Dental implant

Abstract

A dental implant including a dental implant basic body extending along a longitudinal axis from an apical end to an opposite coronal end, which includes an anchoring part facing the apical end and intended to be anchored in bone of a patient, and a head part facing the coronal end and intended to form the basis on which a suprastructure is mounted. The anchoring part includes a shaft that is substantially cylindrical or that tapers toward the apical end in a cone-like manner. At least a portion of the shaft forms a bone tissue contact region, the outer surface forming a bone tissue contact surface. Coronally to the contact region a soft tissue contact region is arranged, the outer surface forming a soft tissue contact surface. The implant further includes nanostructures formed on the soft tissue contact surface which extend in at least two dimensions to 200 nm at most.

Claims

1. A dental implant comprising a dental implant basic body extending along a longitudinal axis A from an apical end to a coronal end arranged opposite to the apical end, said dental implant basic body comprising an anchoring part facing the apical end and intended to be anchored in bone of a patient, and a head part facing the coronal end and intended to form the basis on which a suprastructure is mounted, said anchoring part comprising a shaft having a basic form that is substantially cylindrical or that tapers in a direction toward the apical end, at least a portion of the shaft forming a bone tissue contact region, the outer surface of which forms a bone tissue contact surface, and a soft tissue contact region being arranged coronally to said bone tissue contact region, the outer surface of the soft tissue contact region forms a soft tissue contact surface, wherein the dental implant further comprises nanostructures formed on the soft tissue contact surface, said nanostructures extending in at least two dimensions to 200 nm at most; and the soft tissue contact surface is macroscopically and microscopically smooth.

2. The dental implant according to claim 1, wherein the soft tissue contact surface of the dental implant basic body on which the nanostructures are formed is machined or polished.

3. The dental implant according to claim 1, wherein the dental implant basic body is made of titanium or a titanium alloy.

4. The dental implant according to claim 1, wherein said nanostructures comprise titanium hydride and/or titanium oxide.

5. The dental implant according to claim 1, wherein the nanostructures are at least predominantly in crystalline phase.

6. The dental implant according to claim 1, wherein the nanostructures have an average length-to-diameter ratio of more than 1 to 1.

7. The dental implant according to claim 1, wherein the nanostructures have an average diameter of about 10 nm to 150 nm and an average length of about 5 nm to 500 nm.

8. The dental implant according to claim 1, wherein the soft tissue contact surface has a hydrophilicity defined by a contact angle of less than 90 when contacted with water.

9. The dental implant according to claim 1, wherein the bone tissue contact region extends from the apical end in a direction to the coronal end in a length l.sub.bcr ranging from 4 to 16 mm.

10. The dental implant according to claim 1, wherein the soft tissue contact region extends from a respective end of the bone tissue contact region in a direction to the coronal end in a length l.sub.scr ranging from 1 mm to 3 mm.

11. A process for providing sites of improved protein adherence on a dental implant basic body extending along a longitudinal axis A from an apical end to a coronal end arranged opposite to the apical end, said process comprising growing nanostructures on a soft tissue contact surface of the dental implant basic body by treating the soft tissue contact surface with an aqueous solution; wherein the dental implant basic body comprises: an anchoring part facing the apical end and intended to be anchored in bone of a patient, and a head part facing the coronal end and intended to form the basis on which a suprastructure is mounted, said anchoring part comprises a shaft having a basic form that is substantially cylindrical or that tapers in a direction toward the apical end, at least a portion of the shaft forms a bone tissue contact region, the outer surface of which forms a bone tissue contact surface, a soft tissue contact region is arranged coronally to said bone tissue contact region, the outer surface of the soft tissue contact region forms the soft tissue contact surface on which the nanostructures are grown, and the soft tissue contact surface is macroscopically and microscopically smooth.

12. The process according to claim 11, wherein the dental implant basic body is made of titanium or a titanium alloy.

13. The process according to claim 11, wherein the aqueous solution is an acidic solution comprising at least one component selected from the group consisting of hydrogen fluoride, nitric acid, hydrochloric acid, sulphuric acid, tartaric acid, oxalic acid, citric acid, acetic acid, and mixtures thereof.

14. The process according to claim 11, wherein the growing of the nanostructures is performed by cathodic polarization, in which the dental implant basic body forms the cathode.

15. The process according to claim 14, wherein the soft tissue contact surface is pickled with a pickling solution in order to at least partially remove a titanium oxide layer present on the soft tissue contact surface before performing the cathodic polarization.

16. The process according to claim 15, wherein the pickling solution comprises at least one component selected from the group consisting of nitric acid, hydrofluoric acid, ammonium fluoride, hydrochloric acid, sulphuric acid, and mixtures thereof.

17. The process according to claim 14, wherein the cathodic polarization is performed in a buffer having a pH in a range of from 0 to 6.

18. The process according to claim 14, wherein the cathodic polarization is performed at a temperature in a range of from 5 to 95 C.

19. The process according to claim 11, wherein the nanostructures are grown on the soft tissue contact surface by storing the soft tissue contact surface in the aqueous solution.

20. The process according to claim 19, wherein the storing is performed for at least one month.

21. The process according to claim 19, wherein the storing is performed above room temperature.

22. The process according to claim 11, further comprising roughening the bone tissue contact surface of the dental implant basic body.

23. The process according to claim 22, wherein the bone tissue contact surface is roughened by sand-blasting, machining, acid-etching, or combinations thereof.

Description

(1) The present invention is further illustrated by way of the attached figures, of which

(2) FIG. 1 shows a dental implant according to the present invention, comprising a dental implant basic body with nanostructures formed on the soft tissue contact region; and

(3) FIG. 2 shows a picture of the soft tissue contact surface of a dental implant according to the present invention, said picture being obtained by Field Emission Scanning Electron Microscopy.

(4) The dental implant 2 shown in FIG. 1 comprises a dental implant basic body 10, which extends along a longitudinal axis A from an apical end 12 to a coronal end 14 arranged opposite to said apical end.

(5) In the apical end region, the dental implant basic body 10 comprises an anchoring part 16 which is intended to be anchored in bone of a patient.

(6) In the coronal end region, the dental implant basic body 10 comprises a head part 18, which is intended to form the basis on which a suprastructure is mounted.

(7) The anchoring part 16 comprises a shaft 20, which has a basic form that is substantially cylindrical tapering into a rounded tip towards the apical end 12 and on which an outer thread 21 is formed. The shaft 20 forms a bone tissue contact region 22 which extends from the apical end 12 in the direction to the coronal end 14, i.e. in longitudinal direction, in a length l.sub.bcr and which is destined to be in contact with bone when in the implanted state.

(8) Coronally adjacent to the bone tissue contact region 22 a soft tissue contact region 24 is arranged, which from the respective end of the bone tissue contact region 22 extends in the direction to the coronal end 14, i.e. in longitudinal direction, in a length l.sub.scr and thereby widens in a cup shape.

(9) At the outermost coronal end 14 of the dental implant basic body 10 and directly adjacent to the soft tissue contact surface, a shoulder 26 is formed, which frusto-conically tapers towards the coronal end 14. Further, the coronal end 14 is provided with a recess 28, into which a abutment (not shown) can be fitted.

(10) The outer surface of the bone tissue contact region 22 forms a bone tissue contact surface 30, which typically has an osteointegrative surface topography, e.g. obtainable by sand-blasting and subsequent acid-etching.

(11) The outer surface of the soft tissue contact region 24 forms a soft tissue contact surface 32. On the soft tissue contact surface 32, nanostructures are formed, which will be illustrated by way of FIG. 2.

(12) In an alternative to the embodiment shown in FIG. 1, in which the soft tissue contact surface 24 widens in direction to the coronal end 14, it is also possible for the soft tissue contact region to be cylindrical and/or to be kept very short.

(13) During implantation, the bone tissue contact region 22 is preferably embedded completely in the bone of the patient andafter implantationis therefore surrounded by the bone. A rapid development of a primary stability is thereby achieved by the outer thread 21 engaging in the bone of the patient.

(14) During the healing period, the bone tissue contact region 22 ossifies with the bone, while the soft tissue contact region 24 with the nanostructures formed thereon interacts with the soft tissue surrounding the dental implant 2. In this regard, the nanostructures function as sites of improved protein adherence, in particular for transmembrane proteins, more particularly integrins, of the surrounding soft tissue cells.

(15) After the healing period, a suprastructure can be mounted on the head part 18 of the dental implant 2. This is typically done with the aid of an abutment, which is fixed in a manner known per se by retaining means, typically a screw, the outer thread of which cooperates with an inner thread (not shown) formed in the recess 28. In order not to allow any micro-gaps to be present between the shoulder 26 and the abutment, the outer surface of the shoulder 26 supporting the abutment is typically smooth.

(16) Alternatively to these two-part dental implant systems, the dental implant system can also be a one-part dental implant system, in which no separate secondary part/abutment is used as mounting part but in which the mounting part is formed in one piece with the dental implant.

EXAMPLES

Treatment of the Samples

(17) Titanium samples were grinded and polished and were then washed with NaOH at 40% (w/v) and HNO.sub.3 at 40% (w/v) in an ultrasonic bath to remove contaminants, then washed with deionized water to reach a neutral pH and stored at room temperature in 70 vol.-% ethanol.

(18) After the polishing and cleaning steps, some of the samples were treated (pickled) for one minute in a solution containing 15 wt.-% HNO.sub.3 and 5 wt.-% HF (solution C1) at room temperature (samples p1). Alternatively, samples were treated in a solution C1 diluted twice with deionized water (samples p2), diluted five times with deionized water (samples p5) and diluted ten times with deionized water (samples p10).

(19) Immediately after the pickling treatment, the samples were washed by dipping in a beaker containing deionized water for 10 seconds, then mounted on a sample holder forming a cathode for cathodic polarization (or cathodic hydridation).

(20) For the cathodic hydridation, current densities at 5, 10 and 15 mA/cm2 were used. The hydration was performed at room temperature and the duration of the hydridation was set to 0.5, 2 and 5 hours. As electrolyte, tartaric acid at 1 M of concentration, pH 1.9, was used.

Nanoscale Analysis of the Samples

(21) Following the hydridation step, a nanoscale analysis of each of the modified surfaces was performed using a Field Emission Scanning Electron Microscope (FE-SEM; Quanta 200F, FEI, The Netherlands).

(22) As an example for the pictures obtained, FIG. 2 shows the surface of sample p1, with the cathodic polarization being performed at a current densities of 5 mA/cm.sup.2 and with the duration of the hydridation being set to 0.5 hours.

(23) As given in the picture, the ruler at the bottom of the picture corresponds to 2 m. The white spots show the nanostructures, in the particular case nano-nodules, with a diameter well below 200 nm. These form retention sites for improved protein adherence of the surrounding soft tissue.