WO2012095878A1

WO2012095878A1 - Semi-worked composite material for dental implants

Info

Publication number: WO2012095878A1
Application number: PCT/IT2011/000011
Authority: WO
Inventors: Umberto Ratti
Original assignee: Bioloren S.R.L.
Priority date: 2011-01-13
Filing date: 2011-01-13
Publication date: 2012-07-19

Abstract

A semi-worked piece of composite material for dental implants comprising a polymeric matrix portion (2) and a plurality of primary fibres (3) buried in the polymeric matrix portion (2) and aligned along a major extension path (P). The semi-worked piece comprises a reinforcing jacket (4) including reinforcing fibres (5) buried in the polymeric matrix portion (2) and inclined relative to the major extension path (P) of the primary fibres (3). The reinforcing jacket (4) has a section transverse to said major extension path (P) which is closed loop-wise.

Description

SEMI-WORKED · COMPOSITE MATERIAL PIECE FOR DENTAL IMPLANTS

Description

The present invention relates to a semi-worked piece of composite material for making dental implants. In particular the semi-worked piece is used for making dental posts or stumps.

Known in the dental/odontological field is use of composite materials for making articles of manufacture or devices for dental implants, i.e. when artificial rebuilding of an operated tooth is required. The commonly made articles of manufacture/devices for the above purpose are (endosseous or endodontic) posts or stumps on which dental crowns are subsequently mounted, which crowns reproduce the original shape of the tooth before the odontological operation.

The composite materials comprise a polymeric matrix inside which fibres of high mechanical strength are buried. Generally these composite materials have mechanically resistant fibres of elongated and continuous shape, more particularly the fibres being disposed under a condition of mutual parallelism.

Taking into account the uniqueness of the odontological cases requiring rebuilding with dental posts or stumps, the latter cannot be made in series. Thus the dentists generally start from a semi-worked piece like that according to the present invention, and submit it to mechanical workings, to turning and/or milling operations for example, so as to obtain the particular post or stump. The known semi-worked pieces, exactly during these working steps, show some drawbacks. In fact, the semi- worked pieces made up of composite materials in which the fibres are longitudinal and parallel, appear to be poorly resistant to mechanical actions that do not operate in the longitudinal extension direction of said fibres. In other words, stresses transverse to the fibres that are usually generated during workings can lead to structural relaxation of the polymeric matrix and consequent loss of the article of manufacture. Yet more particularly, these composite materials are said to appear anisotropic, which means that they have different mechanical features depending - on the direction along which they are stressed.

The problem concerning anisotropy of the composite materials for dental use has been already dealt with. For instance, in document WO2010/109496 a construction solution is shown for a composite material comprising different material layers superposed on each other. Each individual layer is obtained from a polymeric matrix and a plurality of resistant fibres disposed along a single direction or in a weft and warp configuration. Each individual layer is superposed in such a manner that the fibres are arranged in different directions, so as to ensure mechanical strength under any load condition.

This approach however has some disadvantages. In fact the intensive use of the resistant fibres inside the polymeric matrix greatly increases the production costs of the semi-worked piece. In addition, a high strength in all directions being obtained, the mechanical workings become more difficult, thus wearing out the utilised tools to a greater extent. The technical task underlying the present invention is to propose a semi-worked piece of composite material for dental implants overcoming the above mentioned drawbacks of the known art.

In particular, it is an aim of the present invention to make available a semi-worked piece of composite material for dental implants capable of withstanding stresses caused by the mechanical workings for making dental posts and/or stumps and having low production costs.

It is a further aim of the present invention to make a semi-worked piece for dental implants having an optimised reinforcing structure for manufacturing dental posts and/or stumps.

The technical task mentioned and the aims specified are substantially achieved by a semi-worked piece of composite material for dental implants, comprising the technical features set out in one or more of the appended claims.

Further features and advantages of the present invention will become more apparent from the description given by way of non-limiting example of a preferred but not exclusive embodiment of a semi-worked piece for dental implants of composite material as shown in the accompanying drawings, in which:

- Fig. 1 shows a perspective view of a semi-worked piece according to the present invention;

- Fig. 2 is a section view of the semi-worked piece seen in Fig. 1 taken along line II-II;

- Fig. 3 is a section view of the semi-worked piece in Fig. 1 taken along line III-III; - Fig._. 4 is- a perspective view of a variant of the semi-worked piece of the invention; and

- Fig. 5 is a section view of the semi-worked piece in Fig. 4 taken along line IV-IV.

With reference to the drawings, a semi-worked piece of composite material for dental implants as shown in Fig. 1 has been generally identified by reference numeral 1. The semi-worked piece 1 comprises a portion of polymeric matrix 2. This polymeric matrix portion 2 can be formed with an epoxy or polyester resin. More particularly it can consists of a material of the PEEK or PEKK type. The composite material of which the semi- worked piece 1 is made comprises a plurality of primary fibres 3 buried in the polymeric matrix portion 2 and disposed along a major extension path P. In other words, the primary fibres 3 run along a common direction identified by the major extension path P. More particularly, the primary fibres 3 can be disposed almost parallel to each other. In a preferred embodiment of the semi-worked piece 1 according to the present invention, the major extension path P is substantially rectilinear. As a result, in this case, also the primary fibres 3 are substantially rectilinear and almost parallel to each other. The primary fibres 3 can be made of a glass fibre, aramidic fibre or carbon fibre (or also, still by way of example, of quartz or polyethylene fibre) , depending on the specific requirements of mechanical strength that are wished to be given to the semi-worked piece 1.

The semi-worked piece 1 further comprises a reinforcing jacket 4 in turn comprising reinforcing fibres 5 buried in the polymeric matrix portion 2 as well. These reinforcing fibres 5 are inclined to the major extension path P and therefore appear to be inclined to the primary fibres 3. The reinforcing jacket 4 has a section transverse to said major extension path P which is closed to form a loop. In other words, the reinforcing jacket 4 has such a spatial extension as to create a closed outline looking at the section transverse to the major extension path P of the semi- worked piece 1. The loop-shaped closed outline can show the most different and polygonal geometries depending on the specific requirements and the type of article of manufacture that is wished to be obtained from the semi-worked piece 1. The reinforcing jacket 4 is disposed in the polymeric matrix portion 2 along the whole peripheral region of said polymeric matrix portion 2. In other words, based on the outer geometry that is wished to be given to the semi-worked piece 1, and more particularly to the polymeric matrix portion 2, the reinforcing jacket 4 is positioned in the peripheral regions in the vicinity of the outer surfaces of the semi-worked piece so as to enable reinforcement of most of the semi-worked piece and consequently allow the inner regions of the semi-worked piece to be machined without running the risk of breaking said piece under the tools' action.

In a preferred embodiment, the reinforcing jacket 4 has a tubular configuration extending along the major extension path P of the primary fibres 3. In other words, looking at the reinforcing jacket 4 during a step preceding the operation of burying it in the polymeric matrix portion 2, it has the shape of a tube of appropriate sizes that by its action contains the composite material subsequently included inside it. In particular, the reinforcing fibres 5 can develop in a helical pathway around the major extension path P of the primary, fibres 3. As shown in Fig. 1, the reinforcing jacket 4 in the tubular configuration is formed with a plurality of reinforcing fibres 5 helically extending following a given inclination relative to the primary fibres 3 along the major extension path P.

In particular, the reinforcing fibres 5 are disposed within the polymeric matrix portion 2 at an inclination included between 30° and 60° relative to the major extension direction P of the primary fibres 3, as shown in Fig. 1. In the preferred embodiment, the inclination of the reinforcing fibres 5 is about 45° relative to the major extension direction P.

In addition, these reinforcing fibres 5 can consist of glass fibre, aramidic fibre, carbon fibre, quartz fibre or polyethylene fibre. In particular the reinforcing fibres 5 can be made of a material different from that selected for the primary fibres 3, depending on the specific requirements of mechanical strength that are wished to be given to the semi-worked piece 1.

In this preferred embodiment, the polymeric matrix portion 2 too is formed in such a manner as to obtain a semi-worked piece 1 of cylindrical shape. In this case the semi-worked piece 1 has a geometric extension axis almost coincident with the major extension path P of the primary fibres 3. Consequently, the reinforcing jacket 4 too is made in a tubular configuration with a cylindrical cross-section in which the radius Rc of the reinforcing jacket 4 is included between 0.5 and 0.8 of the radius Rm of the polymeric matrix portion 2 in which it is buried. In the preferred embodiment, the polymeric matrix portion 2 and reinforcing jacket 4 in their cylindrical configurations are coaxial with each other. In other words, the cylinder axis defined by the polymeric matrix portion \2 and that defined by the reinforcing jacket 4 are almost coincident and correspond to the major extension path P of the primary fibres 3.

In an alternative embodiment shown in Fig. 4, the semi- worked piece 1 has a hole 6 formed along the major extension path P. In this embodiment the radius Rc of the reinforcing jacket 5 is included between the radius Rf of hole 6 and 0.8 of the radius Rm of the polymeric matrix portion 2.

The preferred use of the semi-worked piece 1 is accomplishment of posts or stumps for dental implants. In fact, starting from the semi-worked piece of the present invention, different articles of manufacture for dental use for dental implants can be made.

Finally, an article of manufacture obtained from the semi-worked piece 1 according to the present invention can be included in an assembling kit for dental implants. The kit comprises an article of manufacture of odontological use obtained from a semi-worked piece 1 which has a flare abutment element 10 and a fastening member 11 provided with an abutment head 12 coming into contact with the abutment element 10 of the semi-worked piece 1 at a single contact point 13.

The invention as described reaches the intended purposes and achieves the previously mentioned important advantages. The semi-worked piece comprising the reinforcing jacket having a closed cross-section achieves the important advantage of having a structure resistant to stresses due to mechanical workings, more particularly to the loads acting transversely of the orientation of the primary fibres of the composite material of which the semi-worked piece is made. The particular arrangement of the reinforcing jacket allows the mechanical strength of the semi-worked piece to be improved with a small use of reinforcing fibres, so that the production costs of the semi-worked piece can be greatly reduced. At the same time, the structure of the semi-worked piece enables dental posts or stumps of great strength to be obtained, which are also optimised in terms of productions costs, and can be manufactured through easy machining operations.

Claims

1. A semi-worked piece of composite material for dental implants, comprising:

- a polymeric matrix portion (2);

- a plurality of primary fibres (3) buried in said polymeric matrix portion (2) and substantially aligned along a major extension path (P) ;

characterised in that it comprises:

- a reinforcing jacket (4) including reinforcing fibres (5) buried in said polymeric matrix portion (2) and inclined to the major extension path (P) of the primary fibres (3), said reinforcing jacket (4) having a section transverse to said major extension path (P) that is closed loop-wise.

2. A semi-worked piece as claimed in claim 1, characterised in that the reinforcing jacket (4) is disposed along the whole peripheral region of the polymeric matrix portion (2).

3. A semi-worked piece as claimed in claim 1 or 2, characterised in that the reinforcing jacket (4) has a tubular configuration extending along the major extension path (P) of the primary fibres (3).

4. A semi-worked piece as claimed in anyone of the preceding claims, characterised in that the polymeric matrix portion (2) is of cylindrical shape with a geometric extension axis thereof almost coincident with the major extension path (P) of the primary fibres (3) and in that the reinforcing jacket (4) has a radius (Rc) included between 0.5 and 0.8 of the radius (Rm) of said polymeric matrix portion (2).

5. A semi-worked piece as claimed in claim 4, characterised in that the polymeric matrix portion (2) and reinforcing jacket (4) are coaxial with each other.

6. A semi-worked piece as claimed in anyone of the preceding claims, characterised in that the reinforcing fibres (5) extend in a helical pathway around the major extension path (P) of the primary fibres (3) .

7. A semi-worked piece as claimed in anyone of the preceding claims, characterised in that the reinforcing fibres (5) are disposed at an inclination included between 30° and 60° relative to the major extension path (P) of the primary fibres (3), being preferably disposed at 45°.

8. A semi-worked piece as claimed in anyone of the preceding claims, characterised in that it has a hole (6) formed along the major extension path (P) of the reinforcing fibres.

9. An article of manufacture for odontological use for dental implants, characterised in that it is obtained from a semi-worked piece (1) as claimed in anyone of the preceding claims.

10. A kit for assembling dental implants, characterised in that it comprises:

an article of manufacture for odontological use obtained from a semi-worked piece (1) as claimed in anyone of claims 1 to 8 and comprising a flared abutment element (10) ; ..

- a fastening member (11) comprising an abutment head (12) coming into contact with said abutment element (10) at a single contact point (13).