Patent Application
20140272788
This disclosure relates to dental implants and more specifically to a twist locking mechanism for the attachment of a dental implant and an abutment.
A well-known procedure is the dental restoration of a partially or wholly edentulous patient with artificial dentition. Typically, a dental implant is seated into the bone of a patient's jaw. The dental implant includes a socket, e.g., a bore, which is accessible through the overlying or surrounding gum tissue for receiving and supporting one or more attachments or components which, in turn, are useful to fabricate and support prosthodontic restorations. The dental implant generally includes a threaded bore to receive a retaining screw for holding mating components therein. Dental implant procedures may use a variety of implanting modalities, for example, blade, threaded implant, or smooth push-in implant.
Single tooth restorations present the unique requirement that they must be supported non-rotationally on an underlying abutment. When a prepared natural tooth is the underlying abutment, this requirement is met in the normal course of preparing the abutment with a non-circular cross-section. Likewise, when the underlying abutment is a post fitted onto an implant, this requirement is met by preparing the post with a noncircular cross-section. This latter scenario can be more complicated due to the added connection between the implant and the abutment.
Typically, a dental implant is implanted into the bone of a patient's jaw and comprises a socket, e.g., a bore, which is accessible through the overlying or surrounding gum tissue for receiving and supporting one or more attachments or components which, in turn, are useful to fabricate and support the prosthodontic restoration. Dental implant procedures may use a variety of implanting modalities, for example, blade, threaded implant, or smooth push-in implant.
While numerous design iterations have been marketed, overall there have been three generations of the implant-abutment interface within these assemblies: an external hex implant, an internal connection implant, and a vertical connection assembly. The external hexagonal implant design has a hexagonal shape (or another anti-rotation feature) protruding out of the implant and the corresponding abutment has a female hexagonal receptacle. There is a surface below the hexagonal protrusion on which the abutment is seated. The hexagonal protrusion acts to constrain the abutment from rotating around the longitudinal axis as well as preventing movement on the plane coincident with the implant seating surface. Unfortunately, such an interface has virtually no stability until the screw is introduced and fully seated between the abutment and the implant. The screw is essentially the sole component resisting bending forces.
In contrast, the internal connection implant design has a hexagonal female member (or other anti-rotation feature) extruded into the implant, and the corresponding abutment has a male hexagonal protrusion. The abutment is seated on the same surface as the external hexagonal design, the only difference being that the anti-rotation feature on the implant is located below this surface. The benefit of this system is that it has intrinsic stability without the screw, and then experiences increased stability once the screw is introduced and fully seated. The system responds in a more unified manner to bending forces. While this system has advantages over the external hex implant, the disadvantage (which applies to the external hex as well) is that it is prone to leak at the implant-abutment interface (seating surface) due to “lifting” of the abutment under load that may create an intermittent gap resulting in bacteria penetration and subsequent crestal bone loss.
Another alternative interface is an internal/vertical connection implant assembly where the abutment sits “vertically” within the implant assembly and is supported by the internal sidewalls. In addition to this vertically interfacing aspect, many abutments contain a male anti-rotation feature at the bottom and the corresponding implants have a female receptacle (similar to the internal connection implant design). The main benefits of this design are that the two components effectively wedge together, creating a seal impenetrable to bacteria and the abutment receives added lateral support from the implant due to interaction of the abutment sidewalls with the interior surfaces of the implant. However, such designs suffer from vertical location variability. The accuracy of the fit of the final implant restoration (i.e., crown) is largely dependent on the ability to reliably transfer the location of the implant throughout the multiple steps involved in fabricating the restoration. The currently marketed vertical connection implant systems are susceptible to significant vertical location variability, and subsequent customer dissatisfaction. Location variability is undetectable until the very last step in the restorative process when the patient receives their restoration where it becomes apparent the restoration is too high or too low relative to the original tooth. For example, due to the required manufacturing tolerances, each time an abutment (or other male part) is mated with an implant (or other female part) the initial vertical position is destined to change. Further, once the parts are mated and torque is applied to the screw attaching the abutment to the implant, there is relative motion (or vertical displacement) between the male and female components. The magnitude of this motion is dependent on multiple variables, including but not limited to the screw torque, the surface finishes, and the component specifications.
Thus, there is a need for an interface between a dental implant and a mating component such as an abutment that locks the abutment in place relative to the implant before the mating screw is installed. There is a further need for an interface between a dental implant and abutment that creates a seal between the two components. There is a further need for an interface between a dental implant and an abutment that positions the abutment at a controlled vertical and angular location relative to the implant.
An example of the present disclosure is a dental restoration system including an implant having a tip and an opposite cylindrical socket. The socket has an interior surface having a sloped rim surface and a groove with a vertical and horizontal channel. A mating component has an interface section including a collar having a radial tab. The collar is attached to a conical interface surface. The tab slides in the vertical channel when the mating component is inserted into the implant. The tab fits in the horizontal channel of the groove to lock the mating component in place when the mating component is rotated. The conical interface contacts the sloped rim surface of the cylindrical socket to create a seal when the tab is fit into the horizontal channel.
Another example is a method of connecting a mating component to an implant. The implant has a tip and an opposite cylindrical socket. The socket includes an interior surface having a sloped rim surface and a groove with a vertical and horizontal channel. The mating component has an interface section having a collar having a radial tab. The collar is attached to a conical interface surface. The interface section is inserted in the cylindrical socket such that the radial tab aligns with the vertical channel of the groove. The mating component is moved so the radial tab slides down into the vertical channel. The mating component is turned so the radial tab slides into the horizontal groove and the sloped rim surface of the implant contacts the conical interface of the mating component to create a seal.
The foregoing and additional aspects and implementations of the present disclosure will be apparent to those of ordinary skill in the art in view of the detailed description of various embodiments and/or aspects, which is made with reference to the drawings, a brief description of which is provided next.
The foregoing and other advantages of the present disclosure will become apparent upon reading the following detailed description and upon reference to the drawings.
While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
The interface between implant 102 and abutment 104 is further detailed in
As shown in
The abutment 104 includes a roughly cylindrically shaped post 132 and a stem 134 extending in a relative downward direction from the post 132. The stem 134 includes a male interface portion 136 adapted to be locked into the female interface 118 of the implant 102 when the abutment 104 is assembled with the implant 102. The interface portion 136 has a collar 138 that is sized to be insertable in the female interface 118 of the implant 102. The collar 138 has a series of five radial tabs 140 spaced equidistantly around the outer perimeter of the collar 138. The radial tabs 140 allow the abutment 104 to be locked into the implant 102 when the two components are joined together. In this example, the collar 138 has substantially the same height as the radial tabs 140 but the collar 138 may be longer than the radial tabs 140. The post 132 has a base 150 and an opposite end 152 through which a screw may be inserted to fix the abutment 104 to the implant 102. The stem 134 has a conical surface 154 which is tapered from the base 150 of the post 132 to the collar 138. In this example, the implant 102 is fabricated from commercially pure titanium and the abutment 104 is fabricated from titanium alloy. Other materials such as zirconia or PEEK may be used to fabricate the implant 102 and the abutment 104.
As shown in
The locking process of attaching the abutment 104 with the implant is shown in
The interface created between the female interface 118 of the implant 104 and the interface portion 136 of the abutment 104 locks the abutment 104 in place relative to the implant 102 to allow the attachment screw to be inserted to join the abutment 104 to the implant 102. The implant 102 is first seated in the bone. As shown in
The abutment 104 is then twisted or rotated so the radial tabs 140 are moved into the horizontal channels 174 as shown in
As may be shown above, each vertical channel 172 leads to the corresponding helical horizontal channel 174 that provides the retention, anti-rotation and seal of the connection between the abutment 104 and the implant 102 by use of rotation to vertically draw the abutment 104 into final connecting position to the implant 102. Further, the engagement of the abutment 104 within the helical horizontal channel 174 provides predictability for vertical position of the abutment 104 interfacing with the implant 102. Thus, the radial tabs 140 in the final location within the respective horizontal channels 174 positions the abutment 104 at a controlled vertical and angular location relative to the implant 102.
It should be understood that the general interface features of the collar 138 with tabs 140 and the sloped interface surface 154 may be used with any suitable mating component such as a driver, an impression coping, a healing abutment, cover screw, direction/depth indicators or an RFA strut.
While particular implementations and applications of the present disclosure have been illustrated and described, it is to be understood that the present disclosure is not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations can be apparent from the foregoing descriptions without departing from the spirit and scope of the invention as defined in the appended claims.
