Patent Description:
Devices for radiation curing articles have been used in numerous industries; however, there remains a need for improvements in performance as well as user control of the devices. Examples of such prior art are: <CIT>, which discloses a method for polymerizing or cross-linking a dental composition that includes a photosensitive material; <CIT>, which discloses method and an apparatus for use in the curing of fusible materials which after being filled into a mould are cured by means of radiation, and <CIT>, which discloses a method of post-curing a modeled object in a green state based on modeling data generated according to a working model includes a curing step of exposing the modeled object to light while the modeled object is fitted to the working model to secondary-cure the modeled object.

In a first aspect, an apparatus is provided. The apparatus includes a) a housing; b) a chamber disposed in the housing; c) at least two light emitting diodes (LEDs) disposed within the housing; and a user interface disposed on an exterior of the housing. The chamber is configured to be adaptable to each of an open configuration, a closed configuration, and a hermetically sealed configuration, and the chamber includes a material transparent to actinic radiation. Light from the at least two LEDs enters the chamber from more than one direction. The user interface includes a display and a plurality of program switches configured to adjust at least three operational parameters of the apparatus. The at least three operational parameters comprise <NUM>) light intensity provided by the at least two LEDs, <NUM>) length of time of light provided by the at least two LEDs, and at least one of 3a) delay time between initiation of light provided by the at least two LEDs and initiation of vacuum pulled on an interior of the chamber by the vacuum pump or 3b) delay time between initiation of vacuum pulled on an interior of the chamber by the vacuum pump and initiation of light provided by the at least two LEDs. The apparatus further includes a vacuum pump operatively connected to the chamber.

An article includes a plurality of layers of at least one photopolymerized crosslinked composition. Further, the article contains <NUM>% by weight or less of extractable components, based on the total weight of the article, when extracted with <NUM> volume percent ethanol in water. The article is made by a process including a) obtaining a photopolymerizable composition; b) selectively curing the photopolymerizable composition using actinic radiation to form an article having a plurality of layers of at least one photopolymerized composition; c) removing excess photopolymerizable composition from the article; d) placing the article in the apparatus of the first aspect; e) inputting a post-cure program or accessing a saved post-cure program through the user interface; and f) running the post-cure program. The post-cure program includes i) light intensity provided by the at least two LEDs, ii) length of time of light provided by the at least two LEDs, and at least one of iiia) delay time between initiation of light provided by the at least two LEDs and initiation of vacuum pulled by the vacuum pump or iiib) delay time between initiation of vacuum pulled on an interior of the chamber by the vacuum pump and initiation of light provided by the at least two LEDs.

In a second aspect, a method of post-curing an article is provided. The method includes a) obtaining an article; b) placing the article in an apparatus; c) inputting a post-cure program or accessing a saved post-cure program through the user interface; and d) running the post-cure program. The apparatus includes <NUM>) a housing; <NUM>) a chamber disposed in the housing; <NUM>) at least one light source comprising two light emitting diodes (LEDs) disposed within the housing; <NUM>) a user interface disposed on an exterior of the housing, the user interface comprising a display and a plurality of program switches configured to adjust at least three operational parameters of the apparatus; and <NUM>) a vacuum pump operatively connected to the chamber. The post-cure program includes i) light intensity provided by the at least one light source, ii) length of time of light provided by the at least one light source, and at least one of iiia) delay time between initiation of light provided by the at least one light source and initiation of vacuum pulled by the vacuum pump or iiib) delay time between initiation of vacuum pulled on an interior of the chamber by the vacuum pump and initiation of light provided by the at least one light source.

An article may be made by the method of the second aspect.

In a third aspect, a system is provided. The system includes a) an apparatus of the first aspect; and b) an article including at least one photopolymerized composition.

It has been discovered that apparatuses of the present disclosure can provide greater user control than previous devices. Moreover, methods of using the apparatuses and articles post-cured according to at least certain embodiments of this disclosure were found to provide articles having a low extractables content, e.g., as compared to instead using other post-curing methods.

While the above-identified figures set forth several embodiments of the disclosure other embodiments are also contemplated, as noted in the description. Not every feature is illustrated in each figure. In all cases, this disclosure presents the invention by way of representation and not limitation.

As used herein, the term "essentially free" in the context of a composition being essentially free of a component, refers to a composition containing less than <NUM>% by weight (wt. %), <NUM> wt. % or less, <NUM> wt. % or less, <NUM> wt. % or less, <NUM> wt. % or less, <NUM> wt. % or less, or <NUM> wt. % or less of the component, based on the total weight of the composition.

As used herein, the term "polymeric" refers to containing at least one polymer.

As used herein, the term "cavity" refers to an empty space, which is defined by at least one wall of a (e.g., solid) object.

As used herein, "curing" means the hardening or partial hardening of a composition by any mechanism, e.g., by heat, light, radiation, e-beam, microwave, chemical reaction, or combinations thereof. 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. As used herein, "cured" refers to a material or composition that has been hardened or partially hardened (e.g., polymerized or crosslinked) by curing.

As used herein, "transparent" refers to a material that has a thickness of <NUM> millimeters or less and has at least <NUM>% transmittance, <NUM>% transmittance, or optionally greater than <NUM>% transmittance over a particular range of wavelengths.

In this application, terms such as "a", "an", and "the" are not intended to refer to only a singular entity, but include the general class of which a specific example may be used for illustration. The terms "a", "an", and "the" are used interchangeably with the term "at least one. " The phrases "at least one of" and "comprises at least one of" followed by a list refers to any one of the items in the list and any combination of two or more items in the list.

As used herein, the term "or" is generally employed in its usual sense including "and/or" unless the content clearly dictates otherwise.

Also herein, all numbers are assumed to be modified by the term "about" and preferably by the term "exactly. " As used herein in connection with a measured quantity, the term "about" refers to that variation in the measured quantity as would be expected by the skilled artisan making the measurement and exercising a level of care commensurate with the objective of the measurement and the precision of the measuring equipment used.

As used herein as a modifier to a property or attribute, the term "generally", unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring absolute precision or a perfect match (e.g., within +/- <NUM> % for quantifiable properties). The term "substantially", unless otherwise specifically defined, means to a high degree of approximation (e.g., within +/- <NUM>% for quantifiable properties) but again without requiring absolute precision or a perfect match. Terms such as same, equal, uniform, constant, strictly, and the like, are understood to be within the usual tolerances or measuring error applicable to the particular circumstance rather than requiring absolute precision or a perfect match.

In a first aspect, the present disclosure provides an apparatus. The apparatus comprises:.

Apparatuses according to at least certain embodiments of the present disclosure advantageously provide increased user control over operation of the apparatuses.

Referring to <FIG>, an apparatus <NUM> according to the first aspect comprises a housing <NUM> and a chamber <NUM> disposed in the housing <NUM>. The housing <NUM> is typically formed of polymeric material, metal, and/or glass. The chamber <NUM> is configured to be adaptable to each of an open configuration (<FIG>, in which a hinged lid <NUM> is raised to allow access to the interior of the chamber <NUM>), a closed configuration (<FIG>, in which the hinged lid <NUM> is shut), and a hermetically sealed configuration (<FIG>, in which the hinged lid <NUM> is shut and atmosphere cannot leave or enter the chamber due to the presence of a flexible sealing element <NUM> that can be seen in <FIG>). The inclusion of a flexible sealing element <NUM> assists in the capability of adjusting the pressure inside of the chamber <NUM> and maintaining a selected pressure (e.g., using a vacuum pump <NUM>) within the chamber <NUM> when the hinged lid <NUM> is closed. One suitable flexible sealing element is a rubber o-ring.

The chamber <NUM> comprises a material transparent to actinic radiation. For instance, the chamber may comprise a material that is transparent to actinic radiation having wavelengths of at least <NUM> nanometers (nm), <NUM> or greater, <NUM> or greater, <NUM> or greater, <NUM> or greater, <NUM> or greater, <NUM> or greater, or <NUM> or greater; and <NUM> or less, <NUM> or less, <NUM> or less, <NUM> or less, <NUM> or less, or <NUM> or less. Stated another way, material of which at least a portion of the chamber is made is transparent to actinic radiation between <NUM> and <NUM> or between <NUM> and <NUM>. Suitable materials of which at least a portion of the chamber is made that are transparent to actinic radiation include glass and quartz. For example and without limitation, in some embodiments the chamber <NUM> comprises at least two, at least three, or at least four glass walls through which actinic radiation enters the chamber. In some embodiments, the chamber <NUM> comprises at least two, at least three, or at least four quartz walls through which actinic radiation enters the chamber. Combinations of glass and quartz can be included in the same chamber, if desired. In the embodiments shown in <FIG>, the chamber <NUM> is cylindrical and has one curved side wall.

At least two light emitting diodes (LEDs) <NUM> are disposed within the housing <NUM>, such that light from the at least two LEDs <NUM> enters the chamber <NUM> from more than one direction. In some embodiments, a first LED is positioned to direct light through a first major surface of the chamber <NUM> and a second LED is positioned to direct light through an opposing second major surface of the chamber <NUM>. In other embodiments, a floor of the chamber is the first major surface of the chamber and a lid of the chamber <NUM> is the second major surface of the chamber. Referring to <FIG>, in some embodiments the apparatus <NUM> further comprises a third LED positioned to direct light through a third major surface <NUM> of the chamber, wherein the third major surface <NUM> is directly adjacent to each of the first major surface of the chamber <NUM> and the second major surface of the chamber <NUM>. Similarly, in some embodiments the apparatus <NUM> further comprises a fourth LED positioned to direct light through a fourth major surface of the chamber <NUM>, wherein the fourth major surface <NUM> is opposite the third major surface of the chamber <NUM>. The use of at least two LEDs directing light from different directions can assist in exposing up to an entire sample to radiation simultaneously during the post-cure treatment. It will be understood that reference to "a first LED" encompasses the presence of more than one LED located at the position of the first LED, e.g., an array of individual LED bulbs may be provided as each of the first LED, the second LED, etc., rather than "a first LED" being limited to a single LED bulb.

In some embodiments, each of the LEDs provide light having a peak wavelength between <NUM> and <NUM>. In certain embodiment, at least two LEDs are present that provide light having a peak wavelength below <NUM>, above <NUM>, or both. Preferably, the (e.g., at least two) LEDs provide a light intensity of <NUM> milliwatts per square centimeter (mW/cm<NUM>), or greater, <NUM> mW/cm<NUM> or greater, <NUM> mW/cm<NUM> or greater, <NUM> mW/cm<NUM> or greater, <NUM> mW/cm<NUM> or greater, or <NUM> mW/cm<NUM> or greater; and <NUM> mW/cm<NUM> or less, <NUM> mW/cm<NUM> or less, <NUM> mW/cm<NUM> or less, or <NUM> mW/cm<NUM> or less. Stated another way the LEDs may provide a light intensity of <NUM> to <NUM> mW/cm<NUM> or <NUM> to <NUM> mW/cm<NUM>.

Referring to <FIG>, in some embodiments, the apparatus <NUM> further comprises a diffusing element <NUM> disposed between at least one LED <NUM> and the chamber <NUM>. A diffusing element is an optical element or a collection of elements having light transmission of at least <NUM>%. Diffusing elements can be volume diffusers such as diffuser plates, or foams. They can also be surface diffusers, diffractive or holographic diffusers, bead coated substrates, or surface structure on substrates. An exemplary surface diffuser is available, for example, as an optical ground glass diffuser from Edmund Optics Inc. , Barrington, USA. The apparatus may include a diffusing element positioned to diffuse light provided from any one or more of the light sources; e.g., an apparatus having four light sources may include one, two, three, or four separate diffusing elements.

In many embodiments, the apparatus <NUM> further comprises a reflective material <NUM> positioned in the housing <NUM> to reflect actinic radiation through a first major surface of the chamber <NUM> or an opposing second major surface of the chamber <NUM>. Suitable reflective materials include for instance and without limitation, metals such as aluminum or silver. The reflective material is optionally a layer that is either self-supporting or is a coating layer on a substrate (e.g., a polymeric and/or a glass substrate).

The apparatus <NUM> further comprises a user interface <NUM> disposed on an exterior <NUM> of the housing. The user interface <NUM> comprises a display <NUM> and a plurality of program switches <NUM> configured to adjust at least three operational parameters of the apparatus. In addition, the apparatus <NUM> comprises a vacuum pump <NUM> operatively connected to the (e.g., curing) chamber <NUM>, for instance using tubing <NUM> connected to the vacuum pump <NUM> and to the chamber <NUM>, placing the two in fluid communication with each other. As used herein, "operatively connected" refers to two structures and/or devices that are attached (either directly or indirectly) such that each structure and/or device is capable of functioning with the other. For example, a vacuum pump may be operatively connected to a chamber using tubing, wherein the vacuum pump lowers the pressure in the chamber by pulling a vacuum through the tubing between the vacuum pump and the chamber to evacuate gas from the chamber. An advantage of employing a vacuum evacuation of the chamber is that it will assist in removing volatile components in the article, if present in the particular article disposed in the chamber. Further, oxygen can be a cure inhibitor, thus removing ambient oxygen from the chamber may assist in increasing the extent of cure, cure speed, or both, during post-curing of the article.

Preferably, the vacuum pump is configured to achieve an absolute pressure inside the chamber of <NUM> millibars (mbar) or greater, <NUM> mbar or greater, <NUM> mbar or greater, <NUM> mbar or greater, <NUM> mbar or greater, <NUM> mbar or greater, <NUM> mbar or greater, <NUM> mbar or greater, or <NUM> mbar or greater; and <NUM> mbar or less, <NUM> mbar or less, <NUM> mbar or less, <NUM> mbar or less, <NUM> mbar or less, <NUM> mbar or less, <NUM> mbar or less, <NUM> mbar or less, or <NUM> mbar or less. Stated another way, the vacuum pump can be configured to achieve an absolute pressure inside the chamber of <NUM> to <NUM> mbar, <NUM> to <NUM> mbar, or <NUM> to <NUM> mbar. The extent of vacuum within the chamber can vary according to the particular application. In the embodiment shown in <FIG>, the vacuum pump <NUM> is located on the exterior of the housing <NUM>, and an optional three-way valve <NUM> is shown that connects the chamber <NUM> to the vacuum pump <NUM> and/or to a gas source <NUM>. The three-way valve <NUM> also connects to tubing <NUM> that is connected to the gas source <NUM>. Other typical connectors such as fittings or valves could optionally be used in conjunction with the vacuum pump <NUM>. In the embodiment shown in <FIG>, the vacuum pump <NUM> is located within the housing <NUM> and a first valve <NUM> and a second valve <NUM> are each operatively connected to the chamber <NUM> (e.g., via tubing <NUM> and <NUM>, respectively). The first valve <NUM> operatively connects the chamber <NUM> to the vacuum pump <NUM> and the second valve <NUM> operatively connects the chamber <NUM> to the gas source <NUM>. Suitable gas sources include, for example, a container (e.g., pressurized gas cylinder) holding compressed gas, e.g., an inert gas. Typical inert gases for use with the apparatus include nitrogen, argon, and/or helium. An advantage of employing both a vacuum and a gas is providing control over the contents of the atmosphere of the entire chamber. This is contrast to introducing a gas into the chamber without first removing the ambient atmosphere, wherein a possibility exists that the gas does not completely displace the ambient atmosphere, particularly around an article to be post-cured.

Referring to <FIG>, an exemplary apparatus <NUM> is shown in which an optional release valve <NUM> operatively connects the chamber <NUM> to an exterior of the housing <NUM>, such as through tubing <NUM>. In use, the release valve provides a conduit through which pressure can be equalized between the interior of the chamber and ambient pressure outside of the apparatus. This is advantageous for being able to open the lid of the chamber following use of a vacuum or a gas within the chamber.

To accommodate a change in pressure, preferably the chamber <NUM> is formed of material(s) capable of maintaining its structural integrity at a range of internal pressures. In an embodiment, a chamber comprises a toughened safety glass with a compressive strength of <NUM>-<NUM> N/mm. The glass thickness can be calculated according to DIN standard <NUM>:<NUM>-<NUM> "Pressure resistant circular sight glasses of borosilicate glass without limitation in the range of low temperature". The glass thickness needed for a particular chamber is dependent on the size of the chamber being formed. One suitable glass thickness is approximately <NUM> millimeters.

Referring to <FIG>, an exemplary user interface <NUM> is shown. The user interface <NUM> has a display <NUM> and numerous program switches <NUM> comprising at least one button, at least one dial (e.g., in <FIG>), or a combination thereof. The embodiment shown in <FIG> includes eleven buttons <NUM>. Any number of buttons <NUM> (or dials) can be dedicated to either raising or lowering selected values of parameters such as gas flushing time, light intensity (e.g., power), vacuum delay time, and/or time of light emission. Often, the user interface comprises a start button <NUM>, which may be configured (e.g., electronically coupled to the LEDs) such that pressing the start button initiates light emitted by the LEDs. Optionally, the start button <NUM> is configured (e.g., electronically coupled to the program switches <NUM>) to initiate a program that has been entered via the user interface. In some embodiments, the user interface <NUM> comprises a touch screen <NUM> that provides the display and the plurality of program switches (e.g., in <FIG>). In other embodiments, the display <NUM> is not a touch screen. Advantageously, in some embodiments the program switches <NUM> are further configured to adjust a time of flushing the chamber <NUM> with a gas from the gas source <NUM>, pressure of flushing the chamber <NUM> with the gas, or both.

Referring again to <FIG>, in some embodiments the apparatus <NUM> further comprises a processor <NUM>. The processor <NUM> causes the (e.g., at least two) LEDs <NUM> to emit light and the vacuum pump <NUM> to operate according to a program inputted through the user interface <NUM>. Any suitable computer processor could be incorporated into the apparatus. In select embodiments, the processor <NUM> further comprises a memory <NUM>, which provides the capability of causing the LEDs <NUM> to emit light and/or the vacuum pump <NUM> to operate according to a program that is stored in the memory <NUM>. The processor <NUM> is electronically coupled to the user interface <NUM>, either wirelessly or physically via electrical connections. An advantage of including a memory is that the device would have the capability of logging a program that has been run and optionally reporting out details of a post-cure program for a particular article, especially for an article that requires regulatory approval.

In some embodiments, operational parameters of the apparatus that are adjustable by the user interface comprise <NUM>) light intensity provided by the LEDs, <NUM>) length of time of light provided by the LEDs, and <NUM>) delay time between initiation of light provided by the LEDs and initiation of vacuum pulled on an interior of the chamber by the vacuum pump. In some embodiments, operational parameters of the apparatus that are adjustable by the user interface comprise <NUM>) light intensity provided by the LEDs, <NUM>) length of time of light provided by the LEDs, and <NUM>) delay time between initiation of vacuum pulled on an interior of the chamber by the vacuum pump and initiation of light provided by the LEDs. Hence, a user has options for the order and timing of performing post-cure steps and can customize a post-cure treatment for a particular sample by selecting variations of these operational parameters.

Suitable lengths of time for light to be provided by the LEDs comprise <NUM> minute or greater, <NUM> minutes or greater, <NUM> minutes or greater, <NUM> minutes or greater, <NUM> minutes or greater, <NUM> minutes or greater, <NUM> minutes or greater, <NUM> minutes or greater, <NUM> minutes or greater, <NUM> minutes or greater, <NUM> minutes or greater, <NUM> minutes or greater, <NUM> minutes or greater, <NUM> minutes or greater, <NUM> minutes or greater, or <NUM> minutes or greater; and <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, or <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, or <NUM> minutes or less, such as <NUM> minutes to <NUM> minutes.

Suitable times between initiation of light provided by the LEDs and initiation of vacuum pulled on an interior of the chamber by the vacuum pump comprise <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, or <NUM> seconds or greater; and <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, or <NUM> minute or less, such as <NUM> seconds to <NUM> minutes.

Suitable times between initiation of vacuum pulled on an interior of the chamber by the vacuum pump and initiation of light provided by the LEDs comprise <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, <NUM> seconds or greater, or <NUM> seconds or greater; and <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minutes or less, <NUM> minute or less, <NUM> seconds or less, <NUM> seconds or less, or <NUM> seconds or less, such as <NUM> seconds to <NUM> seconds.

In a second aspect, an article is provided. An article comprises a plurality of layers of at least one photopolymerized crosslinked composition, the article comprising <NUM>% by weight or less of extractable components, based on the total weight of the article, when extracted with <NUM> volume percent ethanol in water, the article made by a process comprising:.

Referring to <FIG>, the article may be made by a process including obtaining a photopolymerizable composition <NUM>; selectively curing the photopolymerizable composition using actinic radiation to form an article comprising a plurality of layers of at least one photopolymerized composition <NUM>; and removing excess photopolymerizable composition from the article <NUM>. Next, the article is placed in an apparatus (e.g., as described above in detail with respect to the first aspect) <NUM>, followed by inputting a post-cure program or accessing a saved post-cure program through the user interface <NUM> and running the post-cure program <NUM>. The post-cure program comprises <NUM>) light intensity provided by at least two light sources (e.g., LEDs); <NUM>) length of time of light provided by at least two light sources; and at least one of 3a) delay time between initiation of light provided by the light sources and initiation of vacuum pulled by the vacuum pump or 3b) delay time between initiation of vacuum pulled on an interior of the chamber by the vacuum pump and initiation of light provided by the light sources. Suitable light intensities and times are as described above with respect to the apparatuses.

In an embodiment, the post-cure program comprises turning on a first light source for a predetermined amount of time, followed by turning on a second light source for a predetermined amount of time, wherein the amounts of time may be the same or different. The first light source and the second light source can be employed for either some or no overlapping time. Optionally, the first light source may provide a different light wavelength (or range of wavelengths) and/or intensity than the second light source.

In some embodiments, the post-cure program is inputted through the user interface shortly before running that post-cure program. In some embodiments, the post-cure program is saved in a memory of a processor, either due to being pre-installed by the apparatus manufacturer or entered and saved by a user. To save a program, after each operational parameter has been chosen for the program, a user can activate (e.g., press and hold a program switch such as any one of P1, P2, or P3 buttons <NUM> shown in <FIG>) for up to several seconds for the inputted program to be saved to that program switch. When a saved program is subsequently being accessed, a user may simply select the program by activating a program switch (e.g., pressing a button, turning a dial, touching a touch sensor display in a certain place, etc.) to which the program is saved.

In some embodiments, following the post-cure program, the article contains <NUM>% by weight or less of extractable components, based on the total weight of the article, when extracted with <NUM> volume percent ethanol in water, <NUM>% by weight or less, <NUM>% by weight or less, <NUM>% by weight or less, <NUM>% by weight or less, <NUM>% by weight or less, or <NUM>% by weight or less of extractable components; and <NUM>% by weight or more, <NUM>% by weight or more, <NUM>% by weight or more, <NUM>% by weight or more, or <NUM>% by weight or more of extractable components, based on the total weight of the article, when extracted with <NUM> volume percent ethanol in water. A suitable test procedure for determining the amount of extractable components includes placing an article having a total surface area of <NUM><NUM> in a <NUM> milliliter (mL) glass vial and weighing the vial. <NUM> of solvent (<NUM> volume % ethanol/Milli-Q water) is added to the vial, with one <NUM> blank (vial containing solvent but without articles). The vials are covered with TEFLON caps and the samples are kept at <NUM> for <NUM> hours while shaking at <NUM> revolutions per minute (RPM) in a shaker (e.g., a LabLine Benchtop incubated shaker, Model No. <NUM>). The samples are allowed to cool before transferring the extraction solution to a new <NUM> glass vial. A <NUM> aliquot is transferred to a pre-weighed <NUM> glass vial and set to evaporate under a nitrogen purge. The vials are then weighed once the solvent evaporates, until a constant weight is reached. % Residue is calculated using the formula below. The test is typically completed in triplicates, all run at the same time, with the result being the average of the replicates.

Various photopolymerizable compositions are suitable for use in the methods according to the present disclosure. The compositions include at least one polymerizable component. The term "component" encompasses compounds, monomers, oligomers, and polymers. A "polymerizable component," for reference purposes herein, comprises a hardenable component that can be cured to provide a printed article. In some embodiments, for instance, hardening comprises irradiating with actinic radiation having sufficient energy to initiate a polymerization or cross-linking reaction. For instance, in some embodiments, ultraviolet (UV) radiation, e-beam radiation, or both, can be used.

In any embodiment, the photopolymerizable composition includes at least one of a (meth)acryl component, an epoxy component, a polyalkylene component, a polyalkylene oxide component, a polyester component, a polycarbonate component, a urethane component, a polyamide component, a thiol component and an ene component that is different from the (meth)acryl component, or combinations thereof. In some embodiments, a photopolymerizable composition includes a (meth)acryl component in combination with one or more of an epoxy component, a polyalkylene component, a polyalkylene oxide component, a polyester component, a polycarbonate component, a urethane component, and/or a polyamide component.

Suitable photopolymerizable compositions include for instance and without limitation, the compositions described in detail in the following published applications: <CIT>); <CIT>), <CIT>), <CIT>), and <CIT>); and published applications <CIT>)), <CIT>)), <CIT>), <CIT>), <CIT>), <CIT>), <CIT>, <CIT>), <CIT>), and <CIT>). Suitable articles that may be made using photopolymerizable compositions include for instance and without limitation, dental articles, such as to crowns, bridges, veneers, inlays, onlays, fillings, and prostheses (e.g., partial or full dentures); and orthodontic appliances and devices such as orthodontic brackets, buccal tubes, lingual retainers, orthodontic bands, class II and class III correctors, sleep apnea devices, bite openers, buttons, cleats, and other attachment devices. In select embodiments, the article is an orthodontic article or a dental restoration.

In certain embodiments, the photopolymerized composition comprises a (meth)acryl polymer and at least one ceramic material, a urethane (meth)acryl polymer, a polyalkylene oxide (meth)acryl polymer, a polyalkylene oxide urethane (meth)acryl polymer, a polyester urethane (meth)acryl polymer, a polycarbonate urethane (meth)acryl polymer, a polyamide polymer, an epoxy (meth)acrylate polymer, a thioether polymer, or any combination thereof. In an embodiment, the photopolymerized composition comprises a (meth)acryl polymer and at least one ceramic material. In an embodiment, photopolymerized composition comprises a polycarbonate urethane (meth)acryl polymer. As used herein, the term "(meth)acrylate" is a shorthand reference to acrylate, methacrylate, or combinations thereof, "(meth)acrylic" is a shorthand reference to acrylic, methacrylic, or combinations thereof, and "(meth)acryl" is a shorthand reference to acryl and methacryl groups. "Acryl" refers to derivatives of acrylic acid, such as acrylates, methacrylates, acrylamides, and methacrylamides. By "(meth)acryl" is meant a monomer or oligomer having at least one acryl or methacryl groups, and linked by an aliphatic segment if containing two or more groups. As used herein, "(meth)acrylate-functional compounds" are compounds that include, among other things, a (meth)acrylate moiety.

In some embodiments, the photopolymerizable composition contains ceramic particles as a ceramic material. As used herein, "ceramic particle" includes particles of amorphous material, glass, crystalline ceramic, glass-ceramic, and combinations thereof, and refers to non-metallic materials produced by application of heat or made by a chemical synthesis process. Ceramic particles are usually classified as inorganic materials. The term "amorphous material" with respect to ceramic particles refers to a material derived from a melt and/or a vapor phase as well as a material made from chemical synthesis, wherein the material lacks long range crystal structure as determined by X-ray diffraction and/or has an exothermic peak corresponding to the crystallization of the amorphous material as determined by DTA (differential thermal analysis). For instance, amorphous silica nanoparticles may be generated by condensation of silanes to form the nanoparticles.

In many embodiments, the optional ceramic particles comprise metal oxide ceramic particles, non-oxide ceramic particles, or any combination thereof.

Preferably, the ceramic particles are selected from the group consisting of zirconia (ZrO<NUM>), silica (SiO<NUM>), alumina (Al<NUM>O<NUM>), yttria (Y<NUM>O<NUM>), ceria (CeO<NUM>), magnesium-magnesia aluminate (MMA), magnesium oxide (MgO), hydroxyapatite (Cas(PO<NUM>)<NUM>OH), fluorapatite (Ca<NUM>(PO<NUM>)<NUM>F), chlorapatite (Cas(PO<NUM>)<NUM>Cl), calcite (CaCO<NUM>), cordierite (Mg<NUM>Al<NUM>Si<NUM>O<NUM>), silicon carbide (SiC), silicon nitride (Si<NUM>N<NUM>), boron carbide (B<NUM>C), titanium diboride (TiB<NUM>), zirconium diboride (ZrB<NUM>), boron nitride (BN), titanium carbide (TiC), zirconium carbide (ZrC), aluminium nitride (AlN), calcium hexaboride (CaB<NUM>), MAX phase (Mn+<NUM>AXn), and any combination thereof. In select embodiments, high-purity particles are used, in which the total content of metal impurities is preferably less than <NUM> ppm, particularly preferably less than <NUM> ppm. In alternate embodiments, particles are used having a total content of metal impurities of about <NUM>,<NUM> ppm. Suitable ceramic particles are described in detail in published Application <CIT>.

In some embodiments, the photopolymerizable composition, which may be a slurry or sol, comprises <NUM> wt. % or greater ceramic particles, based on the total weight of the photopolymerizable composition, <NUM> wt. % or greater, <NUM> wt. %, <NUM> wt. %, <NUM> wt. %, <NUM> wt. %, <NUM> wt. %, <NUM> wt. %, <NUM> wt. %, <NUM> wt. %, <NUM> wt. %, <NUM> wt. % or <NUM> wt. % or greater; and <NUM> wt. % or less, <NUM> wt. % or less, <NUM> wt. % or less, <NUM> wt. % or less, <NUM> wt. % or less, <NUM> wt. % or less, or <NUM> wt. % or less ceramic particles, based on the total weight of the photopolymerizable composition. In some embodiments, the photopolymerizable composition (e.g., slurry or sol) comprises <NUM> volume percent (vol. %) or greater ceramic particles, based on the total volume of the photopolymerizable composition, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. % or <NUM> vol. % or greater; and <NUM> vol. % or less, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, <NUM> vol. %, or <NUM> vol. % or less ceramic particles, based on the total volume of the photopolymerizable composition.

As used herein, "sol" refers to a continuous liquid phase containing discrete particles having sizes in a range from <NUM> nanometer (nm) to <NUM>. "Slurry" refers to a continuous liquid phase containing discrete particles having sizes in a range from greater than <NUM> to <NUM> micrometers or from greater than <NUM> to <NUM> micrometers. A slurry may optionally further contain discrete particles having sizes in a range from <NUM> nanometer (nm) to <NUM>. As used herein, a "particle" refers to a substance being a solid having a shape which can be geometrically determined. The shape can be regular or irregular. Particles can typically be analyzed with respect to e.g., particle size and particle size distribution. A particle can comprise one or more crystallites. Thus, a particle can comprise one or more crystal phases.

The ceramic particles typically comprise an average (mean) particle size diameter (i.e., D<NUM>) of <NUM> nanometer (nm) or greater, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> micrometer, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, or <NUM> micrometers or greater; and a D<NUM> of <NUM> micrometers or less, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometers, <NUM> micrometer, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> or less. The average (mean) particle size (D<NUM>) refers to that particle diameter at which <NUM> percent by volume of the particles in a distribution of particles have that diameter or a smaller diameter, as measured by scanning electron microscopy or transmission electron microscopy. Preferably, the average particle size is of the primary particles.

Photopolymerizable compositions of the present disclosure typically include at least one photoinitiator. Suitable exemplary photoinitiators are those available under the trade designations OMNIRAD from IGM Resins (Waalwijk, The Netherlands) and include <NUM>-hydroxycyclohexyl phenyl ketone (OMNIRAD <NUM>), <NUM>,<NUM>-dimethoxy-<NUM>,<NUM>-diphenylethan-<NUM>-one (OMNIRAD <NUM>), bis(<NUM>,<NUM>,<NUM> trimethylbenzoyl)phenylphosphineoxide (OMNIRAD <NUM>), <NUM>-[<NUM>-(<NUM>-hydroxyethoxy)phenyl]-<NUM>-hydroxy-<NUM>-methyl-<NUM>-propane-<NUM>-one (OMNIRAD <NUM>), <NUM>-benzyl-<NUM>-dimethylamino-<NUM>-(<NUM>-morpholinophenyl)butanone (OMNIRAD <NUM>), <NUM>-Dimethylamino-<NUM>-(<NUM>-methyl-benzyl)-<NUM>-(<NUM>-morpholin-<NUM>-yl-phenyl)- butan-<NUM>-one (OMNIRAD <NUM>), <NUM>-methyl-<NUM>-[<NUM>-(methylthio)phenyl]-<NUM>-morpholinopropan-<NUM>-one (OMNIRAD <NUM>), Oligo[<NUM>-hydroxy-<NUM>-methyl-<NUM>-[<NUM>- (<NUM>-methylvinyl)phenyl]propanone] ESACURE ONE (Lamberti S. , Gallarate, Italy), <NUM>-hydroxy-<NUM>-methyl-<NUM>-phenyl propan-<NUM>-one (DAROCUR <NUM>), <NUM>, <NUM>, <NUM>-trimethylbenzoyldiphenylphosphine oxide (OMNIRAD TPO), and <NUM>, <NUM>, <NUM>-trimethylbenzoylphenyl phosphinate (OMNIRAD TPO-L). Additional suitable photoinitiators include for example and without limitation, benzyl dimethyl ketal, <NUM>-methyl-<NUM>-hydroxypropiophenone, benzoin methyl ether, benzoin isopropyl ether, anisoin methyl ether, aromatic sulfonyl chlorides, photoactive oximes, and combinations thereof. In some embodiments, a cationic photoinitiator is present in compositions that include epoxy component, for example. Further, a thermal initiator can optionally be present in a photopolymerizable composition described herein. For instance, a free-radical photoinitiator, a cationic photoinitiator, a thermal photoinitiator, or any combination thereof may be present in a photopolymerizable composition.

Suitable cationic photoinitiators include for instance and without limitation, bis[<NUM>-diphenylsulfoniumphenyl] sulfide bishexafluoroantimonate; thiophenoxyphenylsulfonium hexafluoroantimonate (available as CHIVACURE <NUM> from Chitec (Houston, TX), tris(<NUM>-(<NUM>-acetylphenyl)thiophenyl)sulfonium tetrakis(pentafluorophenyl)borate, tris(<NUM>-(<NUM>-acetylphenyl)thiophenyl)sulfonium tris[(trifluoromethyl)sulfonyl]methide, and tris(<NUM>-(<NUM>-acetylphenyl)thiophenyl)sulfonium hexafluorophosphate, [<NUM>-(<NUM>-methylethyl)phenyl](<NUM>-methylphenyl) iodonium tetrakis(pentafluorophenyl)borate, <NUM>-[<NUM>-(<NUM>-chlorobenzoyl)phenylthio]phenylbis(<NUM>-fluorophenyl)sulfonium hexafluoroantimonate, and aromatic sulfonium salts with anions of (PF<NUM>-m(CnF2n+<NUM>)m)- where m is an integer from <NUM> to <NUM>, and n is an integer from <NUM> to <NUM> (available as CPI-<NUM> or CPI-<NUM>, which are monovalent sulfonium salts from San-Apro Ltd. , (Kyoto, JP) TK-<NUM> available from San-Apro Ltd. , or HS-<NUM> available from San-Apro Ltd.

In some embodiments, a photoinitiator is present in a photopolymerizable composition in an amount of up to about <NUM>% by weight, based on the total weight of polymerizable components in the photopolymerizable composition (e.g., not including components such as ceramic particles). In some cases, a photoinitiator is present in an amount of about <NUM>-<NUM>% by weight, <NUM>-<NUM>% by weight, or <NUM>-<NUM>% by weight, based on the total weight of the photopolymerizable composition.

In some embodiments, a thermal initiator is present in a photopolymerizable composition or in an amount of up to about <NUM>% by weight, based on the total weight of polymerizable components in the photopolymerizable composition. In some cases, a thermal initiator is present in an amount of about <NUM>-<NUM>% by weight, based on the total weight of polymerizable components in the photopolymerizable composition. Suitable thermal initiators include for instance and without limitation, peroxides such as benzoyl peroxide, dibenzoyl peroxide, dilauryl peroxide, cyclohexane peroxide, methyl ethyl ketone peroxide, hydroperoxides, e.g., tert-butyl hydroperoxide and cumene hydroperoxide, dicyclohexyl peroxydicarbonate, <NUM>,<NUM>,-azo-bis(isobutyronitrile), and t-butyl perbenzoate. Examples of commercially available thermal initiators include initiators available from DuPont Specialty Chemical (Wilmington, DE) under the VAZO trade designation including VAZO <NUM> (<NUM>,<NUM>'-azo-bis(<NUM>-methybutyronitrile)) VAZO <NUM> (<NUM>,<NUM>'-azo-bis(isobutyronitrile)) and VAZO <NUM> (<NUM>,<NUM>'-azo-bis(<NUM>,<NUM>-dimethyvaleronitrile)), and LUCIDOL <NUM> from Elf Atochem North America, Philadelphia, PA.

In some embodiments of compositions including free-radically polymerizable components, the composition contains a first free-radical photoinitiator having sufficient absorbance at a first wavelength range; and a second free-radical initiator selected from a second photoinitiator having sufficient absorbance at a second wavelength range, wherein the second wavelength range is different than the first wavelength range, or a thermal free-radical initiator. Some suitable first free-radical photoinitiators include for instance and without limitation, acyl phosphine oxide and alkyl amine acetophenone. Some suitable second free-radical photoinitiators include for instance and without limitation, photoinitiators comprising photoinitiator groups selected from benzil ketal or hydroxy-acetophenone. Suitable thermal free-radical initiators may include a peroxide or azo group. Additional details regarding such combinations of a first free-radical photoinitiator with either a thermal free-radical initiator or a second free-radical photoinitiator are described in published Application <CIT>).

In some embodiments of compositions including free-radically polymerizable components, the composition contains a polymer or macromolecule comprising a free-radical photoinitiator group, for instance including a polymer or macromolecule backbone and pendent photoinitiator groups. Suitable photoinitiator groups include for instance and without limitation, a hydroxy or alkyl amino acetophenone photoinitiator. Additional details regarding such polymers and macromolecules comprising a free-radical photoinitiator group are described in published Application <CIT>).

In certain aspects, the use of more than one initiator assists in increasing the percentage of monomer that gets incorporated into the reaction product of polymerizable components and thus decreasing the percentage of the monomer that remains uncured.

Data representing an article may be generated using computer modeling such as computer aided design (CAD) data. Image data representing the (e.g., polymeric) article design can be exported in STL format, or in any other suitable computer processable format, to the additive manufacturing equipment. Scanning methods to scan a three-dimensional object may also be employed to create the data representing the article. One exemplary technique for acquiring the data is digital scanning. Any other suitable scanning technique may be used for scanning an article, including X-ray radiography, laser scanning, computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound imaging. Other possible scanning methods are described, e.g., in <CIT>). The initial digital data set, which may include both raw data from scanning operations and data representing articles derived from the raw data, can be processed to segment an article design from any surrounding structures (e.g., a support for the article). In select embodiments, scanning techniques may include, for example, scanning a patient's mouth to customize an orthodontic article for the patient.

Often, machine-readable media are provided as part of a computing device. The computing device may have one or more processors, volatile memory (RAM), a device for reading machine-readable media, and input/output devices, such as a display, a keyboard, and a pointing device. Further, a computing device may also include other software, firmware, or combinations thereof, such as an operating system and other application software. A computing device may be, for example, a workstation, a laptop, a personal digital assistant (PDA), a server, a mainframe or any other general-purpose or application-specific computing device. A computing device may read executable software instructions from a computer-readable medium (such as a hard drive, a CD-ROM, or a computer memory), or may receive instructions from another source logically connected to computer, such as another networked computer. Referring to <FIG>, a computing device <NUM> often includes an internal processor <NUM>, a display <NUM> (e.g., a monitor), and one or more input devices such as a keyboard <NUM> and a mouse <NUM>. In <FIG>, a dental crown <NUM> is shown on the display <NUM>.

Referring to <FIG>, a system <NUM> is provided, which may be used to form the article. The system <NUM> comprises a display <NUM> that displays a 3D model <NUM> of an article (e.g., a dental crown <NUM> as shown on the display <NUM> of <FIG>); and one or more processors <NUM> that, in response to the 3D model <NUM> selected by a user, cause a 3D printer / additive manufacturing device <NUM> to create a physical object of the article <NUM>. Often, an input device <NUM> (e.g., keyboard and/or mouse) is employed with the display <NUM> and the at least one processor <NUM>, particularly for the user to select the 3D model <NUM>.

Referring to <FIG>, a processor <NUM> (or more than one processor) is in communication with each of a machine-readable medium <NUM> (e.g., a non-transitory medium), a 3D printer / additive manufacturing device <NUM>, and optionally a display <NUM> for viewing by a user. The 3D printer / additive manufacturing device <NUM> is configured to make one or more articles <NUM> based on instructions from the processor <NUM> providing data representing a 3D model of the article <NUM> (e.g., an aligner article <NUM> as shown on the display <NUM> of <FIG>) from the machine-readable medium <NUM>.

Referring to <FIG>, for example and without limitation, an additive manufacturing method comprises retrieving <NUM>, from a (e.g., non-transitory) machine-readable medium, data representing a 3D model of an article according to at least one embodiment of the present disclosure. The method further includes executing <NUM>, by one or more processors, an additive manufacturing application interfacing with a manufacturing device using the data; and generating <NUM>, by the manufacturing device, a physical object of the article. For example, the additive manufacturing equipment can selectively cure a photopolymerizable composition to form an article having a plurality of layers. One or more various optional post-processing steps <NUM> may be undertaken. Typically, remaining unpolymerized photopolymerizable component may be cured, such as in an apparatus according to the first aspect.

Additionally, referring to <FIG>, a method of making an article comprises receiving <NUM>, by a manufacturing device having one or more processors, a digital object comprising data specifying a plurality of layers of an article; and generating <NUM>, with the manufacturing device by an additive manufacturing process, the article based on the digital object. Again, the article may undergo one or more steps of post-processing <NUM>.

<FIG> shows an exemplary stereolithography apparatus ("SLA") that may be used with photopolymerizable compositions and methods described herein. In general, the SLA <NUM> may include a laser <NUM>, optics <NUM>, a steering lens <NUM>, an elevator <NUM>, a platform <NUM>, and a straight edge <NUM>, within a vat <NUM> filled with the photopolymerizable composition. In operation, the laser <NUM> is steered across a surface of the photopolymerizable composition to cure a cross-section of the photopolymerizable composition, after which the elevator <NUM> slightly lowers the platform <NUM> and another cross section is cured. The straight edge <NUM> may sweep the surface of the cured composition between layers to smooth and normalize the surface prior to addition of a new layer. In other embodiments, the vat <NUM> may be slowly filled with liquid resin while an article is drawn, layer by layer, onto the top surface of the photopolymerizable composition.

A related technology, vat polymerization with Digital Light Processing ("DLP"), also employs a container of curable polymer (e.g., photopolymerizable composition). However, in a DLP based system, a two-dimensional cross section is projected onto the curable material to cure the desired section of an entire plane transverse to the projected beam at one time. All such curable polymer systems as may be adapted to use with the photopolymerizable compositions described herein are intended to fall within the scope of the term "vat polymerization system" as used herein. In certain embodiments, an apparatus adapted to be used in a continuous mode may be employed, such as an apparatus commercially available from Carbon 3D, Inc. (Redwood City, CA), for instance as described in <CIT> and <CIT>).

More generally, the photopolymerizable composition is typically cured using actinic radiation, such as UV radiation, e-beam radiation, visible radiation, or any combination thereof. The skilled practitioner can select a suitable radiation source and range of wavelengths for a particular application without undue experimentation.

After the 3D article has been formed, it is typically removed from the additive manufacturing apparatus and rinsed, (e.g., an ultrasonic, or bubbling, or spray rinse in a solvent, which would dissolve a portion of the uncured photopolymerizable composition but not the cured, solid state article (e.g., green body). Any other conventional method for cleaning the article and removing uncured material at the article surface may also be utilized. In some embodiments, removing uncured material at the article surface comprises moving the article and thereby generating a mass inertial force in uncured photopolymerizable composition disposed on the article, thus forming a coating layer of uncured photopolymerizable composition on the article. The mass inertial force can be generated using a centrifuge, a shaker, or a mixer that spins along one or more axes. Suitable ways of generating a mass inertial force are described, for instance, in published Application <CIT>). For instance, the source of the mass inertial force may be generated using a centrifuge, a shaker, or a mixer that spins along one or more axes. In some embodiments, the moving of the object is a rotation or spinning of the object. Accordingly, the mass inertial force may be generated by a centrifugal force. One suitable mixer that spins along more than one axis is a dual asymmetric centrifugal mixer, such as the DAC <NUM> FVZ available from Flacktek, Landrum, SC. A dual asymmetric centrifugal mixer provides simultaneous dual axis spinning that automatically reorients the article during spinning, which tends to pull uncured composition out of concave features of the article in a short period of time (e.g., <NUM>, <NUM>, or <NUM> seconds or less).

In a fifth aspect, a system is provided. The system comprises:.

In some embodiments, the article may be as described in detail above with respect to the second aspect. Optionally, the article comprises a plurality of layers of at least one photopolymerized composition. Suitable systems are shown in <FIG>, which each comprise an apparatus <NUM> and an article <NUM> (e.g., a dental crown). The article is typically partially cured when placed in the chamber of the apparatus.

In a third aspect, a method of post-curing an article is provided. The method comprises:.

In a fourth aspect, another article is provided. The article is made by the method according embodiments of the third aspect. In some embodiments, the article comprises an orthodontic article or a dental restoration.

Referring to <FIG>, post-curing an article may comprise obtaining an article <NUM> and placing the article in an apparatus <NUM> (e.g., an apparatus according to the first aspect). The method further comprises, inputting a post-cure program or accessing a saved post-cure program through the user interface <NUM> and running the post-cure program <NUM>. The program comprises <NUM>) light intensity provided by at least one light source; <NUM>) length of time of light provided by at least one light source; and at least one of 3a) delay time between initiation of light provided by at least one light source and initiation of vacuum pulled by a vacuum pump or 3b) delay time between initiation of vacuum pulled on an interior of the chamber by a vacuum pump and initiation of light provided by at least one light source. Suitable light sources include for instance and without limitation, LEDs, UV lamps, fluorescent tubes, and lasers. In certain embodiments, two light sources, three light sources, four light sources, or more, are used. As noted above, a single light source in one location also encompasses an array in that location.

In some embodiments, the article may be formed using additive manufacturing, such as described in detail above. The article optionally comprises a plurality of layers of at least one photopolymerized composition, which can be provided by obtaining a photopolymerizable composition; selectively curing the photopolymerizable composition using actinic radiation to form an article comprising a plurality of layers of at least one photopolymerized composition; and removing excess photopolymerizable composition from the article. Suitable photopolymerizable and photopolymerized compositions are discussed in detail above with respect to the article.

In some embodiments, the article may be formed using methods such as casting or molding.

Objects and advantages of this disclosure 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 disclosure. Unless otherwise noted or otherwise apparent from the context, all parts, percentages, ratios, etc. in the Examples and the rest of the specification are by weight.

An all-composite dental crown is formed using <NUM> ESPE SINFONY paste (available from <NUM> ESPE, St. Paul, MN) by building up the crown on a model in layers of at least one selected color of paste (e.g., including Opaque paste O A0 - O D4, Dentin paste D A0 - D D4, Incisal paste E1 - E4, Intensive-Opaque paste IO <NUM> - IO <NUM>, Opaque-Dentin paste DO1 - DO <NUM>, Enamel-effect paste E5 - E6, Magic Intensive paste I1 - I11, and/or Transparent-Opal paste T1-T4), each layer having a maximum <NUM> millimeter thickness. Each layer is polymerized using a VISIO Alfa curing device (available from <NUM> ESPE) prior to applying the next layer. Next, the crown is lifted off the model and placed in the apparatus according to the first aspect described in detail above. Final polymerization of the dental crown is conducted in the apparatus for <NUM> minute of light exposure using a wavelength spectrum of <NUM>-<NUM> without vacuum, followed by <NUM> minutes of light exposure with vacuum of <NUM> mbar, also at a wavelength spectrum <NUM>-<NUM>.

Claim 1:
An apparatus (<NUM>) comprising:
a) a housing (<NUM>);
b) a chamber (<NUM>) disposed in the housing (<NUM>), the chamber (<NUM>) configured to be adaptable to each of an open configuration, a closed configuration, and a hermetically sealed configuration, wherein the chamber (<NUM>) comprises a material transparent to actinic radiation;
c) at least two light emitting diodes, LEDs, (<NUM>) disposed within the housing (<NUM>), wherein light from the at least two LEDs (<NUM>) enters the chamber (<NUM>) from more than one direction;
d) a vacuum pump (<NUM>) operatively connected to the chamber (<NUM>); and
e) a user interface (<NUM>) disposed on an exterior (<NUM>) of the housing (<NUM>), the user interface (<NUM>) comprising a display (<NUM>) and a plurality of program switches (<NUM>) configured to adjust at least three operational parameters of the apparatus (<NUM>), wherein the at least three operational parameters comprise <NUM>) light intensity provided by the at least two LEDs (<NUM>), <NUM>) length of time of light provided by the at least two LEDs (<NUM>), and at least one of 3a) delay time between initiation of light provided by the at least two LEDs (<NUM>) and initiation of vacuum pulled on an interior of the chamber by the vacuum pump or 3b) delay time between initiation of vacuum pulled on an interior of the chamber by the vacuum pump and initiation of light provided by the at least two LEDs.