GB2487553A

GB2487553A - Locking device for dental components

Info

Publication number: GB2487553A
Application number: GB201101324A
Authority: GB
Inventors: Kullberg Fredrik Herr; Thomas Eriksson
Original assignee: Nobel Biocare Services AG
Current assignee: Nobel Biocare Services AG
Priority date: 2011-01-26
Filing date: 2011-01-26
Publication date: 2012-08-01
Also published as: GB201101324D0

Abstract

A prosthetic component 1 for mounting to a dental implant platform 20 is described. The prosthetic component 1 comprises a shaft 7 having and a longitudinal axis and being configured to interface with a socket of the dental implant platform 20. The prosthetic component 1 also comprises a resilient member 8 partially located in a recess 9 on the shaft 7 when in an uncompressed state. The resilient member 8 is compressible into the recess 9 towards the longitudinal axis. The resilient member 8 acts to create a frictional force between the shaft 7 and implant platform 20. The resilient member 8 may be a ring shaped spring or a spring and head member (Fig 5a). The component can be useful as a temporary method of fixing.

Description

LOCKING DEVICE FOR DENTAL COMPONENTS

Field of the Invention

This invention pertains in general to the field of oral, dental or maxillofacial restorative medical procedures, and products related thereto. More particularly the invention relates to devices and methods for fixing together dental implants and corresponding components.

Background of the Invention

A number of different prosthetic components may be attached to a typical dental implant (or, as implied throughout the specification and claims, a dental implant replica), via a variety of methods. A prosthetic component is either; a component which secures a dental prosthesis to a dental implant, the dental prosthesis itself, or a component mounted directly to the implant or implant replica for scanning, such as a position locator. A prosthetic component is not a driver or other manipulation tool typically used by a clinician. A typical example of the attachment of a prosthetic component to a dental implant is the attachment of an abutment component to an implant by means of a fastening screw. This technique is a secure method of fixing the component together but requires an additional tool (a screw driver) and a degree of skill and patience for screwing the components together.

It may be necessary to attach certain prosthetic components to an implant in a temporary manner, such that the prosthetic component is quickly and easily fixed to the implant, and similarly easily removed. An example of this type of procedure is the fixture of a position locator component, to an implant replica for the duration of a scan of the position locator. In this case, the position locator would need only to be installed for a relatively brief period of time and the process of fixing the position locator to the implant replica using a screw would be relatively time consuming.

Therefore, a relatively temporary method of fixing the position locator component to the implant replica would be desirable.

The dental implant provides an implant platform having a defined connection interface for fixation of dental prosthesis to the jaw bone. Dental comprise dental bridges, single tooth prosthesis, etc. As described above, the dental prosthesis may be directly fixated to the dental implant or intermediate components, such as an abutment component. Various implant platforms are known in the art for providing a connection interface between a dental implant and an abutment or other mating component. In general, the connection platforms can be characterized as external or internal. An example of an external connection platform is a dental implant with a hexagonal protrusion at the proximal end of the implant. See e.g., the Brànemark System(R) sold by Nobel Biocare(TM). An example of an internal connection platform can be found in U.S. Pat. No. 6,733,291, which describes a dental implant with an internal multi-lobed interlock for mating with an abutment. See also NobelReplace(TM) sold by Nobel Biocare(TM). Another example of an internal connection is U.S. Pat. No. 4,960,381, which discloses a dental implant comprising a socket with a conical upper portion, a registration portion below the conical upper portion and an internally-threaded shaft below the registration portion. An important reason for using a defined platform for the fixation of position locators to an implant or implant replica is that the platform allows the rotation, orientation and position of the implant to be precisely known relative to the position locator. However, the platform provides no means for securing the component to the implant in a temporary or permanent manner.

Figure 1 shows a known technique for providing a temporary method of fixing a component to an implant or implant replica. A position locator 100 is shown having an interface which is secured in the socket of the implant via a plurality of fingers 110.

As the interface shaft of the position locator is inserted into the socket of the implant, the outer surface 120 of the fingers slide against the inside surface of the socket, creating a frictional force. This frictional force means that a certain minimum amount of force is required in order to insert or remove the position locator from the socket of the implant. This gives the position locator a stable interface with the implant platform during position registration, which allows accurate position readings to be made for the implant. A component and an implant are said to be interfaced when the upper surface of the dental implant and the complementary lower surface of the component meet, There are several problems with the above technique. Firstly, the fingers of the position locator are typically made of the same material as the entire rest of the component, for ease of production and cost reasons. The entire component is one piece. Manufacturing a separate fingered interface unit for attachment to the component would be both costly, complex, and would introduce a number of new and undesirable engineering challenges. Since the component would typically be made out of hard material, such as titanium, the fingered interface unit would also comprise the hard material. In the case of titanium, which has low resilience, the fingered interface unit would consequently have a poor degree of elasticity. If the component was inserted into the implant in an incorrect manner causing the fingers to be bent out of shape, the lack of resilience in the fingers would result in immediate and irreparable damage. The hexagonal nature of the fingered interface unit is defined by the shape of the hexagonal socket of the implant, and requires that, within certain tolerances, the fingered interface unit is inserted with the correct orientation. If it is inserted with an incorrect orientation and force is applied, the fingers of the fingered interface unit are bent.

Another problem with this solution is that the fingers are delicate and complex to manufacture relative to the rest of the component. This can increase manufacturing cost and introduce a higher rate of errors for the entire component in the manufacturing process.

Therefore, what is needed is a simpler and more cost efficient temporary fixing solution between an implant and the corresponding component.

Summary of the Invention

Accordingly, embodiments of the present invention preferably seek to mitigate, alleviate or eliminate one or more deficiencies, disadvantages or issues in the art, such as the above-identified, singly or in any combination by providing a component according to the appended patent claims.

An embodiment of the invention provides a prosthetic component for mounting to a dental implant platform, the prosthetic component comprising a shaft, the shaft having a longitudinal axis and being configured to interface with a socket of the dental implant platform, wherein the prosthetic component further comprises a resilient member partially located in a recess on the shaft when in an uncompressed state, and compressible into the recess towards the longitudinal axis.

Another embodiment of the invention provides a method for mounting a prosthetic component to a dental implant platform, the prosthetic component comprising: a shaft having a longitudinal axis and configured to interface with a socket of the dental implant, a compressible resilient member located in a recess on the shaft, compressible to reside entirely within the space defined by the recess and configured to expand radially relative to the longitudinal axis of the shaft when uncompressed, the method comprising the steps of: inserting the prosthetic component into the mouth of the socket of the dental implant platform, inserting the prosthetic component into the socket until the resilient member contacts the inner surface of the socket, further inserting the prosthetic component into the socket to compress the resilient member until the shaft is interfaced with the socket of the dental implant platform.

Aspects of the present invention will now be described by way of example with reference to the accompanying drawing. In the drawings: Figure 1 shows a typical component of the prior art.

Figure 2 shows a schematic illustration of a component, including the resilient member, according to an embodiment of the invention.

Figure 3a shows a schematic illustration of the component of figure 2 installed in a replica implant.

Figure 3b shows a cross-sectional view of the resilient member, component shaft and implant.

Figure 4a shows a schematic close-up illustration of the resilient member in the implant.

Figure 4b shows an alternative embodiment to that shown in figure 4a.

Figure 5a shows a schematic illustration of an alternative embodiment having a spring and spring head in a bore within the shaft.

Description of embodiments

Specific embodiments of the invention will now be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.

The following description focuses on an embodiment of the present invention applicable to a dental restorative procedure. However, it will be appreciated that the invention is not limited to this application but may be applied to many other surgical procedures, including for example maxillofacial restorative surgical procedures.

As the present invention relates to the devices and methods for fixing together dental implants or dental implant replicas to their respective components, it is understood that, throughout the specification and claims, any reference to a dental implant also implicitly covers a dental implant replica.

The device shown in figure 2 illustrates a first embodiment of the invention. In figure 2, prosthetic component 1 is a position locator used to determine the position and orientation of an implant in a patient's jaw. The position locator has a cylindrical portion 2, a conical portion 3, a top portion 4 comprising outer surface 5, and a connection interface 6, forming a one-piece body.

When scanned using scanning apparatus, different parts of the position locator play different roles in providing information about the position and orientation of the locator. The conical portion 3 is used to interface with an internal connection platform of the dental implant, which in this case, is a complementary sloping surface on the interior surface of the dental implant socket. This connection platform ensures that the position of the position locator relative to the dental implant is accurately known.

The conical portion may be replaced with a flat surface perpendicular to the longitudinal axis of the position locator where the cylindrical portion 2 meets narrower shaft portion 6. This surface would instead correspond with an external connection platform on the dental implant.

The outer surface 5 of top portion 4 is used to determine the position in space of the position locator 1 and the rotation of the position locator, which in turns allows the determination of the rotation of the implant and the hex shaped connector of the implant. In this manner, a vector for the position and orientation of the position locator 1 is determinable by optical scanning. When the position locator 1 is affixed to another structure with mating connection interface 6, such as a dental implant, it has a precisely defined geometrical relation and position in relation to the other structure.

By registering the position locator 1, the position of the other structure can be determined as there is a defined relation between the two. Connection interface 6 is described in greater detail below.

In this embodiment, prosthetic component parts 2, 3, 4, and shaft 7 (described below) form a one piece body made of titanium. The surface of the cylindrical portion 2, a conical portion 3, and a top portion 4 further comprises a titanium oxide layer.

The oxidized surface has a surface roughness. Titanium is a particularly advantageous material for the body of the position locator because it allows the titanium oxide layer to be easily provided on the surface of the body. A titanium oxide surface layer is particularly optically advantageous, as described below.

The position locators are typically produced by turning and/or milling from a raw material. Machining steps, such as milling or turning of a metal, result in a machined surface of the positioning locator body which is very smooth and glossy.

This can be the case particularly with hard metals such as titanium. Such machined surfaces have proven to be less well suited for detection by optical scanners, as described in US 6,590,654. In particular, US 6,590,654 describes conoscopic holographic scanning, which can generate erroneous and unstable measurements when scanning position locators having machined surfaces. This is due to the optical properties of the machined surfaces being too glossy. Incident light from the scanner light source is mostly reflected by the glossy surface and does not reach the optical detector, which is oriented in the same direction as the incident light beam. When the incident light beam is directed non-perpendicularly onto a machined surface, it is reflected away. As a consequence, little or no backscattered light reaches the detector and a position and orientation of the position locator cannot be accurately determined. For instance, a position and orientation of a cylindrical, partly frusto conical position locator is not determined sufficiently well for providing data suitable for producing components to be used in dental prosthesis procedures. The measurement result has to lie within tolerances of as low as in the range of a few micrometers. This is of particular of importance where a plurality of dental implants are used for affixing a single structure, like a dental bridge, to a jaw. Where a dental bridge framework is produced from erroneous data, it will not fit the implants installed in the patient. Similarly for a single tooth prosthesis, such narrow tolerances are needed in order to provide a dental prosthesis that fit in relation to surrounding teeth.

Where a single tooth prosthesis is produced from erroneous data, it will not fit into the space provided by the surrounding teeth. This is costly and cumbersome for the patient and has to be avoided.

One technique to address this problem is to form a layer of material at the machined surface which reduces the degree of glossiness of the surface. Preferably, the layer of material would provide a surface roughness to the machined surface and, consequently, better optical properties. A titanium oxide layer has been demonstrated to be suitable for this purpose as it considerably improves the optical properties of the surface with regard to optical scanning of the surface. In this manner, the final dimension of the position locator with the finished surface is determinable with high precision. Therefore, it is of particular advantage to have a titanium body, the surface of which can then be oxidised, for example by means of an anodic oxidation process.

U.S. Pat. No. 7,713,307, incorporated by reference, describes a titanium oxidising technique for producing a oxidising layer called TiUnite ® having particular advantageous properties. In a preferred embodiment of the invention, a surface layer of TiUnite ® is arranged on the machined surface of the position locator.

An essential element of prosthetic component 1 (the position locator in the first embodiment) is interface 6 which is configured to provide prosthetic component 1 with a stable support in the dental implant (or implant replica). As shown in figure 2, the connection interface of the first embodiment comprises a shaft 7, a recess 9 and resilient member 8. Figure 3a shows the position locator of figure 2 inserted into dental implant 20.

Shaft 7 extends along the longitudinal axis of the prosthetic component from the conical portion 3 of the position locator and has a length to complement the socket of dental implant 20. The shaft has a hexagonal cross-section, and both the size, length, and cross section of the shaft are complemented in the corresponding interface socket of the dental implant. The hexagonal cross section of the shaft and corresponding interface socket prevent provide the position locator with rotational fixedness. Other cross sections may be used, which also provide the shaft and socket with anti-rotational fixedness, including octagon, star shaped, other non-round shapes etc. Furthermore, the shaft of the prosthetic component may be tapered or straight, with a corresponding complementary shape in the dental implant socket.

The shaft comprises a recess 9 configured to receive a resilient member 8.

The first embodiment describes a circumferential recess around the shaft of the positional locator configured to accommodate a ring-shaped spring located around the shaft. The recess may take the form of a trench. The trench may define a smoothly curving circular course around the circumference of the shaft. A cross-sectional view of this is shown in figure 3b. As the outer surface of the shaft has a hexagonal cross-section, the depth of the trench relative to the surface of the shaft will vary as the circular path of the recess comes nearer and closer to the hexagonal path of the shaft surface. The space defined by the recess is the volume of open space that replaces the material of the shaft that would otherwise be at the position of the recess.

The inner diameter of the ring-shaped spring 8, when uncompressed, is configured to be smaller than the largest diameter of the shaft (the diameter of the shaft measured across the central axis will vary due to the hexagonal cross section of the shaft), such that the ring is held in place within the recess and cannot slip loose and slide up or down the shaft. Furthermore, the ring-shaped spring is configured to have an outer diameter which is at least greater than the smallest diameter of the surface of the shaft, such that at least a portion of the spring expands perpendicular to the axis of the shaft, outside of the space defined by the recess when uncompressed.

The outer surface of the ring shaped spring when uncompressed may have a greater diameter than the diameter of the shaft proximal to the mouth of the recess.

The ring-shaped spring is configured to be compressible to a degree, so that a force can be applied to the spring to push it back into the recess. This is achieved by making the resilient member out of a resilient material such as plastic or stainless steel. The ring of the ring-shaped spring may also comprise a gap. In an uncompressed position, the gap is open, but when the ring is compressed, the gap is closed as the ring is pressed to a smaller size.

An advantage of having a separate prosthetic component body and resilient member is that, whilst the material of the prosthetic component body is hard and unresilient, the material of the ring-shaped spring 8 can be a single piece of resilient, compressible material. This allows the advantageous properties of each material to be harnessed for task performed by the respective part. The resilient member, which is required to flex, will not be damaged by doing so, whereas the titanium material of the first prosthetic component body can still be provided with the titanium oxide layer.

This is enabled by the simplistic design of this embodiment, which avoids any complex or fragile components, allowing simpler and more cost effective manufacturing.

In the first embodiment, the recess and spring arrangement provide a temporary fixing mechanism in the following manner. As shown in figure 4a, when the shaft of the position locator is inserted into the socket of the dental implant, the portion of the spring extending beyond the surface of the shaft makes contact with the inner surface 21 of the socket and introduces a frictional force, which provides an additional grip between the shaft and the socket. By allowing the spring to retreat into the recess when compressed, the frictional force is maintained regardless of how tightly fitting the shaft and the socket are. The stiffness and size of the spring can be adjusted to vary the degree of grip, a larger stiffness or size resulting in a greater frictional force.

The result of this grip is a limited mechanism for fixing the position locator to the dental implant or dental implant replica. This fixing technique may allow a number of procedures to be managed without the use of an additional screw and screw driver. For example, when scanning an implant replica, position locator and corresponding impression of the oral cavity of the patient, the position locator can be fixed into the dental implant by hand by inserting the position locator into the implant with sufficient force to overcome the frictional force exerted by the spring. This will then prevent the locators from coming loose and falling out when the impression is manipulated by a technician.

Furthermore, this fixing technique may also allow simplified procedures when also using a screw and screw driver. For example, in one embodiment, the force required to insert the prosthetic component into the socket of the implant is greater than the force exerted on the prosthetic component by gravity. This allows the prosthetic component to stay in place when an implant is in an upside down configuration, for example when inserted into an upper jaw bone. A clinician can then insert the prosthetic component into the upside down implant by hand where it is held in place by the spring, release his grip on the prosthetic component, and then secure the prosthetic component to the implant more permanently using a screw and screwdriver, without the prosthetic component falling out in the interim.

Figure 4b shows an embodiment similar to the first embodiment, wherein the socket of the dental implant is configured with a socket recess 50 on the inner surface of the socket corresponding to the position of the ring-shaped spring, such that when the shaft 7 is inserted into the socket and the ring-shaped spring 8 draws parallel with the socket, the ring-shaped spring snaps into the space defined by the socket recess. Once the ring shaped spring has expanded out into the space defined by the socket recess, the spring latches into the socket recess, exerting a larger grip on the surface of the socket. The force required to compress the spring back into the shaft recess in order to release the shaft is larger than the normal frictional force when sliding the shaft in the socket. This mechanism provides a snap lock.

In further embodiments, other configurations of the shaft recess and corresponding spring are envisaged. The recess and spring may have a helical configuration, having a greater frictional surface area than a straightforward ring shape. Alternatively, the spring may have a hexagonal shape to more closely match the shape of the shaft. Other shapes are envisaged to match the other possible shaft designs mentioned above.

Furthermore, multiple recesses and corresponding springs may be used on one shaft, to increase or distribute the frictional force over a large area.

The prosthetic component may also have an interface to allow a manipulating tool, such as a screwdriver, to be used to position and insert the prosthetic component into the implant. The interface for manipulation may comprise a suitable recess or protrusion to complement the head of the manipulating tool.

A second embodiment of the invention shown in figure 5a comprises a similar position locator to that described in the first embodiment, the recess and corresponding resilient member have a spring and head configuration.

Shaft 61 comprises a recess 62 within which spring 64 attached to ball 63 are located. Recess 62 maybe a simple bore in the body of the shaft. Spring 64 is configured to extend head 63 partially beyond the surface of shaft 61 when uncompressed. When force is applied to the outside surface of the ball, the spring is compressed and the ball is moved into the recess. Similarly to the first embodiment, this results in a frictional force between the surface of the ball and the inner surface of the socket when the shaft is inserted into the socket. By allowing the ball to be pressed into the recess against the pressure of the spring, the frictional force between the ball and the socket surface is kept largely constant regardless of how tightly fitting the shaft and the socket are.

Similarly to the first embodiment, the material of the spring and ball maybe different to the material of the position locator body. A preferred material would be stainless steel for the spring and the ball, for its resiliency and non-oxidising properties.

In a similar embodiment shown in figure 5b, the inner surface of the implant socket comprises a recess configured to complement the head of the resilient member, which provides a snap fit similar to the embodiment shown in figure 4b.

In another embodiment of the invention, the prosthetic component is an abutment to be fixed to a dental implant. In this case, the fixing methods described in the embodiments above are particularly useful when fixing the abutment to a dental implant installed in the upper jaw of the patient using a screw. As described above, the abutments are prevented from falling out by means of the grip provided by the friction or snap force. The abutment may be made of titanium and have a layer of titanium oxide at least partially covering the surface of the abutment.

In another embodiment, the prosthetic component is part of a temporary prosthesis used for testing the aesthetic appeal of a proposed prosthetic design. This allows a temporary prosthesis to be temporarily inserted into an implant in a patient's mouth whilst in the dentist's chair.

Claims

CLAIMS1. A prosthetic component for mounting to a dental implant platform, the prosthetic component comprising a shaft, the shaft having a longitudinal axis and being configured to interface with a socket of the dental implant platform, wherein the prosthetic component further comprises a resilient member partially located in a recess on the shaft when in an uncompressed state, and compressible into the recess towards the longitudinal axis.
2. The prosthetic component of claim 1, wherein the recess is a circumferential recess on the shaft and the compressible resilient member is a ring shaped spring located in the recess.
3. The prosthetic component of any preceding claim, wherein the recess is a bore extending in a radial direction towards the longitudinal axis and the compressible resilient member comprises a spring and a head component, and is configured to extend a surface of the head component exterior to the space defined by the recess when the resilient member is uncompressed.
4. The prosthetic component of any preceding claim, wherein the compressible resilient member is comprised of at least a first type of material, and wherein a single piece of a second type of material form the remaining parts of the prosthetic component.
5. The prosthetic component of claim 4, wherein the first material(s) comprising the compressible resilient member has a higher resiliency that the material(s) comprising the single piece of a second material.
6. The prosthetic component of claim 5, wherein the second material is titanium.
7. The prosthetic component of claim 6, wherein the single piece of a second material at least partially comprises a titanium oxide exterior surface.
8. The prosthetic component of any preceding claim, wherein the shaft of the prosthetic component has a non-round cross section adapted to anti-rotationally mate with a socket of a dental implant platform.
9. The prosthetic component of any preceding claim, wherein the prosthetic component is an implant position locator.
10. The prosthetic component of any preceding claim, wherein the prosthetic component is an abutment.
11. The prosthetic component of any preceding claim, wherein the prosthetic component further comprises a component interface surface adapted to interface with an implant interface surface of the dental implant platform.
12. An arrangement of the prosthetic component of any preceding claim and a dental implant platform, wherein the shaft of the prosthetic component has a shape that is complementary to the shape of a socket of the dental implant.
13. The arrangement of claim 12, the dental implant platform further comprising a recess on the inner surface of the socket, wherein the resilient member of the prosthetic component is configured to latch with the recess on the inner surface of the socket of the dental implant when the shaft of the prosthetic component is in a desired position within the socket.
14. The arrangement of claims 12 or 13, wherein the shaft of the prosthetic component and the socket of the dental implant are adapted to anti-rotationally mate.
15. A method for mounting a prosthetic component to a dental implant platform, the prosthetic component comprising: a shaft having a longitudinal axis and configured to interface with a socket of the dental implant, a compressible resilient member located in a recess on the shaft, compressible to reside entirely within the space defined by the recess and configured to expand radially relative to the longitudinal axis of the shaft when uncompressed, the method comprising the steps of: inserting the prosthetic component into the mouth of the socket of the dental implant platform, inserting the prosthetic component into the socket until the resilient member contacts the inner surface of the socket, further inserting the prosthetic component into the socket to compress the resilient member until the shaft is interfaced with the socket of the dental implant platform.
16. The method of claim 15, wherein the step of further inserting the prosthetic component into the socket to compress the resilient member until the shaft is interfaced with the socket of the dental implant platform, wherein the inside surface of the socket comprises a recess configured to partially receive the compressible member such that the resilient member expands into the recess on the inside surface of the socket, latching the component to the implant.