Link:  Pharm/Biotech Resources

Title:  Method, arrangement and use of an implant for ensuring delivery of bioactive substance to the bone and/or tissue surrounding the implant

United States Patent:  6,918,766

Issued:  July 19, 2005

Inventors:  Hall; Jan (Göteborg, SE); Lööf; Lennart (Västra Frölunda, SE)

Assignee:  Nobel Biocare Ab (SE)

Appl. No.:  980009

Filed:  May 23, 2000

PCT Filed:  May 23, 2000

PCT NO:  PCT/SE00/01029

371 Date:  February 28, 2002

102(e) Date:  February 28, 2002

PCT PUB.NO.:  WO00/72778

PCT PUB. Date:  December 7, 2000

In connection with implants for bone or tissue, delivery of bioactive substances to the bone or tissue is ensured. The implant is designed with an internal space, and one or more bodies comprising the bioactive substance are designed to cooperate with the bone and/or tissue structure surrounding the implant and to release the bioactive substance to the said structure. The said body or bodies is/are applied in the space in order thereby to be exposed to the surrounding structure and deliver the bioactive substrate or substances to the latter.

DESCRIPTION OF THE INVENTION

Technical Problem

In connection with implants of the type in question, it is important to establish an appropriate substance layer function at and in connection with the implant. The main object of the invention is to solve this problem, among others.

It is important to be able to use tried and tested experience with proven and effective implant structures without essentially affecting these in other respects. The invention solves this problem too.

In connection with clinically well-designed implants, it is important to be able to achieve an effective use and release function for the bioactive substance in question, all of which substance must be able to be used effectively. In various designs, it is also important to be able to control the release function during the incorporation process, for example so that an initially high release function is available during a first time period and a lower release function is obtained during a second time period, or vice versa. The variations in question must be able to be effected by choice of differently structured implants in terms of the support function for the bioactive substance arranged in the respective implant. The invention solves this set of problems too.

One object of the invention is thus to combine the properties of clinically efficient implant elements and clinically efficient supports for growth factors, by modifying the geometry of existing implant elements in order to obtain secure containment of the substance in the element. Such a novel implant element can permit rapid incorporation of surrounding tissue and stable fixation even in non-optimal bone qualities, and it does this by virtue of the stimulation activity from the growth factors which are released from the support or body.

A further object of the invention is to make available an implant element with an external structure which is similar to or corresponds to the clinically efficient implant elements, so-called fixtures, which permit positioning of efficient supports or bodies with respective growth factors and a sought release of these growth factors into the tissue which is stored in the body of the implant element. Such a combination of implant element and support permits stimulation of bone growth in the tissue surrounding the implant element and also rapid incorporation and stable fixation of the implant elements in mineralized tissue.

SOLUTION

The features which can principally be regarded as characterizing a method according to the invention are that the implant is designed with an internal space and, if appropriate, one or more channels and/or recesses leading from the internal space to the outside or outside part of the implant facing towards the structure, that one or more bodies comprising the bioactive substance are designed to cooperate with the bone and/or tissue structure surrounding the implant so as to be able to release the bioactive substance to the said surrounding structure. Further characteristics are that the said body or bodies is/are applied in the said space and, if appropriate, also in one or more of the said channels and/or recesses, in order thereby to be exposed to the said surrounding structure and deliver the bioactive substance to the latter during the said period.

An arrangement according to the invention can principally be regarded as being characterized in that the implant is designed with one or more internal spaces and, if appropriate, one or more channels or recesses which lead from the internal space or spaces to the outside of the implant. Further characteristics are that one or more bodies comprising the bioactive substance are designed to cooperate with the surrounding bone and/or tissue structure so as to release the bioactive substance to the surrounding structure, and that the body or bodies is/are assigned a position or positions in the space or spaces in which they are exposed for the said cooperation and release directly or via the said channel(s) or recess(es).

In one embodiment, each body is in the form of a spongy body or cloth saturated in or treated with the bioactive substance. Alternatively, the body can be in the form of a gel which comprises the bioactive substance. The spongy body, the cloth or the gel has a softness which permits distinct application in the space concerned while at the same time ensuring that it is held in place by frictional cooperation, adhesive cooperation, etc., with the wall of the respective space. In a preferred embodiment, the implant or implant element has clinically effective geometrical properties, for example in the shape of a cylindrical or conical solid with an outer surface which is in direct contact with the surrounding body tissue.

The bioactive substance can be a substance belonging to the superfamily TGF-β. In a preferred embodiment, the implant element has a threaded outer surface and a conically narrowing part. The latter part has an open section with an axial hole or recess for the said support or body. The hole or recess is open towards the end surface of the conical part. One or more through-holes communicate with the said axial holes and extend radially through the implant body part at right angles to the longitudinal axis of the implant in order to permit direct release of bioactive substance from the said support through the said holes or openings.

The internal space in question can thus comprise a mouth part or recess part with identical cross-sectional areas, and the body or support can fill both the internal space and the recess.

In one embodiment, the said axial hole can extend from the conical part through the main part of the implant body in order to permit release of growth factors along the length of the implant body through a suitable number of holes, channels and/or recesses in the wall of the implant element. The design and structure of the body/support or bodies/supports are chosen on the basis of a predetermined or anticipated release function. A first body can assume a first position in which the first body is arranged with a first degree of exposure, and a second body assumes a second position in which the second body has a second degree of exposure less than the first degree of exposure, or vice versa, for the purpose of permitting a controlled or optimum release function for the bioactive substance in question.

Alternatively, each body can be arranged in such a way that, in the said cooperation and release function, it varies the degree of release of the bioactive substance during the release period and, for example, effects a greater degree of release at the start of the period, or vice versa. In a further embodiment of the element, the design(s) or extent(s) of the space or spaces and any associated channels or recesses are chosen on the basis of a predetermined or anticipated release function. The channels or recesses can be arranged with different cross-sectional areas and/or extents, which means that different parts of the same body or different bodies are subject to different degrees of exposure in the release function, for the purpose of permitting a controlled or optimum release function for the implant situation in question. In a further embodiment, two bodies can be situated at a distance from each other inside the implant or implant element in order to serve different parts of the surrounding bone and/or tissue structure. The body can be absorbable in association with the release of substance. The body (bodies) can first be applied in the space and thereafter saturated with substance, which saturation can be effected with substance at different concentrations and/or quantities for the purpose of achieving a predetermined or anticipated release function.

A use according to the invention can principally be regarded as being characterized in that the implant is used to support, in one or more internal spaces, one or more bodies comprising the bioactive substance, and, via possible attachments to the space or spaces, to expose the body or bodies in order to release the bioactive substance to the surrounding bone and/or tissue structure.

Advantages

By means of what has been proposed above, a novel aid is obtained for use in surgery for the purpose of obtaining effective incorporation processes in tissue, for example bone tissue. An implant according to the invention, provided with support(s) or body (bodies), can be made commercially available. Alternatively, the implant and support/body/bodies can be made available separately and joined together in situ by the person concerned, for example the surgeon. Various types of supports with different release functions and release times can be included within one range. Various types of implants or implant elements with different systems of channels and internal spaces can be made available in order to permit different release functions and release times. In addition, each body can be saturated with substance in a different quantity and/or concentration. Well-proven surgical procedures, substances and implant designs can be used in different implantation situations, which can include implantation in hard or soft dentine.
 

Claim 1 of 18 Claims

1. A method for using an implant element for delivering at least one bioactive substance to bone or tissue structure surrounding an implant, comprising:

providing an implant element comprising:

a head part arranged to be acted upon by a turning tool,

a threaded outer surface, and

a conical tip opposite the head part;

providing an open section in the conical tip, wherein the open section comprises an axial hole that is open towards an end surface of the conical tip, and wherein the open section comprises at least one radial through-hole which communicates with the axial hole and extends radially through the implant element to the outer surface of the implant element;

providing at least one body in the open section, wherein the at least one body is arranged to permit direct release of the at least one bioactive substance from the body to the bone or tissue structure through the axial hole and the at least one radial through-hole;

and applying the at least one bioactive substance to the at least one body before or after providing the at least one body in the open section.

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