WO2006025777A1

WO2006025777A1 - Implant for dental prosthesis, and method and system for producing the implant

Info

Publication number: WO2006025777A1
Application number: PCT/SE2005/001201
Authority: WO
Inventors: Matts Andersson
Original assignee: Nobel Biocare Services Ag
Priority date: 2004-09-01
Filing date: 2005-08-11
Publication date: 2006-03-09
Also published as: US20080090211A1; EP1791490A1; SE0402108L; SE530060C2; SE0402108D0; EP1791490A4

Abstract

An implant is arranged with a body shape for application by means of an inner part to jaw bone and for supporting a dental prosthesis by means of an outer part. The inner part is made with compressed or sintered titanium powder and the outer part is made with compressed powder in the form of zirconium dioxide. The metal and ceramic powders are sintered together to form the body shape in a single piece. The invention also relates to a method and system for producing the implant. The invention eliminates the need to conceal dark coloring caused by the metal powder where the implant emerges from a hole in the jaw bone. The fixture can thus be better adapted to the existing coloring of the dental prosthesis in question.

Description

Implant for dental prosthesis, and method and system for producing the implant

The present invention relates to an implant arranged with a body shape for application by means of an inner part to jaw bone and for supporting a dental prosthesis by means of an outer part.

The invention also relates to a method and a system for producing such an implant.

It is already known to produce implants and other prosthetic constructions from compressed (sintered) metal powder, with use preferably being made of titanium powder, if appropriate in the form of an alloy. See for example WO 00/15137 and WO 03/061509.

It is also already known to produce crowns and other prosthetic parts from compressed (sintered) ceramic powder, see for example WO 97/01408.

It is also already known to provide fully automatic production systems for dental products,^' see" EP 490848 and EP 634150 among others.

Implants made of titanium or alloyed titanium now represent a well proven and satisfactory product which has great biocompatibility with the human body and which can therefore constitute a very advantageous basis, from the medical point of view, for a prosthetic fixture.

However, the proposed type of material has a serious disadvantage in that it has a relatively dark color, and this means that the portion of the implant situated at the upper part of the hole in which the implant is fitted ^■ and at the gum is difficult to conceal by - application of layers thereon. The dark color shows ^• through and prevents a completely satisfactory result — "? — from the esthetic point of view. The present invention intends to solve these problems inter alia.

It is also important that a biocompatible and effective material can be retained in all parts of the implant and that well proven application and production methods can be used without the need for substantial changes that greatly increase costs. The invention solves this problem too.

The feature which can principally be regarded as characterizing an implant according to the invention is, inter alia, that the inner part is made completely or partially of compressed (sintered) powder of biocompatible metal, preferably titanium or alloyed titanium, and that the outer part is made completely or partially of compressed powder of biocompatible ceramic, preferably zirconium dioxide, which metal and ceramic powders are additionally .compressed or pressed together to form the aforementioned body shape in a single piece.

In a preferred embodiment, the inner part can be fitted in a hole in the jaw bone and is able to cooperate substantially with the jaw bone, while the outer part is intended to extend through the upper part of the hole and through the gum and out into the oral cavity. The compressed ceramic powder, pressed together with the compressed metal powder, has a light color or shade or is substantially white. The metal powder can be made up of or consist of alloyed titanium of grade four, and it can comprise ca. 6% aluminum and ca. 4% vanadium. In said further developments, there is also a specific choice of particle size or grain size. The implant can be made up of more parts than two, in different or layered powder types with or without specific transition layers between respective part, pairs. The expression layered is intended to signify layers which are of the same type but which are not located next to one another, and are instead separate from another powder type. Other developments of the inventive concept are set forth in the dependent claims relating back to the main implant claim.

A method for production of an implant may principally be regarded as being characterized in that metal powder for complete or partial formation of the inner part and ceramic powder for complete or partial formation of the outer part are applied and compressed and pressed together under vacuum in a pressing tool for formation of the body shape. The compression and pressing together take place in a common step. In a preferred embodiment, the metal powder used can be an alloyed titanium powder and the ceramic powder used can be zirconium dioxide. The particle or grain sizes can be chosen to optimize the strength of the compressed or sintered powder types. The pressing together yields temperatures of ca. HOO⁰C. The tool can be configured with graphite components in a manner known per se. The pressing tool is designed with one or more mold cavities with smooth mold cavity walls. Further developments are set forth in the attached dependent claims relating to .the novel method.

A system for producing an implant according to the invention can principally be characterized by identification members for determining the inner and outer parts' shapes and relationships to one another, and members which depending on the powder types and particle and/or grain sizes determine the powder quantities for the inner and outer parts and a possible transition layer between the parts. Further characteristics are that application members are provided for applying the metal and ceramic powders in a pressing tool, and members for setting the compression pressure and duration of the compression pressure depending on the chosen or desired temperature which is to be present during the compression and pressing together (sintering) .

In further developments of the system according to the .invention, the tool is designed with a number of mold cavities which preferably extend in parallel and which, at their first ends, are arranged opposite a common piston or counterstay member and, at their other ends, are arranged opposite individual counterstay or piston members. At the common piston and/or counterstay member, the tool can have funnel-shaped or cone-shaped portions. In one embodiment, the system can be included as a module in a substantially fully automated production system, for example of the Prdeera® type.

By means of what has been proposed above, a color or shade in common with the prosthesis can also be obtained at the upper parts of the implant or at those parts which emerge from the hole via the gum. Conventional powder compositions can be used for the implant. The pressing together of the different powder types has been shown to function extremely well and gives excellent properties from the point of view of strength in the transition layer between the different powder types.- If so desired, the implant can be made up of more than two parts, with, different or layered powder types in the different parts.

Presently proposed embodiments of an arrangement, method and system will be described below with reference to the attached drawings, in which:

Figure 1 is a vertical section showing the novel implant applied to the jaw bone and gum of a human, and a dental prosthesis (partially shown)^' connected to the implant,

Figure 2 is a schematic representation . showing a module included in a substantially fully automatic production arrangement of the O

Procera® type,

Figure 3 is a perspective and schematic view of a tool for production of an implant according to Figure 1,

Figure 4 is a vertical section showing the tool according to Figure 3,

Figure 5 is a vertical section showing a second embodiment of an implant produced by the tool,

Figure 6 ^' is a vertical section showing a second embodiment of a tool in which a number of implants are produced simultaneously,

Figure 7 is a perspective view, obliquely from above, of the tool according to Figure 6,

Figure 8 shows a side view of a structural embodiment ^' of the tool,

Figure 9 shows a perspective view of samples produced according to the novel method, and

Figure 10 is a diagram showing, among other things, the temperature arising in connection with the use of the tool according to Figure 8.

The invention can be applied to a production principle of the Arcam® type and can be used in connection with so-called "Rapid Prototyping" with stereolithography or SLA. Alternately, SLS can be used which concerns use of powder material in plastic. According to the present invention, metal, for example in the form of titanium or alloyed titanium in powder form, will be combined with ceramic, zirconium dioxide being used in the present illustrative embodiment. In the illustrative embodiment, the particle size and grain size of the different powder types are in the range from a few nanometers to ca. 200 nanometers. Thus, for example, the titanium alloy used can be grade 4, cf. ASTM B 346, ASTM F 67, ASTM F 136. In the case of alloyed titanium, it is possible to include, in the titanium, 4 - 8%, preferably ca. 6% Al, and 2 - 6%, preferably ca. 4% vanadium. The implant or dental product in question is to be combined in metal and ceramic material which cannot be alloyed together. The implant thus includes different material types which are optimized with respect to the tissue and jaw bone in terms of strength, appearance, etc.

In Figure 1, a jaw bone in the human mouth 1 is indicated by 2. The gum of the jaw bone is indicated by 3. A hole 4 is formed through the gum and in the jaw bone, and an implant 5 according to the invention is placed in the hole. The implant can have an external thread 6 by means of which the implant can be screwed into the hole in a manner known per se. Alternately, the external thread can be omitted and the implant can be driven down into the hole and retained in the latter with precision fit between the implant and the hole. The implant is made up of an inner part 5a which is inserted fully into the hole. The implant also has an outer part 5b which extends from the upper parts 6a of the hole and through the gum 3. At its outer parts 5b, the implant supports a dental prosthesis which can be of various types. The design of the implant and the application of the dental product to the implant can be in a manner known per se. A direction of viewing 8 is also indicated in Figure 1. The inner part 5a is made of metal powder of said type which has a substantial and well proven stability function at the same time as a well proven biocompatibility with respect to the jaw bone. The outer part 5b is made of ceramic powder and has a bright shade of color or is substantially white, which means that a dark color, typical of metal powder, does not show through from the implant and prosthesis structure in said direction of viewing 8. The upper parts of the implant and the prosthesis can thus merge naturally with the tooth color at the gum and the upper parts 2a at the gum. From the esthetic point of view, this is a considerable advance in dental treatment techniques. In one illustrative embodiment, the implant includes a transition zone 5c which comprises metal powder and ceramic powder in combination.

In Figure 2, a substantially fully automatic production system of the Procera® type is indicated by 9. In accordance with the invention, a module function 10 is to be able to be included. The module function will implement the production method for the implant in the system according to Figure 1. The system 9 comprises, in a known manner, identification and ordering equipment 11 which, via connection 12, can transmit information il to the system 9, the connection transforming the ordering information il' to the system 9. Correspondingly, the system 9 can communicate with the orderer 11 by means of information i2 and i2' . The system 9 has an internal ^• management and treatment function, and reference may be made here for example to WO 98/44865. The system 14 comprises a unit 14 controlling and instructing the new module 10. The module unit can thus comprise identification members 15

■ which, depending on the information 16 from the unit

14, determines the shapes and relationships of the inner and outer parts 5a and 5b (Figure 1) . The module 10 also comprises a member 17 which, depending on the powder type and particle and/or grain sizes, determines the powder quantities for the inner and outer parts and optionally the transition layer 5c (cf. Figure 1) between the parts. This determination is also effected from the unit 14 by means of a control which has been indicated by 18 in Figure 2. Application members 19 are also included for applying the metal and ceramic powders in a pressing tool which operates with vacuum cavity and is described in more detail below. The application members cooperate with or comprise members for setting the compression pressure and duration of the compression pressure as a function of the chosen temperature which is to be present during the compression and pressing together. The part or parts 19, 20 are controlled with control information 21. By means of the module part 10, the system 9 produces the implant 5' with inner part 5a' , outer part 5b' and transition layer or transition zone 5c' . The implant is sent in a manner known per se, for example by post or parcel delivery, to the orderer or orderer function 1. The order can be made over the public communications 12, for example via the public telecommunications network, computer networks (Internet), etc. Different internal signals in the system 9 have been symbolized by 22, 23, 24, 25 and 26.

In Figures 3 and 4, a pressing tool operating with vacuum cavity is shown symbolically by 27. The pressing tool can be made up of graphite components 28, 29 and 30. The graphite unit 28 can consist of a cylindrical unit which has a through-hole, for example central hole 31 or cavity (vacuum- cavity) , in which the pistons or counterstays 29, 30 operate. In the present case, the units 29 and 30 function as two pistons 32, 33 which can move toward and away from one another. When the powders are applied in the cavity 31, the piston part 29 is removed and the zirconium dioxide powder 34 is introduced and then the titanium powder 35, or vice versa, after which the piston 29 is applied in the cavity 31. Thereafter, the pistons 29 and 33 are moved toward one another and the energy is transmitted to the powders, the arrangement providing a vacuum function in the cavity 31. The inner walls or the inner wall of the cavity 31 is/are smooth so that the powders thus pressed together can be removed from the cavity 31 via either one of the piston parts 29 and 30. The cavity 31 is given a rod shape which corresponds to the outer shape of the implant 5 (cf. Figures 1 and 2) . The rod- shaped unit which is the result of the pressing under vacuum is then subjected to machining during which the implant can be provided, inter alia, with an external thread. This machining function can be included in the module function described in connection with Figure 2 and has been indicated by 36 in Figure 2. Alternately, the function can be effected otherwise in the system 9. This function can also be controlled, and the control information for the unit 36 has been indicated by 37 in Figure 2. The tool 27 can be a tool known per se.

Figure 5 shows a production method for the rod with titanium powder and zirconium dioxide powder. In this case, the abovementioned layer 38 is obtained in which the zirconium dioxide and the titanium powder have been mixed. This layer 38 can be given a thickness t, which can be ca. 1 - 3% of the total length L of the finished pressed rod.

Figures 6 and 7 show a second embodiment of 29' of the pressing tool which effects the compression and pressing together of the metal and ceramic powders . This case involves joint production of a number of rod- shaped elements which are to constitute the base of the implant. In the illustrative embodiment in Figure 6, three cavities arranged in parallel are indicated by 31', 31'' and 31'''. In this case, there is a common piston 29' for all the' cavities. The tool has individual pistons 30' , 30" and 30"' for the cavities in question. The last-mentioned pistons can be actuated jointly by a common piston 39._. At their upper parts, said cavities 31', 31'' and 31"' have funnel-shaped portions, of which three 40, 41 and 42 have been shown in the figure. In the proposed case, zirconium dioxide 34" is applied in the respective cavity 31', 31", 31" ' , after which titanium powder or alloyed titanium powder is applied in said cavities 31', 31" and 31'" and in the funnel-shaped parts 40, 41 and 42. In this case, the titanium powder has been designated by 35'' . In this way, an actuating force on the piston 29' can be increased in the cavities 31', 31'' .and 31''' such that sufficient energy is obtained during the compression and pressing together in the cavities. Figure 7 shows how seven parallel cavities with funnel- shaped extents can be arranged in the cylindrical part 27'. In this case, only one individual piston 31'' is shown together with the symbolically indicated piston 39. The extent and number of the cavities can of course be varied.

Figure 8 shows a practical and structural illustrative embodiment of the whole construction of the tool, said tool having been arranged to provide sufficient energy for the compression and pressing together of the metal and ceramic powders. In this case too, the pistons 29 and 30 are arranged in the cylinder 28. These pistons are acted upon in turn via first actuating members 43, 44 which have a diameter d well in. excess of the diameter d' for the respective piston 29, 30. Said actuating parts 43, 44 are in turned acted upon by actuating parts 45 and 46 with diameters D which are well in excess of the diameters d for the parts 43 and 44. In this way, an amount of energy obtained from actuating forces F and F' on the units 45 and 46 can be substantially increased during the actuation of the pistons 29 and 30. The amounts of energy thus increased can result in the required compression and pressing pressure under which the metal powders form a rod- shaped integral unit.

Figure 9 is intended to show two examples of pressing together or compression to a common unit in accordance with the invention. In the present case, the samples have been designated by 47 and 48. The ceramic powder has been indicated by 49 and 49' and the titanium powder by 50. The sample 48 has been partially surface- treated, the lighter or white coloring 49' for the ceramic powder being shown, and also the darker coloring for the titanium powder 5.

Figure 10 shows how a temperature of HOO⁰C is obtained for the above-described sintering or compression or pressing together of ceramic powder and titanium powder Ti/3Y-TZP, SPS. The sintering can, for example, take place for two minutes under 50 mPa after the temperature of 1100°C has been reached. In Figure 10, reference number 51 shows that said figure of 1100⁰C can be reached after ca. 300 - 400 seconds by means of the above-described method and tool. A pressure of 40 - βO mPa, preferably said 50 mPa, can be used for between 1 and 3 minutes, preferably 2 minutes. The right-hand vertical axis in the diagram shows the number of degrees and the horizontal axis shows the time in seconds. The left-hand vertical axis shows the movements of the powder particles in the ceramic powder, the displacements having been indicated in ΔZ . Said displacements as a function of time have been indicated by the curve 52. In connection with the sintering or compression function, the pressure will be indicated in addition to the indication of the temperature, during compression. This can be symbolized by the unit 36 and the control function 37.

The invention is not limited to the embodiment described above by way of example, and instead it can be modified within the scope of the attached patent claims.

Claims

Patent claims

1. An implant arranged with body shape for application by means of an inner part (5a) to jaw bone (2) and for supporting a dental prosthesis

(7) by means of an outer part (5b), characterized in that the inner part is made completely or partially of sintered or compressed powder of biocompatible metal, preferably titanium or alloyed titanium, and in that the outer part is made completely or partially of compressed powder of biocompatible ceramic, preferably zirconium dioxide, which metal and ceramic powders are additionally compressed to form the body shape.

2. The implant as claimed in patent claim 1, characterized in that the inner part can be fitted in a hole (6) in the jaw bone and is able to cooperate substantially with the jaw bone, and in that the outer part (5b) is intended to extend through the upper part (6a) of the hole and through the gum (3) and out into the oral cavity

(D- ^■

3. The implant as claimed in patent claim 1, 2, characterized in that the compressed ceramic powder pressed together with the compressed metal powder has a light color or shade or is substantially white.

4. The implant as claimed in patent claim 1, 2 or 3, characterized in that the metal powder is made up of or consists of alloyed titanium with particle size or grain size four, and it comprises ca. 6% aluminum and ca. 4% vanadium.

5. The implant as claimed in patent claim 4, characterized in that the alloyed titanium is made up of particles or grains of the order of size of from a few nanometers.

6. The implant as claimed in any of patent claims 1- 5, characterized in that it is made up of more parts than two, in different or layered powder types with or without specific transition layers between respective part pairs.

7. A method for production of an implant arranged with a body shape which is applied with an inner part to jaw bone (2) , and with an outer part in which a dental prosthesis (7) is supported, characterized in that metal powder for complete or ^• partial formation of the inner part and ceramic powder for complete or partial formation of the outer part are applied and sintered or compressed and pressed together under vacuum in a pressing tool for formation of the body shape.

8. The method as claimed in patent claim 7, characterized in that the metal powder chosen is an alloyed titanium powder and the ceramic powder chosen is zirconium dioxide.

9. The method as claimed in patent claim 7 or 8, characterized in that the alloyed titanium powder chosen is a powder with particle sizes or grains of the order of from a few nanometers and upward.

10. The method as claimed in patent claim 7, 8 or 9, characterized in that the sintering or compression temperature is chosen at ca. HOO⁰C with a duration of ca. 2 minutes and an established pressure of ca. 50 mPa.

11. The method as claimed in any of patent claims 7 - 10, characterized in that the pressing tool is designed with one or more mold cavities with smooth mold cavity walls.

12. A system for producing an implant with a body shape for application by means of an inner part to jaw bone and for supporting a dental prosthesis by- means of an outer part, characterized in that identification members for determining the inner and outer parts' shapes and relationships to one another, members which depending on the powder type and particle and/or grain sizes determine the powder quantity for the inner and outer parts and a possible transition layer between the parts, application members for applying said metal and ceramic powders in a pressing tool, and in that the application members comprise or cooperate with setting of compression pressure and duration of the compression pressure depending on the chosen temperature and chosen pressure which is to be present in the sintering obtained by the compression and/or pressing together.

13. The system as claimed in patent claim 12, characterized^' in that the tool is designed with a number of mold cavities which preferably extend in parallel and which, at their first ends, are arranged opposite a common piston or counterstay member and, at their other ends, are arranged opposite individual counterstay or piston members.

14. The system as claimed in patent claim 12 or 13, characterized in that the tool at the common piston and/or counterstay member has funnel-shaped and/or cone-shaped portions.

15. The system as claimed in patent claim 12, 13 or 14, characterized in that it is included as a module (10) in ' a substantially fully automatic production system (9) , for example of the Procera® type.