Dental prosthesis system comprising a connecting screw made of metallic zirconium

Abstract

The invention relates to a dental prosthesis system having an implant (1) for osseointegration into a jaw bone, in particular made of ceramic, an abutment (2), in particular made of ceramic, and a connecting screw (3) for connecting the implant (1) and the abutment (2). The connecting screw (2) consists of a metallic zirconium with a chemical purity of at least 85 wt.%, in particular at least 90 wt.%.

Description

[0001] Dental prosthesis system with a connecting screw made of metallic zirconium

[0002] Field of the invention

[0003] The invention relates to a dental prosthesis system comprising an implant for osseointegration in a jawbone, an abutment and a connecting screw for connecting the implant and the abutment.

[0004] background

[0005] In dental implantology, dental prosthesis systems made of titanium are still mainly used. Titanium is characterized by excellent corrosion behavior and therefore has good immunological compatibility compared to other metals. Such dental prosthesis systems usually consist of an implant which is anchored in the bone, an abutment to hold the dental crown and a connecting screw, with all three elements being made of titanium or a suitable titanium alloy. The abutment has a through-hole which is designed to receive the connecting screw in order to fix the abutment in the implant by screwing. The abutment usually comprises an abutment head and an abutment stem. The through-hole penetrates the head and stem.The implant has an opening at its distal end, for example in the form of a blind hole, which accommodates the abutment stem and the connecting screw. Typically, an internal thread is located in this opening. When fixing the abutment in the implant, the abutment is first positioned in the implant, the connecting screw is inserted through the through hole, and screwed tight.

[0006] This connection of abutment to implant has proven successful in dental prosthesis systems in which all components are made of titanium or titanium alloys. The ductile behavior and plastic deformability of titanium or titanium alloys enable the absorption of bending loads that act on the tooth crown and the underlying abutment during chewing. This material behavior ensures at least a partial seal, particularly between the abutment and implant. This applies in particular to the tensile and compressive forces that occur.

[0007] Alternatively, dental prosthesis systems are used in which the abutment and implant are made of ceramic. Ceramic implants can be connected with a screw made of titanium, gold, or a metal-free PEEK-carbon fiber composite. The connecting screw is tightened with a torque of approximately 25-35 Ncm. This results in considerable and clearly visible metallic abrasion, particularly in ceramic implants with a titanium screw. In patients with a titanium intolerance, this induces undesirable inflammatory symptoms that can lead to a lack of bony integration, perigingivitis, and peri-implantitis. Such patients are therefore discouraged from purchasing such dental prosthesis systems.

[0008] Another alternative is to bond the abutment and implant together. Such systems solve the problem of wear, but are more complicated to handle during surgery and are unpopular due to their lack of reversibility.

[0009] Description of the invention

[0010] The objective is to provide a dental prosthesis system that is suitable for patients with titanium intolerance and easy to use. This objective is achieved by the dental prosthesis system according to the independent device claim. Accordingly, the dental prosthesis system comprises

[0011] - an implant for osseointegration into a jawbone. The implant is made primarily of ceramic.

[0012] - an abutment, particularly made of ceramic.

[0013] - a connecting screw to connect the implant and the abutment.

[0014] The implant is the part of the dental prosthesis system anchored in the jawbone. The abutment is a separate part from the implant. The abutment will later serve to hold the dental crown. It is placed on the implant and secured with a connecting screw.

[0015] The connecting screw consists of a metallic zirconium with a chemical purity of at least 85% by weight, in particular at least 90% by weight. The chemical purity shall be measured by atomic absorption spectrometry.

[0016] Since zirconium, like titanium, is a base metal, a thin, ceramic layer of zirconium dioxide ZrÜ2 is always formed on its surface.

[0017] Because zirconium exhibits mechanical properties comparable to titanium, no increased diameter or limitations on prosthetics are necessary. Since zirconium can also be anodized, resulting in color spectra similar to titanium, the connecting screw can appear colored. This has aesthetic advantages.

[0018] Experience shows that a dental prosthesis system with a connecting screw made of zirconium does not cause any undesirable inflammatory symptoms in patients with a titanium intolerance.

[0019] Zirconium and hafnium cannot be separated chemically. Therefore, even pure zirconium still contains hafnium. In particular, metallic zirconium contains less than 4.5% hafnium by weight.

[0020] Advantageously, the metallic zirconium comprises in weight percent: less than 0.05% carbon, less than 0.2% metals selected from the group comprising chromium and iron, less than 0.025% nitrogen.

[0021] In particular, the metallic zirconium comprises in weight percent: 1 to 2% tin or 2 to 3% niobium .

[0022] Zirconium, hafnium, niobium, carbon, chromium, iron and nitrogen advantageously complement the above-mentioned areas to 100%.

[0023] Suitable materials include:

[0024] Zr 705 (UNS R60705) is a zirconium alloy with niobium additions. It contains less than 0.05% carbon, less than 0.2% metals selected from the group consisting of chromium and iron, less than 0.025% nitrogen, 95.5% zirconium (including a maximum of 4.5% hafnium), and 2 to 3% niobium. This alloy exhibits good resistance in highly corrosive environments, is very tough, and has good mechanical properties.

[0025] - Zr 704 (UNS R60704) is a zirconium alloy with tin additions. It contains less than 0.05% carbon, between 0.2% and 0.4% metals selected from the group consisting of chromium and iron, less than 0.025% nitrogen, 97.5% zirconium (including a maximum of 4.5% hafnium), and 1 to 2% tin.

[0026] - Zr 702 (UNS R60702) is an unalloyed zirconium alloy. It contains less than 0.05% carbon, less than 0.2% metals selected from the group consisting of chromium and iron, less than 0.025% nitrogen, and 99.2% zirconium (including a maximum of 4.5% hafnium).

[0027] The materials Zr 705, Zr 704, Zr 702 are distributed, for example, by the company Metalcor, Essen, Germany.

[0028] In particular, the metallic zirconium has a tensile strength of at least 380 N / mm 2 , in particular at least 420 N / mm 2 , in particular at least 580 N / mm 2 . A high tensile strength of the material is required in order to be able to tighten the connecting screw sufficiently.

[0029] The connecting screw made of metallic zirconium advantageously has a non-metallic surface layer on its surface. In particular, the non-metallic surface layer is a zirconium oxide layer, i.e., consisting of ZrO2. The surface layer forms spontaneously, and the thickness of the surface layer can be increased using various surface engineering processes.

[0030] In particular, the non-metallic surface layer has an average thickness of at least 5 pm, in particular at least 10 pm, in particular at least 15 pm. The thickness is to be determined by microscopy. Such a layer thickness provides sufficient protection to prevent metallic abrasion.

[0031] It is advantageous to anodize or thermally oxidize the surface of the connecting screw. This allows the protective surface layer to be created to the thickness required for the application of the connecting screw.

[0032] The implant and / or the abutment are advantageously made of zirconium dioxide or doped zirconium dioxide.

[0033] In particular, the connecting screw has a screw head, wherein the screw head has a diameter of a maximum of 2.7 mm, in particular a maximum of 2.6 mm, in particular a maximum of 2.5 mm, in particular a maximum of 2.4 mm. Such small diameters are comparable to titanium screws and facilitate the assembly of the dental prosthesis system by the medical professional.

[0034] In particular, the abutment comprises a continuous opening for the passage of the connecting screw and, in particular, the implant comprises a receiving opening for receiving the connecting screw. Brief description of the drawings

[0035] Further embodiments, advantages, and applications of the invention will become apparent from the dependent claims and the following description with reference to the figures. In these figures:

[0036] Fig. 1 a denture with an implant and a dental crown;

[0037] Fig. 2 a denture system; and

[0038] Fig . 3 the dental prosthesis system according to Fig . 2 in a sectional view .

[0039] Way to implement the invention

[0040] Fig. 1 shows a schematic representation of a set of teeth with a tooth gap into which a dental prosthesis system according to the invention is to be integrated. The dental prosthesis system comprises an implant 1, an abutment 2 and a connecting screw 3 which connects the abutment 2 to the implant 1. In the present illustration in Fig. 1, the implant 1 is already screwed into the jawbone 5 by means of its external thread 12 and the abutment 2 is screwed to the implant 1 by means of the non-visible connecting screw 3. The dental crown 5 will be fixed to the abutment 2. When chewing, forces of up to 800 N occur which must be withstood by the dental prosthesis system.

[0041] Fig. 2 shows the denture system as already depicted in Fig. 1. Fig. 2 is a side view of the denture system. It comprises the implant 1 and the abutment 2. The implant 1 and the abutment 2 are made of a ceramic material, preferably zirconium dioxide.

[0042] Fig. 3 shows a sectional view of the dental prosthesis system according to Fig. 2. In this sectional view, in addition to the implant 1 and the abutment 2, the connecting screw 3 is also visible. The implant 1 has a receiving opening 11 and the abutment 2 has a through-bore 21. The receiving opening 11 and the through-bore 21 accommodate the connecting screw 3 in order to connect the implant 1 and the abutment 2 in this way. An external thread 12 is arranged on the outer surface of the implant 1, with which the implant 1 can be screwed into the jawbone.

[0043] The connecting screw 3 is made of a zirconium alloy Zr705, the chemical composition of which has already been described. The tensile strength is 580 N / mm 2 The connecting screw 3 comprises a surface layer 31 made of zirconium dioxide, which has a layer thickness of at least 10 μm prior to assembly in the dental prosthesis system. Abrasion may have occurred during the insertion and tightening of the connecting screw 3, so that the connecting screw 3 has an irregularly thick surface layer 31 in the assembled state.

[0044] The connecting screw 3 comprises a screw head 32 and a screw shaft 33. The screw head 32 includes a recess 34 for receiving a screwing tool. The diameter D of the screw head is 2.4 mm.

[0045] The screw shaft 33 has a circumferential external thread 35 on its outer surface, which corresponds to an internal thread 13 in the receiving opening 11.

[0046] While preferred embodiments of the invention are described in the present application, it is to be clearly understood that the invention is not limited thereto and may be embodied in other ways within the scope of the following claims.

[0047] List of reference symbols I Implant

[0048] II Receiving opening

[0049] 12 external threads

[0050] 13 Internal thread 2 Abutment

[0051] 21 Through hole

[0052] 3 connecting screw

[0053] 31 Surface layer

[0054] 32 Screw head 33 Screw shaft

[0055] 34 recess

[0056] 35 external thread

[0057] 4 jaw bones

[0058] 5 Crown D Diameter of the screw head

Claims

Patent claims 1. Comprehensive denture system - an implant (1) for osseointegration in a jawbone (4), in particular made of ceramic, - an abutment (2), in particular made of ceramic, - a connecting screw (3) for connecting the implant (1) and the abutment (2), characterized in that the connecting screw (2) consists of a metallic zirconium with a chemical purity of at least 85% by weight, in particular at least 90% by weight.

2. A dental prosthesis system according to claim 1, wherein the metallic zirconium comprises less than 4.5% hafnium by weight.

3. Dental prosthesis system according to one of the preceding claims, wherein the metallic zirconium comprises in weight percent: less than 0.05% carbon, less than 0.2% metals selected from the group comprising chromium and iron, less than 0.025% nitrogen.

4. A dental prosthesis system according to any one of the preceding claims, wherein the metallic zirconium comprises in weight percent: 1 to 2% tin or 2 to 3% niobium.

5. Dental prosthesis system according to one of the preceding claims, wherein the metallic zirconium has a tensile strength of at least 380 N / mm 2 , in particular at least 420 N / mm 2 , in particular at least 580 N / mm 2 has.

6. Dental prosthesis system according to one of the preceding claims, wherein the connecting screw (3) made of metallic zirconium has a non-metallic surface layer (31) on its surface.

7. Dental prosthesis system according to claim 6, wherein the surface layer (31) is a zirconium dioxide layer.

8. Dental prosthesis system according to claim 6 or 7, wherein the non-metallic surface layer (31) has an average thickness of at least 3 pm, in particular at least 5 pm, in particular at least 10 pm.

9. Dental prosthesis system according to one of the preceding claims, wherein the implant (1) and / or the abutment (2) consist of zirconium dioxide or doped zirconium dioxide.

10. Dental prosthesis system according to one of the preceding claims, wherein the connecting screw (3) has a screw head (32), wherein the screw head (32) has a diameter (D) of a maximum of 2.7 mm, in particular a maximum of 2.6 mm, in particular a maximum of 2.5 mm, in particular a maximum of 2.4 mm.

11. Dental prosthesis system according to one of the preceding claims, wherein - the abutment (2) has a through opening (21) for the passage of the connecting screw (3), and - the implant (1) has a receiving opening (11) for receiving the connecting screw (3).

12. A method for producing a dental prosthesis system according to claim 6 and one of the preceding claims, wherein the surface layer (31) of the connecting screw (3) is produced by anodizing.

13. A method for producing a dental prosthesis system according to any one of claims 1 to 11, wherein the Surface layer (31) of the connecting screw (3) is produced by thermal oxidation.

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