COATING OF DENTAL PROSTHETIC SURFACES COMPRISING A DISTINCT LAYER OF A SYNTHETIC HYDROXYAPATITE

Abstract

Subject matter of the invention are prosthetic mouldings, which have, at least area by area, at least one layer of biomimetic apatite selected from fluorapatite, hydroxylapatite or their mixtures on their surface, wherein the surface of the mouldings has micromechanical anchoring positions at least in this area to improve mechanical connection of apatite to the surface. Another subject matter of the invention are mouldings for use in dental, prosthetic treatment for tooth loss, in particular for cellular attachment of cells to prosthetic mouldings. Moreover, subject matter of the invention is the method for the production of the prosthetic mouldings.

Claims

1. A prosthetic moulding, wherein the moulding has, at least area by area, at least one layer of biomimetic apatite selected from fluorapatite, hydroxylapatite or their mixtures on its surface, wherein the surface has micromechanical anchoring positions at least in this area.

2. The moulding according to claim 1, wherein the layer thickness of the at least one apatite layer is at least 1 μm.

3. The moulding according to claim 1, wherein the moulding is an enossal implant (1), dental, enossal (intraosseous) implant (1), connecting element (2), mounting element (3), dental sleeve, abutment (2), suprastructure (2), part of a dental prosthesis, total denture, orthopedic prosthesis or parts thereof, artificial tooth, veneer, inlay, onlay, dental supporting structure (2,3), bridge (4), crown (4), relining, denture saddle, bone prosthesis, joint prosthesis, revision total joint endoprosthesis, and/or spacer.

4. The moulding according to claim 1, wherein the moulding is a connecting element (2), a mounting element (3), dental, enossal dental implant (1), and/or an implant post (2).

5. The moulding according to claim 1, wherein the moulding is formed of titanium, titanium alloy, titanium oxide, cobalt-chromium alloy, CoCrMo alloy, gold, dental ceramic, zirconium oxide, lithium disilicate, polymer, polymer mixture, dental prosthetic plastic.

6. The moulding according to claim 1, wherein the biomimetic apatite comprises amino acids, amino acid derivatives, proteins and/or denatured collagen.

7. The moulding according to claim 1, wherein at least one area of the surface of the moulding has micromechanical anchoring positions, which comprise a porous and/or rough surface topography.

8. The moulding, according to claim 1, wherein a) the surface of the prosthetic moulding has, area by area, micromechanical anchoring positions in the area, which is later arranged in the area of the gums (6), b) the surface of the prosthetic moulding has, area by area, micromechanical anchoring positions in the area, which is later arranged in the area of epithelial cells, of the gums, of the gingiva, gingival epithelial cells, fibroblasts, or the area of the epithelial cuff (junctional epithelium), wherein the prosthetic moulding is selected from connecting element (2), mounting element (3), abutment, implant (1), upper, outer prosthetic structure (4), crown (4), suprastructure (4), enossal implant (1), dental enossal (intraosseous) implant (1), dental sleeve, part of a dental prosthesis, part of a bone prosthesis, total denture, orthopedic prosthesis or parts thereof, artificial tooth, veneer, inlay, onlay, dental supporting structure (2,3), bridge (4), relining, denture saddle, bone prosthesis, joint prosthesis, revision total joint endoprosthesis, and/or spacer.

9. The moulding according to claim 1, wherein the biomimetic apatite is selected from fluorapatite, hydroxylapatite or their mixtures and has at least a carbon content of in the range of 0.25 to 2.5% by weight.

10. A method for the deposition of biomimetic apatite selected from fluorapatite, hydroxylapatite or their mixtures on a prosthetic moulding, comprising the steps of (i.a) providing a prosthetic moulding, wherein at least one area of the surface of the moulding has micromechanical anchoring positions, or (i.b) treating at least one area of the surface of the prosthetic moulding, and obtaining micromechanical anchoring positions, and optional (ii) treating at least one area of the surface of a prosthetic moulding, with a pretreatment compositions having a defined pH value, (iii) contacting at least this area of the prosthetic moulding comprising micromechanical anchoring positions with a composition containing phosphate ions, which comprises a gel forming agent, whereby a gel layer is formed, (iv) optionally applying a further layer, contacting the first gel layer with a further composition which comprises a gel forming agent, forming a further gel layer, (v) contacting the first gel layer or the further layer with a composition containing calcium ions, whereby a gel layer is formed, (vi) depositing biomimetic apatite selected from fluorapatite, hydroxylapatite or their mixtures on the surface of the prosthetic moulding.

11. The method according to claim 10, wherein (a) the composition containing phosphate ions comprises, (a.1) at least one gel forming agent, (a.2) water-soluble phosphates or phosphates being hydrolysable to water-soluble phosphate ions, (a.3) optionally fluoride, (a.4) optionally a carboxylic acid or a buffer system of pH 4 to 7, (a.5) optionally glycerin, and (b) wherein the composition containing calcium ions comprises, (b.1) at least one gel forming agent (b.2) calcium ions, (b.3) optionally glycerin.

12. The method according to claim 10, wherein treating the surface of the moulding comprises mechanical, chemical, electrochemical treatment and/or treating in a plasma process or by a combination of the methods, and an area of the surface of the prosthetic moulding having micromechanical anchoring positions is obtained, and optionally the surface is activated by a chemical, electrochemical and/or in a plasma process.

13. The method according to claim 10, wherein the composition containing phosphate ions and/or calcium ions, each independently, comprises amino acids, derivatives of amino acids, proteins collagen, or denatured collagen.

14. The method according to claim 10, wherein the gel forming agent comprises gelatine.

15. The method according to claim 10, wherein the composition containing phosphate ions and/or calcium ions, each independently, has a content of water.

16. An intermediate, comprising a prosthetic moulding, wherein the moulding has, at least area by area, at least one gel layer of a composition containing phosphate ions on its surface, and optionally thereon a further gel layer, and optionally a gel layer of a composition containing calcium ions.

17. A prosthetic moulding obtainable by a method according to claim 10.

18. Method of using biomimetic apatite for coating, at least area by area, of prosthetic mouldings.

19. Method of using a composition containing phosphate ions and of a composition containing calcium ions according to claim 10, or of formulations containing these compositions, for biomimetic deposition of apatite on a surface of a prosthetic moulding, wherein the surface has micromechanical anchoring positions or, wherein the surface of the moulding has been activated mechanically, chemically, electrochemically and/or by means of a plasma process prior to deposition.

20. Method according to claim 19, characterised in that a deposition, at least area by area, of biomimetic apatite ensues, and/or an essentially homogenous depositions of apatite ensues in this area.

21. A moulding according to claim 1 for use in dental, prosthetic, or surgical treatment for tooth loss for cellular attachment of cells of the gums or mucosal cells of the gums via hemidesmosomes or other biological mechanisms to areas contacting the moulding.

Description

[0072] The invention is elucidated in more detail with the figures, without limiting the invention to the subject matter of the figures.

[0073] The figures show schematically:

[0074] FIG. 1a: an edentulous area 0 in which a crown 4 shall be inserted,

[0075] FIG. 1b: the edentulous area in which an implant 1 with a connecting element 2 has been inserted in the bone,

[0076] FIG. 1c: implant 1 with connecting element 2, mounting element 3 and crown 4.

[0077] FIG. 2: cross section (without perspective) of a jaw area comprising gums 5a, gingiva 5a and jawbone 5b, showing the area 6 of connecting element 2 or implant 1 (prosthetic moulding, respectively) in the gums 5a of the epithelial cuff (junctional epithelium).

[0078] FIG. 3: Typical structure of a prosthetic tooth restoration 8 comprising an implant 1, a connecting element 2, the upper, outer prosthetic structure 4, e.g. dental crown, suprastructure optionally with outer coating, the area 6, in particular (junctional epithelium) of the implant and/or connecting element in the gums as well as a fixation screw 7.

[0079] FIG. 4: Shows different installation situations of implants 1 in the jawbone with or without connecting element 2.

[0080] FIG. 5: Shows a multitude of prosthetic restorations with crowns 4 comprising prosthetic mouldings according to the invention, such as connecting element 2 (abutment, spacer, pillar, post, implant shoulder etc.) optionally with connecting screw.

[0081] FIG. 6: Shows different installation situations of implants 1 in the jawbone with or without connecting element 2, wherein the surfaces, labelled by A, of the connecting elements have micromechanical anchoring positions with a biomimetically deposited apatite layer.

[0082] FIG. 7: cross section (without perspective) of a jaw area comprising gums 5a, gingiva 5a and jawbone 5b, showing the area 6 of connecting element 2 or implant 1 (prosthetic moulding, respectively) in the gums 5a of the epithelial cuff (junctional epithelium), wherein the surfaces, labelled by A, of the connecting elements have micromechanical anchoring positions with a biomimetically deposited apatite layer.

[0083] FIGS. 8a to 8e: titanium surface; FIG. 8a: non-enlarged and FIGS. 8b to 8e: enlarged (bar=1000 micrometers (FIG. 8b), =50 micrometers (μm) (FIG. 8c), 30 micrometers (FIG. 8d) and 20 micrometers (FIG. 8e)).

[0084] FIG. 9a: 7-fold coating on one side, layer thickness 14 to 30 μm

[0085] FIG. 9b: layer thickness of the biomimetic apatite layer: X1: ca. 14 μm, X2: ca. 30 μm

[0086] FIG. 10: REM picture of the biomimetic apatite layers (largely parallel arrangement of the almost vertical needles; bar=50 μm)

[0087] FIG. 11: enlargement of deposited biomimetic apatite layers

EXEMPLARY EMBODIMENTS

[0088] In the following, production of the gels is described in performed experiment. Basically, cross linking with GDA (glutardialdehyde) is not required for in vitro coating, but optionally possible.

[0089] 2C (two-component)—method example: (recipe for coating of Ti small plates having micromechanical anchoring positions)

Pretreatment Composition:

[0090] For the pretreatment composition, 0.1 mol Tris buffer is added to a 1 molar calcium chloride solution setting the pH value to 9.0.

Composition Containing Ca-Ions:

[0091] (i) For the Ca-gel: solving of 147 g CaCl.sub.2×2H.sub.2O with 47.5 g lactic acid in 800 ml water. A pH value of 10.5 is set using 106 ml 5 N NaOH. For the production of the gel, 18 ml of said solution are mixed with 6 g glycerin and 8 g calcium sulfate and 13.6 g 300 Bloom gelatine and heated. The liquid gel is spread with a squeegee to a thickness of 1 mm or pressed in a template having a wall thickness of 1 mm. Subsequent to solidifying the strips are cut into squares of 1×1 cm.

[0092] (ii) 2 g of a 25% GDA solution (glutardialdehyde) is topped up with water to 100 ml and gel squares are bathed therein for 20 s. Subsequently, the adhered liquid is carefully blown away. Now, the gels are analogously treated from the other side. The gel squares are shrink-wrapped in aluminium bags and individually harvested right before application.

Composition Containing Phosphate Ions:

[0093] (i) 59 g Na.sub.2HPO.sub.4 is set to a pH value of 4.0 with 91 g lactic acid, 6.6 g Olaflur, 6 ml 5 N NaOH, 300 ml water and topped up to 500 ml. 24 ml of the solution and 6 g glycerin and 10 g of a 300 Bloom pork rind gelatine are prepared into a viscous solution by heating. A little liquid is inserted in a template having a wall thickness of 500 μm and pressed under 2 bar pressure. Subsequent to solidifying, the strips are removed from the template and cut into squares of 1×1 cm.

[0094] (ii) 1.5 g of a 25% GDA solution is topped up with water to 100 ml and gel squares are bathed therein for 20 s. Subsequently, the adhered liquid is carefully blown away. Now, the gels are analogously treated from the other side. The gel squares are shrink-wrapped in aluminium bags and individually harvested right before application.

Coating of Ti Small Plates:

[0095] The surface of the Ti small plates was previously treated in non-thermic plasma (cold plasma). FIGS. 8a to 8e show the titanium surface, FIG. 8a non-enlarged and FIGS. 8b to 8e show the strongly porous surface being enlarged (bar=1000 μm (FIG. 8b), =50 μm (FIG. 8c), =30 μm (FIG. 8d) and =20 μm (FIG. 8e)). The surface exhibits a comprehensively distributed, micromechanical anchoring positions in the form of a porous surface. The pore diameters are in a range of about 0.5 μm to 20 μm.

[0096] 6 titanium small plates, respectively, are treated with the pretreatment composition and coated with each a piece of phosphate gel and a piece of calcium gel for evaluation of mineralisation activity. In order to emphasize the morphological modification of the titanium surface, one half of the slice was masked so that it may only remineralise on one side. The samples are stored in climatic chamber at 37° C. and 95% humidity and were cleaned with lukewarm water and soft toothbrush after 8 to 12 hours.

[0097] Pictures of the surface were taken after 7, 10, 12 and 17 replacement intervals by means of 3D microscope (Keyence) and the layer thickness were determined from the difference in height between coated and uncoated side. Subsequently, the sample was brightly polished carefully using 4000 sand paper and the layer thickness was determined again. Completeness of coating was analysed by means of REM.

TABLE-US-00001 Number of replacement intervals Layer thickness biomimetic apatite [μm]  1 Almost continuous coating (non-opening type)  7 14 to 31 10 18 to 42 12 18 to 50 17 20 to 60  21* 24 to 30 mean 28 [μm] *polishing ensues after 17 replacement intervals subsequently 4 further replacement intervals

[0098] The still uncoated titanium surface having micromechanical anchoring positions in the form of a strongly porous surface structure comprising pore diameters of 1 to 7 μm, see FIG. 8e, is shown in various enlargements in FIGS. 8a to 8e. FIGS. 9a and 9b show titanium surfaces coated on one side with biomimetic apatite after 7 replacement intervals. The layer thickness of the apatite layer is at 14 to 30 μm. FIG. 10 shows an REM picture of the biomimetically deposited apatite layers according to the invention and largely parallel arrangement of the almost vertical needles. Arrangement of the crystallite needles to apatite layers of the biomimetic apatite is clearly shown in the REM picture of FIG. 11.

[0099] XRD diffractograms (5° to 100° (2Theta)) were acquired in reflection with X'Pert Pro MPD from biomimetically deposited fluorine apatite layers, which may unambiguously be assigned to crystalline fluorapatite. FIG. 12 shows a XRD diffractrogram of fluorapatite crystallised from gelatine as fluorapatite with gelatine (source of radiation: Copper (Cu)). The XRD lines may unambiguously be assigned to Ca.sub.5(PO.sub.4).sub.3F, fluorapatite (hexagonal). Subsequently, the samples were analysed in elementary analyzer LECO “RC-612” regarding gelatine being present due to biomimetically deposited fluorapatite. The carbon content in biomimetically deposited apatite could be determined at 0.5% by weight.

LIST OF REFERENCE NUMERALS

[0100] 0 edentulous area in the jaw [0101] 1 implant [0102] 2 connecting element (abutment, spacer, pillar, post, implant shoulder etc.) optionally with connecting screw [0103] 3 mounting element [0104] 4 upper, outer prosthetic structure, for example dental crown, superstructure optionally with outer coating [0105] 5 jaw area comprising gums and jawbone; [0106] 5a gums, gingiva; 5b: bone [0107] 6 area of the implant and/or connecting element in the gums [0108] 7 fixation screw [0109] 8 prosthetic restoration comprising 1, 2 optionally 3, as well as 4, 6 and 7 [0110] A surface having micromechanical anchoring positions, such as, for example, a porous area, a roughed, etched or an area mechanically treated with solid particles, and having at least one layer of biomimetically deposited apatite

[0111] The prosthetic mouldings according to the invention comprising an apatite layer, which preferably is arranged in the patient in the epithelial cuff (junctional epithelium) serves for lastingly and biologically durably linking an edentulous area 0, such as shown in FIG. 1a, with an implant 1 supported crown 4 (FIGS. 1b and 1c). Said linkage is dynamic. It may therefore be broken and may coalesce again. Using prosthetic mouldings according to the inventions enables attachment of the mouldings to gingiva epithelial cells in the epithelial cuff (junctional epithelium) by means of hemidesmosomes. Bacterial contamination in the area of the implant may be reduced by this measure and biological linkage to this point of contact may be obtained. FIG. 2 shows a situation without apatite layer and with apatite layer according to the invention in FIG. 7. The prosthetic moulding according to the invention, here the connecting element 2, has a biomimetically deposited apatite layer according to the invention in the area of the gums 5a of the epithelial cuff (junctional epithelium) 6. Said biomimetically deposited apatite layer preferably comprises a content of amino acids, amino acid derivatives, proteins, denatured collagen, in particular the apatite comprises components of collagen, denatured collagen, gelatine protein chains, gelatine glycerin gel of the compositions from which the apatite is deposited.

[0112] FIGS. 4 and 6 show different installation situations of implants 1 with different connecting elements 2, wherein in FIG. 6, the connecting elements 2 have different areas, labelled by A, of the surface. Said areas A have micromechanical anchoring positions, such as, for example, a porous area, a roughened, etched or an area mechanically treated with solid particles. A biomimetic apatite layer of at least 1 μm (micrometer) to 100 μm or to 1 mm is grown up on these micromechanical anchoring positions. According to the invention, the biomimetic apatite layer is obtained by crystallisation of apatite from the afore-mentioned compositions, in particular gels. The biomimetic apatite is later, in the mouth of the patient, linked to the epithelial cells of the gingiva, in particular the epithelial cuff (junctional epithelium), by cellular attachment, in particular via hemidesmosomes.

[0113] FIGS. 3 and 5 show typical mouldings of a prosthetic tooth restauration, wherein FIG. 3 shows the particular mouldings and FIG. 5 the assembled prosthetic mouldings for insertion in an upper jaw.

[0114] The person skilled in the art knows that, according to the invention, all appropriate mouldings made of every physiologically suitable material may be provided with a biomimetic apatite layer as prosthetic mouldings. Absorbable mouldings may also be used as prosthetic mouldings.