Preformed stainless-steel crowns are still the preferred choice for whole or partial replacements of teeth. They are a very durable and reliable restoration for a tooth in need of complete coverage. However, stainless-steel crowns have an unattractive appearance. Thus, there is a need for stainless-steel dental crowns that have a more natural look with preferably a more natural look with a tooth-like appearance. Various dental crowns and methods of making dental crowns are disclosed, for example in: U.S. Pat. Nos. 4,068,379; 6,663,390; 6,106,295; 7,008,229; 8,597,762; 9,044,292; U.S. Patent Publication 2009/0286205; PCT Patent Application No. 2018/058590; Chinese Pat. No. 1,163,093; European Pat. No. 0156273; European Pat. No. 0051704; and German Patent Publication 3600977. However, it is always desirable to create better solutions for creating long lasting dental crowns.
Some aspects of the present disclosure provide a dental crown. The dental crown could include a metal shell shaped to cover a portion of a tooth of a patient, the metal shell comprising: a continuous non-porous, metal or metal-composite layer; a coating retention layer adjacent the metal layer, wherein coating retention layer is three-dimensionally printed and comprises a plurality of coating retention elements, wherein the retention layer comprises a plurality of interstitial regions between the retention elements and the adjacent metal layer, and wherein a plurality of apertures is formed between the plurality of retention elements.
Other aspects of the present disclosure provide a method of forming a dental crown. The method may include three-dimensionally printing a metal shell and a coating retention layer to form a dental crown, wherein the coating retention layer comprises a plurality of apertures wherein an interface between the metal base layer and the coating retention layer comprises a plurality of interstitial regions, and wherein both the shell and coating retention layer comprise three-dimensional printed materials.
Some other aspects of the present disclosure provide a method of forming a dental crown. The method may include providing a multilayer construction comprising: a continuous, nonporous metal base layer; a three-dimensionally printed coating retention layer adjacent to the metal base layer, wherein the coating retention layer comprises a plurality of coating retention elements, wherein there are a plurality of apertures between the coating retention elements, further wherein an interface between the metal base layer and the coating retention elements comprises a plurality of interstitial regions; forming the multilayer construction into dental crown blank.
The details of one or more examples of this disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of this disclosure will be apparent from the description and drawings, and from the claims.
There has been a long-standing need for both temporary and permanent esthetic metal crowns for dental patients. Traditionally, dental patients have received dental crowns made from stainless steel because they are very durable and provide reliable restorations for the patient's tooth. However, stainless steel crowns have an unattractive appearance. Thus, there is a need for stainless steel dental crowns that have a more natural look with preferably a tooth-like color. Attempts have been made using resins, such as polyesters, epoxies, acrylics, and high-density polyethylene, to form an esthetically pleasing appearance on the outside of the crown. But, as illustrated by
The scale of the teeth shown and the crown 10 to be placed thereon is for ease of illustration and should not be considered to be at the correct scale. Furthermore, the portion of the tooth 12, which has been ground away, is also for illustration purposes only.
The dental crown 10 has a metal layer or foil 20, shown as a metal shell. The metal for the shell 20 is preferably stainless steel, but also could be aluminum, tin, silver, gold and any alloys thereof. The metal layer is preferably a continuous layer and nonporous. This is to prevent the coating material from seeping into the interior of the crown, which might interfere with the crown preparation and placement. The dental crown 10 has a coating retention layer 22. The retention layer 22 is preferably stainless steel, but also could be aluminum, tin, silver, gold and any alloys thereof. The shell 20 and retention layer 22 may be both manufactured by three-dimensional printing, as described in more detail below. Alternatively, just the retention layer 22 may be manufactured by three-dimensional printing. With three-dimensional printing manufacturing process, the retention layer 22 can be designed with features (such as interstitial regions described below) to enhance the retention of the polymer coating; such retention layer features may be difficult or impossible to fabrication with typical manufacturing processes that are not additive manufacturing processes.
The retention layer 22 keeps the coating 24 highly retained on the metal shell 20, even after long periods of use. Due to the mechanical structure of the retention layer, the coating 24 is strongly adhered to the metal shell 20 by the physical interaction of the cured coating layer with the retention layer, as described in more detail below relative to
In one exemplary embodiment, the three dimensionally printed coating retention layer 22 is made to resemble a mesh of intermingled, elongated metal strands 26, printed into a variety of patterns. Examples of some patterns are illustrated in
In one exemplary embodiment the dental crown 10 of the present invention is formed from a laminate construction that includes the three-dimensional printed coating retention layer 22.
As illustrated in
One exemplary embodiment for diffusion bonding the metal layer 20 to the coating retention layer 22 is shown in
Alternatively, other bonding processes may be used, other than diffusion bonding. For instance, welding or brazing may be used to bond the three-dimensional printed coating retention layer 22 to the metal base layer 20, while still maintaining the interstitial regions 32 between the two layers.
Instead of diffusion bonding or other bonding processes, three-dimensional printing processes may be used to integrally form the layer 20 and retention layer 22 during one or more three-dimensional printing process. During such printing processes powder or liquid base material is built into a solid object. One preferred method of three-dimensional printing of the layers 20, 22 is using powder bed fusion. Presently, a laser-based process (referred to in the literature as selective laser sintering, selective laser melting, direct metal laser sintering and others) and electron beam melting may be used for such powder bed fusion.
With a laser based process, a high-powered laser beam is focused onto a bed of powdered metal where thin solid layers (10-120 μm) are fused until the 3D object is built. The entire fabrication chamber is kept in an inert environment such as purified nitrogen or argon. The chamber may optionally be heated above room temperature. Depending on the amount of energy applied by the laser beam, the powder may be caused to sinter together, creating a slightly porous final article, or melt completely, creating a completely dense or almost completely dense final article. Optional post print heat treatments can be used to alter the microstructure of the printed article, optionally with the addition of pressure, as in a hot isostatic pressure apparatus, which can densify the printed article.
Instead of using a laser beam to melt or sinter the powder, with the electron beam melting technologies, a focused electron beam is used to selectively melt layers of powder (50-100 μm) in vacuum. Also, while building the part, an elevated temperature of close to the melting point of the material being processes is maintained in the chamber to reduce the residual stresses. Initially, a tungsten or other filament is heated over 3000° C., which causes electrons to be emitted, and subsequently, potential difference between a cathode and an anode causes the electrons to accelerate. The electrons are focused and detected using magnetic coils to form a narrow high energy beam that attacks the surface of the powder. Eventually, the kinetic energy transferred through friction creates the heat that is necessary to melt the metal powder. The main differences between the different powder bed fusion technologies are the operational parameters such as melting temperature, energy source, power, laser/electron beam absorption/reflections coefficients, thermal conductivity, chamber conditions, temperature reached, along with other parameters such layer thickness, build orientation and grain size, which may be optimized by one skilled in the art. The processes describe above for additive manufacturing of metal objects are described only for non-limiting illustrative purposes as examples of processes that may be used to print embodiments of the present disclosure. It is understood that other methods of three-dimensionally printing metal and metal composite objects may be used to print the coating retention layer 22 of the present disclosure.
For three-dimensional metal printing or additive printing, the dental crown of the present invention, cobalt chrome (Co—Cr) and titanium (Ti) are the most commonly used alloys. The metal powder of Co—Cr also typically contains molybdenum silicon, iron, manganese, nickel and carbon. The metal powders used in three-dimensional printing are a mixture of particles with sizes ranging between 10 and 50 μm. In some embodiments, the metal powder may a stainless-steel alloy powder composition, and particularly, may be a 17-4PH alloy steel powder. The standard 17-4PH alloy composition includes the following approximate weight percents: Cr=15.5-17.5%, Ni=3.5-4.5%, Cu=3.5-4.5%, Nb+Ta=0.15-0.45%, Si=0-1%, Mn=0-1%, P=0-0.04, C=0.07% max, and Fe balance. The 17-4PH alloy delivers the corrosion resistance of a 304 austenitic stainless steel, yet is as strong as 420 martensitic stainless. The 17-4 PH (US designation) corresponds to 1.4542 European designation. An important characteristic of the 17-4 PH powder material in conventional use is that it can be post-hardened by precipitation hardening (“PH”) to significantly increase the hardness. One supplier of commercially available 17-4PH stainless steel powder; D90<22 μm, is Sandvik Osprey Ltd., of Neath, UK.
In one embodiment, layers 20 and 22 are three-dimensionally printed as a unitary part in the final or near-final shape of a dental crown, such as represented by
In one exemplary embodiment, a deep-drawing die is illustrated schematically in
The deep-drawing die set 100 includes a base plate 102, a drawing punch 104 arranged stationary on the upper side of the base plate 102, and a sheet-metal holder 106 which surrounds the drawing punch 104 in a ring shape and is arranged on a supporting plate 108 which likewise surrounds the drawing punch 104 in a ring shape and is borne by spindle sleeves 110 which can be moved vertically be means of a hydraulic moving device (not illustrated) so that the supporting plate 108 can be moved with the sheet metal holder 106 arranged thereon along the vertical direction drawing 112.
The deep-drawing die set 100 also includes a drawing member 114 which is arranged above the drawing punch 104 and the sheet metal holder 106 and comprises, for its part, a ring-shaped drawing ring support 116 and a drawing ring 118 held on its underside.
The drawing ring support 116 is held at its upper side on a holding plate 120 which can be moved by means of a hydraulic moving device (not illustrated) along the direction of drawing 112 relative to the drawing punch 104 and the sheet metal holder 106.
The drawing member 114 forms the first deep-drawing die part 122 of the deep-drawing die set 100; the drawing punch 104 forms the second deep-drawing die part 124 of the deep-drawing die set 100.
A first deep-drawing process is carried out as follows with the deep-drawing die set 100 described above.
First, the drawing member 114 and the sheet metal holder 106 are displaced into their respective upper starting positions by means of the respective hydraulic moving devices (not illustrated).
In the upper starting position of the sheet metal holder 106, the essentially flat upper side of the sheet metal holder 106, the essentially flat upper side of the sheet metal holder 106 is arranged above the upper side of the drawing punch 104.
In this position, the dental blank 126, from which the drawn part is intended to be produced, is inserted into the deep-drawing die set 100 such that the edge of the blank 126 rests on the sheet metal 106, as illustrated in
Subsequently, the deep-drawing die set 100 is closed in that the drawing member is displaced by means of the hydraulic moving device (not illustrated) downwards out of its upper starting position to such an extent along the direction of drawing 112 until the underside of the drawing ring 118 on the upper side of the blank 126 and the edge of the blank 126 is clamped between the drawing ring 118 and the sheet metal holder 106, as illustrated in
In the subsequent method step, the blank 126 is formed into a drawn part 128 in that the spindle sleeves 110 with the supporting plate 108 arranged thereon and the sheet metal holder 106 as well as the drawing member 114 are moved downwards by means of the hydraulic moving device (not illustrated) along the direction of drawing 112 relative to the drawing punch 104 by the drawing depth, wherein the blank 126 held securely at its edge between the drawing ring 118 and the sheet metal holder 106 fits closely along the outer contours of the drawing ring 118 and the drawing punch 104, as illustrated in
Once the desired drawing depth for the first deep-drawing process is reached, the spindle sleeves 110 are moved back into their upper starting position with the supporting plate 108 arranged thereon and the sheet metal holder 106 and the deep-drawing die set 100 is opened in that the drawing member 114 is moved further along the direction of drawing 112 upwards into its upper starting position, as illustrated in
As a result, the drawn part 128 formed during the first deep-drawing process is accessible from outside the deep-drawing die set 100 and can be removed from it. There are often successive deep drawing die sets that continue to form the drawn part 128 to the final desired dimensions. The drawn part 128 may then be converted into a dental crown 10 of the present invention by trimming the excess flange around the portion that contacted the sheet metal holder 106.
In one embodiment, after the three-dimensionally printed retention layer 22 and metal base layer 20 are bonded, they may be coated with a polymeric composition to form a dental blank 130.
Optionally, to increase the bonding of the coating 24 to the retention layer 22 and to metal base layer 20, both layers may be sandblasted or otherwise physically or chemically treated to prime the surface prior to the coating process.
One way to apply the esthetic layer 24 is to electrostatically apply a powder to the metal retention layer 22 and base layer 20. One example of suitable powder is ALESTA epoxy-polyester hybrid, which is commercially available from Axalta Coating Systems based in Houston, Tex.
The hardenable compositions of the present disclosure are typically hardenable due to the presence of a polymerizable component. As used herein, the term “hardenable” refers to a material that can be cured or solidified, e.g., by heating to remove solvent, heating to cause polymerization, chemical crosslinking, radiation-induced polymerization or crosslinking, or the like.
In some embodiments, the compositions can be hardened (e.g., polymerized by heat, conventional photopolymerization and/or chemical polymerization techniques) after it has been applied to the surface of a dental article.
In certain embodiments, the compositions are photopolymerizable, i.e., the compositions contain a photo initiator system that upon irradiation with actinic radiation initiates the polymerization (or hardening) of the composition. In other embodiments, the compositions are chemically hardenable, i.e., the compositions contain a chemical initiator (i.e., initiator system) that can polymerize, cure, or otherwise harden the composition without dependence on irradiation with actinic radiation. Such chemically hardenable compositions are sometimes referred to as “self-cure” compositions.
In other embodiments, the compositions are thermally polymerizable, i.e., the compositions contain a thermal initiator system that upon heating or other application of thermal energy initiates the polymerization (or hardening) of the composition.
As used herein, the term “(meth)acrylate” is a shorthand reference to acrylate, methacrylate, or combinations thereof, and “(meth)acrylic” is a shorthand reference to acrylic, methacrylic, or combinations thereof. As used herein, “(meth)acrylate-functional compounds” are compounds that include, among other things, a (meth)acrylate moiety.
The polymerizable component typically comprises one or more ethylenically unsaturated compounds, with or without acid functionality. Examples of useful ethylenically unsaturated compounds include acrylic acid esters, methacrylic acid esters, hydroxy-functional acrylic acid esters, hydroxy-functional methacrylic acid esters, and combinations thereof. The polymerizable component may comprise one or more ethylenically unsaturated compounds, with or without acid functionality that is phosphorylated, such as a phosphorylated methacrylate. In some embodiments, the polymeric composition comprises a polymerizable component is selected from the group consisting of phenoxyethyl methacrylate, urethane dimethacrylate, polyethylene glycol methacrylate, polypropylene glycol methacrylate, triethyleneglycol dimethacrylate, the diglycidyl methacrylate of bisphenol A, and combinations thereof.
One suitable coating is taught as microparticle coating in U.S. Pat. No. 9,044,292, “Dental Articles include a Ceramic and Microparticle Coating, and Method of Making the Same,” which is hereby incorporate by reference.
In one embodiment, the composition is a polymer or copolymer chosen from epoxy, polyester, and hybrids thereof. In another embodiment, the composition may be a thermoplastic polymer. If so, the thermoplastic polymer could be from polyetheretherketone (PEEK), polyaryletherketone (PAEK), polyphenolsulfones, polyethersulfones, polyacrylamide, PTFE or combinations thereof.
Preferably, the coating composition is retained on the metal shell with a minimum bond strength of at least 5 MPa. This is to provide a dental crown that will endure the various forces applied to it while the patient is chewing.
In one preferred embodiment, the metal shell has a thickness in the range of 50 to 250 micrometers. In a more preferred embodiment, the metal shell 20 has a thickness in the range of 50 to 150 micrometers. In another preferred embodiment, the coating retention layer 22 has a thickness in the range of 50 to 125 micrometers. Overall, the dental crown 10 has a thickness in the range of 50 to 700 micrometers. Such preferred thickness ranges provide flexibility and durability.
Replacing a tooth with a crown is often considered a cosmetic procedure rather than a medical procedure, as it improves the appearance of a patient's teeth.
First, in referring to
Now, referring to
Referring to
Referring to
In certain embodiments, a method of making a portion of the esthetic dental crown 10 is provided, specifically the portion representing the layer 20 and coating retention layer 22. The method comprises receiving, by a manufacturing device having one or more processors, a digital object comprising data specifying a plurality of layers of layers 20, 22; and generating, with the manufacturing device by an additive manufacturing process, the layers 20, 22 based on the digital object. The layers 20, 22 include a mesh of intermingled, elongated metal strands 26, printed into a variety of patterns, with a number of layers of metal directly bonded to each other. Additionally, referring to
The following embodiments are intended to be illustrative of the present disclosure and not limiting.
Embodiment 1 is a dental crown comprising: a metal shell shaped to cover a portion of a tooth of a patient, the metal shell comprising: a continuous non-porous, metal or metal-composite layer; a coating retention layer adjacent the metal layer, wherein coating retention layer is three-dimensionally printed and comprises a plurality of coating retention elements, wherein the retention layer comprises a plurality of interstitial regions between the retention elements and the adjacent metal layer, and wherein a plurality of apertures is formed between the plurality of retention elements.
Embodiment 2 is a dental crown of embodiment 1, further comprising a hardenable coating composition applied on the coating retention layer and continuous within the plurality of the interstitial regions and apertures to mechanically retain the coating composition to the coating retention layer of the shell.
Embodiment 3 is the dental crown of embodiment 1-3, wherein the continuous non-porous metal layer is three-dimensionally printed with the retention layer.
Embodiment 4 is the dental crown of embodiment 1-3, wherein the retention elements of the coating retention layer comprise a grid, or a mesh, comprising a plurality of elongated metal strands, and the interstitial regions underlie at least a portion of the strands.
Embodiment 5 is the dental crown of embodiment 2, wherein a plurality of apertures between the plurality of elongated metal strands comprise 10 to 60 percent of the area of the coating retention layer.
Embodiment 6 is the dental crown of embodiment 1-4, wherein the open spaces between the elongated strands comprise 30 to 40 percent of the area of the coating retention layer.
Embodiment 7 is the dental crown of embodiments 1-4, wherein the coating retention layer comprises a mesh of elongated metal strands, wherein the metal strands comprise a plurality of coating retention elements and the interstitial regions underlie at least a portion of the strands.
Embodiment 8 is the dental crown of embodiments 1-7, wherein the hardenable coating composition is hardened or cured by heating to remove solvent, heating to cause polymerization, chemical crosslinking, radiation-induced polymerization or crosslinking.
Embodiment 9 is the dental crown of embodiments 1-8, wherein the composition comprises a polymer or copolymer chosen from epoxy, polyester, and hybrids thereof.
Embodiment 10 is the dental crown of embodiments 1-8, wherein the composition comprises a thermoplastic polymer.
Embodiment 11 is the dental crown of embodiment 10, wherein the composition comprises a thermoplastic polymer chosen from polyetheretherketone (PEEK), polyaryletherketone (PAEK), polyphenolsulfones, polyethersulfones, polyacrylamide, PTFE and combinations thereof.
Embodiment 12 is the dental crown of embodiments 1-11, wherein the metal shell and/or the coating retention layer comprise stainless steel.
Embodiment 13 is the dental crown of embodiments 1-12, wherein the coating composition is retained on the metal shell with a minimum bond strength of 5 MPa.
Embodiment 14 is the dental crown of embodiments 1-13, wherein the composition comprises a polymerizable component selected from the group consisting of phenoxyethyl methacrylate, urethane dimethacrylate, polyethylene glycol methacrylate, polypropylene glycol methacrylate, triethyleneglycol dimethacrylate, the diglycidyl methacrylate of bisphenol A, and combinations thereof.
Embodiment 15 is the dental crown of embodiments 1-14, wherein the metal shell has a thickness in the range of 50 to 250 micrometers.
Embodiment 16 is the dental crown of embodiments 15, wherein the metal shell has a thickness in the range of 50 to 150 micrometers.
Embodiment 17 is the dental crown of embodiments 1-14, wherein the coating retention layer has a thickness in the range of 50 to 125 micrometers.
Embodiment 18 is the dental crown of embodiments 1-16, wherein the dental crown has a thickness in the range of 50 to 700 micrometers.
Embodiment 19 is the dental crown of embodiments 1-18, wherein the hardenable coating composition comprises powder.
Embodiment 20 is a method of forming a dental crown, comprising: three-dimensionally printing a metal shell and a coating retention layer to form a dental crown, wherein the coating retention layer comprises a plurality of apertures, wherein an interface between the metal base layer and the coating retention layer comprises a plurality of interstitial regions, and wherein both the shell and coating retention layer comprise three-dimensional printed materials.
Embodiment 21 is the method of embodiment 20, further comprising applying a hardenable coating composition onto the coating retention layer and continuously within the plurality of the interstitial regions and apertures.
Embodiment 22 is the method of embodiments 20-21, wherein the coating retention layer comprises a mesh structure of elongated metal strands, and wherein the plurality of interstitial regions is between the metal strands and the base layer.
Embodiment 23 is the method of embodiments 20-22, further comprising hardening the coating composition to form a coating overlying at least a portion of the coating retention layer.
Embodiment 24 is the method of embodiments 20-23, wherein the coating step includes electrostatically powder coating the retention layer and subsequently heating.
Embodiment 25 is the method of embodiments 20-24, wherein the composition is hardened or cured by heating to remove solvent, heating to cause polymerization, chemical crosslinking, radiation-induced polymerization or crosslinking.
Embodiment 26 is the method of embodiments 20-25, wherein the thermoplastic composition comprises a polymer or copolymer chosen from epoxy, polyester, and hybrids thereof.
Embodiment 27 is the method of embodiments 20-26, wherein the coating comprises a thermoplastic polymer.
Embodiment 28 is the method of embodiments 20-27, wherein composition comprises a thermoplastic polymer, and wherein the thermoplastic polymer is chosen from polyetheretherketone (PEEK), polyaryletherketone (PAEK), polyphenolsulfones, polyethersulfones, polyacrylamide, PTFE, and combinations thereof.
Embodiment 29 is the method of embodiment 20-28, wherein the composition comprises a polymerizable component is selected from the group consisting of phenoxyethyl methacrylate, urethane dimethacrylate, polyethylene glycol methacrylate, polypropylene glycol methacrylate, triethyleneglycol dimethacrylate, the diglycidyl methacrylate of bisphenol A, and combinations thereof.
Embodiment 30 is the method of embodiments 20-29, wherein the plurality of apertures between the elongated strands comprise 10 to 70 percent of the area of the coating retention layer.
Embodiment 31 is the method of embodiment 30, wherein the plurality of apertures between the elongated strands comprise 30 to 40 percent of the area of the coating retention layer.
Embodiment 32 is the method of embodiments 30-31, wherein at least one of the metal base layer and the coating retention layer comprise stainless-steel, or wherein both the metal base layer and the coating retention layer comprise stainless steel.
Embodiment 33 is the method of embodiments 20-32, wherein the coating composition is retained on the shell with at least a bond strength of 5 MPa.
Embodiment 34 is the method of embodiments 20-33, further comprising: selecting the dental crown of embodiment 1 to cover a tooth portion of a patient; customizing the dental crown for the patient; and attaching the dental crown to the tooth of the patient.
Embodiment 35 is a method of forming a dental crown, comprising: providing a multilayer construction comprising: a continuous, nonporous metal base layer; a three-dimensionally printed coating retention layer adjacent to the metal base layer, wherein the coating retention layer comprises a plurality of coating retention elements, wherein there are a plurality of apertures between the coating retention elements, further wherein an interface between the metal base layer and the coating retention elements comprises a plurality of interstitial regions; and forming the multilayer construction into dental crown blank.
Embodiment 36 is the method of embodiment 35, wherein the continuous non-porous metal layer is three-dimensionally printed with the coating retention layer.
Embodiment 37 is the method of embodiments 35-36, wherein the forming step comprises pressing the blank through a die.
Embodiment 38 is the method of embodiments 35-37, wherein the forming step comprises deep drawing the blank according to standard DIN 8584-3.
Embodiment 39 is the method of embodiments 35-37, wherein the coating retention elements comprise a mesh of elongate metal strands, wherein the plurality of apertures is between the plurality of metal strands, and wherein the plurality of interstitial regions between the metal strands and the base layer.
Embodiment 40 is the method of embodiments 35-39 further comprising applying a hardenable coating composition onto the coating retention layer and continuously within the plurality of the interstitial regions and apertures.
Embodiment 41 is the method of embodiments 35-40, further comprising hardening the composition on the coating retention layer.
Embodiment 42 is the method of embodiments 35-41, wherein the composition is hardened or cured by heating to remove solvent, heating to cause polymerization, chemical crosslinking, radiation-induced polymerization or crosslinking.
Embodiment 43 is the dental crown of embodiments 35-42, wherein the composition comprises a polymerizable component is selected from the group consisting of phenoxyethyl methacrylate, urethane dimethacrylate, polyethylene glycol methacrylate, polypropylene glycol methacrylate, triethyleneglycol dimethacrylate, the diglycidyl methacrylate of bisphenol A, and combinations thereof.
Embodiment 44 is the method of embodiments 35-43, wherein the composition comprises a polymer or copolymer chosen from epoxy, polyester, and hybrids thereof.
Embodiment 45 is the method of embodiments 35-44, wherein the coating composition comprises a thermoplastic polymer, and wherein the thermoplastic polymer is chosen from polyetheretherketone (PEEK), polyaryletherketone (PAEK), polyphenolsulfones, polyethersulfones, polyacrylamide, PTFE, and combinations thereof.
Embodiment 46 is the method of embodiments 35-45, wherein at least one of the metal base layer and the coating retention layer comprises stainless-steel, or wherein both the metal base layer and the coating retention layer comprises stainless steel.
Embodiment 47 is the method of embodiments 35-46, wherein the coating retention layer comprises a mesh of elongate metal strands, and the interstitial regions underlie at least a portion of the strands.
Embodiment 48 is the method of embodiments 35-47, wherein the coating composition is retained on the metal shell with a minimum bond strength of 5 MPa.
Embodiment 49 is the method of embodiments 35, 37-48, wherein the metal base layer is diffusion bonded to the coating retention layer.
Embodiment 50 is the method of embodiment 49, wherein diffusion bonding comprises heat/pressure.
Embodiment 51 is the method of embodiments 40-50, wherein the coating step includes electrostatically powder coating the retention layer and heating.
Embodiment 52 is the method of embodiment 35-51, further comprising: selecting the dental crown of embodiment 19 to cover a tooth portion of a patient; customizing the dental crown for the patient; and attaching the dental crown to the tooth of the patient.
Embodiment 53 is a non-transitory machine-readable medium having data representing a three-dimensional model of a dental crown, when accessed by one or more processors interfacing with a 3D printer, cause the 3D printer to create a coating retention layer adjacent a metal layer of the dental crown, wherein the dental crown comprises: a metal shell shaped to cover a portion of a tooth of a patient, the metal shell comprising: a continuous non-porous, metal or metal-composite layer; wherein the coating retention layer comprises a plurality of coating retention elements, wherein the retention layer comprises a plurality of interstitial regions between the retention elements and the adjacent metal layer, and wherein a plurality of apertures is formed between the plurality of retention elements.
Embodiment 54 is a method comprising: retrieving, from a non-transitory machine-readable medium, data representing a 3D model of a metal shell shaped to cover a portion of a tooth of a patient for a dental crown, the metal shell comprising: a continuous non-porous, metal or metal-composite layer; a coating retention layer adjacent the metal layer, wherein coating retention layer is three-dimensionally printed and comprises a plurality of coating retention elements, wherein the retention layer comprises a plurality of interstitial regions between the retention elements and the adjacent metal layer, and wherein a plurality of apertures is formed between the plurality of retention elements, wherein the metal shell comprises a plurality of layers of metal directly bonded to each other; executing, by one or more processors, a 3D printing application interfacing with a manufacturing device using the data; and generating, by the manufacturing device, a physical object of the metal shell.
Embodiment 55 is a dental crown generated using the method of Embodiment 54.
Embodiment 56 is a method of forming a metal shell shaped to cover a portion of a tooth of a patient for a dental crown, the method comprising: receiving, by a manufacturing device having one or more processors, a digital object comprising data specifying a plurality of layers of a metal shell, the metal shell comprising: a continuous non-porous, metal or metal-composite layer; a coating retention layer adjacent the metal layer, wherein coating retention layer is three-dimensionally printed and comprises a plurality of coating retention elements, wherein the retention layer comprises a plurality of interstitial regions between the retention elements and the adjacent metal layer, and
wherein a plurality of apertures is formed between the plurality of retention elements, wherein the metal shell comprises a plurality of layers of metal directly bonded to each other; and generating, with the manufacturing device by an additive manufacturing process, the metal shell based on the digital object.
Embodiment 57 is a system comprising: a display that displays a 3D model of a metal shell shaped to cover a portion of a tooth of a patient for a dental crown; and one or more processors that, in response to the 3D model selected by a user, cause a 3D printer to create a physical object of the burner body, the metal shell comprising: a continuous non-porous, metal or metal-composite layer; a coating retention layer adjacent the metal layer, wherein coating retention layer is three-dimensionally printed and comprises a plurality of coating retention elements, wherein the retention layer comprises a plurality of interstitial regions between the retention elements and the adjacent metal layer, and wherein a plurality of apertures is formed between the plurality of retention elements, wherein the metal shell comprises a plurality of layers of metal directly bonded to each other.
Advantages and embodiments of this invention are further illustrated by the following examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this invention. All parts and percentages are by weight unless otherwise indicated.
A stainless steel dental crown with a retentive surface can be 3D printed from 17-4PH stainless steel powder (D90<22 μm, Sandvik Osprey, Neath, UK). The crown can be printed, for example, using a ProX DMP 200 powder bed fusion 3D printer (3D Systems, Rock Hill, S.C.). The crown can be printed using 30 μm layer height. Table 1 shows the laser parameters that can be used for printing the crown, based on the printer manufacturer's recommendations. Where necessary, during printing, retentive surface structures can be held up using a mesh support structure, generated using ProX DMP Manufacturing software (3D Systems). This support structure can be later removed, and the crown can be cleaned ultrasonically to remove excess powder. A stainless steel dental crown with a retentive surface structures can be 3D printed as described above with retentive structures according to, for example, any one of
The 3D printed dental crown according to Example 1 can be coated with a polymeric material to provide a more aesthetic tooth-like appearance. The 3D printed dental crown according to Example 1 can be coated with, 3M FILTEK Supreme Ultra Flowable Restorative composite material, directly extruded from a syringe (with the tip immersed in the material to prevent bubbles) so that the coating material flows into the interstitial regions of the retentive surface structures. The coating can be shaped accordingly and then light cured for 30 seconds using a 400-500 nm visible curing light device, such as, for example 3M ELIPAR DeepCure-S LED Curing Light.
The 3D printed dental crown according to Example 1 can be coated with a polymeric material to provide a more aesthetic tooth-like appearance. The 3D printed dental crown according to Example 1 can be dry-powder coated with an electrostatic spraying process using the following powder: RAL 9001 Cream—Polyester TGIC Weather Resistant Powder Coating. The 3D printed crown with retentive surface structures can be first washed with cleaning solution and rinsed with water prior to electrostatic coating. The electrostatic spraying process application of the powder coating ensures that the polyester coating covers the surface of the 3D printed dental crown and into the interstitial regions of the retentive surface structures. After the electrostatic spraying process application of the powder coating, the coated crown can be baked at 400° F. (204° C.) for 10 minutes. The final coating can be approximately 125 micrometers thick.
Filing Document | Filing Date | Country | Kind |
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PCT/IB2019/060488 | 12/5/2019 | WO | 00 |
Number | Date | Country | |
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62776666 | Dec 2018 | US |