A spacer for dental implants.

(54) NAME Dental implant spacer (56) Published Publications: --- (57) Abstract:

The invention relates to a spacer for dental implants made of a biocompatible material. The spacer comprises an inner sleeve spacer element (4) of titanium which is included in a screw connection between an attachment (fixture) (1) implanted in the jawbone and a dental prosthesis structure whose joint surface (11) is located above the gum so as to accommodate the load band. . The spacer further comprises an outer spacer sleeve (12) of porcelain or ceramic which completely or partially encloses the inner sleeve spacer element (4). The ceramic or porcelain sleeve can, by grinding and coating with porcelain in different colors, be made to mimic gums and gums and thus does not break to the same extent against the natural gum color and gum color as the titanium material does.

ALL 38 8122 ΛΑ

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The numbers in brackets indicate international identification code, INID code. Letters in clamps indicate international document code.

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The invention relates to a spacer for dental implants made of a biocompatible material and constituting a connecting element in a detachable screw connection between an attachment (fixture) implanted in the jawbone and a dental prosthesis structure, the joint surface of which is located above the gum.

It is known to permanently anchor oral prostheses in the jawbone by means of helical fasteners, so-called fixtures, made of a biocompatible material, preferably pure titanium. The method that has been found to provide the highest anchoring stability and which has been used clinically for over 20 years is the so-called osseointegration method developed by Professor Per-Ingvar Brånemark and co-workers and described in, for example,

Brånemark / Zarb / Albrektsson: Tissue-Integrated Prostheses, Quintessence Books, 1985.

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The method is based on a very precise and atraumatic insertion technique of the fixture so that a direct contact, ie an exact adaptation without intermediate connective tissue, occurs between the fixture and the bone tissue. Such direct contact between the fixture and bone tissue provides the best conditions for a truly permanent anchoring of a dental prosthesis.

The helical fixtures made of pure titanium are surgically inserted into the jawbone in a first operation followed by a critical length of critical length during which the fixture is covered by intact mucosa. During this healing phase, the bone tissue grows firmly and forms a unit with the implanted fixture. In a second operation, the fixture is then exposed and a spacer is applied to the fixture with the aid of a spacer screw. Then the dental prosthesis itself is anchored in the form of a bridge construction by means of a fastening screw which in turn attaches to the spacer screw.

• s A bridge structure is anchored by means of several fixtures, for example six pieces, and corresponding spacers which form connecting elements between the bridge structure and the fixtures. In order to be able to absorb the high oral loads to which the screw joint is subjected, the spacers are made of a biocompatible material with very good strength properties, for example titanium, etc.

The connecting members (base part) to the fixture will normally be enclosed by the gums after the operation. However, the main body of the spacer will protrude above the gumline in the gap formed between the gumline and the joint surface of the bridge structure. This exposure of the spacers usually rarely presents any inconvenience since the spacers are hidden behind the lips. However, in some cases where the lips are highly drawn, the spacers will be visible even in speech and normal mimicry, which can be disturbing for aesthetic reasons due to the metal surface of the spacer interrupting the color of the surrounding gum and gums of the patient.

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Even in cases where the spacers are very rarely exposed to the environment, it can be disruptive to the patient for psychological reasons. Also, it is not possible to design the bridge structure so that it descends toward the gumline and conceals the spacers because a sufficiently wide gap or space must exist between the gumline and the joint surface of the bridge structure around the spacer to enable cleaning in the boundary zone between the implant material and gum tissue. Such cleaning is very important in preventing inflammation of the gums, which can spread in the border zone between the implant material and the bone tissue and jeopardize the anchoring of the dental implant.

The object of the invention is to solve the aforementioned problems and to design the spacer so that it becomes less prominent in cases where it is exposed to the environment. The invention provides a solution to these problems and how the problems have been solved is apparent from the characterizing part of claim 1.

In the following, the invention will be described in more detail with reference to the accompanying drawings, in which Fig. 1 shows a section through a first embodiment of the invention and Fig. 2 shows an alternative embodiment in connection with an angled spacer.

Figure 1 shows a fastener in the form of a cylindrical screw 1 of titanium with an external thread 2 intended to be inserted into a pre-drilled hole in the jaw bone for permanent anchoring of a dental prosthesis. Attached to the upper portion 3 of the fixture is a spacer which comprises a substantially tubular spacer 4 also, made of titanium and a spacer 5 provided with a threaded portion 6 which engages an internally threaded bore 7 in the upper portion of the fixture to lock the spacer 4 fixture.

Both the fixture and the spacer screw are of a known per se and will therefore not be described in more detail here. Both consist of standard components included in the Nobelpharma Implant System. However, the spacer has been modified from prior spacers.

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The spacer member 4 is provided with a lower generally conical tapered portion 8 for gum passage and an upper cylindrical portion 9 which projects over the gum edge 10 and extends from said conical portion up to the joint surface 11 of a prosthetic structure (dental bridge), not shown. The spacer element 4 is made of pure titanium which is documented biocompatible and which has good strength properties to be able to absorb the forces of the screw joint.

Depending on the conditions in the mouth, after fitting the prosthetic structure, the cylindrical portion of the spacer element will normally be exposed. As mentioned initially, it should also be that way to facilitate cleaning around the spacers. However, because the titanium in the spacer breaks off gum and gum paint, this can be aesthetically disruptive for some patients. According to the invention, therefore, at least the cylindrical portion of the spacer element 4 is provided with a cladding in a tooth-like material, preferably ceramic or porcelain. This lining is provided as a sleeve 12 which can be loose and only attached to the spacer 4 by light clamping between the prosthesis and spacer. Due to the crack sensitivity of the material, the sleeve should not be load bearing. Alternatively, the sleeve feels fired directly against the titanium in the spacer.

The sleeve 12 of ceramic or porcelain can be ground and coated with porcelain in different colors at a dental laboratory for detailed analysis.^:adaptation to the prevailing situation in the patient's mouth. Sealing of the microscopic gaps in the joints between the sleeve 12 and the spacer 4 can be done with bio-adapted joint materials known per se. In cases where the sleeve is detachable, the advantage is that the spacer sensitive spacer is not contaminated or otherwise adversely affected during the dental process.

The spacer 4 is preferably provided with a pivot 13 for the spacer 12, whereby the outer contour 14 of the porcelain / ceramic at the shoulder 15 in the pivot is adapted to the outer contour of the spacer.

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As already mentioned, the spacer sleeve 12 can be loosely fitted to the spacer 4 or fired directly against the titanium therein. Preferably, however, the porcelain / ceramic in the spacer sleeve is applied to a thin cylinder 16 of gold, alumina or similar material as shown in both Figs. 1 and 2. If necessary, a bevel 17 of the cylinder 16 is made at the connection to the shoulder 15 in the spacer element so that The ceramic connects directly to the titanium in the spacer surface.

Figure 2 shows an example of an angled spacer member 18 with an outer cladding in the form of a spacer sleeve 19 of a kind similar to that already described in Fig. 1. In this case, the spacer sleeve 19 simultaneously forms a seal against the screw passage 20 of the spacer member 18.

By designing the spacer in the manner now described, the tissue in the innermost, most critical zone will abut against the titanium of the spacer 4 while the sleeve 12 borders the outer portion of the soft tissue and cladding the protruding portion of the spacer 4. '-. is taken up by the spacer 4 and the connection of the denture occurs above the gum line as in existing systems. In this way, the documented advantages of the existing distance system are retained, while the appearance of advantageous coating can be introduced without strength problems.

Although the invention is specifically intended to be used in conjunction with bridge structures, it can also be used in tooth replacement. Previous dental structures have meant that the entire denture is attached directly to the fixture under the gums, which means fitting problems (hidden joint) as well as disruption of the gingival dentition to the distance. According to the invention, a separate spacer sleeve can instead be applied to the spacer element and the denture itself can be tested without any fitting problems against the hidden joint under the gumline.

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