Dental screws and dental fixation devices

Abstract

This disclosure provides dental screws for fastening dental components together. [Solution] A dental fixation set comprising a dental screw 10 and a dental fixation device, wherein the dental screw and the dental fixation device each include a torque limiting portion, and the torque limiting portion of the dental screw is configured to withstand a maximum torque higher than the maximum torque that can be transmitted by the torque limiting portion of the dental fixation device.

Description

Technical Field

[0001] The present invention relates to dental screws, dental fixtures, dental fixation sets, and dental restoration support sets.

Background Art

[0002] Dental restorations fixed in a patient's mouth using dental implants have proven to be a very successful solution for replacing one or more teeth. Nowadays, there are many techniques for dental treatment that enable the cosmetic integration of dental restorations into the patient's dentition. Furthermore, from a functional perspective, these dental restorations are basically the same as the one or more natural teeth they replace, so patients do not experience significant changes compared to healthy natural teeth.

[0003] In order to be able to provide such solutions for dental restorations to patients in a customized and economical way, dental restorations generally have a modular design. Therefore, these dental restorations are adapted to individual patients by selecting a combination of dental components that will bring about the desired results for replacement. The combination of dental components may simply be a dental implant directly connected to an artificial tooth. More generally, it is a combination of an abutment, a dental implant, and an artificial tooth, and the abutment is arranged between the dental implant and the artificial tooth. Such abutments can be used as one-piece abutments and multi-piece abutments. Further components that may be present in dental restorations are bridge elements, caps, etc.

[0004] One of the most common methods for assembling combinations of dental components is the use of dental screws. Dental screws allow for both the assembly and disassembly of dental restorations. This is particularly advantageous when fitting dental restorations in a dental laboratory or in the dental chair. Furthermore, using screws makes it much easier to modify at least some parts of the dental restoration than, for example, using dental cement to connect these components. Such dental screws are proposed in WO2018 / 091515A1, WO2017 / 070335A1, and US8,029,282B2.

[0005] However, as the number of components increases, smaller dental screws are needed to optimize the fit of the dental restoration. Smaller dental screws also offer greater flexibility in areas of the dentition where space is quite limited, such as the front teeth.

[0006] These dental screws are used to assemble and secure dental components together, and chewing forces are primarily transmitted through these dental components. Therefore, the main function of dental screws is to attach and maintain the assembly. Furthermore, the smaller the dental screw, the more materials can be designed into the dental component to increase its strength to withstand chewing forces. [Overview of the project]

[0007] Considering the above, one of the objectives of this disclosure was to provide a design for dental screws that would allow for further size reduction. However, the smaller the screw, the more difficult it is to handle. Consequently, another objective of this disclosure was to improve the handling of such small dental screws. Furthermore, these smaller dental screws are less susceptible to the risk of damage to the screw or dental components, particularly when transmitting torque during tightening. Therefore, improving the transmission of torque between fixtures, screws, and / or dental components became yet another objective of this disclosure. The inventors also had in mind the cost-effective manufacture of these dental screws, drivers, and dental components.

[0008] To address these objectives, the Disclosure provides a dental screw for fastening dental components together. The dental screw has a proximal end, a distal end, and a longitudinal axis. The dental screw further includes a screw head at the proximal end, which includes an instrument engagement interface for engaging a fixation instrument, and a screw shank distal to the screw head. The screw shank comprises a torque limiting portion and a threaded portion distal to the torque limiting portion for engaging with a dental component. The dental screw is configured to transmit a minimum torque of 26 Ncm, and the torque limiting portion is configured to limit the transmittable torque to a predetermined maximum torque, particularly under maximum tensile and / or shear stresses, in order to prevent damage to the threaded portion. Specifically, the present invention provides the following configurations [1] to

[20] . [1] A dental screw (10) for fixing dental components (1, 2) together, wherein the dental screw (10) has a proximal end (11), a distal end (12), and a longitudinal axis (LS), and further includes a screw head (13) at the proximal end, which includes an instrument engagement interface (20) for engaging a fixing instrument (30), and further includes a screw shank (14) distal to the screw head (13), the screw shank (14) including a torque limiting portion (15), and a threaded portion (16) distal to the torque limiting portion (15) for engaging with the dental components (1, 2), the dental screw (10) is configured to transmit a minimum torque of 26 Ncm, and the torque limiting portion is configured to limit the transmittable torque to a maximum torque in order to prevent damage to the threaded portion. [2] The dental screw (10) according to [1], wherein the torque limiting portion (15) has the minimum section modulus along the screw shank. [3] A dental screw (10) according to [1] or [2], wherein the maximum torque that can be transmitted in the torque limiting portion (15) is 38 Ncm, 36 Ncm, 34 Ncm, or 32 Ncm. [4] A dental screw (10) according to any one of [1] to [3], wherein the torque limiting portion (15) is configured to withstand a maximum tensile force in the range of 300 N to 500 N, preferably in the range of 350 N to 450 N. [5] A dental screw (10) according to any one of [1] to [4], wherein the instrument engagement interface (20) includes a torque transmission zone (25b) having a cross section perpendicular to the longitudinal axis (LS) including a profile of four or five convex and / or flat sections (21) alternating with four or five concave sections (22). [6] The dental screw (10) according to [5], wherein the convex section (21) and the concave section (22) form longitudinal engagement projections (24) extending radially toward the longitudinal axis (LS) from a circle having a maximum inner diameter (26), and the longitudinal engagement projections (24) preferably have chamfers (27) at their proximal ends. [7] The dental screw (10) according to any one of [1] to [6], wherein the instrument engagement interface (20) includes a pickup zone (25a) that tapers toward the distal end (12) of the dental screw, preferably the pickup zone (25a) is located adjacent to the torque transmission zone (25b), proximal to the torque transmission zone (25b), and / or at least partially along the torque transmission zone (25b). [8] The instrument engagement interface (20) further includes a verification zone (25c) for verifying the type of dental screw (10), the verification zone (25c) preferably located at the distal end of the instrument engagement interface, the dental screw (10) as described in any one of [1] to [7]. [9] A dental fixation device (30) having a proximal end (31), a distal end (32), and a longitudinal axis (LT), wherein the dental fixation device (30) comprises a screw engagement interface (40) at the distal end for engaging a dental screw (10), in particular a dental screw as described in any one of [1] to [8], and comprises a torque limiting portion (35) proximal to the screw engagement interface, the torque limiting portion being configured to limit the transmittable torque to a maximum torque in order to prevent damage to the screw engagement interface.

[10] The torque limiting portion (35) is configured to withstand a maximum torque of 35 Ncm or less, preferably in the range of 27.5 Ncm to 34 Ncm, more preferably in the range of 28 Ncm to 33 Ncm, as described in [9], the dental fixation device.

[11] The screw engagement interface (40) includes a torque transmission zone (45b) having a cross section perpendicular to the longitudinal axis (LT), which includes four or five convex and / or flat sections (41) alternating with four or five concave sections (42), The convex and / or flat sections (21) and the concave section (22) form an engagement structure (44) along the longitudinal axis (LT) of the dental fixation device (30) according to [9] or

[10] , wherein the engagement structure (44) preferably has a curved profile in cross-section along the longitudinal axis (LT).

[12] The dental fixture (30) described in

[11] , wherein the convex and / or flat section (41) and the concave section (42) are connected at a transition point (43), and at each transition point, the angle α between the tangent to the profile of the concave section and the tangent to the convex or flat section is in the range of 90° to 180° or 90° to 160°, preferably in the range of 95° to 150°.

[13] The screw engagement interface (40) includes a pickup zone (45a) for holding a dental screw (10), wherein the pickup zone (45a) is preferably adjacent to and proximal to the torque transmission zone (45b) and / or at least partially along the torque transmission zone (45b) of the dental fixation device (30) according to any one of [9] to

[12] .

[14] The screw engagement interface (40) further includes a verification zone (45c) for verifying the type of dental screw (10) when engaging the dental screw, wherein the verification zone (45c) is preferably located at the distal end of the instrument engagement interface, as described in any one of [9] to

[13] .

[15] A dental fixation set comprising a dental screw (10), in particular a dental screw (10) as described in any one of [1] to [8], and a dental fixation device (30), in particular a dental fixation device (30) as described in any one of [9] to

[14] , A dental fixation set comprising a dental screw and a dental fixation device, each including torque limiting portions (15, 35), wherein the torque limiting portion (15) of the dental screw is configured to withstand a maximum torque higher than the maximum torque that can be transmitted by the torque limiting portion (35) of the dental fixation device.

[16] The dental screw (10) includes an instrument engagement interface (20), the instrument engagement interface (20) includes a torque transmission zone (25b) having a cross section which includes convex and / or flat sections (21) alternating with concave sections (22), The dental fixation device (30) includes a screw engagement interface (40), the screw engagement interface (40) includes a torque transmission zone (45b) which includes convex and / or flat sections (41) alternating with concave sections (42), The dental fixation set according to

[15] , wherein, in the engaged state of a dental screw and a dental fixation device for transmitting torque, at least intermediate sections of each of the convex and / or flat sections of the dental screw face the profile of the concave section (22) of the device engagement interface (20) at a certain distance.

[17] A dental fixation set according to

[15] or

[16] , wherein the torque transmission zone (25b) of the dental screw (10) and the torque transmission zone (45b) of the dental fixation device (30) have rotational play, particularly in the range of 1° to 3.5°, preferably 1.5° to 3°, when engaged with each other.

[18] A dental fixation set according to any one of

[15] to

[17] , comprising a dental screw (10) and a dental fixation device (30), each having pickup zones (25a, 45a) configured to engage with each other by friction.

[19] A dental fixation set according to any one of

[15] to

[18] , wherein the dental screw (10) and the dental fixation device (30) each have verification zones (25c, 45c) configured to allow engagement of the torque transmission zone (45b) of the dental fixation device (30) and the torque transmission zone (25b) of the dental screw (10) when the dental fixation set is fully engaged. A dental restorative support set comprising a dental screw and dental components (1;2) as described in any one of paragraphs

[20] [1] to [8], wherein the dental components are, in particular, a dental implant (3), an abutment (2), and / or an artificial tooth.

[0009] A torque limiting section implemented as part of the screw shank will break the screw shank if the torque exceeds the maximum torque, particularly the maximum tensile and / or shear stress. In other words, the material of the dental screw in the torque limiting section cannot withstand the shear force caused by the torque applied through the instrument engagement interface, exceeding the maximum torque. However, dental screws are configured to transmit a minimum torque of 26 Ncm to ensure that dental components are securely fastened together.

[0010] As a result, the torque limiting portion prevents damage to the threaded portion of the dental screw, as well as to the threaded portion of the dental component with which the dental screw is engaged. For example, the dental component could be a dental implant, and the torque limiting portion prevents the dental screw from damaging the implant. Consequently, this configuration of the dental screw also benefits the patient by preventing the implant from being modified due to such damage.

[0011] Generally, dental screws engage with a first dental component in a threaded manner to secure a second dental component to the first dental component. Due to predetermined breakage of the dental screw at the torque limiting portion, the second dental component to which the dental screw is intended to secure can be easily removed. Furthermore, the section of the shank that remains engaged with the first dental component after breakage can also be easily removed using an instrument such as pliers. As a result, the first dental component remains intact and does not need to be replaced. In fact, the only part that needs to be replaced is the dental screw itself.

[0012] The torque limiting portion is preferably located adjacent to (partially) the screw head so that, after the torque limiting portion fails, the majority of the shank that engages with the dental component remains within the dental component into which the dental screw engaged before the failure. This facilitates the easy removal of the remaining shank of the dental screw from this dental component. In other words, the torque limiting portion is preferably located in the crown (proximal) portion of the screw.

[0013] Because a torque limiting section exists, it is possible to further reduce the size of the dental screw without risking breakage of the dental screw in sections that could damage dental components.

[0014] To weaken the dental screw at the torque limiting portion, the torque limiting portion may be designed to have the minimum section modulus along the shank.

[0015] Therefore, the cross-section of the torque-limiting portion is designed to minimize resistance to torque, and thus, if a torque exceeding the maximum torque it is designed to transmit is applied, it will break first. In other words, the section modulus of the torque-limiting portion is smaller than that of the rest of the shank, including the threaded portion. The section modulus is also preferably smaller than that of any cross-section of the screw head designed to transmit torque applied through the tool engagement interface.

[0016] Alternatively or additionally, the torque limiting portion may include at least one notch for initiating breakage, may be made of different materials, and / or may have different material properties.

[0017] Preferably, the maximum torque that can be transmitted through the torque limiting section is 38 Ncm, 36 Ncm, 34 Ncm, or 32 Ncm. Applying torque exceeding the torque value selected for the design of the dental screw will cause the torque limiting section to break, and therefore the dental screw to break.

[0018] Furthermore, the torque limiting portion can be configured to withstand a maximum tensile force in the range of 300 N to 500 N, preferably in the range of 350 N to 450 N.

[0019] When torque is applied, a tensile force acts along the screw shank between the head of the screw and the threaded portion, i.e., similarly along the torque limiting portion. If the maximum tensile force beyond which the dental screw is designed is exceeded, especially while torque is being applied, the screw shank ruptures at the torque limiting portion, and thus the dental screw is configured to break.

[0020] The instrument engagement interface can include a torque transmission zone having a cross-section perpendicular to the longitudinal axis of the dental screw, including profiles of four or five convex and / or flat sections alternating with four or five concave sections, respectively.

[0021] These concave and convex sections form a wavy profile around the longitudinal axis of the dental screw. As a result, the transmission of torque through the instrument engagement interface is enhanced. This is mainly caused by the torque transmitted across a more radially extended contact surface between the corresponding dental fixture and the dental screw. Furthermore, no force needs to be applied in the direction of the longitudinal axis of the dental screw to keep the dental fixture and the dental screw engaged during the application of torque to fix the dental screw to the dental component.

[0022] Furthermore, having four or five convex and / or flat sections alternating with four or five concave sections enables the design of a small screw head with a wall thickness sufficient to transmit a predetermined torque, while at the same time enabling a compact design of the screw. Also, a driver with a small diameter can be used. The greater the number of sections, the larger the driver needs to be, resulting in a larger screw head size and / or a thinner wall that weakens the screw. The tool engagement interface is preferably formed as a recess.

[0023] As found, a large number of concave sections and convex and / or flat sections mainly weakens the screw head, while a small number of concave and convex / flat sections shows detrimental effects related to torque transmission.

[0024] Preferably, the convex and / or flat sections and the concave sections are connected or joined at the transition points, and at each transition point, the angle between the tangent to the profile of the concave section and the tangent to the convex section is in the range of 90° to 180° or 90° to 160°, preferably in the range of 95° to 150°.

[0025] Implementing the angle of the transition point for the design of the dental screw within the above range has been shown to result in smooth and efficient torque transmission.

[0026] The transition points between the alternating concave sections and the convex and / or flat sections can be points along the profile of the tool engagement interface, where two alternating sections transition continuously or smoothly from one to the other. In this case, the transition point represents a point where the curvature changes sign with a continuous change in slope. As a result, the tangent to this transition point has the same slope if it is based on the adjacent concave section or the adjacent convex and / or flat section.

[0027] Alternatively, a transition point can also be a point where alternating sections transition from one to the other in a discontinuous manner. In this case, the curvature changes sign or direction due to the abrupt change in gradient. As a result, the tangent at this transition point derived based on an adjacent convex section will have a different gradient compared to the tangent at this transition point derived based on an adjacent concave and / or flat section.

[0028] The convex and / or flat sections and the concave sections may form longitudinal engaging projections that extend radially toward the longitudinal axis from a circle having the maximum inner diameter. The engaging projections preferably have chamfers at their proximal ends.

[0029] These longitudinal engaging projections are configured to engage with a retaining device and receive torque from this device. In other words, they form at least part of the torque transmission zone. If a chamfer is present at the proximal end of the engaging projection, it is easier for the dental professional to engage the retaining device with the dental screw. More specifically, a chamfer preferably located at the entrance of the device engagement interface guides the retaining device into engagement.

[0030] The instrument engagement interface may include a pickup zone that tapers from the proximal to the distal end of the dental screw. Preferably, the pickup zone is located adjacent to the torque transmission zone, proximal to the torque transmission zone, and / or at least partially along the torque transmission zone.

[0031] The tapering of the pickup zone allows the dental screw to be held in place by frictional force in the dental retainer. In other words, the dental retainer can be inserted into the pickup zone. Sufficient pressure is then applied to push the dental retainer into the pickup zone. This establishes a friction mat that can be easily reversed. For this reversible friction mat, the tapering angle is preferably selected in the range of 5° to 12°, particularly 6° to 9°, or substantially 7°. Alternatively, it may be in the range of 10° to 12°, or substantially 11°.

[0032] In particular, if the pickup zone extends at least partially along the torque transmission zone, i.e., if the torque transmission zone and the pickup zone at least partially overlap or are identical, the tapered configuration offers the advantage of continuously efficient torque transmission in the presence of wear. More specifically, if the instrument engagement interface of a dental fixation device and / or dental screw is prone to wear, the dental fixation device is simply inserted further into the tapered torque transmission zone. Thus, since the structure in which torque is transmitted remains essentially the same even when wear occurs, the torque transmission is essentially unchanged.

[0033] On the one hand, if the torque transmission zone and the pickup zone overlap at least partially, this allows for a more compact design of the screw head and the fixture along their longitudinal axis. On the other hand, if the pickup zone and the torque transmission zone do not overlap, wear may be reduced, and the functional and spatial separation of the two zones may allow for a more precise fit of the dental screw and fixture.

[0034] The instrument engagement interface may further include a verification zone for verifying the type of dental screw. The verification zone is preferably located at the distal end of the instrument engagement interface.

[0035] Based on the verification zone, dental professionals are positioned to verify whether a dental screw is suitable for use with a dental fixation device or dental component. For example, if a dental professional cannot fully insert the fixation device and / or engage the device engagement interface, this indicates that an unsuitable screw or dental component has been selected for assembly. As a result, such verification zones prevent damage to dental components or dental screws when their components do not complement each other.

[0036] As an alternative to or addition to the verification zone, a suitable combination of dental components and dental screws can also be ensured by constituting these two dental components, which can only be assembled with a dental screw that is correctly positioned and oriented. This is described in particular in relation to Figure 5 of the international application also filed by the present applicant under the number PCT / EP2018 / 071797, which is incorporated herein by reference.

[0037] Furthermore, this disclosure provides a dental fixation device. The dental fixation device has a proximal end, a distal end, and a longitudinal axis. The dental fixation device includes a screw engagement interface at the distal end for engaging a dental screw, in particular the aforementioned dental screw, and has a torque limiting portion proximal to the screw engagement interface. The torque limiting portion is configured to limit the transmittable torque to a maximum torque in order to prevent damage to the screw engagement interface.

[0038] The advantages of dental fixation devices that include torque limiting sections are similar to those achieved with torque limiting sections integrated into dental screws. More specifically, the torque limiting section is configured to break if the torque transmitted by the dental fixation device exceeds a predefined maximum torque. This breakage prevents damage to the dental screw. After the breakage, the parts of the dental fixation device separated by the torque limiting section can be easily removed, allowing another dental fixation device to be used to finish the assembly or to remove the dental screw to, for example, investigate the cause of the breakage. In either case, the torque limiting section of the dental fixation device prevents damage from occurring at the level of dental components such as dental implants and abutments.

[0039] As already discussed above, the torque limiting portion also allows for smaller designs of dental screws. Safety factors typically included to prevent damage or breakage of the dental screw, or any dental component engaged with or secured to the dental screw, can be reduced. Instead of attempting to prevent any damage, damage is controlled by a predetermined breakage of the dental screw. In other words, the safety provided by the safety margin is replaced, at least in part, by a safety mechanism of controlled breakage.

[0040] The torque limiting section can be configured to withstand a maximum torque of 35 Ncm or less, preferably in the range of 27.5 Ncm to 34 Ncm, and more preferably in the range of 28 Ncm to 33 Ncm.

[0041] Higher values ​​in these ranges, such as 30-34 Ncm, are preferably used for dental fixation devices that can transmit torque while the longitudinal axis of the dental fixation device and the longitudinal axis of the dental screw are inclined relative to each other. Lower values ​​in these ranges, such as 27.5-29 Ncm, are sufficient for dental fixation devices that do not allow such inclination during torque transmission.

[0042] The screw engagement interface may include a torque transmission zone having a cross-section perpendicular to the longitudinal axis, which includes four or five convex and / or flat sections alternating with four or five concave sections. The convex and / or flat sections and the concave sections form an engagement structure around the longitudinal axis along the dental fixture.

[0043] The advantages of such a configuration of torque transmission zones have already been discussed in relation to the corresponding zones of dental screws. Regarding dental fixation devices, it should be noted that using five convex and / or flat sections alternating with five concave sections is particularly advantageous if the dental fixation device is designed to transmit torque even in the aforementioned angular relationship with the dental screw.

[0044] A dental fixation device that enables angled torque transmission between the longitudinal axis of the dental fixation device and the longitudinal axis of a dental screw preferably has a curved profile in a cross section (longitudinal section) along the longitudinal axis.

[0045] The curved profile preferably extends across the angle in this longitudinal cross-section, and torque is transmitted between the dental fixture and the dental screw while the relative angle between their longitudinal axes is in the range of 0° to 25°. As a result, the curved profile may extend over a range of at least 25°.

[0046] The concave section preferably has a curved profile in a cross section perpendicular to the longitudinal axis of the dental fixture. Furthermore, the convex section may have a curved profile, particularly a circular profile, or may include a profile that is both curved and straight (linear). This corresponds to the convex and flat sections along the circumference of the screw engagement interface. As mentioned above, it is also possible to use a flat section instead of a convex section. Those skilled in the art will understand that a flat section is represented by a straight line in the cross section of the fixture perpendicular to the longitudinal axis.

[0047] Preferably, the convex and / or flat sections and the concave sections are connected or merged at a transition point, and at each transition point, the angle between the tangent to the profile of the concave section and the tangent to the convex section is in the range of 90° to 180° or 90° to 160°, preferably in the range of 95° to 150°.

[0048] Similar to dental screws, implementing transition point angles for the design of dental fixation devices within the above range has been shown to result in smooth and efficient torque transmission.

[0049] Angle ranges from 90° to 110°, and especially lower angles in the range of 96° to 104°, particularly enhance torque transmission between the instrument engagement interface of a dental screw and the screw engagement interface of a dental fixation device.

[0050] Angle ranges from 130° to 180°, and especially larger angles in the range of 142° to 148°, can be advantageously combined with more of the aforementioned concave sections and convex and / or flat sections, particularly five of each. These angle ranges result in efficient torque transmission. They further enable the configuration of a screw engagement interface that can transmit torque while the longitudinal axis of the tool and the longitudinal axis of the screw are not aligned, i.e., tilted relative to each other.

[0051] The angle at the transition point of the dental screw profile preferably substantially matches the angle at the transition point of the dental fixation device.

[0052] The transition points between alternating concave sections and convex and / or flat sections may be points along the profile of the screw engagement interface, where the two alternating sections transition continuously or smoothly from one to the other. In this case, the transition point represents a point where the curvature changes sign with a continuous change in gradient. As a result, the tangents at these transition points have the same gradient, if based on adjacent concave sections or adjacent convex and / or flat sections.

[0053] Alternatively, a transition point can also be a point where alternating sections transition from one to the other in a discontinuous manner. In this case, the curvature changes sign or direction due to the abrupt change in gradient. As a result, the tangent at this transition point derived based on an adjacent convex section will have a different gradient compared to the tangent at this transition point derived based on an adjacent concave and / or flat section.

[0054] The screw engagement interface may include a pickup zone for holding a dental screw, which is preferably located adjacent to, proximal to, and / or at least partially along with the torque transmission zone.

[0055] The presence of a pickup zone facilitates the handling of dental screws, as they can be handled while attached to dental fixtures. This is also advantageous because it prevents contamination of the dental screws during handling.

[0056] The pickup zone may have a conical shape, especially if it only needs to transmit torque while the longitudinal axes of the dental screw and the dental fixation device are aligned with each other.

[0057] Alternatively, the pickup zone may also have a curved profile in its longitudinal section, as described above in relation to the curved torque transmission zone of the dental fixture. Such a pickup zone may also function, at least partially, as a torque transmission zone.

[0058] In any case, the pickup zone could interact with a dental screw having a tapered instrument engagement interface to establish pickup and retention functions, for example, through friction.

[0059] The screw engagement interface may further include a verification zone for verifying the type of dental screw when engaging the dental screw. The verification zone is preferably located at the distal end of the instrument engagement interface.

[0060] As explained above in relation to dental screws, the verification zone is intended to verify the proper use of dental fixation devices. For example, this includes cases where a dental fixation device is used in conjunction with a corresponding dental screw. Therefore, it is possible to prevent unintended use of dental fixation devices.

[0061] Furthermore, this disclosure provides a dental fixation set, which includes a dental screw, in particular a dental screw having one of the configurations described above. The dental fixation set also includes a dental fixation device, in particular a dental fixation device configured as described above. The dental screw and the dental fixation device each include a torque limiting portion, the torque limiting portion of the dental screw being configured to withstand a maximum torque higher than the maximum torque that can be transmitted by the torque limiting portion of the dental fixation device.

[0062] To transmit torque, dental fixation devices and dental screws correspond to each other. More specifically, the instrument engagement interface of the screw and the screw engagement interface of the dental fixation device correspond to each other.

[0063] The aforementioned relationship between the torque limiting portion of the dental fixation device and the torque limiting portion of the dental screw ensures that breakage of the dental screw and dental fixation device during use first occurs on the side of the fixation device. As a result, damage to the dental screw or dental component is prevented. Designing the fixation set so that breakage occurs away from the dental component that is meshing with the dental screw (such as a dental implant) makes it easier to replace any of these dental components, dental screws, or dental devices.

[0064] The dental screw of a dental fixation set may include an instrument engagement interface, in which case the instrument engagement interface includes a torque transmission zone having a cross-section that includes convex and / or flat sections alternating with concave sections, the convex and concave sections preferably having a curved profile. To transmit torque, in the engaged state of the dental screw and dental fixation instrument, at least the intermediate sections of each convex and / or flat section of the dental screw face the profile of the concave section of the instrument engagement interface at a certain distance.

[0065] Due to this distance, the convex and / or flat sections of the dental retainer do not engage with the dental screw. This prevents the transmission of torque from the dental retainer to the dental screw, which is otherwise rather inefficient. Torque transmission can also cause increased wear due to the orientation of the contact surfaces, which negatively affects torque transmission, as will be explained in more detail below. In other words, in such a configuration, torque transmission occurs primarily at the transition point between the concave and convex and / or flat sections of the screw engagement interface of the dental retainer and the instrument engagement interface of the dental screw.

[0066] This configuration also reduces wear on the convex and / or flat sections of the dental fixation device. Wear can be further reduced by using steel as the material for the dental fixation device, and preferably titanium or a titanium alloy as the material for the dental screw.

[0067] The torque transmission zones of dental screws and dental fixation devices have rotational play, particularly in the range of 1° to 3.5°, preferably 1.5° to 3°, when engaged with each other.

[0068] In other words, the cross-sectional profiles of the torque transmission zones of the dental screw and the dental retainer correspond to each other, but do not necessarily have to perfectly match, so they are configured to have such rotational play. This rotational play serves as tactile feedback to the dental professional in determining the start of torque transmission. In particular, the dental professional can easily notice when contact is established between the profiles of the dental retainer and the dental screw during rotation, and thus torque transmission begins. Rotational play also facilitates the insertion of the dental retainer. This is especially true when the dental retainer is configured to allow (only) torque transmission when the longitudinal axis of the dental retainer and the longitudinal axis of the dental screw are aligned with each other.

[0069] Dental screws and dental fixation devices may further include pickup zones configured to engage with each other by friction. As already described above, such pickup zones facilitate the handling of dental screws and prevent contamination, especially since dental professionals do not need to directly grasp the dental screws.

[0070] Dental screws and dental fixation devices may each further include a verification zone configured to enable engagement of the torque transmission zone of the dental fixation device and the torque transmission zone of the dental screw when the dental fixation set is fully engaged.

[0071] In other words, torque transmission is only truly effective when the validation zones of the dental screw and dental fixator are fully engaged. Without full engagement, torque transmission is at least barely achievable, and preferably impossible. As described above, this prevents damage to dental fixators, dental screws, and dental components that are not intended for use in combination.

[0072] Furthermore, the present disclosure provides a dental restorative support set comprising a dental screw, in particular a dental screw having the above configuration, and a dental component, wherein the dental component is in particular a dental implant, an abutment, and / or an artificial tooth.

[0073] This combination allows for a smaller dental screw design, which increases the strength of the dental restorative support set and / or enables a smaller size of the dental restorative support set.

[0074] A dental screw may include a support surface. The support surface may be inclined with respect to the longitudinal axis of the dental component. Thus, the dental component includes a screw seat. The screw seat can be inclined at an angle with respect to the longitudinal axis of the dental screw, and as a result, at least in the pre-fixed state, contact between the support surface of the dental screw and the screw seat is generally established by line contact. While the screw seat and the support surface are in contact, the longitudinal axis of the screw seat is aligned with the longitudinal axis of the support surface.

[0075] The angular relationship between the support surface of a dental screw and the screw seat of a dental component, which results in line contact between the support surface and the screw seat at least initially, has the advantage that this contact is more predictable than surface contact, leading to better predictability of the fastening process. As a result, it helps to predetermine the flow of forces within the screw, and therefore improves the predictability of failure. Line contact is preferably located on or near the outer diameter of the screw head.

[0076] When fixed, the angular gap between the support surface of the dental screw and the screw seat of the dental component can be closed at least partially. As a result, the increase in torque at the end of fixation is suppressed. Dental professionals can more easily predict the end of fixation. Consequently, the likelihood of damage to the dental screw, dental fixation device, or dental component is reduced.

[0077] Preferably, both the screw sheet and the support surface are formed as surfaces with a conical angle.

[0078] A dental screw includes a threaded portion, and a dental component includes a threaded hole. In a fixed state, the threaded flanks of the threaded portion and the threaded flank of the threaded hole, which are in contact with each other, are in contact along at least 70% of the radial length of the profile.

[0079] In other words, when we look at the contact between the two flanks of the threads of a dental screw and the dental component in the longitudinal cross-sectional profile of a fixed screw, the two thread profiles are in contact with each other along at least 70% of their respective lengths. More specifically, the proximal flank of the threaded portion of the dental screw is in contact with the distal flank of the threaded hole of the dental component along at least 70% of its respective length along the threaded flank, radially with respect to the longitudinal axis of the dental screw.

[0080] This configuration has the advantage that the surface contact between the dental screw and the dental component is enhanced compared to conventional threads such as metric ISO threads, resulting in a more uniform distribution of force for securing the dental screw within the threaded hole of the dental component. It also allows for the accumulation of tensile force required for fastening with fewer rotations, thus enabling faster fastening and allowing for the design of shorter screws. This allows for a smaller design of the threaded holes in the dental screw and dental component. The strength of the dental restorative support set can be increased and / or its total size can be reduced.

[0081] The following drawings illustrate preferred embodiments of the present invention. These embodiments should not be construed as limitations, but rather as merely to enhance the understanding of the present invention in the context of the subsequent description. In these drawings, the same reference numerals refer to features having the same or equivalent function and / or structure throughout the drawings. Descriptions of these repeated features are generally omitted for the sake of brevity. [Brief explanation of the drawing]

[0082] [Figure 1] This is a cross-sectional view of a dental screw along its longitudinal axis, and in particular, a cross-sectional view of the instrument engagement interface of the dental screw. [Figure 2] Figure 1 is a plan view of the instrument engagement interface of a dental screw. [Figure 3] Figures 3a and 3b are cross-sectional views perpendicular to the longitudinal axis of the dental screw shown in Figures 1 and 2, and show the screw engagement interface and the instrument engagement interface that engages with the dental fixation device. [Figure 4] Figures 3a and 3b are partial side views of dental fixtures. [Figure 5] Figures 3 and 4 show cross-sectional views of the dental fixture perpendicular to the longitudinal axis at the level of the torque transmission section of the fixture. [Figure 6] Figures 6a and 6b are cross-sectional views at the level of the instrument engagement interface, showing the engagement with a dental fixation device along the longitudinal axis of the dental screw. [Figure 7] This is a three-dimensional diagram of a dental screw according to another embodiment. [Figure 8] Figure 7 is a three-dimensional view of a dental fixation device according to another embodiment for fixing a dental screw. [Figure 9] Figure 8 shows a detailed diagram of the screw engagement interface of a dental fixation device. [Figure 10] Figures 10a and 10b illustrate the function of the verification zone of the screw engagement interface. [Figure 11] This is a side view of another embodiment of a screw engagement interface for a dental fixation device. [Figure 12] Figure 11 is a front view of the screw engagement interface of a dental fixation device. [Figure 13] This is a schematic cross-sectional view of a screw-type engagement between a dental screw and a dental implant. [Figure 14] This is a cross-sectional view along the longitudinal axis of an engaged dental screw, abutment, and implant according to yet another embodiment. [Modes for carrying out the invention]

[0083] Figure 1 is a cross-sectional view of a dental screw 10 along its longitudinal axis LS according to an embodiment. Hereinafter, the cross-section along the longitudinal axis will also be referred to as the longitudinal section. The longitudinal section of the dental screw 10 in Figure 1 shows a portion of the screw head 13 and screw shank 14. The screw head 13 includes an instrument engagement interface 20. As shown in Figure 1, the instrument engagement interface 20 is preferably formed as a recess.

[0084] To transmit torque, the device engagement interface 20 includes an engagement structure. This engagement structure includes convex sections 21 and concave sections 22. The convex sections 21 alternate with the concave sections 22. There are an equal number of convex sections 21 and concave sections 22. As shown in the figure, these sections are arranged on the inner circumferential wall of the device engagement interface 20 and form a torque transmission zone 25b.

[0085] The instrument engagement interface 20 of the exemplary embodiment of the dental screw shown in Figure 2 includes five convex sections 21 and five concave sections 22. As seen in the section perpendicular to the longitudinal axis LS of the dental screw 10 (hereinafter also referred to as the perpendicular section), the convex sections 21 and concave sections 22 form a longitudinal engagement projection 24 extending from a circle 26. This circle is determined by the maximum inner diameter of the instrument engagement interface 20. As will be further described below, in the case of a tapered instrument engagement interface 20, the diameter of the circle 26 decreases from the proximal end to the distal end of the dental screw 10.

[0086] To achieve a compact yet durable design for the dental screw 10, it has been found advantageous to provide four or five concave and convex sections in each of the instrument engagement interfaces 20. Preferably, the screw engagement interface of the dental fixation instrument includes several concave and convex sections corresponding to the number of concave and convex sections of the dental screw to be engaged.

[0087] As will be explained in more detail below, the five sections of each convex and concave section are preferable for a fixture that allows for efficient and angular torque application (i.e., torque application by angle).

[0088] Multiple sections of each of the concave and convex sections have been found to be particularly advantageous for combinations of dental screws and fixtures in which the longitudinal axes are aligned during torque application. In such embodiments, the geometry of the engagement structure results in highly precise engagement and efficient torque transmission.

[0089] In the exemplary embodiment of the dental screw and fixation device shown in the figure, the concave section 22 and the convex section 21 have curved profiles. Nevertheless, as previously stated, the convex section 21 may also be planar. The concave section 22 and the convex section 21 form an engagement structure. Along the profile of the engagement structure in a vertical cross-section, the concave section 22 and the convex section 21 are connected at a transition point 23. In the embodiment of Figure 2, the transition between the concave section 22 and the convex section 21 is continuous.

[0090] However, as described above, the transitions between these sections can be discontinuous. An example of a discontinuous transition along the profile of the engagement structure is shown in Figure 5 for the fixture 30. In this case, the transition point 43 of the screw engagement interface 40 of the fixture 30 is discontinuous with respect to the change in inclination. Due to this discontinuity, the transition point 43 represents an angle along the profile of the screw engagement interface 40, as seen in a cross section perpendicular to the longitudinal axis LT of the dental fixture 30. In the engagement structure 44, this transition point 43 of the profile results in a longitudinal edge (see Figure 4).

[0091] At the transition point 23, torque transmission from the fixing instrument 30 to the dental screw 10 is most effective. The tangent to the profile of the instrument engagement interface 20 at this transition point 23 extends in the direction closest to the radial direction. As a result, the torque applied by the fixing instrument occurs at this point along the engagement profile of the instrument engagement interface 20, with the largest force component perpendicular to the surface and the smallest force component parallel to this surface. Consequently, at this point, torque transmission between the dental fixing instrument and the dental screw 10 is very efficient, while the amount of wear is relatively small. Therefore, it is advantageous to transmit torque between the fixing instrument and the dental screw 10 at and near the transition point 23.

[0092] The dental fixation device 30 for transmitting torque to the dental screw 10 includes an engagement structure 44 corresponding to the engagement structure 24. Figure 5 shows an exemplary embodiment of such a dental fixation device 30 having the engagement structure 44 in a cross section perpendicular to the longitudinal axis LT of the device. The engagement structure 44 of the dental fixation device 30 is part of the torque transmission zone 45b (see Figure 4). Corresponding to the dental screw 10, the cross-sectional profile of the engagement structure 44 includes a convex section 41 and a concave section 42. The convex section 41 and the concave section 42 merge or transition to each other at a transition point 43. Similar to the transition point 23 of the torque transmission zone 25b of the dental screw 10, the transition point 43 can be a continuous or discontinuous point of transition 43. As already described above, the transition point 43 of the dental fixation device 30 shown in Figure 5 is a discontinuous transition point.

[0093] Furthermore, the concave section 42 is preferably curved. The convex section 41 may be curved and / or flat. In the exemplary embodiment shown in Figure 5, the convex section 41 is curved, and more specifically, circular.

[0094] As described above, the angle of the transition point 43 between the tangent to the convex section 41 and the tangent to the concave section 42 is preferably in the range of 90° to 180° or 90° to 160°, preferably 95° to 150°. The closer this angle is to 90°, the more efficient the torque transmission from the dental fixation device 30 to the dental screw 10 at the transition point 43 becomes. At 90°, torque transmission is basically circumferential. There is essentially no force component acting parallel to the surface of the engagement structure 44 (extending radially), and as a result, wear of the surface caused by torque transmission can be basically prevented. For example, the dental fixation devices 130 and 230 shown in Figures 8 to 11 are designed for such efficient torque transmission.

[0095] Figure 3 shows a dental retainer 30 inserted into a dental screw 10 (see Figure 3a). Next, the dental retainer 30 is rotated about its longitudinal axis LT so that the engagement structure 44 of the dental retainer 30 engages with the engagement structure 24 of the dental screw 10 (see Figure 3b). As described above, this rotational play provides tactile feedback to the dental professional and facilitates the insertion of the screw engagement interface 40 of the retainer 30 into the instrument engagement interface 20 of the dental screw 10. The rotation of the screw engagement interface 40 inside the instrument engagement interface 20 about the aligned longitudinal axes LT and LS from the intermediate position in Figure 3a to the engagement position in Figure 3b is about 0.5 times β. As described above, the rotational play β of the rotational engagement orientation, i.e., between the orientation of the engagement for fixing and the orientation of the engagement for loosening, is preferably 1° to 3.5°, preferably 1.5° to 3°.

[0096] When engaged, torque is transmitted across the concave section 42 of the dental retainer 30 to the convex section 21 of the dental screw 10. This is schematically shown by a thick black line in Figure 3b. More specifically, torque is transmitted along the profiles of the engaging structures 24, 44, between the transition points 23, 43 and an intermediate position, preferably the center position, along the concave section 42 of the retainer 30 and the convex section 21 of the dental screw 10. In other words, in the region of the convex section 41 of the retainer 30 and the convex section 21 of the dental screw 10, torque transmission along the profile is essentially absent. This is because there is a gap between the convex section 41 and the concave section 22, which face each other while engaged. As a result, no wear occurs in this region. Furthermore, torque is applied efficiently at and around the transition points. Torque transmission also occurs in regions further away from the outer wall of the dental screw 10, i.e., in regions of thicker wall thickness. This, along with the transmission of torque along the curved concave section 42 and the corresponding curved convex section 21, prevents stress concentration. As a result, these features also enable a more compact design for dental screws.

[0097] Figure 4 shows a partial view of the dental fixation device 30 in a longitudinal section. The dental fixation device 30 is also shown in a longitudinal section of Figure 6, which is further referenced below. As shown in Figure 4, the torque transmission zone 45b of the screw engagement interface 40 is curved. More specifically, it is essentially a circular profile, particularly at least in part. Furthermore, at the distal end 32, the dental fixation device 30 preferably has a rounded tip 33. This geometric configuration allows the dental fixation device 30 to be tilted while transmitting torque from the dental fixation device 30 to the instrument engagement interface 20 of the dental screw 10 via the screw engagement interface 40. This is shown, for example, in Figure 6, where the longitudinal axis LS of the dental screw is tilted with respect to the longitudinal axis LT of the fixation device 30. Furthermore, the curved and rounded configuration of the screw engagement interface 40 prevents damage or scratching to the surface of the engagement structure 24, which, apart from this, could reduce the strength of the dental screw 10. Similar to the dental screw 10, the torque transmission zone 45b also functions as a pickup zone 45a, as will be described in more detail below.

[0098] The dental fixation device in Figure 4 also includes a torque limiting portion 35 proximal to the screw engagement interface 40. Preferably, the shank 36 is positioned between the screw engagement interface 40 and the torque limiting portion 35 so that the dental fixation device 30 does not break inside the instrument engagement interface 20 of the dental screw 10 in the event of breakage. This facilitates the removal of any portion of the dental fixation device 30 that remains inside the instrument engagement interface 20.

[0099] As already explained above, the torque limiting portion 35 is configured to break if the applied torque exceeds a predetermined maximum value. Preferably, the torque limiting portion is configured to withstand a maximum torque of 35 Ncm or less, preferably in the range of 27.5 Ncm to 34 Ncm, and more preferably in the range of 28 Ncm to 33 Ncm.

[0100] As shown in Figure 4, the torque limiting portion 35 may be designed with a reduced cross-section so that the strength at this cross-section is reduced. In other words, the torque limiting portion 35 has the lowest section module along the dental fixture 30. As a result, the torque limiting portion 35 has a lower section modulus than the waist portion adjacent to the screw engagement interface 40 and the shank 36.

[0101] As shown in Figure 1, the convex sections 21 of the instrument engagement interface 20 that form the tips of the longitudinal engagement projections 24 are chamfered at their proximal ends, i.e., at the entry point of the dental fixation device into the instrument engagement interface 20. The resulting chamfers 27 facilitate the insertion of the dental fixation device. On the one hand, they allow for the initial insertion of the dental fixation device when the engagement structure 44 of the dental fixation device 30 is not properly aligned with the engagement structure 24 of the dental screw 10 in the rotational direction. On the other hand, the longitudinal axis LS of the dental screw 10 may initially be excessively inclined with respect to the longitudinal axis LT of the fixation device 30. In this case, the chamfers 27 have a guiding function.

[0102] Furthermore, the dental screw 10 in Figure 1 includes a tapering instrument engagement interface 20. More specifically, the instrument engagement interface 20 narrows in the direction from the proximal end 11 to the distal end of the dental screw 10. In other words, the instrument engagement interface 20 can have a substantially conical shape. Due to its tapering shape, the instrument engagement interface 20 forms a pickup zone 25a for picking up and holding the dental screw. In this exemplary embodiment of the dental screw, the pickup zone 25a and the torque transmission zone 25b overlap each other, as shown in Figures 1, 2, and 6.

[0103] The pickup function will be described in more detail below with reference to Figure 6. As shown in Figure 6a, when the retaining device 30 is inserted into the recess of the instrument engagement interface 20 along the longitudinal axis LS, the retaining device 30 can engage with the dental screw 10 by friction. Because the instrument engagement interface 20 is tapered, the friction generated by the insertion of the retaining device 30 enables the pickup function. More specifically, the dental screw 10 can be held by the retaining device 30.

[0104] As described above, the tapering angle can preferably be selected in the range of 5° to 12°, particularly 6° to 9°, or substantially 7°. Alternatively, it may be in the range of 10° to 12°, or substantially 11°. These values ​​allow for secure retention of the dental screw while simultaneously allowing for easy disengagement of the connection between the fixing device 30 and the dental screw 10. Thus, these angles also prevent the occurrence of unwanted wear.

[0105] In addition to its pickup function, the tapering of the instrument engagement interface 20 also ensures optimal engagement between the engagement structure of the dental retainer 30 and the dental screw 10. This is schematically shown in Figures 6a and 6b. In Figure 6a, the dental retainer 30 has its initial size, i.e., it has not undergone wear. As a result, engagement between the dental retainer 30, more specifically the screw engagement interface 40, occurs on the proximal side of the instrument engagement interface 20 of the dental screw 10.

[0106] Preferably, the dental retainer 30 is configured to be reusable and preferably made of metal, particularly steel. As a result, wear occurs during the continuous use and reuse of the instrument. Wear occurring in the engagement structure 44 of the dental retainer 30 results in a reduction in the size of this structure. However, since the instrument engagement interface 20 of the dental screw 10 is tapered, the dental retainer 30 is simply pushed further into the instrument engagement interface 20. This ensures that the same quality of engagement is achieved and that torque is efficiently transmitted. This is shown in Figure 6b, where the worn dental retainer 30 is now engaged more distally with the instrument engagement interface 20 of the dental screw 10.

[0107] Figure 7 shows another embodiment of the dental screw 110. As shown in Figure 7, the dental screw 110 includes a torque limiting portion 115 directly adjacent to the screw head 113. Those skilled in the art will also understand that such a torque limiting portion 115 may also be located along the screw shank 14, either at the same or a different location along the screw shank 14, as in the embodiment of the dental screw 10 shown in Figure 1.

[0108] Similar to the torque limiting portion 35 described in relation to the dental fixation device 30, the torque limiting portion 115 has the smallest section modulus along the body portion of the dental screw 110 that transmits torque, i.e., the body portion that is subjected to increasing shear and tensile stresses during the fixation of the dental screw 110.

[0109] The torque limiting portion 115 is part of the screw shank 114 and is positioned along the screw shank 114. The end of the screw shank 114, i.e., the distal end 112 of the dental screw 110, has a threaded portion 116. The threaded portion 116 is for engaging with dental components such as a dental implant 401 or an abutment 402 (see Figure 14). For example, the dental screw 110 can be used to attach an abutment 402 to a dental implant 401.

[0110] As already defined above, the minimum torque that the torque limiting portion 115 of the dental screw 110 should withstand and transmit is preferably 26 Ncm. If the maximum torque value is exceeded, the torque limiting portion 115 should prevent breakage of any part of the dental screw 110 distal to the torque limiting portion 115, particularly the threaded portion 116. By controlling the breakage of the dental screw in this manner, it is ensured that the dental component engaged with the dental screw 110 remains intact. This is particularly advantageous when the dental component is a dental implant fixed within the patient's bone tissue, as this prevents the implant from being modified.

[0111] Figure 8 shows another embodiment of the dental fixation device 130. The screw engagement interface 140 at the distal end 132 of the dental fixation device 130 also comprises a convex section 141 and a concave section 142 that form a circumferential engagement structure 144. The dental fixation device 130 is preferably configured for a dental screw having an engagement structure with a corresponding number of convex and concave sections. As described above, the convex sections may also be at least partially planar.

[0112] Nevertheless, the dental fixation device 130 differs in particular from the dental fixation device 30 in the previous figure with respect to the screw engagement interface 140. Specifically, the screw engagement interface includes four convex and concave sections instead of five.

[0113] Moving to Figure 9, the screw engagement interface 140 of the dental fixation device 130 also differs from the previous embodiment in that the pickup zone 145a is separated from the torque transmission zone 145b. More specifically, the torque transmission zone 145b is located distal to and adjacent to the pickup zone 145a. In other words, the pickup zone 145a does not overlap with the torque transmission zone 145b. The pickup zone 145a is essentially conical in shape to engage with the corresponding pickup zone of the dental screw by friction, facilitating the handling of the dental screw, as already described above.

[0114] The torque transmission zone 145b of the dental fixation device 130 in Figure 9 has a concave shape similar to the pickup zone 145a, but instead may have a cylindrical shape as shown in another embodiment of the dental fixation device 230, which is shown in Figures 11 and 12 and will be described further below.

[0115] In addition to the pickup zone 145a and the torque transmission zone 145b, the dental fixation device 130 includes a verification zone 145c adjacent to its distal end 132. On the one hand, this verification zone 145c has the function of preventing engagement with the instrument engagement interface 120b of a dental screw 110b that does not have a correspondingly shaped verification zone (see Figure 10b). Furthermore, a dental screw 110b without a corresponding verification zone may also prevent engagement with the pickup zone 145a because the dental fixation device 130 cannot be inserted with sufficient clearance into the instrument engagement interface of the dental screw 110b in order to bring engagement to these zones.

[0116] On the other hand, if the dental screw 110a includes a corresponding verification zone, such as the dental screw 110a in Figure 10a, the dental fixation device 130 can engage with the device engagement interface 120a of this screw.

[0117] Figures 11 and 12 show yet another embodiment of a dental fixation device 230, which has a screw engagement interface 240 similar to the screw engagement interface 140 of the previous embodiment. However, unlike the previous embodiment, the dental fixation device 230 does not include a verification zone. Instead, the screw engagement interface 240 may include only a pickup zone 245a and a torque transmission zone 245b. In the embodiment of the dental fixation device 230 shown in Figure 11 and the embodiment of the dental fixation device 130 shown in Figure 10, the torque transmission zones 145b, 245b are located distal to and adjacent to the pickup zones 145a, 245a, but those skilled in the art will understand that this order can naturally be reversed. Thus, the pickup zones 145a, 245a can be located distal to the torque transmission zones 145b, 245b. Furthermore, the pickup zones 145a, 245a and the torque transmission zones 145b, 245b do not need to be adjacent to each other and may be spaced apart from each other.

[0118] For cost-effective manufacturing, the concave section 242 is machined proximal to the screw engagement interface 240. As a result, the pickup zone 245a essentially has a conical shape interrupted by the concave section. However, this may result in more pronounced friction between the pickup zone 245a and the corresponding dental screw, but is not functionally necessary. The same applies to the dental fixation device of the previous embodiment.

[0119] Figure 12 shows a front view of the dental fixation device 230 as seen from the distal end 232. As shown in this figure, the screw engagement interface 240 comprises four convex sections 241 alternating with four concave sections 242. As already mentioned in relation to previous embodiments, the convex sections 241 may instead be flat sections. In this exemplary embodiment, the convex sections 241 are curved and have a particularly circular shape when viewed in cross-section perpendicular to the longitudinal instrument axis LT.

[0120] As shown in the example in Figure 12, the angle α between the tangent to the convex section and the tangent to the concave section is at least close to the optimal angle of approximately 90° for movement, as described above. In other words, angle α is in the lower range described above. Thus, the configuration of the torque transmission zone 245b of the screw engagement interface 240 results in efficient torque transmission and a low tendency to wear during continuous use and reuse. To keep the dental fixation device of this disclosure with minimal wear, at least the screw engagement interface, preferably the fixation device, is made of metal, particularly steel.

[0121] Unlike the dental fixation device 30 in the previous figure, the screw engagement interface 240 can engage with the instrument engagement interface of a dental screw only if the instrument's longitudinal axis LT and the longitudinal axis are essentially aligned. As described above, this alignment can be facilitated by providing a chamfer at the entry point of the dental screw into the instrument engagement interface.

[0122] Figure 13 is a schematic cross-sectional view of a screw engagement between a dental component, specifically a dental implant 301, and a dental screw 310. Naturally, this configuration can be applied to any combination of dental components and dental screws.

[0123] When tightened, the distal flank 303 of the dental implant's threads is in firm contact with the proximal flank 318 of the dental screw's threaded portion 316. Therefore, the force generated by tightening the dental screw 310 to secure another dental component to the dental implant 301 is transmitted as a contact force between the threaded flanks 303 and 318.

[0124] In the configuration of this disclosure, the threaded hole of implant 301 and the outer threads of dental screw 310 are dimensioned such that the overlap of the dental flanks, shown as solid black lines in Figure 13, is at least 70% of the radial length of each threaded flank. The radial length of the threaded flank is defined as the length between the tip and root of the thread, and is capable of transmitting force longitudinally through the threaded screw shaft of the dental screw or the threaded hole of the dental component. For comparison, ordinary threads, such as those conforming to ISO standards, overlap by at least 60%.

[0125] Furthermore, the overlap of the screw connection in this embodiment is a maximum of 90%, 93%, and preferably 96%. Nevertheless, the strength of the thread can be significantly improved, especially with a minimum overlap difference of 10% compared to ISO threads. This result allows for a more compact design of the dental screw 310 because the compression force is transmitted more effectively in this screw connection.

[0126] Figure 14 shows a partial longitudinal cross-sectional view along the longitudinal axis LS of the screw. This shows an abutment 402 fixed to a dental implant 401 via a dental screw 410. As described above, the torque limiting portion of the dental screw according to this disclosure is sized to transmit at least a minimum amount of torque. Furthermore, the dental screw is configured to control fracture at torque values ​​exceeding the maximum torque value.

[0127] When the dental screw 410 shown in Figure 14 is fixed to the dental implant 401, the support surface 417 of the screw head 413 at the distal end of the screw head 113 is pressed against the screw seat 404 of the dental abutment 402. As a result of the contact established between the support surface 417 and the screw seat 404, a portion of the torque transmitted from the dental fixation device (not shown) via the instrument engagement interface 420 of the dental screw 410 is transmitted to the abutment 402.

[0128] As also shown in Figure 14, the screw seat 404 and the support surface 417 are conical. The conical shapes of the screw seat 404 and the support surface 417 have different conical angles. Preferably, the conical angle of the support surface 417 is larger than that of the screw seat 404. However, a configuration in which the conical angles are dimensionally determined in the reverse is alternatively possible. The difference in conical angles between the support surface 417 and the screw seat 404 is shown as γ in Figure 14.

[0129] This angle γ establishes contact between the support surface 417 and the screw seat 404 essentially as line contact. This is advantageous on the one hand because such line contact reduces the torque transmitted from the dental screw 410 to the abutment 402. On the other hand, the torque transmitted to tighten the screw connection but not used can be determined more precisely. Both advantages allow for more predictable behavior of the torque-limiting portion of the dental screw 410. In other words, this configuration makes the failure of the dental screw 410 at the torque-limiting portion more manageable and thus can contribute to a more compact design of the dental screw 410.

[0130] As mentioned above, the gap created by the difference γ between the cone angles can be at least partially closed at the end of the fixing process of the dental screw 410. This closure of the gap is caused by the deformation of the screw seat 404 and the support surface 417, further reducing the amount of torque transmitted toward the threaded portion of the dental screw 410 compared to the amount of torque transmitted toward the abutment 402. This change in the transmission ratio provides a damping effect during torque application, allowing for more precise adjustment of the maximum torque at the end that secures the threaded connection between the dental screw 410 and the dental implant 401. Thus, these features of the screw seat 404 and the support surface 417, as well as their configuration in the dental assembly, also enable a more compact design of the dental screw 410. [Explanation of symbols]

[0131] The following lists the last two digits of the reference symbols used in the description and drawings. In these drawings, these digits refer to features having the same or equivalent function and / or structure. The first digit represents the embodiment. 1. Dental implants 2 Abutments 3. Flank with threaded hole 4 Screw Seat 10 dental screws 11 Proximal end 12 Distal end 13 Screw head 14 Screw shank 15 Torque limiting section 16. Threaded portion 17 Support surface 18. Flank of the threaded portion 20. Instrument engagement interface 21 Convex section 22 Concave section 23 Transition points 24. Engagement Structure of Dental Screws 25a Pickup Zone 25b Torque transmission zone 25c Verification Zone 26. Circle with the largest inner diameter 27 Chamfering 30 Fixtures 31 Proximal end 32 Distal end 33. Round tip 35 Torque limiting section 36 Shank 40 Screw Engagement Interface 41 Convex section 42 Concave section 44 Engagement structure of fixing device 45a Pickup Zone 45b Torque transmission zone 45c Verification Zone Longitudinal axis of the LS screw Longitudinal axis of LT fixing device α Angle at the transition point between the tangent of the convex section and the tangent of the concave section β Rotational play between dental screws and fixation devices γ Difference in the cone angle between the screw seat and the support surface of the screw head

Claims

[Claim 1] A dental fixation set comprising a dental screw (10) and a dental fixation device (30), A dental fixation set comprising a dental screw and a dental fixation device, each including torque limiting portions (115, 35), wherein the torque limiting portion (115) of the dental screw is configured to withstand a maximum torque higher than the maximum torque that can be transmitted by the torque limiting portion (35) of the dental fixation device.

Images