SYSTEM AND METHOD FOR MANUFACTURING DENTAL WORKPIECE

Technical Field

[0001] The present disclosure relates generally to a manufacturing system and, more particularly, to a system and method for manufacturing a multi-layer prosthesis.

Background

[0002] A prosthesis is an artificial body part that replaces a damaged or missing body part. Prostheses can be permanently joined to the body (e.g., implanted via surgery) or temporarily connected to the body (e.g., via straps, retainers, snaps, etc.). Prostheses are made from a wide range of materials that corresponds with an intended-use environment. Prostheses may be functional, ornamental, or both functional and ornamental. Examples of common prostheses include dental implants, orthopedic joints, and limbs.

[0003] A dental prosthesis generally includes a substructure that is surgically implanted into a patient's mouth, a superstructure that connects to the substructure, and a veneer that is adhered to the superstructure. Additive manufacturing is a known process of creating the superstructure of a dental prosthesis.

[0004] During additive manufacturing, layers of material are deposited in an overlapping manner under the guided control of a computer. One technique of additive manufacturing is known as direct metal laser sintering (DMLS). The DMLS technique uses a laser to direct a high-energy beam into a powdered metal medium at precise locations corresponding to features and dimensions of the superstructure. As the energy beam contacts the powdered metal, the powdered metal melts and welds to (previously melted layers of) the superstructure. A similar technique of additive manufacturing is known as directed energy deposition (DED), also referred to as laser metal deposition. The DED technique uses a deposition head, which is similar to an inkjet head, to supply metal powder to the focus of a laser beam, which melts the powder that welds to (previously melted layers of) the superstructure.

[0005] In some situations, the powdered metal medium includes oxidation particles that improve adherence of the veneer to the superstructure. These particles oxidize during heating, and thereby create an exposed layer of metal-oxide. The particles provide roughness to the superstructure that promotes mechanical connection with the veneer, while the metal-oxide enhances a chemical bond with the veneer.

[0006] While acceptable for some applications, it has been found that the metal-oxide layer, when it contacts the gingiva of a patient's mouth, can be problematic. For example, the metaloxide layer can cause permanent discoloration of the gingiva (e.g., graying of the gingiva). In addition, the metal-oxide layer can pose a biological risk.

[0007] Currently, dental technicians reduce the risks associated with the metal-oxide layer by blasting away the metal-oxide (e.g., with sand and/or glass particles) in an area adjacent to the gingiva. This, however, may remove portions of the superstructure that mate with the substructure. As a result, the fit between the superstructure and the substructure may be degraded.

[0008] The disclosed system and method are directed to overcoming one or more of the problems set forth above and/or other problems of the prior art. In particular, the invention is directed towards a system according to claim 1, a method according to claim 10 and a superstructure according to claim 15. Advantageous embodiments are the subject of the dependent claims. They may be combined freely unless the context clearly indicates otherwise.

Summary

[0009] In one aspect, the present disclosure is directed to a system for manufacturing a prosthesis, in particular a superstructure of a dental prosthesis. The system may include a build chamber, a first material source having a first material stored therein, a second material source having a second material stored therein, and an energy source. The system may also include a controller programmed to receive digital data corresponding to at least one of a particular patient and the prosthesis. Based on the digital data, the controller may selectively cause only the first material, only the second material, or a combination of the first and second materials to be moved into the build chamber. The controller also may be configured to control operation of the energy source based on the digital data to sinter (or melt) a pattern within material in the build chamber to form a corresponding layer of the prosthesis.

[0010] In yet another aspect, the present disclosure is directed to a method for

manufacturing a prosthesis, in particular a superstructure of a dental prosthesis. The method may include receiving digital data corresponding to at least one of a particular patient and the prosthesis. The method may also include selectively moving only a first material, only a second material, or a combination of the first and second materials into a build chamber based on the digital data. The method may further include sintering (or melting) a pattern within material in the build chamber to form a corresponding layer of the prosthesis based on the digital data.

[0011] Accordingly, a system for manufacturing a superstructure of a dental prosthesis, comprises: a build chamber; a first material source having a first material stored therein; a second material source having a second material stored therein; an energy source; and a controller programmed to: receive digital data corresponding to at least one of a particular patient and the prosthesis; based on the digital data, selectively cause only the first material, only the second material, or a combination of the first and second materials to be moved into the build chamber; and control operation of the energy source based on the digital data to sinter a pattern within material in the build chamber to form a corresponding layer of the prosthesis; wherein the first material comprises a metal powder and the second material comprises additive oxidation particles.

[0012] Suitable metals for the metal powders of the first material in the system and the method according to the invention include cobalt, chromium and alloys comprising cobalt and chromium. A preferred metal is an alloy comprising 60 to 62% by weight of cobalt, 27 to 29% by weight of chromium, 8 to 9% by weight of tungsten and 1 to 2% by weight of silicon, wherein the sum of the weigh-percentages is < 100 weight- %.

[0013] The additive oxidation particles comprise an oxidizable material for better compatibility with ceramic veneer materials. Suitable materials for the additive oxidation particles include copper, tin, indium, iron, titanium, and manganese. In the finished article manufactured by a system and a method according to the invention the content of additive oxidation particles including their oxidized form can be in a range of > 0.1 weight-% to < 2 weight-%) (preferably > 0.5 weight- % to < 1.5 weight-%), based on the total weight of the article.

[0014] The second material may, for example, exclusively comprise the additive oxidation particles or may be a metal powder in which the additive oxidation particles are distributed. In the latter case the metal powder may be the same or a different metal powder than the first material. It is preferred that the metal powder in the first and in the second material are the same.

[0015] In one embodiment of the system the first material source is a first material chamber located adjacent the build chamber; the second material source is a second material chamber located adjacent the build chamber; the system further includes at least one recoater; and the controller is further configured to selectively cause the at least one recoater to move only the first material or only the second material into the build chamber.

[0016] In another embodiment of the system of claim the second material includes an alloy consisting of a base metal powder and additive oxidation particles.

[0017] In another embodiment of the system the base metal powder is an alloy of at least cobalt and chromium and the additive oxidation particles includes particles from at least one of copper, tin, indium, iron, titanium, and manganese.

[0018] In another embodiment of the system the first material includes only the base metal powder.

[0019] In another embodiment of the system the prosthesis includes the superstructure configured to engage an implanted substructure at an engagement interface and the controller is configured to: control the energy source and the at least one recoater to fabricate layers adjacent the engagement interface from only the first material; and control the energy source and the at least one recoater to fabricate layers away from the engagement interface from only the second material.

[0020] In another embodiment of the system the superstructure includes an outer surface configured to engage with a veneer.

[0021] In another embodiment of the system a lower surface of the superstructure abuts an upper surface of the substructure to form the engagement interface.

[0022] In another embodiment of the system a combined thickness of layers fabricated from only the first material is about equal to a distance of the engagement interface below an exposed gingiva surface of a particular patient in which the substructure is implanted.

[0023] In another embodiment of the system the first material source is a first material chamber located adjacent the build chamber; the second material source is an injector located within the build chamber; the system further includes at least one recoater; and the controller is further configured to: selectively cause the at least one recoater to move only the first material into the build chamber; and selectively cause the injector to inject only the second material into the build chamber over a layer of the first material prior to sintering.

[0024] In another embodiment of the system the first material includes only a metal alloy powder and the second material includes only additive oxidation particles.

[0025] In another embodiment of the system the metal alloy powder includes at least cobalt and chromium and the additive oxidation particles includes particles from at least one of copper, tin, indium, iron, titanium, and manganese.

[0026] In another embodiment of the system the prosthesis includes the superstructure configured to engage an implanted substructure at an engagement interface and the controller is configured to: control the energy source and the at least one recoater to fabricate layers adjacent the engagement interface from only the first material; and control the energy source, the at least one recoater, and the injector to fabricate layers away from the engagement interface from the first and second materials.

[0027] In another embodiment of the system a combined thickness of layers fabricated from only the first material is about equal to a distance of the engagement interface below an exposed gingiva surface of the particular patient in which the substructure is implanted.

[0028] The invention is further directed towards a method for manufacturing a

superstructure of a dental prosthesis, comprising: receiving digital data corresponding to at least one of a particular patient and the prosthesis; based on the digital data, selectively moving only a first material, only a second material, or a combination of the first and second materials into a build chamber; and based on the digital data, sintering a pattern within material in the build chamber to form a corresponding layer of the prosthesis; wherein the first material comprises a metal powder and the second material comprises additive oxidation particles.

[0029] The method may be used to generate a transition zone between a first axial zone p and a second axial zone P where at least one material property changes following a gradient. The axial length of the transition zone and therefore the extent over which the gradient is applied may, for example, be > 0.1 mm to < 1 mm. Preferably the material property is the content of the additive oxidation particles (including their oxidized form), Hence, in the transition zone the content of these particles may gradually increase from 0% to 100% of their content in the second zone P. The gradient may be a linear gradient, a parabolic gradient or an exponential gradient. Particularly preferred is a transition zone having a length of > 0.1 mm to < 1 mm, wherein the content of the additive oxidation particles (including their oxidized form) follows a linear gradient from 0% to 100% of their content in the second zone P.

[0030] In an embodiment of the method selectively moving only the first material, only the second material, or the combination of the first and second materials includes pushing material from at least one material chamber located adjacent the build chamber.

[0031] In another embodiment of the method the second material includes an alloy consisting of a base metal powder and additive oxidation particles.

[0032] In another embodiment of the method the base metal powder is an alloy of at least cobalt and chromium and the additive oxidation particles includes particles from at least one of copper, tin, indium, iron, titanium, and manganese. [0033] In another embodiment of the method the first material includes only the base metal powder.

[0034] In another embodiment of the method the prosthesis includes the superstructure configured to engage an implanted substructure at an engagement interface; and sintering the pattern within material in the build chamber to form a corresponding layer of the prosthesis includes: forming layers adjacent the engagement interface from only the first material; and forming layers away from the engagement interface from only the second material.

[0035] In another embodiment of the method forming layers adjacent the engagement interface from only the first material forming layers having a combined thickness about equal to a distance of the engagement interface below an exposed gingiva surface of the particular patient in which the substructure is implanted.

[0036] Another aspect of the invention is a superstructure of the dental prosthesis manufactured via a method according to the invention.

[0037] The superstructure may have a first axial portion p which is adapted to be contacted with a dental implant and a second axial portion P which is adapted to be contacted with a ceramic dental prosthesis. There may be a transition zone between the first zone p and the second zone P where at least one material property changes following a gradient. The axial length of the transition zone and therefore the extent over which the gradient is applied may, for example, be > 0.1 mm to < 1 mm. Preferably the material property is the content of the additive oxidation particles (including their oxidized form), Hence, in the transition zone the content of these particles may gradually increase from 0% to 100% of their content in the second zone P. The gradient may be a linear gradient, a parabolic gradient or an exponential gradient. Particularly preferred is a transition zone having a length of > 0.1 mm to < 1 mm, wherein the content of the additive oxidation particles (including their oxidized form) follows a linear gradient from 0% to 100% of their content in the second zone P.

[0038] Particular preference is given to the following embodiment:

a system for manufacturing a superstructure of a dental prosthesis which comprises: a build chamber; a first material source having a first material stored therein; a second material source having a second material stored therein; an energy source; and a controller

programmed to: receive digital data corresponding to at least one of a particular patient and the prosthesis; based on the digital data, selectively cause only the first material, only the second material, or a combination of the first and second materials to be moved into the build chamber; and control operation of the energy source based on the digital data to sinter a pattern within material in the build chamber to form a corresponding layer of the prosthesis; wherein:

the first material source is a first material chamber located adjacent the build chamber; the second material source is a second material chamber located adjacent the build chamber; the system further includes at least one recoater; and the controller is further configured to selectively cause the at least one recoater to move only the first material or only the second material into the build chamber;

wherein:

the second material includes an alloy consisting of a base metal powder and additive oxidation particles and

wherein:

the base metal powder is an alloy of at least cobalt and chromium; and

the additive oxidation particles includes particles from at least one of copper, tin, indium, iron, titanium, and manganese.

[0039] Particular presence is also given to the following embodiment:

a system for manufacturing a superstructure of a dental prosthesis which comprises: a build chamber; a first material source having a first material stored therein; a second material source having a second material stored therein; an energy source; and a controller

programmed to: receive digital data corresponding to at least one of a particular patient and the prosthesis; based on the digital data, selectively cause only the first material, only the second material, or a combination of the first and second materials to be moved into the build chamber; and control operation of the energy source based on the digital data to sinter a pattern within material in the build chamber to form a corresponding layer of the prosthesis; wherein:

the first material source is a first material chamber located adjacent the build chamber;

the second material source is an injector located within the build chamber;

the system further includes at least one recoater; and

the controller is further configured to:

selectively cause the at least one recoater to move only the first material into the build chamber; and

selectively cause the injector to inject only the second material into the build chamber over a layer of the first material prior to sintering;

wherein:

the first material includes only a metal alloy powder; and

the second material includes only additive oxidation particles and wherein:

the metal alloy powder includes at least cobalt and chromium; and

the additive oxidation particles includes particles from at least one of copper, tin, indium, iron, titanium, and manganese.

[0040] Particular preference is also given to the following embodiment:

a method for manufacturing a superstructure of a dental prosthesis, comprising:

receiving digital data corresponding to at least one of a particular patient and the prosthesis; based on the digital data, selectively moving only a first material, only a second material, or a combination of the first and second materials into a build chamber; and

based on the digital data, sintering a pattern within material in the build chamber to form a corresponding layer of the prosthesis;

wherein:

moving only the first material, only the second material, or the combination of the first and second materials includes pushing material from at least one material chamber located adjacent the build chamber;

wherein:

the second material includes an alloy consisting of a base metal powder and additive oxidation particles and

wherein: the base metal powder is an alloy of at least cobalt

and chromium; and

the additive oxidation particles includes particles from at least one of copper, tin, indium, iron, titanium, and manganese.

Brief Description of the Drawings

[0041] Fig. 1 is an isometric view illustration of an exemplary prosthesis;

[0042] Figs. 2A, 2B, and 2C are illustrations of exemplary embodiments of the prosthesis of

Fig. 1; and

[0043] Figs. 3 and 4 are diagrammatic illustrations of exemplary disclosed systems for manufacturing the prosthesis of Figs. 1, 2A, 2B, and 2C.

Detailed Description

[0044] Figs. 1, 2A, 2B, and 2C illustrate a prosthesis 10 that can be manufactured by exemplary systems 12 and/or 14, which are shown in Figs. 3 and 4, respectively. Prosthesis 10 of Figs. 1, 2A, 2B, and 2C may be manufactured to have any desired shape for use in any number of different applications. For example, prosthesis 10 shown in Figs. 1, 2A, 2B, and 2C is a dental prosthesis intended for permanent or semi-permanent implantation within a patient's mouth (represented by a bone structure 16). It is contemplated, however, that systems 12 and/or 14 could alternatively or additionally be used to manufacture another type of prosthesis (e.g., a joint prosthesis and/or a limb prosthesis - not shown), if desired.

[0045] As a dental-type prosthesis, prosthesis 10 may include a substructure 18, a superstructure 20, and a veneer 22. As shown in Fig. 2A, substructure 18 may be permanently affixed to (e.g., implanted into) bone structure 16, after which superstructure 20 may be engaged with substructure 18 at an engagement interface 24. Veneer 22 may then be mechanically and chemically bonded to an outer surface of superstructure 20.

[0046] Substructure 18 may embody one or more pre-fabricated posts (commonly made from titanium, a titanium alloy or another non-reactive material). Substructure 18 may include body portion 13 and cap portion 15. Body portion 13 of substructure 18 may be positioned within corresponding hole(s) previously drilled into bone structure 16, and may extend from proximal end 21 disposed outside bone structure 16 to distal end 23 disposed within bone structure 16. In some instances, body portion 13 of substructure 18 may include external threads 26 that are used to mechanically engage and/or advance the posts into bone structure 16 below any associated gingiva 28. Body portion 13 of substructure 18 may include a central bore 30 that receives either a threaded portion 32 of superstructure 20 or a separate threaded fastener (not shown) passed down through superstructure 20. Threaded portion 32 may retain superstructure 20 connected to substructure 18. Cap portion 15 may extend from proximal end 21 of body portion 13 to upper surface 36 disposed axially spaced from proximal end 21. In some exemplary embodiments, upper surface 36 of cap portion 15 may be disposed proximate to or below upper surface 41 of gingiva 28.

[0047] Superstructure 20 may embody one or more metallic abutments used to connect veneer 22 to substructure 18. The abutments may be prefabricated to have a standard shape and form (e.g., cylindrical, square, hexagonal, or otherwise standard geometric protrusion) or have a specialized shape and/or form (e.g., angled, chiseled, irregular, and/or tooth-like protrusion) designed for a particular patient and/or veneer 22. The abutment may have a precision-formed lower surface 34 at engagement interface 24 that is designed and

manufactured to provide a desired fit with a corresponding upper surface 36 of substructure 18, whereby said upper surface 36 of substructure 18 may be disposed external to the bore 30. As illustrated in the exemplary embodiment of Fig. 2A, superstructure 20 may include recess 27 configured to receive cap portion 15 of substructure 18. Lower surface 34 of

superstructure 20 may abut upper surface 36 of cap portion 15 forming engagement interface 24. In one exemplary embodiment as illustrated in Fig. 2A, lower surface 34 of superstructure 20, upper surface 36 of cap portion 15, and engagement interface 24 may have a generally inverted U-shape. Lower surface 34 of superstructure 20, upper surface 36 of substructure 18, and engagement interface 24 may be disposed between lower surface 17 of cap portion 15 and upper surface 41 of gingiva 28. In some exemplary embodiments as illustrated in Fig. 2A, lower surface 34 of superstructure 20, upper surface 36 of substructure 18, and engagement interface 24 may be disposed nearer upper surface 41 of gingiva 28 compared to upper surface 25 of bone structure 16.

[0048] Superstructure 20 (or the abutment) may also have an outer surface 38 with properties (e.g., roughness and/or chemical composition) that enhance bonding with veneer 22. A smaller axial portion p of the abutment adjacent engagement interface 24 may lie at least partially below an upper surface 41 of gingiva 28, while a larger axial portion P may protrude past gingiva 28 a distance into the oral cavity of the patient's mouth. It should be noted that the smaller portion p of the abutment, because of its location at least partially below upper surface 41, may directly contact gingiva 28. Depending on the location, of the upper surface 36, the axial portions p and P may have the same or even an inverse dimension to the one described above. In any case, the smaller portion p designates the portion in contact with the implant whereas the larger portion P designates the portion supporting a veneer or other prosthetic parts.

[0049] As will be described in more detail below, the smaller portion p may be formed from a material different than a material used to form the larger portion P. For example, the smaller portion p may be formed from a first material having a lower likelihood of oxidation, while the larger portion P may be formed from a second material having a higher likelihood of oxidation. In the disclosed embodiment, the first material may include an alloy of cobalt and chromium commercially known as Coron®. In the same embodiment, the second material may include a base of Coron®, with oxidation particles dispersed throughout. The oxidation particles may include at least one of copper, tin, indium, iron, titanium, and manganese.

Typically, the Coron® base material comprises about 61% by weight of cobalt, about 28% by weight of chromium, about 8.5% by weight of tungsten and about 1.5% by weight of silicon. The oxidation particles are typically present in an amount of less than 1% by weight. Because both the lower and upper portions p, P may primarily include Coron®, a coefficient of thermal expansion of both portions should be about the same (e.g., similar enough to discourage stress buildup, cracking, or separation during temperature fluctuations). As described above, the oxidation particles may enhance mechanical and/or chemical bonding between superstructure

20 and veneer 22. And because the lower portion p may include a limited number of oxidation particles (e.g., no oxidation particles), it is unlikely that superstructure 20 will cause discoloration of gingiva 28 or pose a biological risk to the patient.

[0050] Veneer 22 may embody a relatively thin glossy shell formed from a glass ceramic (e.g., from lithium silicate, zirconia silicate, etc.). Veneer 22 may provide a desired cosmetic appearance, surface texture, and/or hardness to prosthesis 10, in particular to the

superstructure 20 of a dental prosthesis.

[0051] It should be noted that most prostheses 10, in particular the superstructures 20 of dental prostheses, are customized (e.g., sized, shaped, contoured, and/or finished) for a particular patient based on x-rays of the patient's underlying bone structure 16 and/or 3-D scans of the patient's mouth. Accordingly, the x-rays, scan images, and other similar digital data may at least partially define prosthesis 10, and care should be taken to manufacture prosthesis 10 as close to the digital data as possible such that a rigid, comfortable, and lasting connection between prosthesis 10 and the patient's mouth as well as between the different parts of the prosthesis 10 is obtained.

[0052] Fig. 2B illustrates another exemplary embodiment of prosthesis 10. The embodiment of prosthesis 10 illustrated in Fig. 2B includes several features similar to those already described above with respect to prosthesis 10 of Fig. 2A. Therefore, differences between the embodiments of Figs. 2 A and 2B are highlighted in the following description and a description of the similar features is omitted. Substructure 18 may extend from proximal end

21 disposed within (not shown) or outside bone structure 16 to distal end 23 disposed within bone structure 16. For example, the embodiment of Fig. 2B differs from that of Fig. 2 A in that substructure 18 of the embodiment of Fig. 2B includes body portion 13 but does not include cap portion 15. Further, in the embodiment of Fig. 2B, superstructure 20 may have a generally U-shaped lower surface 34 and body portion 13 of substructure 18 may have a generally U-shaped upper surface 36. Lower surface 34 of superstructure 20 and upper surface 36 of body portion 13 may abut each other to form engagement interface 24 that may have a U-shape and may be disposed generally parallel to lower surface 34 of superstructure 20 and upper surface 36 of substructure 18. Engagement interface 24, in the exemplary embodiment of Fig. 2B, may also be disposed generally orthogonal to longitudinal axis 29 of prosthesis 10. Like the embodiment of Fig. 2A, lower surface 34 of superstructure 20, upper surface 36 of body portion 13 and engagement interface 24 may be disposed, at least partially, between an upper surface 25 of bone structure 16 and an upper surface 41 of gingiva 28. Unlike the embodiment of Fig. 2A, however, in the embodiment of Fig. 2B, lower surface 34 of superstructure 20, upper surface 36 of body portion 13 and engagement interface 24 may be disposed, at least partially, below upper surface 25 of bone structure 16.

[0053] Fig. 2C illustrates another exemplary embodiment of prosthesis 10. The embodiment of prosthesis 10 illustrated in Fig. 2C includes several features similar to those already described above with respect to prosthesis 10 of Fig. 2A and 2B. Therefore, differences between the embodiments of Figs. 2A and 2B are highlighted in the following description and description of similar features is omitted. The embodiment of prosthesis 10 illustrated in Fig. 2C includes substructure 18, superstructure 20, and intermediate structure or cap 19.

Superstructure 20 may also be referred to as a first abutment and cap 19 may be referred to as a second abutment. Substructure 18 may extend from proximal end 21 disposed within (not shown) or outside bone structure 16 to distal end 23 disposed within bone structure 16.

Substructure 18 of the embodiment of Fig. 2C includes body portion 13 but does not include cap portion 15.

[0054] Cap 19 may include a threaded portion 31 that may extend from adjacent proximal end 21 into central bore 30. Threaded portion 31 may be receivable within substructure 18 and may be configured to engage with threads in central bore 30 in substructure 18 or a separate threaded fastener (not shown) may be passed down through cap 19. Cap 19 may also include cap portion 33 disposed external to substructure 18. Cap portion 33 may extend from adjacent proximal end 21 to upper surface 35 axially spaced apart from threaded portion 31. Upper surface 35 of cap 19 may be disposed between proximal end 21 and superstructure 20. Cap portion 33 may include an outer lip 37. In one exemplary embodiment as illustrated in Fig. 2C, outer lip 37 may have a generally cylindrical shape disposed about longitudinal axis 29 of prosthesis 10, although other shapes of outer lip 37 are also contemplated. Outer lip 37 may include lower surface 39 which may abut upper surface 36 of substructure 18. Lower surface 39 of outer lip 37 and upper surface 36 of substructure 18 may be disposed adjacent upper surface 25 of bone structure 16.

[0055] Upper surface 35 of cap 19 may be disposed axially spaced apart from lower surface 39 of outer lip 37. As illustrated in the exemplary embodiment of Fig. 2C, superstructure 20 may include recess 27 configured to receive cap portion 33 of cap 19. Lower surface 34 of superstructure 20 may abut upper surface 35 of cap 19 to form engagement interface 24. Lower surface 34 of superstructure 20, upper surface 35 of cap 19, and engagement interface 24 may have a generally inverted U-shape. Lower surface 34 of superstructure 20, upper surface 35 of cap 19, and engagement interface 24 may be disposed between an upper surface

25 of bone structure 16 and an upper surface 41 of gingiva 28. In some exemplary embodiments as illustrated in Fig. 2C, lower surface 34 of superstructure 20, upper surface 35 of cap 19, and engagement interface 24 may be disposed nearer upper surface 41 of gingiva 28 compared to upper surface 25 of bone structure 16.

[0056] Fig. 3 illustrates system 12 as having as having multiple components that cooperate to manufacture superstructure 20 (referring to Figs. 1 and 2). As shown in this figure, these components may include, among other things, a build chamber 40, a first material chamber 42, a second material chamber 44, at least one recoater 46, an energy source 48, and a controller 50. As will be explained in more detail below, recoater(s) 46 (under the control of controller 50) may push powdered material from first and/or second material chambers 42, 44 into build chamber 40 (in a direction indicated by arrows 52), and energy source 48 (under the control of controller 50) may selectively generate (e.g., sinter) a pattern in the powder to produce layers of solidified material forming superstructure 20. It is contemplated that system 12 could include additional components not shown in Fig. 3, if desired. For example, system 12 could additionally include a housing surrounding build and/or material chambers 40-44 and having a regulated environment (e.g., a vacuum environment or a pressurized inert gas environment), cooling and/or heating circuits, a user interface, etc.

[0057] Build chamber 40 may be configured to house and support superstructure 20 during fabrication thereof. In the disclosed example, build chamber 40 is formed by a plurality of connected walls 54 and a movable stage 56. Walls 54 may surround superstructure 20 on all sides, and stage 56 may function as a floor of build chamber 40 on which superstructure 20 is built. Stage 56 may consist of a platform 58, and one or more actuators 60 that are connected to a bottom of platform 58 opposite superstructure 20. Platform 58 may be generally platelike and oriented in a horizontal plane generally parallel to the trajectory of recoater(s) 46, and actuator(s) 60 may be configured to move platform 58 vertically (i.e., in a direction indicated by an arrow 62) between walls 54 within build chamber 40. Specifically, actuator(s) 60 may be controlled to incrementally step down platform 58 relative to walls 54 after fabrication of each layer of superstructure 20. The amount that platform 58 is stepped down may be about equal to a thickness of each added layer, such that recoater(s) 46 may remain at a relatively fixed horizontal location during each pass across stage 56. Actuator(s) 60 may include, for example, motors, cylinders, valves, solenoids, etc.

[0058] Material chamber 42 may be similar in form to build chamber 40. For example, material chamber 42 may also include a plurality of connected walls 64, a platform 66, and one or more actuators 68 connected to a bottom of platform 66. However, instead of walls 64 surrounding and platform 66 supporting superstructure 20, walls 64 may instead surround a supply of powdered material used to manufacture superstructure 20 and platform 66 may support the material. Actuator(s) 68 may be configured to selectively raise platform 66 (in a direction indicated by an arrow 70) as the material inside material chamber 42 is consumed. In particular, actuator(s) 68 may be controlled to incrementally step up platform 66 relative to walls 64 after recoater 46 pushes a layer of material away from material chamber 42 and into build chamber 40. The amount that platform 66 is stepped up may be equal to or greater than a thickness of each layer added to superstructure 20, such that more than enough material is provided to recoater 46 during each pass across stage 56. Actuator(s) 68 may include, for example, motors, cylinders, valves, etc. It should be noted that build chamber 40 and material chamber 42 may share a common wall in some embodiments.

[0059] Material chamber 44 may be substantially identical to material chamber 42. For example, material chamber 42 may also include a plurality of connected walls 72, a platform 74, and one or more actuators 76 connected to a bottom of platform 74. Walls 72 may surround a supply of powdered material used to manufacture superstructure 20 and platform 74 may support the material. Actuator(s) 76 may be configured to incrementally step up platform 74 (in a direction indicated by an arrow 78) in the same way that actuator(s) 68 step up platform 74. Actuator(s) 76 may include, for example, motors, cylinders, valves, etc. It should be noted that build chamber 40 and material chamber 44 may share a common wall in some embodiments. In the disclosed embodiment, the powder material contained within material chamber 42 is different from the powder material contained within material chamber 44. For example, the powder material in material chamber 42 may be Coron®, while the powder material in material chamber 44 may be a mixture of Coron® and the oxidation particles described above.

[0060] Each recoater 46 may be available in several different forms and configured to move in different ways. In a first example, recoater 46 is an elongated blade or arm that is movable (e.g., translatable by way of one or more actuators - not shown) in the direction of arrow 52. The length direction of recoater 46 may extend generally orthogonal to its travel direction (i.e., out of the page in the perspective of Fig. 3), and the actual length of recoater 46 may be sufficient to extend entirely across openings formed inside of walls 54, 64, and 72. With this configuration, as recoater 46 moves across the associated material chamber 42 or 44 (e.g., from left-to-right for material chamber 42, or right-to-left for material chamber 44), recoater 46 may engage the powdered material therein, which has been previously elevated above a bottom surface of recoater 46 by the associated platform 66 or 74 and actuator(s) 68 or 76. As recoater 46 scrapes across the material, a ridge 80 of the material may be collected at its leading edge. Then, as recoater 46 moves across build chamber 40, material from ridge 80 may fall down onto an earlier fabricated layer of superstructure 20, which has been previously lowered below the bottom surface of recoater 46 by platform 58 and actuator(s) 60. Although two different recoaters 46 are shown and described, it is contemplated that a single recoater 46 could be configured to move material from both of material chambers 42, 44 into build chamber 40, if desired.

[0061] In the disclosed example, energy source 48 includes one or more lasers 82 (e.g., an Excimer laser, a Yb:tungstate laser, a C0 ₂ laser, a Nd:YAG laser, a DPSS laser, or another type of laser known in the art) that are configured to generate one or more beams of energy 84 directed onto the layer of powdered material after deposition by recoater(s) 46. Beam 84 may be capable of heating the powdered material to a level sufficient to sinter (i.e., to coalesce the powdered material into a porous state) or otherwise harden the powdered material. In some embodiments, various optics (e.g., lenses, mirrors, gratings, filters, etc.) 86 may be used to focus, redirect, and/or align beam(s) 84 with a desired pattern on the powdered material, thereby generating a required shape and contour of superstructure 20 corresponding to a height (e.g., a distance away from platform 58) of the layer currently being manufactured. It is contemplated that energy sources other than lasers (e.g., ultraviolet light sources, electromagnetic energy sources, chemical energy sources, etc.) could alternatively be used to sinter or harden the material, if desired.

[0062] Controller 50 may be in communication with recoater(s) 46, actuator 60, actuator 68, actuator 76, laser 82 (or another energy source), optics 86, and/or any other component of system 12. As will be explained in more detail below, controller 50 may use the digital data associated with a particular prosthesis 10 and cause a high-precision 3-D superstructure 20 to be fabricated that is unique to a particular patient (e.g., that matches the size, shape, contour, and/or surface texture of the patient's mouth, and that includes any connecting interfaces to an associated substructure 18 and veneer 22). Controller 50 may embody a single processor or multiple processors that include a means for controlling an operation of system 12. Numerous commercially available processors may perform the functions of controller 50. Controller 50 may include or be associated with a memory for storing data such as, for example, the digital data associated with prosthesis 10, operating conditions of the components of system 12, design limits, performance characteristics or specifications, operational instructions, etc. Various other known circuits may be associated with controller 50, including power supply circuitry, signal conditioning circuitry, solenoid driver circuitry, communication circuitry, and other appropriate circuitry. Moreover, controller 50 may be capable of communicating with the other components of system 12 via either wired or wireless transmission and, as such, controller 50 could be connected directly to these components or alternatively disposed in a location remote from the other components and indirectly connected (e.g., wirelessly).

[0063] As shown in Fig. 4, system 14 may include many of the same components that system 12 includes. For example, system 14 may include build chamber 40, first material chamber 42, in which the powder material may be Coron®, recoater 46, energy source 48, and controller 50. In contrast to system 12, however, system 14 may not include second material chamber 44 or the associated additional recoater 46. Instead, system 14 may include an injector 88 that is configured to separately inject the oxidation particles, or Coron® and the oxidation particles (not illustrated in the Figure), described above onto an earlier-fabricated layer of superstructure 20 (e.g., before or after a new layer of Coron® is deposited by recoater 46). Controller 50 of system 14 may be in further communication with injector 88 and configured to regulate operations of injector 88 in coordination with the other components of system 14. In a further variant of the system, both material chambers may be replaced by one or more deposition heads supplying the first and the second material to the focus of an energy beam 84.

Industrial Applicability

[0064] The disclosed systems and methods may be used to manufacture a wide range of prostheses in an accurate manner. In one example, the disclosed systems and methods may be used to manufacturing dental prostheses, in particular superstructures of dental prostheses. A dental prosthesis manufactured by the disclosed systems may conform well to a patient's mouth because at least part of each prosthesis is customized. Accuracy may be achieved through the use of additive manufacturing processes from a unique combination of materials that reduce or eliminate the need to subsequently blast away engagement interfaces of the dental prosthesis. Discoloration and/or biological risks may be reduced through the use of particular materials at particular locations within the dental prosthesis. Operation of systems 12 and 14 will now be described in detail.

[0065] At a start of a manufacturing event, digital data regarding at least a part of a prosthesis 10 to be produced and implanted may be electronically loaded into controller 50 (referring to Figs. 3 and 4). This digital data may include a shape, a size, a contour, a location, and/or an orientation of an intended-use substructure 18, an intended-use veneer 22, dental devices already existing in the patient's mouth, and/or the patient's mouth itself. Controller 50 may use the digital data to regulate operation of the other components of system 12 and/or 14.

[0066] For example, platform 58 may be lowered in an amount corresponding to a desired thickness of a first layer of superstructure 20. At about the same time, platform 66 may be raised by about this same thickness. Recoater 46 may be driven by associated actuator(s) to push material (e.g., only Coron®) protruding from material chamber 42 above a lower edge of recoater 46 into build chamber 40 and on top of platform 58. The material may be spread across platform 58 in a relatively consistent and well-distributed manner. Thereafter, energy source 48 may be activated to sinter the powdered material (e.g., the Coron®) in a pattern corresponding to the size, shape, and/or contour of superstructure 20 at the particular height above platform 58 within the smaller portion p (referring to Fig. 2). Platform 58 may then be lowered by a thickness of a second layer of superstructure 20, and the process may be repeated until the smaller portion p is completed.

[0067] After the smaller portion p has been completed, a slightly different process may be implemented to complete the larger portion P of superstructure 20. For example, platform 58 may be lowered in an amount corresponding to a desired thickness of a first layer of the larger portion P. At about the same time, platform 74 (in system 12) or platform 66 (in system 14) may be raised by about this same thickness. Recoater 46 may be driven by associated actuator(s) to push material (e.g., Coron® + the oxidation particles, in system 12; or only Coron® in system 14) protruding from the corresponding material chamber above a lower edge of recoater 46 into build chamber 40 and on top of the final layer of the smaller portion p. The material may be spread across platform 58 in a relatively consistent and well- distributed manner. In the example of system 14, injector 88 may additionally be caused to inject oxidation particles into build chamber 40 either uniformly or only at specific locations before or after deposition of the layer of Coron®. Thereafter, energy source 48 may be activated to sinter the powdered material (e.g., the Coron® + the oxidation particles) in a pattern corresponding to the size, shape, and/or contour of superstructure 20 at the particular height above platform 58 within the larger portion P (referring to Fig. 2). Platform 58 may then be lowered by a thickness of an additional layer of superstructure 20, and the process may be repeated until the larger portion P is completed.

[0068] In some embodiments, a heat treatment process may thereafter be performed, during which exposed oxidation particles are caused to oxidize. Superstructure 20 may thereafter be connected to the associated substructure 18 inside the corresponding patient's mouth. Veneer 22 may previously be adhered to superstructure 20.

[0069] It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed system and method. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed system and method. For example, when referring the "mouth" of a particular patient, such reference is intended to encompass only part (e.g., only soft tissue, only hard tissue, a particular combination of soft and hard tissues, etc.) or all of the mouth. The detailed description of one specific metal powder material, i.e. Coron®, and one specific type of additive particles, i.e. oxidation particles, is not meant to limit the described system and method to these specific materials. For example, other metal powder material like cobalt- chromium-molybdenum or cobalt-chromium-nickel compositions may be used. Also other additive particles are contemplated which impart different properties, for example increased stiffness or ductility, to the product without changing the basic alloy as, for example, defined by the main components and a coefficient of thermal expansion similar enough to discourage stress buildup, cracking, or separation during temperature fluctuations. It is intended that the specification and examples be considered as exemplary only.

List of Reference Numerals

10. Prosthesis

12. System for Manufacturing

13. Body Portion (of Substructure)

14. System for Manufacturing

15. Cap Portion (of Substructure)

16. Bone Structure

17. Lower Surface (of Cap Portion)

18. Substructure

19. Cap (Intermediate Structure)

20. Superstructure (Abutment)

21. Proximal End

22. Veneer

23. Distal End

24. Engagement Interface

25. Upper Surface (of Bone Structure)

26. Thread

27. Recess

28. Gingiva

29. Longitudinal Axis

30. Bore

31. Threaded Portion (of Cap)

32. Threaded Portion (of Superstructure)

33. Cap Portion (of Cap)

34. Lower Surface (of Superstructure)

35. Upper Surface (of Cap)

36. Upper Surface (of Cap Portion)

37. Outer Lip

38. Outer Surface (of Veneer)

39. Lower Surface (of Outer Lip)

40. Build Chamber

41. Upper Surface (of Gingiva)

42. First Material Chamber 44. Second Material Chamber

46. Recoater

48. Energy Source

50. Controller

52. Arrow

54. Wall 56 Stage

58. Platform

60. Actuator

62. Arrow

64. Wall

66. Platform

68. Actuator

70. Arrow

72. Wall

74. Platform

76. Actuator

78. Arrow

80. Ridge

82. Laser

84. Beam

86. Optics

88. Injector