, the rotary motor 21 is electrically connected with a connecting cable 31 to a control device, further details of which are not shown. For this purpose, on the one hand, the connecting cable 31 is provided for the power supply and, on the other hand, for the control elements and measuring elements of the rotary motor 21, as a connection to a control device in an external device, by means of which the desired control and measuring functions can be carried out in a programmed manner.

[0024] The rotational torque exerted on the rotor of the rotary motor 21 is preferably influenced by an adjustable current strength of the motor. The pulling force F on the pulling element 15 is thus correspondingly adjusted by means of the control device and is automatically controlled during the pulling-off process. For this purpose, the rotary motor 21 is advantageously equipped with a rotational speed measuring device, further details of which are not shown. The current rotational speed can thus be detected by means of a signal transmitted to the control device and can be evaluated therefrom.

[0025] The rotary motor 21 can be, for example, a brushless DC motor with a non-ferrous winding, with which rotational speeds close to stepless speed changes are possible, as is known, for example, from the Maxon EC motor type from Maxon. Integrated in this rotary motor is a rotational speed measuring device which functions in an inherently known manner by means of Hall sensors as measuring elements.

[0026] As a reduction gear 22, it is also possible to use a device from Maxon, which is configured as a planetary gear, of the Maxon gear type. These are thus not explained any further in terms of details. It is of course possible to use other motors and gears which are suitable for the desired function.

[0027] With a planetary gear, it is possible to reduce the rotational speed of the motor from, for example, 100 to 1000 revolutions per minute to a few revolutions per minute, and with the conversion element 23, with a pitch of, for example, one millimeter, it is possible to adjust the longitudinal adjustment of the carrier 19 and thus of the pulling element 15 along the axis A by a few millimeters per minute, the result of which is that the pulling-off force can be determined optimally.

[0028] Both this rotary motor 21 and the planetary gear 22 are characterized in that, with sufficient output, they exhibit a small cylinder outer diameter, for example, 15 to 30 millimeters, so that the housing 11 can likewise be dimensioned in the shape of a handle-shaped cylinder, the diameter of which is adapted to the palm of a hand held up. The outer shell of the housing 11 can be made of a roughened material or a suitable gripping material in order to allow a firm grip. In this case it consists of several cylinders of the same diameter arranged next to one another, wherein the rotary motor 21 and the reduction gear 22 form a structural unit or module 11", and the support 12 forms a structural unit or module 11' with the cylinders, which can be inserted into one another and secured against rotation.

[0029] According to Figure 3 the graph of the curve, the method of controlling the device 10 is shown at the time of extraction. In this case, the abscissa represents the time t, and the two ordinates represent, on the one hand, the pulling force F with which the pulling element 15 acts on the tooth root, and, on the other hand, the path of movement S per unit of time of the pulling element 15 and of the tooth root, respectively.

[0030] During the extraction process, the device 10 with the support 12, as prepared in a conventional manner, is placed in the mouth of the patient and aligned in such a way that the tooth root to be extracted is located in the pulling element 15 with the pin screwed into it, below or above the pulling element 15, pointing at right angles to the support 12, and the connecting element 15' of the latter is hanging or otherwise connected at the end of the pin.

[0031] As shown before, it must be ensured that the pulling axis and the axis of the tooth root, in which the fibres are held, extend approximately the same or coaxially aligned with one another in order to create optimal conditions for a possible extraction without obstruction. This can be adjusted accordingly at the bearing 12 by means of the nut 17' mounted therein and by means of the adjusting screw 17 and the bearing jaws 16 interacting therewith.

[0032] When the dentist or the professional has correctly and firmly placed the device 10 in the mouth, he can set the rotating motor 21 in motion by means of a switch element, for example by means of a foot pedal or a hand switch, and initiate the pulling in such a way that the pulling element 15 moves in an automated manner with an approximately constant small adjustment path or movement speed S1 per unit of time and a pulling force F1 directed away from the tooth root along the axis A of the housing 11.

[0033] As soon as the pulling element 15 assumes the stretched state, the movement speed drops to a value S0 close to zero with the low pulling force F1 acting, which can occur after only a few millimetres of movement path depending on the positioning of the device 10. By measuring the rotational speed of the rotating motor 21, it is detected that its movement speed drops to near zero and this is signalled to the control device.

[0034] Next, the pulling force F is automatically increased to a predetermined fixed or variable maximum value F max by increasing the electrical output of the rotating motor 21. As a result, a maximum amount of pulling force F max is transmitted onto the tooth root. In general, at the beginning of the increasing pulling force F max , the pulling element 15 increases rapidly from the movement speed S0 of zero to a derived value S 01 , which is due to the fact that first of all the pulling element 15, then the conversion element 23 and the rotating motor 21 are stretched or adjusted to full tension. After this, the movement speed S 01 at the maximum pulling force F max will increase slightly depending on the resistance of the tooth root, asFigure 3 as shown in the middle.

[0035] It is also possible to proceed in such a way that the pulling element 15 does not move at first and that it only moves after a certain period of time in which the load is applied to the fibers holding the tooth root in the jawbone. It can be provided within the framework of the invention that the dentist actuates the switch element during the pulling process so that the rotary motor 21 automatically generates a variable maximum value F max in order to thereby improve the detachment of the tooth root. This maximum value F max may be reduced, for example, by half in an automated manner, then increased again to the full value, and this can occur several times as an oscillating force pattern. It can also occur that the tooth root is positioned in the jawbone in a wedge shape and then the dentist attempts to detach it with appropriate tools.

[0036] When the tooth root has been detached from the jawbone or at least the resistance of the root has been reduced, the output of the rotary motor 21 and thus the pulling force F max is reduced to a certain value F2 and then to the value F0 as a stop. This depends on how far the tooth root has been pulled out and in any case whether it is below the guide element 14. Once the tooth root has become detached or the resistance of the root has been reduced, this leads to an increase in the movement speed S2 at the maximum amount of pulling force. This is recognized by the control device and the program is designed so that the motor output is immediately reduced.

[0037] As an alternative, the movement path of the pulling element 15 in the support 12 can be determined by reference to its longitudinal position. The increase in the motor output before the extraction and / or its reduction after the tooth root has been detached will be determined depending on the reference longitudinal position of the pulling element and not by its movement speed. The movement path of the pulling element can be calculated by the rotational speed of the rotary motor 21 and controlled accordingly.

[0038] The change in the motor output can also be carried out by manual actuation of the switch element, wherein the extraction is initiated, interrupted or stopped by means of the pulling mechanism.

[0039] The invention has been described sufficiently by means of the exemplary embodiments set forth before. However, it can of course also be set forth by further variants.

[0040] In principle, the rotary motor and, if appropriate, also the reduction gear can be integrated in an external device, and the rotary movement and / or linear movement can be connected to the pulling element by means of a transmission element in a flexible tube or the like between the device and the housing. As described in the aforementioned exemplary embodiments, the reduction gear can likewise be accommodated in the housing and it will then be coupled with the rotatable transmission element.

[0041] It is also possible to use a linear motor or rotary motor, which is directly connected to the drawing element via a nut / threaded mandrel. The drawing element can be constructed as more than one longitudinal element, preferably with a parallel orientation, and each uses cables, etc.

Claims

1. An apparatus for tooth root extraction, the apparatus (10) comprising an anterior oral support (12), a traction element (15) guided in the support, and a traction mechanism (20) connectable thereto, wherein the traction element (15) is anteriorly deflected at approximately a right angle to the longitudinal extension of the support (12), the traction mechanism (20) comprising a controllable motor for generating a traction force of the traction element (15), the traction element (15) being connectable to a pin fixable to the tooth root, the controllable motor being housed in a housing (11) having the anterior support (12) or in a separate device, and controlled by a control device in such a manner that, using this controllable motor, such a traction force (F) can be generated. max The material is applied to the pulling element (15) so that the tooth root can be extracted without manual intervention, characterized in that... The device is able to determine the moving path of the pulling element (15) per unit time under a given motor power, or, when the controllable motor is a controllable rotary motor (21), the device is able to determine the moving path or moving speed of the pulling element (15) by the speed of the rotary motor (21) per unit time.

2. The device according to claim 1, characterized in that... The pulling mechanism (20) includes a rotary motor (21) as a controllable motor, a reduction gear (22) rotatably connected to the motor, and a conversion element (23) for converting rotary movement into linear movement for the movement of the pulling element (15).

3. The device according to claim 1 or 2, characterized in that... The housing (11) is configured to have the shape of a handle for holding the device (10) in the pull-out position, and the pull-out mechanism (20) is housed therein.

4. The device according to claim 2, characterized in that... The rotary motor (21) is equipped with a drive shaft on the front side and an electrical connection cable (31, 32) with power supply and control lines for connection to external devices on the rear side. The drive shaft of the rotary motor (21) is rotatably connected to the reduction gear (22), and these are arranged coaxially with the conversion element (23) for converting rotary movement into linear movement.

5. The device according to claim 2, characterized in that... The rotary motor (21) is configured as a brushless DC motor, the reduction gear (22) is configured as a planetary gear, and / or the conversion element (23) is configured as a threaded mandrel / nut combination.

6. The device according to any one of claims 1-5, characterized in that, The movement path of the pulling element (15) in the support (12) is determined by reference to its longitudinal position, and the increase in motor output before the extraction and / or the decrease in motor output after the tooth root is removed are determined based on the determined longitudinal position of the pulling element (15) in the support (12).

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