Dental contra-angle handpiece for processing hard materials inside the patient's mouth

Abstract

A dental contra-angle handpiece is provided that is configured to be particularly suitable for processing hard materials within a patient's mouth. [Solution] A dental contra-angle handpiece 1 for processing hard materials in a patient's oral cavity, comprising an outer sleeve 2 having a handle portion 2A extending along a longitudinal axis 3 and a head portion 2B extending along a rotation axis 4, a collet chuck 5 for holding a processing tool for processing hard materials, rotatably mounted about the rotation axis 4 of the head portion 2B by first and second rolling bearings 6, 7, and a coupling device 8 for connecting the dental contra-angle handpiece 1 to a supply device and / or a control device, wherein the speed transmission ratio of the dental contra-angle handpiece 1 is 1:4±3%, and the collet chuck 5 has a pull-out force of more than 35 N in accordance with ISO14457:2017.

Description

[Technical field]

[0001] The present invention relates to a dental contra-angle handpiece adapted for processing hard materials within a patient's mouth. [Background technology]

[0002] Artificial dental crowns and dentures, such as bridges, are manufactured from various materials. In recent years, zircon has become the preferred material and is used more frequently. This is due, among other things, to the fact that zircon is allergy-free, its color closely resembles the natural color of teeth, as well as its hardness, which is particularly advantageous for dental prostheses that replace several teeth. However, the high hardness of zircon presents a challenge for dentists, especially when zircon crowns and prostheses need to be treated in the patient's mouth, for example when they need to be removed. Currently, conventional handpieces are used, which are intended for treating softer materials, such as natural tooth tissue and caries. When using such contra-angle handpieces to treat hard materials in the patient's mouth, especially zircon, but also other ceramics or particularly hard metal alloys, the treatment takes a long time and / or parts of the contra-angle handpiece that are particularly stressed by the treatment of hard materials wear out or break very quickly. Summary of the Invention [Problem to be solved by the invention]

[0003] The object of the present invention is therefore to design a dental contra-angle handpiece that is particularly suitable for treating hard materials in a patient's mouth, preferably in such a way that it is better able to withstand the greater forces that are generated when treating hard materials in a patient's mouth, both by the hard materials themselves and by the user of the dental contra-angle handpiece. [Means for solving the problem]

[0004] According to the invention, this problem is solved by a dental contra-angle handpiece for processing hard materials in a patient's mouth having the features of claim 1. Particularly advantageous embodiments are set out in the dependent claims.

[0005] The dental contra-angle handpiece according to the invention for processing hard materials in a patient's mouth comprises an outer sleeve which delimits the dental contra-angle handpiece from the surroundings, the outer sleeve having a handle portion extending along a longitudinal axis and a head portion extending along a rotation axis, the longitudinal axis and the rotation axis being arranged at an angle not equal to 0° with respect to each other, so that a processing tool for processing hard materials projects at an angle relative to the handle portion or the longitudinal axis of the dental contra-angle handpiece.

[0006] The dental contra-angle handpiece further comprises a collet chuck for holding a processing tool for processing hard materials, the collet chuck being rotatably mounted about a rotation axis of the head portion by means of first and second rolling bearings, and further comprises a coupling device in the handle portion for connecting the dental contra-angle handpiece with a feed device and / or a control device and / or a motor drive device.

[0007] The speed transmission ratio of the dental contra-angle handpiece according to the present invention is 1:4 ± 3%. For example, the maximum input speed (which of course depends on the drive motor of the dental contra-angle handpiece) is 40,000 U / min (40,000 rpm). The maximum output speed is 160,000 U / min (160,000 rpm). Thus, the transmission ratio of 1:4 ± 3% results in a lower maximum speed compared to other contra-angle handpieces for restorations and prosthetics, which reduces wear on the rotating parts of the dental contra-angle handpiece. This lower wear reduces the high load on the rotating parts of the dental contra-angle handpiece due to processing hard materials in the oral cavity, so that the transmission ratio of 1:4 ± 3% extends the service life of the dental contra-angle handpiece despite the high load when processing hard materials.

[0008] The collet chuck of the dental contra-angle handpiece according to the invention has a pull-out force of more than 35 N, preferably more than 36 N, according to ISO 14457:2017. Thus, the pull-out force is greater than other contra-angle handpieces for restorations and prostheses. A greater pull-out force means that the collet chuck holds the processing tool (rotary instrument) with greater force, i.e. the clamping force of the collet chuck is increased. The pull-out or clamping force is preferably about 20% greater than other contra-angle handpieces for restorations and prostheses. The greater pull-out or clamping force is, for example, due to an increase in at least some of the wall thickness of the collet chuck and / or due to an enlargement of the collet chuck, for example compared to other contra-angle handpieces for restorations and prostheses, and / or due to at least some specific geometric features of the collet chuck. The increased extraction or clamping force advantageously enables the collet chuck to securely hold the processing tool despite the high mechanical loads encountered when processing hard materials in the patient's mouth.

[0009] The first and second rolling bearings of the dental contra-angle handpiece according to the invention are preferably mounted in first and second bearing seats, which are provided in the same bearing body of the head part. This feature increases the mechanical stability of the dental contra-angle handpiece in particular and therefore allows it to better withstand the loads when processing hard materials in the patient's mouth compared to other contra-angle handpieces for restorations and prosthetics. The bearing body is preferably formed in one piece, for example as a bearing sleeve formed in the head part or by the inside of the head part in an outer sleeve. However, the bearing body can also be composed of several parts connected together to form and / or function as a single part.

[0010] Each of the above-mentioned individual features advantageously increases the suitability of the dental contra-angle handpiece according to the invention for processing hard materials, in particular zircon, in the patient's mouth. However, it is particularly advantageous to combine several or all of these features, which, in particular also by means of a synergistic effect, further increase the suitability of the dental contra-angle handpiece according to the invention for processing hard materials. For example, a transmission ratio of 1:4 ± 3% not only leads in itself to a smaller load on the drive train, but also reduces the load on the collet chuck, in addition to the adapted geometry or modified dimensions of the collet chuck described above. Likewise, it is advantageous for the collet chuck that the first and second bearing seats are provided in the same bearing body, because the pressing force exerted by the user on the hard material to be processed can be transferred from the collet chuck to the rolling bearing and the bearing body and absorbed by this bearing body, thereby reducing the load on the collet chuck.

[0011] Hereinafter, the present invention will be described based on a preferred embodiment with reference to the accompanying drawings. [Brief description of the drawings]

[0012] [Figure 1]FIG. 1 is a side view of a dental contra-angle handpiece for processing hard materials in a patient's mouth. [Diagram 2] FIG. 2 is a top view showing the dental contra-angle handpiece in FIG. 1. [Diagram 3] FIG. 1 is a partial cross-sectional view of a dental contra-angle handpiece for processing hard materials in a patient's mouth. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The dental contra-angle handpiece 1 shown in Figures 1 to 3 for processing hard materials, in particular zircon, in a patient's mouth has a handle portion 2A extending along a longitudinal axis 3 and a head portion 2B extending along a rotation axis 4 and comprises an outer sleeve 2 which delimits the dental contra-angle handpiece 1 from the surroundings. The longitudinal axis 3 and the rotation axis 4 are arranged at an angle unequal to 0° relative to each other, so that a processing tool (not shown) for processing hard materials projects at an angle relative to the handle portion 2A or the longitudinal axis 3 of the dental contra-angle handpiece.

[0014] The head part 2B is provided with a collet chuck 5 for holding a processing tool for processing hard materials. The collet chuck 5 is rotatably mounted on the head part 2B about a rotation axis 4 by means of first and second rolling bearings 6, 7, in particular ball bearings. The collet chuck 5 has a processing tool extraction or clamping force of more than 35 N according to ISO 14457:2017, which ensures a secure fixation of the processing tool even when processing hard materials in the patient's mouth.

[0015] The collet chuck 5 is preferably configured as a force-engaging or friction-engaging collet chuck having spring arms 17 formed resiliently relative to the rotation axis 4. The force-engaging collet chuck 5 is advantageously suitable for providing a clamping force sufficient to hold a processing tool when processing hard materials in a patient's mouth.

[0016] The collet chuck 5 further has a tool receiving opening 18 and a tool guide portion 5A. A processing tool can be inserted into and removed from the collet chuck 5 and the dental contra-angle handpiece 1 through the tool receiving opening 18. In the tool guide portion 5A, the shaft of the processing tool is supported radially with respect to the rotation axis 4, in particular when radial forces (with respect to the rotation axis 4) act on the processing tool when processing hard materials in the patient's mouth. The tool guide portion 5A preferably has an inner diameter of 1,6 mm, so that the shaft of the processing tool, when inserted in the collet chuck 5, contacts the inner wall or is at least separated from this inner wall by a minimal gap. The processing guide portion 5A in particular extends from the tool receiving opening 18 towards the spring arm 17 of the collet chuck 5 by a length of at least 4,5 mm, preferably at least 5,0 mm. The increased length of the tool guide portion 5A of at least 4.5 mm and inner diameter of 1.6 mm compared to other contra-angle handpieces for restorations and prosthetics ensures that the processing tool is reliably supported over a longer tool shaft portion when processing hard materials, thereby advantageously providing greater mechanical stability required when processing hard materials.

[0017] The tool guide portion 5A extends from the tool receiving opening 18 for a length of at least 4,5 mm, in particular to a portion 5B of the collet chuck 5 adjacent to the tool guide portion 5A, the inner diameter of which differs from 1,6 mm. The adjacent portion 5B of the collet chuck 5 comprises, for example, the clamping portion of the collet chuck 5 and / or the spring arm 17 of the collet chuck 5 and / or a portion of the collet chuck 5 having an inner diameter of more than 1,6 mm and / or a portion of the collet chuck having an inner diameter of less than 1,6 mm. The tool guide portion 5A is in particular arranged between the tool receiving opening 18 and the spring arm 17 of the collet chuck 5. The tool guide portion 5A is provided in particular in the region of the second rolling bearing 7, which is arranged closer to the tool receiving opening 18, so that the forces acting on the processing tool can advantageously be transmitted directly to the head portion 2B of the dental contra-angle handpiece 1 via the second rolling bearing.

[0018] Preferably, the collet chuck 5 has a length or overall length of at least 12 mm, including the wedge sleeve 19 for removing the processing tool from the collet chuck 5. The increased overall length of the collet chuck 5 of at least 12 mm and the internal diameter of 1.6 mm compared to other contra-angle handpieces for restorations and prosthetics advantageously provides a reliable support of the processing tool over a larger tool shaft portion when processing hard materials, thereby providing a greater mechanical stability required when processing hard materials.

[0019] The first and second rolling or ball bearings 6, 7, which rotatably support the collet chuck 5 in the head part 2B, are mounted in first and second bearing seats 10, 11, respectively, which are provided in the same bearing body 9 of the head part 2B. Due to both bearing seats 10, 11, and thus in particular both rolling bearings 6, 7, being provided in the same bearing body 9, the dental contra-angle handpiece 1 (compared to other contra-angle handpieces for restorations and prosthetics, in which the bearing seats are provided in two different bearing bodies) has a greater mechanical strength, which is necessary when processing hard materials in the patient's mouth.

[0020] The first and second bearing seats 10, 11 are formed by a surface 20 of the bearing body 9 which is substantially parallel to the axis of rotation 4. Advantageously, the bearing body 9 is formed by the head portion 2B of the outer sleeve 2 and / or the surface 20 is formed by the inside of the head portion 2B of the outer sleeve 2. Advantageously, therefore, no additional bearing body is required to form the bearing seats 10, 11 and / or to support the rolling bearings 6, 7. Alternatively, it is of course also possible to form the bearing body 9 with the bearing seats 10, 11 as a separate part, for example a bearing sleeve, which is arranged in the head portion 2B.

[0021] Preferably, the rolling bearings 6, 7 include substantially cylindrical outer rings having outer jacket or circumferential surfaces 21, 22. Preferably, the respective circumferential surfaces 21, 22 of the outer rings of the first and second rolling bearings 6, 7 are mounted in the first and second bearing seats 10, 11 such that they cannot rotate relative to each other.

[0022] Advantageously, at least the first and / or second rolling bearing 6, 7 has a ceramic component, in particular the first and / or second rolling bearing 6, 7 is made of a ceramic material.

[0023] Preferably, at least the first and / or second rolling bearing 6, 7 has at least 9 rolling elements, which is a higher number than other contra-angle handpieces for restorations and prosthetics. This advantageously distributes the forces acting on the processing tool and the dental contra-angle handpiece 1 when processing hard materials in the patient's mouth over a larger number of rolling elements, so that the rolling bearings 6, 7 and the dental contra-angle handpiece 1 are more robust and more suitable for processing hard materials in the patient's mouth. Preferably, the rolling elements have a diameter of about 1 mm.

[0024] Preferably, the first and / or second rolling bearing 6, 7 is configured as a shoulder bearing. A rolling bearing 6, 7 configured as a shoulder bearing is advantageously particularly suitable for absorbing forces acting on the processing tool and on the dental contra-angle handpiece 1 when processing hard materials in the patient's mouth.

[0025] At the end of the handle part 2A remote from the head part 2B, a coupling device 8 is provided for connecting the dental contra-angle handpiece 1 to a feed device and / or a control device and / or a drive device, in particular an electric motor. The drive device can be integrated into the outer sleeve 2 of the dental contra-angle handpiece 1 or can be removably connected to the dental contra-angle handpiece 1 as a separate part via the coupling device 8.

[0026] The handle portion 2A, in particular in the bending region of the handle portion 2A, is provided with an angular gearbox 12. In this case, the output shaft 26 carries a first gear or pinion 13 and the drive shaft 27 carries a second gear 16. The first and second gears 13, 16 mesh with each other to form the angular gearbox 12 configured as a first transmission gearbox. In or on the head portion 2B, a further angular gearbox 28 is provided. It comprises a third gear 29 provided on the output shaft 26 and a toothing 30 connected to the collet chuck 5, which mesh with each other to form the angular gearbox 28 configured as a second transmission gearbox. The angular gearbox 28 is thus configured to transmit the drive movement and torque to the collet chuck 5. The two angular gearboxes 12, 28 are configured and interact with each other such that, for example by their number of teeth, the dental contra-angle handpiece 1 has a transmission ratio of 1:4 ± 3%. This transmission ratio of 1:4 ± 3% has proven to be particularly suitable when processing hard materials in the patient's mouth with regard to the torque at which the hard materials are processed, the processing time of the hard materials as well as the wear on the parts which are particularly subjected to loads in the dental contra-angle handpiece 1.

[0027] Both shafts 26, 27 are rotatably mounted in bearing sleeves 15, 31 via rolling bearings. The bearing sleeves 15, 31 further advantageously have the function of protecting the gearboxes 12, 28 and the rolling bearings from the ingress of particles of the hard material to be processed. In order to allow the first output gear and the second drive gear to mesh with each other, despite being surrounded by the bearing sleeves 15, 31, the bearing sleeve 15, in which the second gear 16 is accommodated, is provided with an opening 14 through which the first gear 13 projects. For sealing purposes, the opening 14 is surrounded by a sealing element, for example an O-ring.

[0028] The head part 2B is preferably provided with a push button 23 for removing the processing tool from the collet chuck 5. The push button 23 is arranged at the end of the head part 2B opposite the tool receiving opening 18. The push button 23 is configured to be movable relative to the outer sleeve 2, in particular the head part 2B. The push button 23 is in particular displaceable in a known manner towards the tool receiving opening 18, whereby the wedge sleeve 19 is also displaced towards the tool receiving opening 18, so that the wedge-shaped extensions of the wedge sleeve 19 engage with the spring arms 17 of the clamping sleeve 5 and move them radially away from each other, so that the processing tool can be inserted into or removed from the clamping sleeve 5.

[0029] The push button 23 preferably has an outer diameter of at least 9.0 mm, which advantageously facilitates the operation of the push button 23, in particular with regard to the increase in the pulling force or clamping force of the clamping sleeve 5 mentioned above.

[0030] Preferably, the push button 23 has a marking for distinguishing the dental contra-angle handpiece 1 from other dental contra-angle handpieces, in particular other dental contra-angle handpieces for restorations and prosthetics. Preferably, the marking of the push button 23 comprises a color and / or an alphanumeric marking or symbol. Particularly preferably, the push button 23 is provided with a color marking or circular area, for example in black (see FIG. 2). Dental contra-angle handpieces usually have a plastic colored ring at the end near the coupling device 8 for differentiation. Providing the push button 23 with a marking makes it easier and safer to recognize and differentiate the dental contra-angle handpiece 1 for processing hard materials in the patient's mouth, which advantageously further reduces the possibility of misusing the dental contra-angle handpiece 1 for processing hard materials.

[0031] Preferably, the dental contra-angle handpiece 1 comprises up to three openings 24 arranged around the tool holder opening 18 for discharging coolant, in particular an air-water spray. This feature also advantageously increases the robustness of the dental contra-angle handpiece 1 compared to other restorative and prosthetic contra-angle handpieces having more than three coolant discharge openings 24.

[0032] A light emitting device 25 for irradiating the treatment tool and / or the treatment site is preferably provided on the dental contra-angle handpiece 1, in particular on the head part 2B or adjacent to the head part 2B, which advantageously improves the user's view of the hard material to be treated. The light emitting device 25 comprises, for example, a light guide made of glass or plastic and / or a light source, in particular a light emitting diode (LED).

[0033] The described or illustrated embodiments serve to particularly illustrate the invention, and therefore features disclosed in one embodiment are not limited to this embodiment but can be combined individually or together with one or more features of other embodiments.

Claims

1. A dental contra-angle handpiece (1) for processing hard materials in a patient's mouth, comprising: an outer sleeve (2) having a handle portion (2A) extending along a longitudinal axis (3) and a head portion (2B) extending along a rotation axis (4) and surrounding the dental contra-angle handpiece (1), the longitudinal axis (3) and the rotation axis (4) being disposed at an angle not equal to 0° with respect to each other; a collet chuck (5) for holding a processing tool for processing hard materials, the processing tool being rotatably mounted in the head portion (2B) about the axis of rotation (4) by means of first and second rolling bearings (6, 7); a coupling device (8) in the handle portion (2A) for connecting the dental contra-angle handpiece (1) to a delivery device and / or a control device; A dental contra-angle handpiece comprising:

1. A dental contra-angle handpiece, comprising: a speed transmission ratio of the dental contra-angle handpiece (1) of 1:4 ± 3%; and a collet chuck (5) having a pull-out force of more than 35 N according to ISO 14457:2017.

2. 2. The dental contra-angle handpiece (1) according to claim 1, characterized in that the first and second rolling bearings (6, 7) are mounted in first and second bearing seats (10, 11), respectively, and the first and second bearing seats (10, 11) are provided in the same bearing body (9) in the head portion (2B).

3. 2. The dental contra-angle handpiece (1) according to claim 1, characterized in that it is provided with an angle gearbox (12) arranged in the handle portion (2A).

4. 4. The dental contra-angle handpiece according to claim 3, characterized in that the first gear (13) of the angle gearbox (12) protrudes into an opening (14) of a bearing sleeve (15) in which the second gear (16) of the angle gearbox (12) is disposed, thereby allowing the first gear (13) and the second gear (16) to mesh with each other.

5. 2. The dental contra-angle handpiece according to claim 1, wherein the collet chuck is configured as a force-engaging collet chuck having a number of spring arms that are elastically configured with respect to the rotation axis.

6. 6. The dental contra-angle handpiece according to claim 5, wherein the collet chuck (5) has a tool receiving opening (18) and a tool guide portion (5A), a processing tool is insertable into and removable from the dental contra-angle handpiece (1) through the tool receiving opening (18), a shaft of the processing tool is supported in the tool guide portion (5A) radially relative to the rotation axis (4), and the tool guide portion (5A) has an inner diameter of 1.6 mm and extends from the tool receiving opening (18) towards the spring arm (17) of the collet chuck (5) by a length of at least 4.5 mm.

7. 7. The dental contra-angle handpiece (1) according to claim 6, characterized in that the tool guide portion (5A) extends to a portion (5B) of the collet chuck (5) adjacent to the tool guide portion (5A), and the inner diameter of the portion (5B) is different from 1.6 mm.

8. 2. The dental contra-angle handpiece (1) according to claim 1, characterized in that the collet chuck (5) has a length of at least 12 mm including a wedge sleeve (19) for removing the processing tool from the collet chuck (5).

9. 3. The dental contra-angle handpiece (1) according to claim 2, characterized in that the first and second bearing seats (10, 11) are formed by a surface (20) of the bearing body (9) that is substantially parallel to the rotation axis (4).

10. 3. The dental contra-angle handpiece (1) according to claim 2, characterized in that the bearing body (9) is formed by the inside of the head part (2B).

11. 3. The dental contra-angle handpiece according to claim 2, wherein the first and second rolling bearings have outer rings with circumferential surfaces mounted on the first and second bearing seats.

12. 3. The dental contra-angle handpiece (1) according to claim 2, characterized in that at least the first or the second rolling bearing (6, 7) has at least nine rolling elements.

13. 3. The dental contra-angle handpiece (1) according to claim 2, characterized in that at least the first or the second rolling bearing (6, 7) is configured as a shoulder bearing.

14. 2. The dental contra-angle handpiece (1) according to claim 1, characterized in that a push button (23) is provided on the head part (2B) for removing the processing tool from the collet chuck (5), the push button (23) having an outer diameter of at least 9.0 mm.

15. 15. The dental contra-angle handpiece (1) according to claim 14, characterized in that the push button (23) has a marking to distinguish it from the dental contra-angle handpiece (1).

16. 2. The dental contra-angle handpiece (1) according to claim 1, characterized in that up to three openings (24) arranged around the tool receiving opening (18) are provided for the discharge of coolant.

17. A dental contra-angle handpiece (1) according to claim 1, A dental contra-angle handpiece, characterized in that a light-emitting device (25) for irradiating light to the treatment tool and / or treatment site is provided on the head portion (2B) or adjacent to the head portion (2B).

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