SUPPORT POST FOR USE IN DENTAL IMPLANT SYSTEM

Abstract: A support post (10) for the use with a dental implant for supporting a prosthesis thereon is disclosed. The support post (10) includes an implant contacting region and a supra-gingival core section (22) which extends from the trans-tissue region for supporting a prosthesis. An interface member (26) is secured to the post at the bottom of the implant contacting region for abutment between the implant contacting region and an implant to which the post is to be secured. The interface member (26) has material properties different from those from which the post is made and compatible with those of the implant. Typically the support post is made of ceramic material while the insert is made of titanium having hardness properties no greater than that of the implant with which it is used.

Description: SUPPORT POST FOR USE IN DENTAL IMPLANT SYSTEM BACKGROUND OF THE INVENTION This invention relates to a suppoπ post for use with a bone-embedded dental implant. Specifically, the invention relates to a support post which is made of a material having different propeπies from the material of the implant with which it is to be used, and which includes an interface made of material compatible in hardness, with the material of the implant with which it is to be used and which is radiopaque. Such suppoπ posts suppoπ a prosthesis superstructure such as an aπificial tooth. Surgical techniques for suppoπ of dental prostheses by means of metallic bone-embedded aπificial root fixtures are well known. According to one prior an technique, a titanium bone-embedded implant fixture is interfaced with a metallic abutment post, on which the superstructure is suppoπed. The post has an internally shouldered access bore through which a screw fastener is inseπed to actually hold the implant and the post assembled. A number of problems and restrictions are presented however in the attachment of and retention of the superstructures to such abutment posts. Specifically, the typical superstructures for use with such posts are made of porcelain. The use of a titanium post generally results in a dark, central rod-like shadow, panicularly when exposed to high-brightness light, which makes the prosthesis somewhat unattractive and able to be distinguished from a natural tooth. Further, since the materials are different, there are sometimes presented problems with securing of the prosthesis to the suppoπ post. One attempt to solve the attractiveness and securing problems has involved making a suppoπ post made entirely of ceramic material, specifically, aluminum oxide. This approach allows direct surface bonding by interaction of a porcelain coping and/or prosthesis to the suppoπ post resulting in a secure and almost seamless bond between the prosthetic structure and the suppoπ post. While presenting an alternative attraction to the use of a titanium suppoπ post, the proposed solution presents a number of previously unanticipated problems. Ceramic materials generally have a much greater hardness than titanium. When such a suppoπ post is used, inevitable rocking of the suppoπ post due to, for example, chewing action, causes a high-stress interaction between the metal implant and the ceramic material of the post. Since ceramic is of greater hardness than the titanium implant, it can and does cause damage to the implant. If sufficient damage is caused, eventual surgical intervention is required to remove and replace the titanium implant. In addition, ceramic material is typically not radiopaque. Thus, when examining the juncture between the suppoπ post and the titanium implant through conventional dental x-ray imaging, the interface between the two elements is not readily viewable and thus adequate x-ray examination cannot be conducted. These and other problems relating to the use of an all-ceramic suppoπ post are avoided by the suppoπ post of the invention as described hereafter. SUMMARY OF THE INVENTION In accordance with one aspect of the invention, there is provided an improved suppoπ post for use with a dental implant for suppoπing a prosthesis thereon. The suppoπ post may include an implant-contacting region such as trans-tissue region integral with the post. A supragingival core section extends from the implant or from the implant-contacting region, such as a trans-tissue region, for suppoπing a prosthesis thereon. An interface member is secured to the post at least at the juncture between the post or the trans-tissue region, if present, for abutment between the post, or the trans-tissue region, and an implant to which the post is to be secured. The interface member has material propeπies different from those from which the suppoπ post is made. In a more specific aspect, the suppoπ post is made of a material having greater hardness than the implant with which it is to be used and the interface member is made of a material having a hardness no greater than the implant with which it is to be used. Preferably, the interface member is opaque to x-rays. Yet more preferably, the suppoπ post is of ceramic material and the interface member is of the same material as the implant with which it is to be used, e.g., titanium. In a yet still more specific aspect, the suppoπ post is hollow with a passageway extending therethrough and the interface member is an inseπ which is press-fitted in the passageway. The inseπ preferably extends completely along the boπom surface of the suppoπ post to prevent contact between the harder material of the suppoπ post and an implant with which it is to be used. Optionally, the inseπ further includes an upper poπion extending coaxially within the passageway in contact with the inner walls of the suppoπ post defining the passageway. The suppoπ post includes a shoulder poπion extending centrally from the inner walls to provide a shoulder for the head of the screw for use in securing the suppoπ post to an implant. BRDEF DESCRIPTION OF THE DRAWINGS Having generally described the invention, the same will become better understood from the following detailed discussion made with reference to the attached drawings wherein: FIG. 1 is a side cross-sectional view of a typical prior an suppoπ post; FIG. 2 is a view as in FIG. 1 showing a suppoπ post with a modification including an interface member in accordance with the invention; FIG. 3 is a perspective view of one embodiment of the interface member employed in connection with the suppoπ post in accordance with the invention; FIG. 4 is a side-cross sectional view showing a typical arrangement of one embodiment of the suppoπ post of the invention with the interface member shown assembled to a dental implant in a typical construction; FIG. 5 is a view similar to FIG. 2 but showing a second embodiment of the suppoπ posts with an alternative structure for the interface member in accordance with the invention; FIG. 6 is a view as in FIG. 4 showing the suppoπ post of FIG. 5 in an assembled configuration with a dental implant; FIG. 7 is a view as FIG. 5 showing an alternative structure of a suppoπ post made of a metal such as titanium having a surface of flame sprayed ceramic on the metal post; and FIG. 8 is a view as in FIG. 5 showing an altemative breakaway arrangement for the screw head avoiding excessive stress from being applied by the suppoπ post onto an implant. DETAILED DISCUSSION Referring now to the drawings in detail, FIG. 1 illustrates generally as element 10 a suppoπ post in accordance with the prior an. The suppoπ post 10 includes an opening 14 at the bottom thereof extending into a passageway 24 which extends upwardly to an open top. The passageway 24 includes at the bottom a shaped region 16, for example, having a multiple flat sides in a generally circular arrangement to prevent rotation of the suppoπ post 10 when in abutment and attached to an implant having a corresponding shaped upper member which fits into the shaped region 16. The passageway 24 narrows through a narrower poπion 18 with shoulder regions 20 providing a shoulder for the head of a screw which is used to secure the suppoπ post 10 to a dental implant. Transgingival region 12 provides a region which is, when attached to an implant, surrounded by the gingival tissue of a patient. An upper-elongated poπion 22 of the suppoπ post is shaped for having a prosthesis, optionally with a coping, secured thereto by any one of a number of different means. In accordance with the prior an, in one aspect the prior an the suppoπ post is made of titanium which includes all of the disadvantages heretofore discussed with respect to securing a prosthesis thereto and with respect to the unattractive appearance given to the prosthesis by virtue of the dark shadow left by the elongated poπion 22 in the center of the prosthesis. In an altemative configuration of the prior an, the suppoπ post 10 of FIG. 1 can be made of all ceramic material such as aluminum oxide, as shown. However, as discussed with reference to such a suppoπ post, the ceramic material is of greater hardness than the implants with which it is to be used, and can damage the implant requiring later surgical intervention due to rocking motion of the suppoπ post 10 on the implant fixture. Fuπher, ceramic is x-ray radiation transparent thereby not permitting adequate x-ray examination of the interface between the bottom of the suppoπ post 10 and the titanium implant with which it is used when secured to an implant in a patient's mouth. FIG. 2 shows one embodiment of the invention which employs the ceramic strucmre shown in FIG. 1 , except that an inseπ 26 is provided to create an interface between the suppoπ post 10 and the implant with which it is used to prevent direct contact between the ceramic material of the suppoπ post and the dental implant. Specifically, as shown in FIG. 2, and more clearly in FIG. 3, the insert 26 includes a wide-bottom poπion 28 having a lower surface 26a which is coextensive with the bottom surface of suppoπ post 10. An upwardly extending narrower-shaped region 30 corresponds to shaped region 16 of the passageway 24 of the suppoπ post 10. and fits therein in a non-rotational manner, with the inner surface of raised portion 30 lncludmg corresponding flat-shaped poπions for non-rotational engagement with the appropπate poπion of the implant with which it is used. A narrower mbular section 32 fits into naπower passageway 18 and the top edge of the mbular section 32 defines an optional additional shoulder poπion 20a for abutment with the head of a screw used to hold the suppoπ post 10 attached to an implant Such an arrangement of this embodiment of the suppoπ post 10 is shown assembled form with an implant 34 in FIG. 4 Specifically, the implant 34, typically made of titanium or titanium alloy, includes a threaded bore 42 for havmg a screw received therein. The suppoπ post 10 is placed in abutment with implant 32 through interface member 26 and is held secured to the implant 34 by means of a screw 36 having a head 38 which rests against shoulders 20/20a with the threaded poπion 40 of the screw m threaded engagement with threaded receivmg bore 42 of the implant. In an alternative configuration shown in FIG. 5, the insert can be an insert 44 which has a ponion 46 coextensive with the inner passageway of the suppoπ post 10 In this embodiment, shoulder 20 of the suppoπ post 10 serves to suppoπ a shoulder poπion 21 of the inseπ 44 which serves to suppoπ the head 38 of screw 36 as shown in FIG 6 A lower surface 46a extends along the bottom of the support post 10 in a manner similar to that of lower surface 26a of the embodiment of FIG. 2. While the insert 26/44 has been described as being made preferably of titanium or titanium alloy , it should be noted that anv other medicalK compatible material ha ing a hardness no greater than the hardness of the mateπal of which the implant 34 is made can be used The only requirement is that the mateπal for the insert 26/44 also be radiopaque, i.e., opaque to x-rays, so that the interface between the support post 10 and the implant 34 can be medically examined, for example, through the use of conventional x-rays. The insert 26, for example, in the embodiment of FIG. 2, can be manufacmred to such high tolerances in the case when titanium is used, that it can be merely press fit in a conventional manner into the support post 10. Altematively, such other securing means such as conventional cement can be used to secure the insert therein. FIG. 7 illustrates yet another embodiment of the support post 10. In this case, the entire post 10 is made of a metal such as titanium or titanium alloy. A layer of ceramic material 55 has been flame sprayed in a conventional manner to adhere onto the surface of the metal suppoπ post 10. A bottom surface 57 of the suppoπ post 10 ensures abutment of metal to metal of comparable hardness between the suppoπ post 10 and an implant against which it abuts. FIG. 8 illustrates yet another embodiment of the suppoπ post 10 similar to that of FIGS. 5 and 6. In this embodiment a breakaway screw head abutment 51 is provided to ensure that excessive forces are not applied to an implant. The depth of notch 53 is selected in accordance with the maximum force allowed to be applied to the implant. The abutment 51 also ensures that there is no ov er tightening of the post 10 onto its corresponding implant. As can be appreciated, the various feamres of the different embodiments can be combined or interchanged as readily apparent to those of ordinary skill in the an. For instance, the breakaway abutments 51 of Fig. 8 can easily be adapted for use in the embodiment of Fig. 6, in a manner which will be apparent to those of ordinary skill in the an. Other similar substimtions can be made between the different embodiments. Thus, it will be appreciated by persons skilled in the an that various deviations from the described embodiments of the invention are possible and that many modifications and improvements may be made within the scope and spirit thereof. It will be understood that the invention is not limited by the specific embodiments described herein, but only by scope of the appended claims.

Claims: What is claimed is: 1. A suppoπ post for use with a dental implant for suppoπing a prosthesis thereon, comprising: an implant-contacting region on the post; a supragingival core section extending from the implant-contacting region for suppoπing at least a prosthesis thereon; and interface means secured to said post at least at the bottom of said implant-contacting region for abutment between the implant-contacting region and an implant to which said post is to be secured, said interface means having material propeπies different from those from which said post is made. 2. A suppoπ post as in claim 1 wherein said suppoπ post is of a material having a greater hardness than the implant with which it is to be used, and said interface means is of a material having a hardness no greater than that of an implant with which it is to be used. 3. A suppoπ post as in claim 1 wherein said interface means is opaque to x-ravs. 4. A support post as in claim 2 wherein said interface means is opaque to x-ravs. 5. A support post as in claim 3 wherein said support post is of ceramic material and said interface means is of the same material as the implant with which it is to be used. 6. A suppoπ post as in claim 5 wherein said interface means is made of at least one of titanium and a dilute alloy. 7. A support post as in claim 4 wherein said suppoπ post is of ceramic material and said interface means is of the same material as the implant with which it is to be used. 8. A support post as in claim 7 wherein said interface means is made of at least one of titanium and a dilute alloy. 9. A support post as in claim 2 wherein said suppoπ post is hollow with a passageway extending therethrough and said interface means comprises an insert which is press fit into said passageway at the bottom of said support post in a manner wherein said insert extends completely along the bottom surface of said support post to prevent contact between the support post and an implant with which it is to be used. 10. A support post as in claim 9 wherein said insert further comprises an upper portion extending coaxially with said passageway in contact with inner walls of said suppoπ post defining said passageway. 11. A suppoπ post as in claim 9 further comprising a shoulder poπion extending centrally from a suppoπ post inner wall defining said passageway to provide a shoulder for the head of a screw for use in securing said suppoπ post to an implant. 12. A suppoπ post as in claim 1 wherein said implant-contacting region is a trans-tissue region. 13. In a suppoπ post for use with a dental implant, the improvement comprising interface means secured to said post at an end face thereof for abutment between said suppoπ post and an implant to which the post is to be secured, said interface means having material propeπies different from those from which the post is made. 14. A suppoπ post as in claim 11 wherein said shoulder poπion is weakened an amount for having it breakaway upon forces greater than a predetermined amount being applied thereto. 15. A suppoπ post as in claim 14 wherein said suppoπ post is of a material having a greater hardness than the implant with which it is to be used, and said interface means is of a material having a hardness no greater than that of an implant with which it is to be used. 16. A suppoπ post as in claim 15 wherein said interface means is opaque to x-rays. 17. A suppon post as in claim 16 wherein said suppoπ post is of ceramic material and said interface means is of the same material as the implant with which it is to be used. 18. A suppoπ post as in claim 17 wherein said interface means is made of at least one of titanium and a dilute alloy. 19. A suppoπ post as in claim 18 wherein said suppoπ post is hollow with a passageway extending therethrough and said interface means comprises an inseπ which is press fit into said passageway at the bottom of said suppoπ post in a manner wherein said inseπ extends completely along the bottom surface of said suppoπ post to prevent contact between the support post and an implant with which it is to be used. 20. A support post for use with a dental implant for supporting a prosthesis thereon, comprising: an implant-contacting region on the post; a supragingival core section extending from the implant-contacting region for supporting at least a prosthesis thereon; said support post being made of a material having material properties like the material properties of an implant to which said suppoπ post is to be attached; and a ceramic coating on the outer surface of said suppoπ post, said ceramic coating having been flame-sprayed to be attached to said support post, and not covering the portion of said suppoπ for abutting against an implant.

Inventors: BEATY KEITH D, LAZZARA RICHARD J, BEATY, KEITH, D., LAZZARA, RICHARD, J.
Applicants: IMPLANT INNOVATIONS INC, IMPLANT INNOVATIONS, INC.
Application year: 1995
Main classification: A61C8
IPC codes: A61C8