Angulated Attachment Device for Dental Prostheses

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to dental attachment devices and, in particular, it concerns second preferred embodiment of an angulated ball attachment device constructed and operational according to the teachings of the present invention.

In many cases of dental implants the implants are inserted in a non-parallel manner, due to bone architecture. Placing a denture over ball attachments which are connected to not parallel implants causes difficulties in the insertion and removal of the denture and causes damage to the ball and transfers damaging forces to the dental implants and the bone. In some cases the implant are located buccally or lingually to the desired location of the ball. Placing a regular ball attachment over a misplaced implant causes difficulties in the fabrication of the denture. In cases of regular implants for fixed restorations, when the implants are inserted at an angle to the prosthetic element other than the desired angle, angulated abutments, as illustrated in Figure Ia, are used. The prior art angulated abutment 1 has an anti-rotational element, usually a hexagonal configuration 2, that engages a compatible anti-rotational element configured in the implant. Further, the prior art angulated abutment 1 has a hollow passageway that opens at opening 3 in the angulated wall 4 and passes through the hexagonal configuration 2 to allow the insertion of the attachment screw 5.

A conventional ball attachment, as illustrated in Figure Ia, has no anti- rotational element and therefore, it can not be used as an angulated ball attachment because the correct angle can not be determined by the doctor.

One prior art solution for providing an angulated ball attachment device is illustrated in Figure 2. This device is a two-part abutment device, in which each

part has an anti-rotational element. The base element 6 has a first anti rotational element 7 which prevents rotation of base element 6 within the implant. Additionally, rotation between base element 6 and plate 9 is prevented by a second anti-rotational configuration in which anti-rotationai pin 10 engages the one of a plurality of anti-rotational holes 8 configured in base element 6. A ball 11 is attached to the edge of plate 9 so as to be angled to the long axis of the dental implant. Both parts are attached to the implant by attachment screw 12. The use of two parts increases the risk of the screw loosening and assembly in the patient's mouth is more difficult for the doctor. Further, if the screw becomes loose, the non-rotational connection between base 6 and plate 9 will not be maintained, which may lead to brakeage of one of the parts or damage to the surrounding area of the mouth.

There is therefore a need for a dental attachment device that allows angulated ball attachment without increasing the risk of screw loosening.

SUMMARY OF THE INVENTION

The present invention is an angulated ball attachment device.

According to the teachings of the present invention there is provided, a device for detachable off-axis attachment of a dental prosthesis comprising: (a) a bone anchoring arrangement having an axis of insertion into the bone and including a rotation prevention configuration shaped to engage the bone so as to prevent rotation of the device about the axis; and (b) an attachment configuration configured for detachable connection of a dental prosthesis, the attachment configuration being located off-axis relative to the axis of insertion, wherein the attachment configuration and the rotation prevention configuration are integrally formed or permanently attached so as to be in non-adjustable spatial relation.

According to a further feature of the present invention, the attachment configuration includes a ball. o

There is also provided according to the teachings of the present invention, a kit for detachable off-axis attachment of a dental prosthesis comprising two of the aforementioned devices, wherein the rotation prevention configuration has 6-fold rotational symmetry, and wherein: (a) a first of the devices has the attachment configuration located off-axis at a first angular position relative to the rotation prevention configuration; and (b) a second of the devices has the attachment configuration located off-axis at a second angular position relative to the rotation prevention configuration, the second angular position being rotated about the axis by an angle of substantially 30 degrees. There is also provided according to the teachings of the present invention, a device for connecting a ball to a bone implant comprising an abutment element and a ball, the abutment element is at least partially inserted inside the bone implant, the ball is permanently connected in fixed spatial relation to the abutment element so as to maintain their connection in case the connection of the abutment element to the bone implant is loosened, the ball is located such that the central long axis of the bone ball is displaced from central long axis of the bone implant.

According to a further feature of the present invention, the angle between the central long axis of the bone implant and the central long axis of the ball is between 0 to 90 degrees. According to a further feature of the present invention, the angle is 15 to 45 degrees.

According to a further feature of the present invention, the long axis of the ball is parallel the long axis of bone implant so the ball is displaced from the center of the bone implant. According to a further feature of the present invention, at least part of the ball is above the internal thread of the implant.

According to a further feature of the present invention, the abutment element has an anti-rotational element to be engaged with an anti-rotational element of the bone implant.

According to a further feature of the present invention, the anti-rotational element of the abutment element is in the shape of hexagon.

According to a further feature of the present invention, the ball is located above one plane of the hexagon. According to a further feature of the present invention, the ball is located above one corner of the hexagon.

According to a further feature of the present invention, the height of the abutment element is between 0.5mm to 6 mm.

According to a further feature of the present invention, the abutment element is angulated.

According to a further feature of the present invention, the ball is located more displaced from the axis of the implant than the abutment element.

According to a further feature of the present invention, the ball is located less displaced from the axis of the implant than the abutment element. According to a further feature of the present invention, the ball is soldered to the abutment element.

According to a further feature of the present invention, the ball and the abutment element are one piece which is milled by a C.N.C machine.

According to a further feature of the present invention, the ball and the abutment element are casted together.

According to a further feature of the present invention, the ball is screwed to the abutment element.

According to a further feature of the present invention, the ball is glued to the abutment element. According to a further feature of the present invention, the abutment element is fixated by a screw to the bone implant.

According to a further feature of the present invention, the abutment element is fixated by a rotating fixating nut to the bone implant.

According to a further feature of the present invention, the abutment is fixated by friction to the bone implant.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

FIG. IA is a perspective view of a conventional prior art angulated abutment device;

FIG. IB is a perspective view of a conventional prior art straight ball attachment device; FIG. 2 is a perspective view of a prior art two-piece angulated ball attachment device with two anti-rotational elements;

FIG. 3 is a perspective view of a first preferred embodiment of an angulated ball attachment device constructed and operational according to the teachings of the present invention, shown connected to a dental implant; FIG. 4 is a perspective view of a first variant of the angulated ball attachment of FIG. 3, in which the ball is located above one plain of the hexagonal anti-rotational configuration of the abutment;

FIG. 5 is a perspective view of a second variant of the angulated ball attachment of FIG. 3, in which the ball is located above one corner of the hexagonal anti-rotational configuration of the abutment;

FIG. 6 is a perspective view of a second preferred embodiment of an angulated ball attachment device constructed and operational according to the teachings of the present invention;

FIG. 7 is a perspective view of a third preferred embodiment of an angulated ball attachment device constructed and operational according to the teachings of the present invention;

FIGS. 8 and 9 are schematic illustrations of alternative attachment configurations, which are known per se in other contexts, which may be used

according to the teachings of the present invention for attachment of a prosthesis to the attachment device of the present invention; and

FIGS. 10-14 are schematic illustrations of further alternative attachment configurations, which are new in their own right, which may be used according to the teachings of the present invention for attachment of a prosthesis to the angulated attachment device of the present invention or to a conventional straight or angled attachment device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is second preferred embodiment of an angulated ball attachment device constructed and operational according to the teachings of the present invention.

The principles and operation of second preferred embodiment of an angulated ball attachment device constructed and operational according to the teachings of the present invention according to the present invention may be better understood with reference to the drawings and the accompanying description.

By way of introduction, the present invention relates an angulated ball attachment device which is deployed such that the ball component is off-set from the central axis of the implant. The ball component and the abutment base element form a single rigid unit that is stable even in case the attachment screw of the device becomes loosened.

In some preferred embodiments the abutment base element is deployed at least partially inside the dental implant.

The angulated ball attachment device of the present invention provides parallel balls which provide easy insertion and removal of the denture by the patient even in cases where the implants are not parallel.

The present invention also provides a method for connecting a ball to a bone implant in which the ball component is fixed attached to the abutment base element, at least a portion of the abutment base element is at least partially

inserted into the bone implant and then attached thereto, and the ball component is positioned such that the central axis of the ball component is off-set from the central axis of the bone implant.

Referring now to the drawings, Figure 2 illustrates a first preferred embodiment of the angulated ball attachment device 100 of the present invention. Embodiment 100 includes a single base element 13 having an anti-rotation element, illustrated here by non-limiting example as a hexagon configuration 14 that is coupled to the implant 45 with a screw 15 as is known in the art. A ball component 16 is rigidly connected to base element 13 at a point that is off-set from the implant central axis 70 of the base element 13. It will be appreciated that ball component 16 may be integrally formed with base element 13, such as by milling or casting. Alternatively, ball component 16 and base element 13 may be independently formed and later joined by soldering, welding or any suitable process, as non-limiting examples. It will be understood that the position of ball component 16 about the implant central axis 70 of the base element 13 is limited by the anti-rotation element that is illustrated here as the hexagon configuration 14, thereby limiting the deployment of the ball component 16 to six positions spaced at 60° intervals about implant central axis 70. In order to provide additional positioning options for ball component 16 about the implant central axis 70, the position of ball component 16 in relationship to the anti-rotation element may be varied, as illustrated by the non-limiting examples of Figures 4 and 5.

In the first variant 100a, as illustrated in Figure 4, the ball component 16 is aligned with one plane 17 of the hexagon configuration 14. In the second variant 100b, as illustrated in Figure 5, the ball component 16 is aligned with one corner 18 of the hexagon configuration 14. By providing these two variants of angulated ball attachment device 100 together as a kit, the doctor is able to place the ball component 16 in any one of twelve different position of ball component 16 spaced

at 30° intervals about implant central axis 70. While these two variants 100a and 100b provide an appropriate solution for most of the clinical situations, it will be appreciated that the anti-rotation element may be configured with substantially any suitable cross-sectional contour so as to provide fewer or additional deployment positions. Such cross-sectional contours may include regular polygons such as, but not limited to, triangle, square, pentagon, heptagon, octagon, nonagon and decagon.

It will be readily appreciated that other variations of angulated ball attachment devices can be constructed by, by non-limiting example, varying the height (length) of the base element 13 preferably in the range of between 0.5mm to 6 mm. Additionally, the distance of the ball component 16 from the implant central axis 70 may be varied.

By varying the distance of the ball component 16 from the implant central axis 70, the angle between the central long axis 71 of the ball component 16 is also varied. Therefore, it will be appreciated that in one embodiment of the present invention, the central axis 71 of ball component 16 may be at angle to the implant central axis 70 of the implant 45. Preferably, the angle between the central axis 70 of the bone implant and the central axis 71 of the ball component is in the range of between 0 to 90 degrees, and most preferably the angle is 15 to 45 degrees. It is also within the scope of the present invention to provide an angulated ball attachment device in which the ball component is not a perfect sphere and in which the central axis of the non-spherical ball component is parallel to the implant central axis 70.

Preferably more than one variant embodiment of ball attachment devices are supplied to the doctor in kit form so as to provide the doctor with an appropriate ball attachment devices in substantially any situation.

Figure 6 illustrates a second preferred embodiment of the angulated ball attachment device 200 of the present invention in which the abutment element 20 is angulated in relation to attachment screw 15 which will align with the central

axis of the implant (not shown) upon installation. This embodiment also provides the ability to deploy the ball component at different positions about the central axis of the implant. It will be appreciated that abutment base element 20 has less material in region 21 that is on the side of abutment base element 20 opposite the ball component 16. This reduces the interference of the abutment base element 20 with the removable dental prosthesis (not shown) with which it will be used. In this embodiment as well, variation of the location of ball component 16 in relation to the hexagon configuration 14 or to the abutment base element 20 may be achieve as described above in regard to embodiment 100. Figure 7 illustrates a third preferred embodiment of the angulated ball attachment device 300 of the present invention in which the ball component is not fixedly attached to the abutment base element 26. This embodiment 300 is similar to the previous embodiments 100 and 200 in that it includes an anti -rotational element, such as the non-limiting example of the hexagon configuration 14 and that the receiving abutment base element 26 is attached to the dental implant (not shown) with a screw 15. As illustrated here, the separate ball component is configured with a threaded extension. Likewise, the receiving abutment base element 26 is configured with an internal threaded hole 27 for receiving the threaded extension of ball component 25. Here too, variation of the location of ball component 25 in relation to the hexagon configuration 14 or to the abutment base element 20 may be achieve as described above in regard to embodiment 100.

It will be appreciated that features common to all of the embodiments of the present invention discussed herein include deploying the ball component so as to be off-set from the central axis on the implant and the ball component is rotatable about the central axis on the implant.

It should be noted that while the description herein is directed toward an angulated ball attachment device, this is not intended as a limitation and the same principles other type of dental abutments for implants or for angulated orthopedic attachment devices. Further, although the embodiments described herein were

configured with a ball component, this is not intended as a limitation and may be applied to substantially any other type of prosthetic connectors. Examples of alternative attachment configurations will now be described briefly with reference to Figures 8-14. In general terms, these alternative attachment configurations include a lower portion 52, forming part of the attachment device, which has one or more internal or external undercuts, and a flexible engagement element 50, typically formed of resilient polymer material, which snap-fits onto the lower portion to engage the undercuts and retain an attached prosthesis in place. The form of Figure 8 corresponds to a configuration commercially available under the name LOCATOR ^® while that of Figure 9 corresponds to a configuration commercially available under the name ERA ^® from Sterngold Dental, LLC (MA, USA). In each case, retention of the prosthesis is achieved by engagement of an engagement element 50 in the form of a polymer cap onto lower portion 52. The configurations are intended to allow some degree of angular freedom, and/or some angular freedom may be provided at the cup-like interface between the polymer cap and an overlying metallic casing (not shown).

In addition to these conventional attachment configurations, it is a further aspect of the present invention, additionally patentable in its own right even when used with an otherwise conventional straight or angled attachment device, to provide attachment configurations and/or attachment kits which provide better control of the retention and angular range of motion than are offered by the conventional forms of attachment discussed above. A number of non-limiting examples of the improved attachment configurations will now be illustrated with reference to Figures 10-14.

Turning first to Figure 10, this illustrates a case in which lower portion 52 is formed with at least two external undercut recesses which lie on an overall generally conical profile ''C". An attachment kit preferably includes at least two types of corresponding caps, each shown here only partially and labeled

respectively "A" and "B". Cap "'A" is configured to engage only one of the at least two undercut recesses, while cap ''B" is configured to engage two undercut recesses. The same principle may be extended to cases of three or more undercut recesses, whether external, internal or both, and correspondingly more caps. By suitable choice of the number of recesses engaged, the position of the recesses engaged, and the fit or misfit of the engagement shape, it is possible to achieve a wide range of different degrees of retention and, largely independently of the degree of retention, a choice or angular ranges of motion.

Figure 11 illustrates a further example of the same concept where cap "A" (again only shown partially) engages two internal recesses and one external recess of lower portion 52, while cap "B" engages two internal recesses and three external recesses of the lower portion 52. In this case, the general profile of both the internal and external recesses is a conical form as illustrated by the straight lines. Figure 12 again illustrates the same underlying concept, but in a case where the internal retention features are in the form of internal projecting features within the caps and complementary shaped recesses on the upper surface of lower portion 52. Adjustment of retention forces between different caps may be achieved by various combinations of varying the number of external recesses engages and varying the number and shape of the internal projecting features within the cap.

Turning now to Figure 13, this shows a spherical or elliptical structure which itself functions as an "undercut" with hollows in different regions which facilitates gripping. This structure can be used alternately with female engagement elements having different undercuts which allow angular movement of the female element over the male element with varying gripping locations. In the variant shown at the bottom of Figure 13, an additional large recess "D" is shown which provides an additional grip for the internal hollow.

Finally, Figure 14 shows two views of a lower portion 52 formed as a round or oval dome with three or more large cavities which may be identical of non-identical to provide gripping locations.

In each of the above novel attachment configurations, the upper element (referred to as "'female"), may be formed from any suitable material including, but not limited to, nylon, any type of plastic, metal or metal alloys including various types of springs, and any combination of such materials. In the case of certain materials, for example, Nickel-Titanium ("Nitinol") alloys, the device may be activated by temperature transition (e.g., body heat), by electric current or by any other physical mechanism to assume a predefined final configuration.

The structures described may be straight or angled, and may allow the prosthesis a range of motion in any desired direction. Where required, a supplementary internal or external gripping element may be incorporated to provide the required function. Each of the upper elements described above may accommodate an overlying metal casing. The structures can be implemented with combinations of full or partial gripping of the external features of the lower element and full or partial gripping of the internal features of the lower element in order to allow a range of motion in all directions in order to reduce stress from the implant, and to allow the prosthesis to settle onto the tissue.

It will be appreciated that the above descriptions are intended only to serve as examples and that many other embodiments are possible within the spirit and the scope of the present invention.