Patent Description:
Milling machines are commonly used in preparing dental restorations by milling standardized blocks of material called stock. Stocks are available in several standardized shapes and sizes.

One standard shape for stock is a cylinder or disc format, such as the common <NUM> diameter and <NUM> tall stock. Dental milling machines secure the stock in place by anchoring to the stock in various fashions. Individual stocks may be enlarged to provide cylinder thicknesses greater than <NUM>. Additional stock, possibly of a smaller diameter, such as about <NUM> in diameter, may be split in half and centered on the top and the bottom of the original <NUM> cylindrical stock. This approach method facilitates extending the original <NUM> to up to <NUM>. Heights in excess of <NUM> are highly uncommon in the manufacturing of dental restorations. Most dental milling machines using this standard generally tolerate a maximum stock height of about <NUM>.

The cylindrical stocks are often made of a single, uniform material. When manufacturing dental implant bridges and bars, titanium or zirconia are common options. Once the stock is milled, the bridge or bar is removed from the remainder of the stock and a dental lab technician completes the manufacturing of the restoration by hand. Existing automatic systems in some labs are limited prepare crowns and bridges made from a single material without staining. Removal of support structures and final polishing of the restoration has recently been automated in at scale. Most dental labs use a <NUM>-axis dental machine, such a VHF S1 or the Imes Icore 350i, either of which can mill artificial dentition from a variety of starting materials, including metal or zirconium. In the case of Zirconium oxide, the dentition may be milled out of green state zirconium oxide in the milling machine, then a technician cuts the dentition out and removes the support structures. Then the technician paints additional materials onto the surface. These additional materials alter the color or appearance of the crown after it is crystalized in a furnace. With a metal base, a technician mills a thimble shape as the base of the crown, then layers of porcelain are sequentially baked using a furnace. The final crown is then polished or glazed.

Some stocks include layers of materials other than the primary material from which the stock is made, such as embedded fiber reinforcements. When stock is manufactured, one fiber mat may be layered onto another with a binding resin between them. Subsequent layers of fiber and resin may be added until the desired thickness is achieved, then the resin is cured, providing a stock of resin with encapsulated fiber mats stacked in layers.

Layering of two differently colored materials on top of each other may facilitate achieving a better aesthetic result in the resulting restoration. Some stock on the market combines layers of pink colors for gums and while colors for teeth in two halves to approximate the junction between the teeth and the gums. Inconsistencies are usually fixed by hand by a dental lab technician after milling. <CIT> discloses a method for fabricating an arch-shaped device for coupling to a patient's mouth; where the method can include disposing each of a plurality of teeth into respective teeth receptors of an inlay device, positioning the inlay device in a recess of a lower portion of a mold device, and coupling the lower portion to an upper portion of the mold device to sandwich the inlay device therebetween, furthermore the method can also include injecting a base compound into an injection hole of the mold device, and processing the base compound to integrate the base compound with the plurality of teeth.

The invention relates to a method of manufacturing a dental restoration according to claim <NUM>. The dependent claims provide further features of the invention. Dentures, appliances and other restorations are often manufactured using milling and pouring flowable material into moulds for setting, which carries benefits in terms of dimensional accuracy and functionality. Other approaches include injection moulding, which carries benefits in terms of material strength. The methods and apparatus described herein supports manufacturing dental appliances, prosthetics or other restorations with both subtractive manufacturing and injection moulding by maintaining orientation of a blank, a mould, a compound stock or any suitable stock that is being subjected to injection moulding followed by precision subtractive manufacturing, including through multiple rounds of injection moulding and subtractive manufacturing.

Generally, artificial dentition is prepared from different material than surrounding portions of a restoration that are intended to resemble gums or other tissue. Artificial dentition may be prepared from layered ceramic or other material designed to provide an appearance similar to natural dentition. Some previous approaches have combined subtractive manufacturing to create a void in a stock to provide a mould, then pouring setting material into the mould to provide a compound stock prepared from the poured material and from the material the mould is prepared form. In many cases, the mould includes the dentition and the poured material provides supporting trays the colour of gums for receiving the user's arches. Manufacturing dental restorations with injection moulding typically includes making replicas, investing the replicas into holders or flasks and pouring gypsum materials to encase the replica. The replica is made out of wax or any suitable material that is removed by exposure to heat through hot liquid, convection air, microwave energy or any suitable approach. After injection, this injection assembly is then placed in conditions to cure the dental acrylic, such as exposure to heat, light, microwaves, other radiant energy or other changes in environmental conditions that result in curing and polymerization.

Dental acrylics that are pourable and cured with time or light may not be as robust as their injected, heat-polymerized alternatives. Color stability and other features may also be improved in injected, heat-polymerized materials compared with pourable dental acrylics. As a result, precision milled dentures may lack the structural advantages of being prepared from heat polymerized or other injection moulded material. However, adding material to a machined void under pressure, such as during injection moulding, is difficult to accomplish inside a milling machine.

Based on the difficulty in preparing quality appliances, prosthetics or other dental restorations, particularly from two or more materials, there is a need for improved methods of manufacture. Herein disclosed is a method of, and apparatus for facilitating, manufacture of a multi-material appliance, prosthetic or other restoration, using a combination of subtractive manufacturing and injection moulding. The method includes, and the apparatus facilitates, preserving orientation of a stock during both injection and subtractive manufacturing, and including through multiple cycles of injection and subtractive manufacturing. Standard subtractive manufacturing and injection moulding devices may be applied in the method and use of the system. The method and system provided herein may be applied to any suitable subtractive manufacturing approach, including milling, laser ablation, fluid jet cutting and abrasive flow machining. Milling will be described as a general example of subtractive manufacturing to describe the method and systems, but the method and systems may be applied to any suitable subtractive manufacturing technique.

In the method, milling follows injection, and regardless of the number of cycles of injection and milling, the milling reduces the contours of the restoration to final dimensions after a flowable injection moulding fluid is set to a solid state. During intermediate steps of the method, the stock is milled after it is set or cured (e.g. post-polymerization, post-cool down to solidify, etc.). The orientation of the stock is preserved between milling and injection cycles, maintaining position within the tolerances of the dental milling machine.

In previous injection moulded denture manufacturing, dimensional errors due to a warping of the material during processing are common. Such errors can detrimentally affect the fit and function of the prosthetic, resulting in negative outcomes ranging from pain to loss of teeth and dental implants. Exact dimensional properties can be achieved by milling the stock after injection moulding. The dimensional accuracy of the resulting dental restoration can exceed the dimensional accuracy achieved by setting of the material after injection moulding. The method and apparatus provided herein allow integration of milling with injection moulded by preserving orientation of the stock between injection and milling cycles, and by providing an effective seal for injection cycles. Injection moulding and milling techniques that were difficult to apply in combination previously can be used together, allowing milling of injection moulded materials.

By applying milling after injection moulding during manufacture, the restoration may be measurably more precise than with injection moulding. Error is introduced during polymerization or hardening of the material. Milling after injection moulding facilitates combining the quick manufacture from injection moulding with the precision of milling. Adaptors that fit both injectors and mills allows use of existing equipment for the injection and for the milling. The injection and sealing apparatus provided herein may be manufactured to address space constraints within milling machines. The injection and sealing apparatus includes an injection face that seals against a stock for injecting under pressure into a mould defined in the stock, and may include an injection head with even distribution of injection apertures over a surface area of the stock that the injection and sealing apparatus covers.

The injection and sealing apparatus may be connected with an injection moulding system for injection of flowable material followed by setting the material, and may be positioned relative to the milling machine to be milled, while maintaining orientation and providing positional certainty to the milling machine, either through a direct connection with the milling machine or through being precisely oriented in a holder. The holder may be secured relative to the milling machine with positional certainty, and may either receive injected material while in the milling machine or may be moved between the milling machine and an injection apparatus while maintaining positional certainty of the stock within the holder. The injection apparatus may be an injection moulding apparatus or any other suitable injection apparatus for providing the flowable injection material to the mould. The sealing and injection apparatus may also include heat exchangers for heating and cooling the stock. The design and injection material composition of the injection unit are prescribed by the processing methods of the material manufacturer. Heating elements integrated into the injection plates may be used to achieve and sustain temperatures necessary to maintain flowability or to cure the material. An enveloping housing may be used to contain the heat and vent the unit.

Once the flowable injection material is injected and set, the milling machine may be applied while preserving orientation to mill the stock to desired dimensions. By preserving orientation of the stock throughout injection and milling protocols, positional certainty is provided to the milling machine. Subsequent layers of the same or other flowable injection material may be injected, set and milled in the same manner. The method may facilitate layered manufactured dentition by adding each layer of a complex tooth geometry using injected materials, mitigating the need for premanufactured teeth.

The flowable injection material may be forced into the mould with a pressure injection system, a gravity assisted pour, by being placed between device and material and squeezed, by being 3D Printed in place or any suitable method. An air extraction system for removing pressure from the mould may include air gaps or vents on the device or milled into the object, a vacuum pump line or chamber, or any suitable pressure release.

Polymerizing or solidifying the flowable material may be based on time exposure, or changes in pressure, temperature or other conditions. Time exposure may have several stages with specific conditions and durations. Pressure exposure changes may include a continuous acrylic injection system, pressure created from installing device with material in between and applying air or fluid pressure lines to increase pressure. Changes in temperature, including over a range of between <NUM> and <NUM>, may be effected by heat exchange fluids circulated through the device, air circulated through device, infrared radiation, electric resistance heating or induction heating. Microwave exposure, UV light exposure based on light emitting diodes with selected wavelengths, or any suitable method, may be applied in a containment chamber integrated with or separate from device.

In a first aspect, herein provided is a method and system for manufacturing dental restorations. A mould is immobilized in a fixed orientation. An injection surface is sealed against the mould. Flowable material is injected into the mould and cured to provide a compound stock. Subtractive manufacturing is applied to the compound stock in the fixed orientation to define precise contours in the stock and provide a dental restoration. The stock may be prepared from a blank with subtractive manufacturing while in the fixed orientation. Additional cycles of injecting, setting and subtractive manufacturing of intermediate stocks and moulds may precede subtractive manufacturing to provide the dental restoration. The stock may be immobilized in the fixed orientation in a holder, and the holder used to transfer the stock between injection and subtractive manufacturing. The stock may include asymmetrical features that facilitate immobilizing the stock in the fixed orientation.

In a further aspect, herein provided is a method of manufacturing a dental restoration comprising: securing an initial mould in an orientation; sealing the initial mould against an injection surface; injecting initial flowable material into the initial mould through the injection surface; setting the initial flowable material, resulting in an initial compound stock secured in the orientation; and applying subtractive manufacturing to the initial compound stock while the initial compound stock is secured in the orientation for providing the dental restoration.

In some embodiments, the initial mould comprises a frame within the initial mould for reinforcing the dental restoration. In some embodiments, the initial mould comprises an orientation specific mould. In some embodiments, the initial mould in the orientation comprises securing the initial mould to a holder, the holder adapted for connecting to both an injection apparatus and to a subtractive manufacturing machine. In some embodiments, securing the initial mould in the orientation comprises matching a profile on the initial mould with a profile on the holder. In some embodiments, securing the initial mould in the orientation comprises securing a blank in the orientation and applying subtractive manufacturing to the blank, resulting in the initial mould. In some embodiments, securing the blank in the orientation comprises securing the blank in a holder. In some embodiments, securing the blank in the orientation comprises connecting the holder to a subtractive manufacturing machine for maintaining the initial mould in the orientation. In some embodiments, injecting the initial flowable material into the initial mould comprises disconnecting the holder from the subtractive manufacturing machine and connecting the holder to an injection apparatus. In some embodiments, securing the blank in the orientation comprises securing the blank in a subtractive manufacturing machine. In some embodiments, injecting the initial flowable material into the initial mould comprises connecting an injection apparatus to the initial mould while the initial mould is secured in the subtractive manufacturing machine.

In some embodiments, securing the initial mould in the orientation comprises securing the initial mould in a holder. In some embodiments, securing the initial mould in the orientation comprises connecting the holder to a subtractive manufacturing machine for maintaining the initial mould in the orientation. In some embodiments, injecting the initial flowable material into the initial mould comprises disconnecting the holder from the subtractive manufacturing machine and connecting the holder to an injection apparatus. In some embodiments, securing the initial mould in the orientation comprises securing the initial mould to a subtractive manufacturing machine. In some embodiments, injecting the initial flowable material into the initial mould comprises connecting an injection apparatus to the initial mould while the initial mould is secured in the subtractive manufacturing machine.

In some embodiments, sealing the initial mould against the injection surface comprises enshrouding the initial mould.

In some embodiments, sealing the initial mould against the injection surface comprises connecting bolts through an injection head and into the initial mould.

In some embodiments, sealing the initial mould against the injection surface comprises applying a bias against the initial mould.

In some embodiments, injecting the initial flowable material into the initial mould comprises injecting the initial flowable material through a plurality of injection apertures regularly spaced from each other over the injection surface. In some embodiments, the initial mould comprises mould apertures defined in the initial mould, the initial mould apertures corresponding to the injection apertures in position for receiving excess initial flowable material from the initial mould.

In some embodiments, setting the initial flowable material comprises changing a temperature of the initial flowable material in the initial mould.

In some embodiments, setting the initial flowable material comprises exposing the initial flowable material to electromagnetic radiation.

In some embodiments, injecting initial flowable material into the initial mould through the injection surface, setting the initial flowable material, and applying subtractive manufacturing the initial compound stock while the initial compound stock is secured in the orientation, are carried out without breaking a seal between the initial mould and the injection surface.

In some embodiments, following injecting initial flowable material into the initial mould through the injection surface, and prior to applying subtractive manufacturing the initial compound stock, a seal between the initial mould and the injection surface is broken.

In some embodiments, applying subtractive manufacturing the initial compound stock while the initial compound stock is secured in the orientation for providing the dental restoration comprises: applying subtractive manufacturing the initial compound stock while the initial compound stock is secured in the orientation, resulting in an intermediate mould; injecting intermediate flowable material into the intermediate mould through the injection surface; setting the intermediate material, resulting in an intermediate compound stock secured in the orientation; and applying subtractive manufacturing to the intermediate compound stock while the intermediate compound stock is secured in the orientation for providing the dental restoration. In some embodiments, the initial flowable material and the intermediate flowable material comprise distinct chemical formulations. In some embodiments, the initial flowable material and the intermediate flowable material comprise the same chemical formulation. In some embodiments, applying subtractive manufacturing to the initial compound stock while the initial compound stock is secured in the orientation for providing the dental restoration comprises executing at least two or more times the steps of applying subtractive manufacturing to the intermediate compound stock, or to a subsequent intermediate compound stock, while the intermediate compound stock or the subsequent intermediate compound stock is secured in the orientation, resulting in a subsequent intermediate mould; injecting subsequent intermediate flowable material into the subsequent intermediate mould through the injection surface; setting the subsequent intermediate material, resulting in the subsequent intermediate compound stock secured in the orientation; and applying subtractive manufacturing to the subsequent intermediate compound stock while the subsequent intermediate compound stock is secured in the orientation. In some embodiments, the intermediate flowable material and the subsequent intermediate flowable material comprise distinct chemical formulations. In some embodiments, the intermediate flowable material and the subsequent intermediate flowable material comprise the same chemical formulation. In some embodiments, a final execution of applying subtractive manufacturing to the subsequent intermediate compound stock while the subsequent intermediate compound stock is secured in the orientation for providing the dental restoration comprises: applying subtractive manufacturing to the subsequent intermediate compound stock while the subsequent intermediate compound stock is secured in the orientation, resulting in a final mould; injecting final flowable material into the final mould through the injection surface; setting the final material, resulting in a final compound stock secured in the orientation; and applying subtractive manufacturing to the final compound stock while the final compound stock is secured in the orientation, resulting in the dental restoration. In some embodiments, the subsequent intermediate flowable material and the final flowable material comprise the same chemical formulation. In some embodiments, the subsequent intermediate flowable material and the final flowable material comprise distinct chemical formulations. In some embodiments, applying subtractive manufacturing to the intermediate compound stock while the intermediate compound stock is secured in the orientation for providing the dental restoration comprises: applying subtractive manufacturing to the intermediate compound stock while the intermediate compound stock is secured in the orientation, resulting in a final mould; injecting final flowable material into the final mould through the injection surface; setting the final material, resulting in a final compound stock secured in the orientation; and applying subtractive manufacturing to the final compound stock while the final compound stock is secured in the orientation, resulting in the dental restoration. In some embodiments, the intermediate flowable material and the final flowable material comprise the same chemical formulation. In some embodiments, the intermediate flowable material and the final flowable material comprise distinct chemical formulations.

In some embodiments, the subtractive manufacturing technique comprises a subtractive manufacturing technique selected from the group consisting of milling, laser ablation, fluid jet cutting and abrasive flow machining.

In a further aspect, not part of the claimed subject matter, there is provided an injection and subtractive manufacturing system for a dental restoration mould comprising: a body; a sealing surface defined on the body for sealing against the mould; an injection inlet defined in the body for receiving a flowable material; an injection flow path defined in the body in fluid communication with the injection inlet for receiving the flowable material; and an injection head in fluid communication with the injection flow path and in fluid communication with the mould for providing the flowable material to the mould.

In some embodiments, the body comprises a heat exchanger for exchanging heat with the body and controlling temperature of the mould.

In some embodiments, the body comprises an insulating portion for masking the injection apparatus from the temperature of flowable material; the injection inlet is defined in the insulation portion; the body comprises a heat exchange portion, the heat exchange portion positioned intermediate the insulating portion and the sealing surface; and the injection flow path provides communication through the insulating portion and the heat exchange portion. In some embodiments, the heat exchange portion comprises a heat exchanger for exchanging heat with the body and controlling temperature of the mould. In some embodiments, the heat exchanger comprises heat exchange flow passages for providing heat exchange fluid to the body and controlling the temperature of the mould.

In some embodiments, the injection inlet is positioned on a lateral portion of the body for facilitating connection to an injection apparatus while the body is secured to the mould in and the mould is secured to a subtractive manufacturing machine.

In some embodiments, the injection head comprises a plurality of apertures spaced across the injection head and corresponding to at least a portion of the surface area of the mould for mitigating bubbles in flowable material when receiving the injection fluid into the mould.

In some embodiments, the system includes a spacer between the injection head and the mould for increasing adding additional material to the mould uniformly across the surface area of the spacer.

In some embodiments, the system includes a holder for maintaining orientation of the mould as between a subtractive manufacturing machine and an injection apparatus.

Embodiments of the present disclosure will now be described, by way of example only, with reference to the attached figures, in which reference numerals sharing a common final two digits refer to corresponding features across figures (e.g. the injection and sealing apparatus <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc.).

Successful manufacturing of dental appliances, prosthetics or other restorations requires a comfortable fit through a full range of motion, functional artificial dentition, and aesthetically consistent artificial dentition. With these criteria met, any minimization of cost provides additional value to manufacturers, end-users and any intermediate members of the supply chain for dental restorations. Currently, restorations are manufactured using approaches including milling and pouring flowable material into moulds for setting. The method and apparatus described herein may be applied to manufacturing dental appliances, prosthetics or other restorations by maintaining orientation of a blank, a mould, a compound stock or any suitable stock that is being subjected to injection moulding followed by precision subtractive manufacturing.

Standard subtractive manufacturing and injection moulding devices may be applied in the method and use of the system. The methods and systems provided herein may be applied to any suitable subtractive manufacturing approach, including milling, laser ablation, fluid jet cutting and abrasive flow machining. Milling will be described as a general example of subtractive manufacturing to describe the method and systems, but the method and systems may be applied to any suitable subtractive manufacturing technique.

Generally, artificial dentition is prepared from different material than surrounding portions of a restoration that are intended to resemble gums or other tissue. Most teeth have a gradual lightening of the shade of the tooth from the gum towards an apex of the tooth. The tooth may exhibit some translucency at its apex. For this reason, many artificial dentition manufactures offer discs that start with a base shade of pearl, then stack increasingly brighter shades of white/pearl colors in layers that have increasing translucency, to attempt to achieve the same esthetic result. Natural teeth also have subtle elements of lighter and darker sections determined by internal structures of dentin and enamel and the gradual shade increase. To achieve these results in prosthetics, simulations of these shades are applied by hand by a skilled technician using a variety of techniques and materials.

Previous approaches to denture manufacture have combined milling a void into a stock to provide a mould, then pouring setting material into the mould to provide a compound stock prepared from at least two materials. Typically, one of the materials provides the dentition while the other material, or one of the other materials, provides a base to which the dentition is connected, and which is intended to resemble gums or other tissue. The poured material is set, and the resulting stock including two or more materials in order to get an intended aesthetic result. Dental acrylics that are pourable and cured with time or light may not be as robust as their injected, heat-polymerized alternatives. As indicated in <NPL>, "Flexural strength of injection-polymerized acrylic resin specimens was higher than that of the conventional method (P=<NUM>). This difference was statistically significant (P=<NUM>). " Color stability and other features may also be improved in injected, heat-polymerized materials compared with pourable dental acrylics. These advantages may be due to a variety of factors including oxidation of amine accelerator in pourable acrylics, less porosity in injected heat polymerized materials, less residual monomer in injected heat polymerized materials, better fidelity of part to mould in injected heat polymerized materials, and other advantages.

<CIT> to Howe shows material being injected into a void with a syringe until the void is full, as shown in Fig.2A of Howe. The material is then subjected to an environment suitable for polymerizing the material as shown in Fig. 2B of Howe. <CIT> to McDermott and Howe shows material being poured into a milled void and polymerized afterwards, as show in <FIG> of McDermott and Howe. Compression of the material is shown in <FIG> through use of an elastomeric cushion during polymerization.

Adding material to a machined void under pressure, such as during injection moulding, is difficult to accomplish inside a milling machine. Some milling machines apply a holder that secures a stock in a fixed position and that can be removed from the milling machine. In such machines, once a stock is secured into the holder, the orientation of the stock is fixed and known to the milling machine. The holder can be removed and reinstalled without affecting the positional certainty of the stock. Removing a holder from a machine may facilitate additions, alterations or other modification to the stock outside the confines of the milling machine. The holder may also facilitate identification of parts that have been cut out of the stock, which may allow other designs to fit into the remainder of the stock by preserving orientation in the holder between milling sessions and allowing the milling machine to orient against previous milling data. If the stock is removed from the holder or loosened and moved, it is unlikely that the stock can ever be placed back in exactly the same orientation, and errors during milling may result. The holder may be connected to the stock about an outer perimeter or contour, at an upper or lower surface of the stock, or any other suitable anchor point.

Standard manufacture of dental restorations using injection moulding with acrylics involves making replicas and investing them into flasks or other holders using gypsum materials to encase the replica. The replica is made out of wax or any suitable material that is removed by exposure to a heat. A injection channel, often made from the same heat or chemically-labile material, is attached to the replica. After the replica has been removed, a void is left in its shape, providing a mould. Two halves of a mould may be held together with a spring clamp during exposure to high-pressure acrylic injection. After injection, the injection assembly may be placed in thermal communication with a water polymerization bath, a conduction heating element, a convection air oven or a microwave for a period of time at a polymerization temperature to heat-cure the dental acrylic. Cooling follows before the new part can be broken out of its flask and gypsum encasing for use.

Result of a study on dimensional inaccuracy resulting from certain injection systems and polymerization of the acrylic are detailed in <NPL>. The Lee et al study shows dimensional inaccuracies and structural weakness for acrylic injection and polymerization, although less so than with other polymerization techniques.

Many dental appliances, prosthetics or other restorations have skeletal frameworks underlying teeth and gum structures. These frameworks are manufactured separately prior to manufacture of the appliance. Artificial dentition and gum elements are then manually to the framework added by a dental lab technician for verification, then processed together with the framework as described above.

Based on the difficulty in preparing quality appliances, prosthetics or other dental restorations, particularly from two or more materials, there is a need for improved methods of manufacture. Herein disclosed is a method of, and system for facilitating, manufacture of a multi-material appliance, prosthetic or other restoration, using a combination of a subtractive manufacturing method and injection moulding. The method includes, and the apparatus facilitates, preserving orientation of a mould during both injection and subtractive manufacturing, and including through multiple cycles of injection and subtractive manufacturing. Milling, laser ablation, fluid jet cutting and abrasive flow machining (through liquids, gases or other fluids) are examples of subtractive manufacturing techniques. Milling will be used as an illustrative example in many portions of this specification, and the approaches disclosed that apply milling may also be applied to laser ablation, fluid jet cutting and abrasive flow machining (through liquids, gases or other fluids) are examples of subtractive manufacturing techniques. The methods and systems described herein may be applied to any subtractive manufacturing technique to preserve orientation of a mould between injection and subtractive manufacturing steps. Standard milling and injection moulding devices may be applied in the method and use of the apparatus.

The method includes, and the system facilitates, milling follows injection, and regardless of the number of cycles of injection and milling, the milling reduces the contours of the restoration to final dimensions after a flowable injection moulding fluid is set to a solid state. During intermediate steps of the method, the stock is milled after it is set or cured (e.g. post-polymerization, post-cool down to solidify, etc.). The orientation of the stock is preserved between milling and injection cycles, maintaining position within the tolerances of the dental milling machine.

By applying a subtractive manufacturing technique after injection moulding during manufacture, the restoration may be measurably more precise than with injection moulding alone. Error is introduced during polymerization or hardening of the material. Applying subtractive manufacturing after injection moulding facilitates combining the quick manufacture of injection moulding with the precision of milling, all using existing equipment.

When applying the method and using the system, a stock is secured in or to a milling machine and also to an injection apparatus. The stock may be a standard <NUM> or <NUM> disc with <NUM> lip, other disc formats with various diameters and thicknesses, cubes, square-blocks, any secured object with an interface capable of making a seal with the injection apparatus, such as a flat surface around at least a portion of its perimeter, for restricting flow of the injected flowable material, or any suitable stock.

The milling machine and the stock may be connected by a securing feature on the milling machine, a securing feature on a holder for the stock, a feature milled or machined into the stock, a premanufactured feature on the stock or any suitable securing feature. The holder may be reversibly connectible with the milling machine and with the injection apparatus for preserving orientation when connected with and removed from each of the milling machine and the injection apparatus. A vacuum, clamp or any suitable external force may be applied to secure and seal an injection head against a flat, curved, or other regular fitted surface of the stock corresponding to the shape of an injection head.

The injection apparatus injects any suitable flowable injection material, including thermoplastic materials, acrylics, dental composites, lithium disilicates, lithium silicates, green-state ceramics (e.g. zirconium oxide, etc.), green-state metals, air, gasses or another medium which can be used to press one material against another. Setting of the flowable injection material may be completed with any combination of time exposure, temperature, pressure, vacuum, gas exposure, UV light exposure, microwave or other energy applications. After injection and setting, the resulting compound stock may be further milled, providing an additional mould into which additional flowable material may be injected to add additional layers to the finalized dental restoration.

Combining injection moulding and milling in one method and system includes practical challenges. Orientation of the stock that is being milled or the mould being injected into must be preserved, which may be accomplished by facilitating injection steps while inside a milling machine, with its close spacing constraints, preserving the stock orientation in a holder, or any suitable method. During injection moulding, air being displaced by the injection moulding fluid must be purged. The environment of the stock must be modified to set the injection moulding fluid, such as by heating or cooling, exposure to light, electromagnetic radiation or other radiative energy, other energy or chemicals, or other suitable approaches to setting the injection moulding fluid inside the stock. A seal must be formed and maintained between the stock and the injection moulding equipment that is capable of holding back the pressure of the injection moulding fluid being injected.

During injection of flowable material into a mould, any air present in the mould will be displaced. Most previous injection moulding of dental restorations apply a gypsum mould, which is porous to air, allowing the flowable injection material medium to push the air into the gypsum. Materials typically used in milling machines are not porous and as a result, an output channel in fluid communication with the injection channels may be milled into the mould to provide an exist path for the air. A vacuum may be connected to the output channel to draw out air while it is being displaced, or vents may be in communication with the output channel to allow the air to be pushed out. The vents may be pre-manufactured or machined into the stock by the milling machine when preparing the mould.

A fluid such as acrylic monomer may be injected prior to the acrylic so the liquid monomer would be displaced by the more viscous injected acrylic. Where fluid monomer is flowing directly on to acrylic from above as more acrylic is added, the monomer may be pushed up and displace the air above it. Monomer is much more fluid than acrylic and may displace smaller cavities of air than acrylic alone. If some monomer is trapped in a cavity, it may dilute into the surrounding acrylic and the region would be unaffected. Removal of bubbles may be facilitated by a vibrating action applied during injection to assist in removing the air, the flowable acrylic monomer or other fluid in the cavity of the mould and in the channel. Removal of bubbles may be facilitated by using a less viscous precursor, which will retain bubbles less effectively than a more viscous precursor.

Environment and other operating conditions are prescribed by the manufacturers of flowable injection material to inject and set the material. In some jurisdictions, regulations require dental lab technicians to be knowledgeable in processing techniques and to consistently apply such techniques when using the materials.

In one example, when applying the injected dental acrylic Ivocap, premixed amounts of monomer and polymer are combined and prepared in a syringe for injection. An air piston pushes the acrylic into a void at approximately <NUM> bar (87psi) of pressure at room temperature for <NUM> minutes. The material is then subjected to a temperature of around <NUM> for <NUM> minutes in a large water bath. Cool down may be completed with cold tap water for <NUM> minutes under continuous injection, then <NUM> additional minutes with the injection apparatus removed. During the heating and cooling cycles the acrylic polymerizes and shrinks slightly. To compensate for this shrinkage, the air piston continuously injects more acrylic into the cavity of the mould. Different methods use convection air to heat and cool the material, with similar procedure and timing on the steps.

There are many other plastic-based dental materials that may be injected (e.g. polyether ether ketone (PEEK), polyetherketoneketone (PEKK), Poly(methyl methacrylate) (PMMA), acetal resin, etc.). Materials such as lithium silicates and disilicates need to be injected at temperatures above <NUM>. To use these high-melting point materials, the mould must be pre-heated to a prescribed temperature, then the heated fluid material injected and maintained under high pressure until it cools and sets. These materials may provide suitable base materials for preparing artificial dentition.

In previous injection moulded denture manufacturing, dimensional errors due to a warping of the material during processing are common. Such errors can detrimentally affect the fit and function of the prosthetic, resulting in negative outcomes ranging from pain to loss of teeth and dental implants. Exact dimensional properties may be achieved by milling the stock after injection moulding. The dimensional accuracy of the resulting dental restoration may exceed the dimensional accuracy achieved by setting of the material after injection moulding. The method and apparatus provided herein allow integration of milling with injection moulded by preserving orientation of the stock between injection and milling cycles, and by providing an effective seal for injection cycles. The seal may be maintained continuously through injection moulding and milling. Injection moulding and milling, techniques that were difficult to apply in combination previously, may be used together, allowing milling of injection moulded materials.

The apparatus provided herein may be manufactured to address space constraints within milling machines. Traditional milling machines have access only on one side with a door and five walls surrounding a milling chamber. The apparatus may be designed as described herein fit into the space restrictions of the milling machine while maintaining a strong seal with the stock. Many of the materials used in injection moulding of dental restorations have their own, usually large, processing machines. These machines are incongruent with standard dental milling machines, and dental technicians typically manually work with parts made from both machines. Any single workpiece prepared from the stock is typically too large to fit into a flask or other working envelopes of the water baths, convection heat ovens, UV light ovens, microwave ovens or other processing machines. The processing machines set, cure or otherwise convert a flowable material to a set material. Milling machines do not typically include a curing step, but many 3D printers do. Most stock milling machines capable of making a denture will not fit into a dental flask. Processing machines are built to house purpose-built flasks securely, and a custom-built larger flask would not be compatible with a purpose-built receptacle. A stock that may fit into traditional flasks is sometimes called 'bridge blocks', intended for the creation of dental bridges of two to five teeth. Nearly all available materials of bridge blocks are incompatible with injection moulding as they require exposure to high temperatures which would incinerate all dental acrylics and thermoplastics.

To expose the injection moulding materials to the conditions found in previous injection moulding systems, a shroud or sealed environment must both accommodate the specific environmental requirements of injection and setting of the injection moulded material, and do so in a form factor sufficiently small to fit inside or on a milling machine. Depending on the environment required, a housing or other containment unit may be applied to envelop the unit, further control the environment and not damage the milling machine.

A containment unit may be used to encapsulate the orientation and sealing system. The containment unit may as a chamber to focus heat, airflow, gases or other fluids, vacuum, microwave or other changes in conditions that may facilitate injection, curing or milling. The containment unit may include a faraday cage could be used around the stock and the injected acrylic to allow exposure to microwaves while the apparatus remains in the milling machine. The containment unit may contain some or all of the injection system which fixes onto the stock. The containment unit would also have to fit within the confines of the milling machine. The containment unit could be used to contain vapours or fumes for safe redirection and expulsion. A heat insulative chamber may mitigate damage to the milling machine resulting from high heat. An airtight and pressure-secure chamber may create and maintain any pressure from vacuum to high pressures, and allow control of exposure to specific gases at selected pressures.

The orientation and sealing system includes an injection and sealing apparatus. The injection and sealing apparatus is connected with a blank, a mould or other stock prepared from one or more materials. The stock is immobilized in a holder or by connection directly to a milling machine. Where a holder is used, the holder may be connected with either the milling machine, or have the injection and sealing apparatus attached for injection moulding, while maintaining orientation and providing positional certainty to the milling machine. The injection and sealing apparatus may be connected with an injection moulding system for injection of flowable material followed by setting the material, or may be milled by the milling machine, while maintaining orientation and providing positional certainty to the milling machine.

The injection and sealing apparatus includes an injection plate. The injection plate is connected with the stock and secured to the stock with sufficient pressure to establish a seal between the injection plate and the stock. The injection plate may be secured to the stock by bolts extending through holes in the stock tightened with nuts. Many alternative approaches to securing the stock to the holder may be applied alone or in combination, including a hole that does not extend all the way though the stock used in conjunction with an expanding bolt, a securing mechanism built into the holder or the milling machine itself, the stock may be machined to fit within the holder at an extremely tight tolerance such that the stock does not rotate relative to the holder, the holder may include walls that are biased inwards.

The injection plate has two sides. The side that faces the stock may include a splayed injection head for evenly distributing flowable injection fluid across the surface area of the stock. The opposing side, facing away from the stock, includes an aperture for engaging with an injection device and receiving an injection of the flowable injection fluid. The aperture is in fluid communication with an injection channel that feeds into the injection head. The splayed or otherwise distributed injection channels of the injection head allow the flowable injection fluid to access the stock across a selected area of the stock.

The injection plate may also include a snaking heat exchange path through a body of the injection plate. The heat exchange path extends across a sufficient area of the injection plate to facilitate heat exchange with the stock. The heat exchange path is fed by a heat exchange input and facilitates flow with a heat exchange output, each of which may be defined in a side of the injection plate. When the bolts that secure the injection plate to the stock are tightened, a seal with the stock is created.

Lines are attached to the heat exchange input and the heat exchange output of the injection plate. The injection plate may be prepared from thermally conductive material to allow heat transfer from the heat exchange flow path to the stock. Controlling flow and temperature of water, glycol, air or other fluids flowing into the heat exchange input, through the heat exchange flow path and out of the heat exchange output allows precise regulation of temperature at the stock to create required environments to process acrylic.

An insulation plate may be connected with the injection plate to insulate an injection apparatus connected with the injection and sealing apparatus from temperature changes at the injection plate. The insulation plate, the injection plate and the stock may have aligned holes into which the bolts or other securing features are inserted to secure the insulation plate and the injection plate to the stock. A gasket may be included between the insulation plate and the injection plate.

A connection point for an injection apparatus is connected with the injection plate. The connection point allows the injection apparatus to be securely connected the injection plate and in fluid communication with the injection head. The connection point may extend through the insulation plate if an insulation plate is used. The connection point may also hold a cartridge of the flowable injection material for directing flowable injection material through the injection head and into the mould. Where the insulation plate is used, it directs heat into the stock and ensures that heat produced by hot water circulation through the heat exchange line does not heat and cure the flowable injection material in the cartridge.

The injection apparatus may use an air piston fed by an airline (e.g. the Ivocap injection system fed with an airline regulated to <NUM> bar, etc.). The air piston may be secured to the connection point. The shape of the connection point allows the air piston's locking mechanism to fully engage and lock as it does with the purpose-built flasks.

The flowable injection material is injected into the mould. Depending on the flowable injection material, the mould may be pre-heated. Air displaced by the injection material may either be vented through designed vents or a vacuum pump used to purge the air from the injection head and mould.

The injection chamber is either the filling of a negative void in the object, or an extension of the height of the object, or both. Extension rings between the injection plate and the object allow additional material to be added to the outside of the object increasing the original proportions of the part.

Once the flowable injection material is injected into the mould, additional steps are often required. In the case of heat polymerized acrylic, the temperatures is increased to about <NUM> using the heat exchanger flow line and maintained for a period of time to harden the acrylic. Water is fed by gravity or pumped through the heat exchanger flow line. Afterwards the unit must be cooled down so cold water through the unit to allow for next steps to occur. Glycol or other fluids may also be used as a heat exchange medium instead of water. A heating element or induction unit integrated into the injection plate may also be used for temperature control.

The injection and sealing apparatus may be removed after draining the water line feeding the heat exchange flow line, removing pressure to the air piston, and disconnecting the nuts and bolts or other securing mechanism holding the injection and sealing apparatus on the stock. The injection plate may be prepared from metal or another material that does not bond to the injected acrylic and that can be disconnected from the stock easily. Where flowable injection material that bonds metal is used, a silicone or Teflon lining may reduce adherence. The installation and removal of the injection and sealing apparatus could also be automated and integrated as part of a milling machine.

Once the flowable injection material is injected and set, the milling machine may be applied while preserving orientation to mill the stock to desired dimensions. Preserving orientation of the stock through injection and milling protocols facilitates positional providing certainty to the milling machine. Subsequent layers of the same or other flowable injection materials may be injected, set and milled in the same manner. The method may facilitate layered manufactured dentition by adding each layer of a complex tooth geometry using injected materials, mitigating the need for premanufactured dentition.

<FIG> shows an exploded view of an orientation and sealing system <NUM>. The system <NUM> includes an injection and sealing apparatus <NUM> and a holder <NUM>.

The injection and sealing apparatus <NUM> includes an injection plate <NUM> connected with an insulation plate <NUM>. The insulation plate <NUM> includes an injection connection point <NUM>. An injection flow path <NUM> is also defined in the insulation plate <NUM> and is in fluid communication with the injection connection point <NUM>. The injection flow path <NUM> is also defined in the injection plate <NUM>, and may have portions that are external to the injection plate <NUM>. The injection plate <NUM> includes a flared injection head <NUM> in communication with the injection flow path <NUM>. A heat exchange input <NUM> is in communication with a heat exchange flow path <NUM>. The heat exchange flow path <NUM> is shown as a tortuous path through the injection plate <NUM>, but any suitable form of heat exchange flow path may be applied for heat exchange within the injection plate <NUM>. The flared head <NUM> may help minimize air bubbles or other irregularities in flow for highly viscous materials.

The holder <NUM> includes a holder body <NUM> with an anchor collar <NUM>, although any suitable immobilization and orientation mechanism may be applied. A mould <NUM> is secured in the holder <NUM> by the anchor collar <NUM>. The mould <NUM> includes dentition <NUM> and a cavity <NUM>. The mould <NUM> may be connected to the injection and sealing apparatus <NUM> through insulation plate apertures <NUM> in the injection plate <NUM>, injection plate apertures <NUM> in the injection plate <NUM> and stock apertures <NUM> in the mould <NUM>.

<FIG> shows an injection apparatus <NUM> connected with the system <NUM>. The injection apparatus <NUM> includes a drive system <NUM> that powers injection of flowable injection material <NUM> from a reservoir <NUM> though an injection system <NUM>. The drive system <NUM> includes a compressed air inlet and piston. The injection apparatus <NUM> is connected with the system <NUM> by connection of a clamp <NUM> to an anchor point <NUM> connected with the insulation plate <NUM>. The injection and sealing apparatus <NUM> is connected with the mould <NUM> in a fixed orientation by three bolts <NUM> that extend through insulation plate apertures <NUM>, injection plate apertures <NUM> and stock apertures <NUM>. The bolts <NUM> are connected with the injection and sealing apparatus <NUM> by nuts <NUM>, forming a seal between the injection plate <NUM> and the mould <NUM>. An inflow line <NUM> is connected with the heat exchange input <NUM> and an outflow line <NUM> is connected with the heat exchange output <NUM>. The mould may be connected with the injection and sealing apparatus and the holder by any suitable connection, including mated elements, holes of any suitable number, geometry, depth or angle. The stock apertures <NUM> may be through the entirety of the mould <NUM> or only a portion of the mould <NUM>.

<FIG> shows a cross-section of the injection and sealing apparatus <NUM> connected with the mould <NUM> and with the injection apparatus <NUM>. The insulation plate <NUM> is prepared from thermally insulative material for protecting the flowable injection material <NUM> located in the anchor point <NUM> from changing temperature when hot or cold fluid flows through the heat exchange flow path <NUM>. The cavity is in fluid communication with a channel <NUM> for allowing flowable injection material <NUM> (<FIG>) to flow out of the cavity <NUM> under pressure after the cavity <NUM> is filled with the flowable injection material <NUM>.

<FIG> shows an exploded view of the system <NUM> during injection of the flowable injection material <NUM>. When the flowable injection material <NUM> is injected into the cavity <NUM> of the mould <NUM>, the injection head <NUM> spreads the flowable injection material <NUM> across the mould <NUM> to fill the cavity <NUM> evenly, minimizing bubbles and irregularities. The flowable injection material <NUM> exits the mould <NUM> similarly dispersed across a surface area.

<FIG> show an exploded view of the system <NUM> and a plan view of the holder <NUM>, after injection. A compound stock <NUM> that includes at least two types of injection material is results from after injection of the flowable injection material <NUM> into the mould <NUM> and setting the flowable material <NUM>. The compound stock <NUM> includes at least the materials from which the dentition <NUM> is made and the set flowable injection material <NUM> that at least some of the remainder of the compound stock <NUM> is made from. The flowable injection material <NUM> may for example be material coloured to resemble gingiva and from which dental trays will be manufactured. The dental trays may be the material in which the dentition <NUM> is anchored.

<FIG> shows a milling machine <NUM> including a mill <NUM> and a milling base plate <NUM>. The holder <NUM> is connected with the milling base plate <NUM>, maintaining orientation of the compound stock <NUM> relative to the mill <NUM> and providing positional certainty.

<FIG> show a restoration <NUM> resulting from milling of the compound stock <NUM> with the mill <NUM>.

<FIG> show an orientation and sealing system <NUM>. The orientation and sealing system <NUM> as shown in <FIG> includes a blank <NUM> in the holder <NUM>. The blank <NUM> must be milled to provide the mould <NUM> shown ins <FIG> and <FIG>. Injection of the flowable injection material <NUM> from the reservoir <NUM> is shown in <FIG>, and the system <NUM> after setting of the compound stock <NUM> is shown in <FIG>.

The orientation and sealing system <NUM> includes a first injection and sealing apparatus 120a and a second injection and sealing apparatus 120b. The first injection and sealing apparatus 120a provides the functionality of the injection and sealing apparatus <NUM> of the system <NUM>. The second injection and sealing apparatus 120b receives the flowable injection material <NUM> from the mould <NUM>, providing pressure relief and establishing fluid communication through the second injection flow path 124b to a vent <NUM> connected with the second insulating plate 130b. The vent <NUM> may be a vent, or may be under vacuum to draw air and the flowable injection material <NUM> through the second injection plate 122b.

<FIG> shows an exploded view of the orientation and sealing system <NUM>. The system <NUM> includes the first injection and sealing apparatus 120a, the second injection and sealing apparatus 120b and the holder <NUM>.

The first injection and sealing apparatus 120a includes the first injection plate 122a connected with the first insulation plate 130a. The first insulation plate 130a includes the first injection connection point 125a. The first injection flow path 124a is defined in the first insulation plate 130a and is in fluid communication with the first injection connection point 125a. The first injection flow path 124a is also defined in the first injection plate 122a, and may have portions that are external to the first injection plate 122a. The first injection plate 122a includes the first flared injection head 126a in communication with the first injection flow path 124a for providing the flowable injection material <NUM> over an even dispersion of the surface area of the first injection plate 122a and the mould <NUM>. The first heat exchange input 132a is in communication with the first heat exchange flow path 134a. The first heat exchange flow path 134a is shown as a tortuous path through the first injection plate 122a, but any suitable form of heat exchange flow path may be applied for heat exchange within the first injection plate 122a.

The holder <NUM> includes the holder body <NUM> with the anchor collar <NUM>, although any suitable immobilization and orientation mechanism may be applied. The mould <NUM> is secured in the holder <NUM> by the anchor collar <NUM>. The mould <NUM> includes dentition <NUM> and the cavity <NUM>. The mould <NUM> may be connected to the first injection and sealing apparatus 120a through insulation plate apertures 131a in the first insulation plate 130a, the first injection plate apertures 121a in the first injection plate 122a and the stock apertures <NUM> in the mould <NUM>. The mould <NUM> may be connected to the second injection and sealing apparatus 120b through the second insulation plate apertures 131b in the second insulation plate 130b, the second injection plate apertures 121b in the second injection plate 122b.

The second injection and sealing apparatus 120b includes the second injection plate 122b connected with the second insulation plate 130b. The second insulation plate 130a includes the second injection connection point 125b. The second injection flow path 124b is defined in the second insulation plate 130b and is in fluid communication with the second injection connection point 125b. The second injection flow path 124b is also defined in the second injection plate 122b, and may have portions that are external to the second injection plate 122b. The second injection plate 122b includes the second flared injection head 126b in communication with the second injection flow path 124b for receiving flowable injection material over an even dispersion of the surface area of the second injection plate 122b. The second heat exchange input 132b is in communication with the second heat exchange flow path 134b. The second heat exchange flow path 134b is shown as a tortuous path through the second injection plate 122b, but any suitable form of heat exchange flow path may be applied for heat exchange within the second injection plate 122b.

<FIG> shows the mould <NUM> secured in the holder <NUM> before injection of the flowable injection material <NUM> into the mould <NUM>.

<FIG> shows the cross-section of the first injection and sealing apparatus 120a connected with the mould <NUM> and with the injection apparatus <NUM>, and of the second injection and sealing apparatus 120b connected with the mould <NUM>. The first insulation plate 130a is prepared from thermally insulative material for protecting the flowable injection material <NUM> located in the anchor point <NUM> from changing temperature when hot or cold fluid flows through the first heat exchange flow path 134a. The cavity is in fluid communication with the channel <NUM> for allowing flowable injection material <NUM> (<FIG>) to flow out of the cavity <NUM> under pressure after the cavity <NUM> is filled with the flowable injection material <NUM>. The flowable injection material <NUM> flows into the second injection plate 122b through the second injection head 126b, and the temperature of the second injection plate 122b may be modulated independent of the temperature of the first injection plate 122a using the second heat exchange flow path 134b. The vent <NUM> may be a vent, or may be under vacuum to draw air and the flowable injection material <NUM> through the second injection plate 122b.

<FIG> shows the mould <NUM> secured in the holder <NUM> during injection of the flowable injection material <NUM> into the mould <NUM>.

<FIG> shows the compound stock <NUM> in the holder after injection of the flowable injection material <NUM> into the mould <NUM> and setting of the flowable injection material <NUM>.

<FIG> show an orientation and sealing system <NUM> that includes a lateral injection port 227a on the first injection and sealing apparatus 220a. The lateral injection port 227a is located on an outer lateral surface of the first injection and sealing apparatus 220a, and the first injection flow path 224a includes a lateral portion through the first insulation plate 130a. The orientation and sealing system <NUM> may be used with the holder <NUM> as shown in <FIG> and <FIG>. Alternatively, the injection and sealing apparatus <NUM> may be used alone and immobilized directly in the milling machine <NUM> as shown in <FIG>.

<FIG> shows an exploded view of the orientation and sealing system <NUM>. The system <NUM> includes the first injection and sealing apparatus 220a, the second injection and sealing apparatus 220b and the holder <NUM>.

The first injection and sealing apparatus 220a includes the first injection plate 222a connected with the first insulation plate 230a. The first insulation plate 230a includes the lateral injection port 227a. The first injection flow path 224a is defined in the first insulation plate 230a and is in fluid communication with the lateral injection port 227a. The first injection flow path 224a is also defined in the first injection plate 222a, and may have portions that are external to the first injection plate 222a. The first injection plate 222a includes the first flared injection head 226a in communication with the first injection flow path 224a for providing the flowable injection material <NUM> over an even dispersion of the surface area of the first injection plate 222a and the mould <NUM>. The first heat exchange input 232a is in communication with the first heat exchange flow path 234a. The first heat exchange flow path 234a is shown as a tortuous path through the first injection plate 222a, but any suitable form of heat exchange flow path may be applied for heat exchange within the first injection plate 222a.

The holder <NUM> includes the holder body <NUM> with the anchor collar <NUM>, although any suitable immobilization and orientation mechanism may be applied. The mould <NUM> is secured in the holder <NUM> by the anchor collar <NUM>. The mould <NUM> includes dentition <NUM> and the cavity <NUM>. The mould <NUM> may be connected to the first injection and sealing apparatus 220a through insulation plate apertures 231a in the first insulation plate 230a, the first injection plate apertures 221a in the first injection plate 222a, the stock apertures <NUM> in the mould <NUM>. The mould <NUM> may be connected to the second injection and sealing apparatus 220b through the second insulation plate apertures 231b in the second insulation plate 230b, the second injection plate apertures 221b in the second injection plate 222b.

The second injection and sealing apparatus 220b includes the second injection plate 222b connected with the second insulation plate 230b. The second insulation plate 230a includes the injection connection point <NUM>. The second injection flow path 224b is defined in the second insulation plate 230b and is in fluid communication with the injection connection point <NUM>. The second injection flow path 224b is also defined in the second injection plate 222b, and may have portions that are external to the second injection plate 222b. The second injection plate 222b includes the second flared injection head 226b in communication with the second injection flow path 224b for receiving flowable injection material over an even dispersion of the surface area of the second injection plate 222b. The second heat exchange input 232b is in communication with the second heat exchange flow path 234b. The second heat exchange flow path 234b is shown as a tortuous path through the second injection plate 222b, but any suitable form of heat exchange flow path may be applied for heat exchange within the second injection plate 222b.

<FIG> shows the injection apparatus <NUM> connected with the system <NUM>. The injection apparatus <NUM> includes the drive system <NUM> that powers injection of flowable injection material <NUM> though the injection system <NUM>. The drive system <NUM> includes the compressed air inlet and piston. The injection apparatus <NUM> is connected with the system <NUM> by connection of the clamp <NUM> to the anchor point <NUM> connected with the insulation plate <NUM>. The injection and sealing apparatus <NUM> is connected with the mould <NUM> in the fixed orientation by three bolts <NUM> that extend through insulation plate apertures <NUM>, injection plate apertures <NUM> and stock apertures <NUM>. The bolts <NUM> are connected with the injection and sealing apparatus <NUM> by nuts <NUM>, forming the seal between the injection plate <NUM> and the mould <NUM>. The inflow line <NUM> is connected with the heat exchange input <NUM> and the outflow line <NUM> is connected with the heat exchange output <NUM>.

<FIG> shows the cross-section of the first injection and sealing apparatus 220a connected with the mould <NUM> and with the injection apparatus <NUM>, and of the second injection and sealing apparatus 220b connected with the mould <NUM>. The first insulation plate 230a is prepared from thermally insulative material for protecting the flowable injection material <NUM> located in the anchor point <NUM> from changing temperature when hot or cold fluid flows through the first heat exchange flow path 234a. The cavity is in fluid communication with the channel <NUM> for allowing flowable injection material <NUM> (<FIG>) to flow out of the cavity <NUM> under pressure after the cavity <NUM> is filled with the flowable injection material <NUM>. The flowable injection material <NUM> flows into the second injection plate 222b through the second injection head 226b, and the temperature of the second injection plate 222b may be modulated independent of the temperature of the first injection plate 222a using the second heat exchange flow path 234b. The vent <NUM> may be a vent, or may be under vacuum to draw air and the flowable injection material <NUM> through the second injection plate 222b.

<FIG> shows the milling machine <NUM> including the mill <NUM> inside a cavity <NUM> defined within an body <NUM> of the milling machine <NUM>. The milling base plate <NUM> may be used as a surface upon which to directly immobilize the mould <NUM> (or a blank, compound stock or restoration).

<FIG> shows the first injection and sealing apparatus 220a immobilized directly in the milling machine <NUM> on the milling base plate <NUM>. The first injection and sealing apparatus 220a is secured to the milling base plate <NUM> by any suitable method, likely orientation specific physical connections.

<FIG> shows an exploded view of the orientation and sealing system <NUM>. The system <NUM> includes the first injection and sealing apparatus 320a, the second injection and sealing apparatus 320b and the holder <NUM>. A first spacer 337a is included between the mould <NUM> and the first injection plate 322a. A second spacer 337b is included between the mould <NUM> and the second injection plate 322b. The spacers provide room for injection of additional flowable injection material to increase a height of the mould <NUM>.

The first injection and sealing apparatus 320a includes the first injection plate 322a connected with the first insulation plate 330a. The first insulation plate 330a includes the first injection connection point 325a. The first injection flow path 324a is defined in the first insulation plate 330a and is in fluid communication with the first injection connection point 325a. The first injection flow path 324a is also defined in the first injection plate 322a, and may have portions that are external to the first injection plate 322a. The first injection plate 322a includes the first flared injection head 326a in communication with the first injection flow path 324a for providing the flowable injection material <NUM> over an even dispersion of the surface area of the first injection plate 322a and the mould <NUM>. The first heat exchange input 332a is in communication with the first heat exchange flow path 334a. The first heat exchange flow path 334a is shown as a tortuous path through the first injection plate 322a, but any suitable form of heat exchange flow path may be applied for heat exchange within the first injection plate 322a.

The holder <NUM> includes the holder body <NUM> with the anchor collar <NUM>, although any suitable immobilization and orientation mechanism may be applied. The mould <NUM> is secured in the holder <NUM> by the anchor collar <NUM>. The mould <NUM> includes dentition <NUM> and the cavity <NUM>. The mould <NUM> may be connected to the first injection and sealing apparatus 320a, separated by the first spacer 337a, through insulation plate apertures 331a in the first insulation plate 330a, the first injection plate apertures 321a in the first injection plate 322a and the stock apertures <NUM> in the mould <NUM>. The mould <NUM> may be connected to the second injection and sealing apparatus 320b, separated by the second spacer 337b, through the second insulation plate apertures 331b in the second insulation plate 330b, and the second injection plate apertures 321b in the second injection plate 322b.

The second injection and sealing apparatus 320b includes the second injection plate 322b connected with the second insulation plate 330b. The second insulation plate 330a includes the second injection connection point 325b. The second injection flow path 324b is defined in the second insulation plate 330b and is in fluid communication with the second injection connection point 325b. The second injection flow path 324b is also defined in the second injection plate 322b, and may have portions that are external to the second injection plate 322b. The second injection plate 322b includes the second flared injection head 326b in communication with the second injection flow path 324b for receiving flowable injection material over an even dispersion of the surface area of the second injection plate 322b. The second heat exchange input 332b is in communication with the second heat exchange flow path 334b. The second heat exchange flow path 334b is shown as a tortuous path through the second injection plate 322b, but any suitable form of heat exchange flow path may be applied for heat exchange within the second injection plate 322b.

<FIG> shows an orientation and sealing system <NUM> in which the injection and sealing apparatus <NUM> includes the injection plate <NUM> and no other plates. The heat exchange flow path between the heat exchange input <NUM> and the heat exchange output <NUM> is included inside the injection plate <NUM>. The heath exchange flow path is not shown and may be prepared similar y to the heat exchange flow path <NUM> of the injection plate <NUM>.

The holder <NUM> includes a holder body <NUM> with an anchor collar <NUM>, although any suitable immobilization and orientation mechanism may be applied. A mould <NUM> is secured in the holder <NUM> by the anchor collar <NUM>. The mould <NUM> includes dentition <NUM> and a cavity <NUM>. The mould <NUM> may be connected to the injection and sealing apparatus <NUM> through the injection plate apertures <NUM> in the injection plate <NUM> and stock apertures <NUM> in the mould <NUM>.

The injection plate <NUM> may be prepared from insulative material at a top portion proximate the injection connection point <NUM>. The injection and sealing system <NUM> may alternatively be applied in such a manner that no flowable injection material is exposed to changes in temperature resulting from use of the heat exchanger features, such as by maintaining an injection temperature until an injection cycle is completed, then flowing heat exchange fluid of a different temperature into the heat exchange inlet <NUM> to induce setting of the flowable injection material.

<FIG> show sequential injection, setting and milling of materials to manufacture the dental restoration <NUM>.

In <FIG>, a first mould 52a prepared from a first material <NUM> includes a first cavity 62a with a first channel 64a to allow air to escape during injection.

In <FIG>, a flowable injection material has been injected and filled the first cavity 62a and set into the first set material 72a, providing the first compound stock 54a. The first channel 64a has been filled with the first set material 72a. The first set material 72a may resemble enamel and defines part of the dentition <NUM> that will be included in the restoration <NUM> (see <FIG>).

In <FIG>, a second mould 52b prepared by milling out the majority of the first set material 72a shown in the first compound stock 54a. The milling defines a second cavity 62b in the second mould 52b with a second channel 64b to allow air to escape during injection. A portion of the first set material 72a remains in the second mould 52b.

In <FIG>, a flowable injection material has been injected and filled the second cavity 62b and set into the second set material 72b, providing the second compound stock 54b. The second channel 64b has been filled with the second set material 72b.

In <FIG>, a third mould 52c prepared by milling out the majority of the second set material 72b shown in the second compound stock 54b. The milling defines a third cavity 62c in the third mould 52c with a third channel 64c to allow air to escape during injection. A portion of the second set material 72b remains in the third mould 52c.

In <FIG>, a flowable injection material has been injected and filled the third cavity 62b and set into the third set material 72c, providing the third compound stock 54c. The flowable injection material has also been injected above the stop of the third mould 52c, providing a layer of the third set material 72c on top of the third compound stock 54c to increase the height of the third compound stock 54c. The third channel 64b has been filled with the third set material 72c.

In <FIG>, the third set material 72c and the first material <NUM> have been milled out to define the restoration <NUM>. The dental restoration <NUM> is connected to the remaining compound stock <NUM> through flash <NUM>, which may be easily removed. The restoration <NUM> includes a maxillary tray <NUM> prepared from a mixture of the first material <NUM> and the third set material 72c, including in the portion of the restoration <NUM> that extends upward above the third mould 52c. The restoration <NUM> also includes dentition <NUM> extending from the maxillary tray <NUM>.

<FIG> shows a mould <NUM> prepared from the first material <NUM>. The cavity <NUM> is defined in the mould <NUM> and includes the channel <NUM> pointing upwards rather then downwards.

<FIG> shows the mould <NUM> in operation with the injection and sealing apparatus <NUM> sealed against the mould <NUM> during injection of the flowable injection material <NUM> through the injection channel <NUM>. Air escaped through the channel <NUM> and the flowable injection material <NUM> is pushed out of the channel <NUM> on the same side of the mould <NUM> as the sealing and injection apparatus <NUM> is sealed with the mould <NUM>. Depending on the specific design of a milling machine or injection apparatus, this placement of the channel <NUM> may facilitate use of the injection and sealing apparatus <NUM> inside the milling machine.

<FIG> show manufacture of a prosthetic <NUM> including a frame <NUM> for structural strength. The prosthetic <NUM> is prepared from the blank <NUM>, which includes the frame <NUM>. The blank <NUM> is milled, and the resulting first mould 652a is injected moulded to provide the first compound blank 654a. After two additional milling and injection moulding procedures, followed by a final milling procedure, the prosthetic <NUM> remains and may be removed from the flash <NUM> for use.

<FIG> shows a frame support <NUM>. The frame support <NUM> includes the frame <NUM> secured within a housing <NUM>. The frame support <NUM> may be prepared from the same material as frame <NUM> or any suitable material.

<FIG> shows the blank <NUM> after filled with the first material <NUM>. The first material <NUM> may be injection moulded or otherwise set into the frame support <NUM>. The housing <NUM> provides form to the blank <NUM> during moulding or setting.

In <FIG>, a first mould 652a has been prepared by milling the first material <NUM> out of the blank <NUM> to define the first cavity 662a. The first cavity 662a is generally divisible into a first input aperture 668a in communication with the first channel 664a through a first communication channel 669a to allow air to escape during injection. A secondary input aperture <NUM> is included opposite the first input aperture 668a and is in communication with a secondary channel <NUM>. Together the first input aperture 668a and the input aperture <NUM> sever the connection between the frame <NUM> and the frame support <NUM>.

In <FIG>, a flowable injection material has been injected and filled the first cavity 662a and set into the first set material 672a, providing the first compound stock 654a. The first channel first cavity 662a, including both the first input aperture 668a and the first communication channel 669a, and the first channel 664a has been filled with the first set material 672a. The first set material 72a may resemble enamel and defines part of the dentition <NUM> that will be included in the restoration <NUM> (see <FIG>).

In <FIG>, a second mould 652b prepared by milling our the majority of the first set material 672a shown in the first compound stock 654a. The milling defines a second cavity 662b in the second mould 652b with a second channel 64b to allow air to escape during injection. The second cavity 662b is divided into a second input aperture 668b in communication with the second channel 664b through a second communication channel 669b to allow air to escape during injection. A portion of the first set material 672a remains in the second mould 652b.

In <FIG>, a flowable injection material has been injected and filled the second cavity 662b and set into the second set material 672b, providing the second compound stock 654b. The second channel 664b has been filled with the second set material 672b.

In <FIG>, a third mould 652c prepared by milling out the majority of the second set material 672b shown in the second compound stock 654b. The milling defines a third cavity 62c in the third mould 52c with a third channel 64c to allow air to escape during injection. The third cavity 662b is divided into a third input aperture 668c in communication with the third channel 664c through a third communication channel 669c to allow air to escape during injection. A portion of the second set material 672b remains in the third mould 652c.

In <FIG>, a flowable injection material has been injected and filled the third cavity 662c and set into the third set material 672c, providing the third compound stock 654c. The flowable injection material has also been injected above the stop of the third mould 652c, providing a layer of the third set material 672c on top of the third compound stock 654c to increase the height of the third compound stock 654c. The third channel 664c has been filled with the third set material 672c.

In <FIG>, the third set material 672c and the first material <NUM> have been milled out to define the restoration <NUM>. The dental restoration <NUM> is connected to the remaining compound stock <NUM> through the flash <NUM>, which may be easily removed. The restoration <NUM> includes a maxillary tray <NUM> prepared from a mixture of the first material <NUM> the first set material 672a and the third set material 672c. The restoration <NUM> also includes dentition <NUM> extending from the maxillary tray <NUM>. The dentition is prepared from the first set material 672a and the second set material 672b.

In preparing the restoration <NUM>, fluids such as air, nitrogen, water, bonding compounds, etching compounds, dental resins and dental composite could be injected between layers of the set material 672a, 672b and 672c. Injection of bonding compounds may strengthen a bond between subsequent layers of set material 672a, 672b and 672c, which added to the dental restoration <NUM>.

<FIG> is a schematic of a method of preparing a dental restoration <NUM> using an injection and sealing apparatus <NUM>. <FIG> includes <FIG>.

<FIG> shows the blank <NUM> prepared from the first material <NUM> is provided. The blank <NUM> includes an orientation specific profile <NUM> for securing the blank <NUM> in the milling machine <NUM> in a defined orientation. The blank <NUM> includes an attachment point <NUM> that may be connected with a restoration or implanted into an individual's dental arch.

<FIG> shows the blank <NUM> is placed in the milling machine <NUM> based on the defined orientation, and the milling machine <NUM> mills the blank <NUM> into the mould <NUM>.

<FIG> shows the mould <NUM> is shown defining a profile around which the flowable injection material <NUM> may be injected and may set around an anchor point <NUM>.

<FIG> shows the injection and sealing apparatus <NUM> is shown with the injection plate <NUM> and a sealing plate <NUM>. Together, the injection plate <NUM> and the sealing plate <NUM> encase the mould <NUM> and seal against the outer surface of the mould <NUM>. The flowable injection material <NUM> flows into the injection plate <NUM> through the injection flow path <NUM>. The sealing plate <NUM> includes a plurality of the vents <NUM>.

<FIG> shows the flowable injection material <NUM> being injected through the injection flow path <NUM>. During injection of the flowable injection material <NUM>, excess flowable injection material <NUM> and other fluids present in the injection and sealing apparatus out of the vents <NUM> through application of force into the injection flow path <NUM>, under vacuum or through any suitable method of drawing excess flowable injection material <NUM> and other fluids out of the vents <NUM>.

<FIG> shows the flowable injection material <NUM> has set around the anchor point <NUM> into the set material <NUM>, providing the compound stock <NUM>. The compound stock <NUM> has been removed from the injection and sealing apparatus <NUM>.

<FIG> shows the milling machine <NUM>, in which the compound stock <NUM> is secured with the orientation specific profile <NUM> maintaining positional certainty with earlier milling at <FIG>.

<FIG> shows the restoration <NUM> after the milling machine <NUM> has milled the set material <NUM> down to the dentition <NUM>, providing the restoration <NUM>. The dentition <NUM> is prepared from the set material <NUM>. The dentition <NUM> is anchored to the attachment point <NUM> by the anchor point <NUM> that was machined into the mould <NUM>. The anchor point <NUM> may be a custom abutment machined into the blank <NUM> when preparing the mould <NUM>. The restoration <NUM> is connected to the orientation specific profile through the flash <NUM>. The flash <NUM> may be cut, broken or otherwise disrupted to remove the restoration <NUM> from the orientation specific profile <NUM>.

The orientation specific profile <NUM> allows the mould <NUM> to be removed from the milling machine <NUM>, connected with the sealing and injection apparatus <NUM>, then after injection and setting of flowable injection material <NUM>, removed from the sealing and injection apparatus <NUM> for connection with the milling machine while maintaining the orientation during milling. The orientation specific profile <NUM> may also be connected with the restoration through the attachment point or otherwise in a manner that does not require breaking the flash from the orientation specific profile (not shown).

<FIG> shows the restoration <NUM> after removal of the flash <NUM> and the orientation specific profile. The restoration <NUM> includes the dentition <NUM>, which is prepared from the set material <NUM>. The dentition <NUM> is connected with the anchor point <NUM>, which is prepared from the first material <NUM>. The attachment point <NUM> allows the restoration <NUM> to be connected with a broader restoration, such as a denture or bridge. The restoration <NUM> may also be used as a crown. In some cases, the blank <NUM>, and as a result the anchor point <NUM> and the attachment point <NUM>, may be prepared from a metal such as titanium and the set material <NUM> may be a lithium disilicate or other material suitable for preparing the dentition <NUM>.

<FIG> shows the blank <NUM> and the injection and sealing apparatus <NUM>. The blank <NUM> is prepared from the first material <NUM>. The blank <NUM> lacks an orientation specific profile prepared from the first material <NUM> for securing the blank <NUM> in a defined orientation in relation to a milling machine. The blank <NUM> includes the attachment point <NUM> that may be connected with a restoration or implanted into an individual's dental arch, and which may provide positional certainty when anchored into a holder during milling. The injection and sealing apparatus <NUM> includes an injection body <NUM>. The injection body <NUM> includes a repositionable milling input <NUM>. The repositionable milling input <NUM> may be translated axially relative to the injection body <NUM> (e.g. as shown in <FIG>, etc.). The repositionable milling input may be located in a sleeve that translates axially along the injection body <NUM>. By allowing axial translation of the mill <NUM>, then in combination with rotation of the blank <NUM> or the composite blank <NUM>, the repositionable milling input <NUM> facilitates milling of the blank <NUM> or the composite blank <NUM> while the injection body <NUM> is sealed against the blank <NUM> or the composite blank <NUM>, and as a result, a new seal need not be formed between subsequent rounds of milling and injection.

<FIG> shows the injection and sealing apparatus <NUM> engaged with the blank <NUM>. The injection body <NUM> enshrouds and seals against the outer surface of the mould <NUM> for injection. The position of the blank <NUM> with respect to the injection and sealing apparatus <NUM> is maintained by the seal between the injection body <NUM> and the blank <NUM>, providing positional certainty between the injection and sealing apparatus <NUM> and the blank <NUM>. The attachment point <NUM> may also provide positional certainty relative to a subtractive manufacturing system.

<FIG> shows the mill <NUM> being applied to mill the blank <NUM> into the mould <NUM> while the blank <NUM> is engaged in and secured to the injection and sealing apparatus <NUM>, providing positional certainty. During milling, lubricant fluid <NUM> may be added to the injection and sealing apparatus <NUM>, in this case through the injection flow path <NUM>, and may alternatively be provided through a separate flow path. During milling, exhaust fluid <NUM> may flow out of the vent <NUM>, and may alternatively be exhausted through a separate flow path. Other fluids, such as air, nitrogen, water, machining fluids, bonding or etching compounds, dental resins and dental composite materials may also be injected through the injection flow path <NUM> or recovered from the vent <NUM>. Injection of bonding compounds may strengthen a bond between subsequent layers of material added to the dental restoration <NUM>. the connection between multiple layers of material The mould <NUM> defines a profile around which the flowable injection material <NUM> may be injected and may set around the anchor point <NUM>. During milling, the mould <NUM> may be rotated relative to the injection body <NUM> to mill different sides of the mould <NUM>. The mould <NUM> may also be rotated relative to the injection body <NUM> inside a sleeve received within the injection body <NUM>, with positional certainty being defined between the sleeve and the injection body <NUM>.

<FIG> shows the mill <NUM> translated downward relative to the injection body <NUM> with the repositionable milling input <NUM> for milling a lower portion of the mould <NUM>. Positional certainty is maintained based on the defined orientation maintained between the injection body <NUM> and the mill <NUM>, and positional certainty is maintained between the injection body <NUM> and the mould <NUM>.

<FIG> shows the injection apparatus <NUM> injecting the flowable injection material <NUM> into the injection body <NUM> through the injection flow path <NUM>. The injection body <NUM> includes the vent <NUM>. During injection of the flowable injection material <NUM>, excess flowable injection material <NUM> and other fluids present in the injection and sealing apparatus out of the vent <NUM> through application of force into the injection flow path <NUM>, under vacuum or through any suitable method of drawing excess flowable injection material <NUM> and other fluids out of the vent <NUM>.

<FIG> shows the compound stock <NUM> being milled by the mill <NUM>. The compound stock <NUM> is prepared when the flowable injection material <NUM> sets into the set material <NUM>. The mill <NUM> mills the set material <NUM> down to the dentition <NUM>, providing the restoration <NUM>. The dentition <NUM> is prepared from the set material <NUM>. The dentition <NUM> is anchored to the attachment point <NUM> by the anchor point <NUM> that was machined into the mould <NUM>. The anchor point <NUM> may be a custom abutment machined into the blank <NUM> when preparing the mould <NUM>. The restoration <NUM> is connected to the unmilled portions of the mould <NUM> through the flash <NUM>. The flash <NUM> may be cut, broken or otherwise disrupted to remove the restoration <NUM> from any remaining first material <NUM>.

<FIG> shows the mill <NUM> translated downward relative to the injection body <NUM> with the repositionable milling input <NUM> for milling a lower portion of the mould <NUM>. Positional certainty is maintained based on the defined orientation maintained between the injection body <NUM> and the mill <NUM>, and positional certainty is maintained between the injection body <NUM> and the mould <NUM>. Maintaining a connection between the mould <NUM> and the sealing and injection apparatus <NUM>, through injection and setting of flowable injection material <NUM>, and also through milling, allows positional certainty to be maintained during both injection and milling while maintain sealing between the injection apparatus <NUM> and the blank <NUM> or the mould <NUM>. The injection apparatus <NUM> and the mill <NUM> may each be connected with the injection apparatus <NUM> throughout the method, or may be disconnected when not required for a given step.

<FIG> shows the restoration <NUM>. The restoration <NUM> includes the dentition <NUM>, which is prepared from the set material <NUM>. The dentition <NUM> is connected with the anchor point <NUM>, which is prepared from the first material <NUM>. The attachment point <NUM> allows the restoration <NUM> to be connected with a broader restoration, such as a denture or bridge. The restoration <NUM> may also be used as a crown. In some cases, the blank <NUM>, and as a result the anchor point <NUM> and the attachment point <NUM>, may be prepared from a metal such as titanium and the set material <NUM> may be a lithium disilicate or other material suitable for preparing the dentition <NUM>. The attachment point <NUM> may also be assymetrically designed to provide positional certainty of the restoration with respect to a holder.

<FIG> is a schematic of a method of preparing a dental restoration <NUM> using an injection and sealing apparatus <NUM>. <FIG> includes Figs. 41A to 41I.

<FIG> shows the blank <NUM> and the injection and sealing apparatus <NUM>. The blank <NUM> is prepared from the first material <NUM>. The blank <NUM> lacks an orientation specific profile for securing the blank <NUM> in a defined orientation within a milling machine. The blank <NUM> includes the attachment point <NUM> that may be connected with a restoration or implanted into an individual's dental arch. The attachment point <NUM> also provides positional certainty if the blank <NUM> is anchored with a holder or milling machine. The injection and sealing apparatus <NUM> includes the injection body <NUM>. The injection body <NUM> includes a repositionable milling input <NUM>. The repositionable milling input <NUM> may be translated axially along the injection body <NUM> and radially around the injection body <NUM> (e.g. as shown in <FIG>, etc.). The repositionable milling input <NUM> may be located in a sleeve that translates axially along the injection body <NUM> and radially around the injection body <NUM>. By allowing axial and radial translation of the mill <NUM>, the repositionable milling input <NUM> facilitates milling of the blank <NUM> or the composite blank <NUM> while the injection body <NUM> is sealed against the blank <NUM> or the composite blank <NUM>, and as a result, a new seal need not be formed between subsequent rounds of milling and injection.

<FIG> shows the injection and sealing apparatus <NUM> engaged with the blank <NUM>. The injection body <NUM> enshrouds and seals against the outer surface of the mould <NUM> for injection. The position of the blank <NUM> with respect to the injection and sealing apparatus <NUM> is maintained by the seal between the injection body <NUM> and the blank <NUM>, providing positional certainty.

<FIG> shows the mill <NUM> mills the blank <NUM> into the mould <NUM> while the blank <NUM> is engaged in and secured to the injection and sealing apparatus <NUM>, providing positional certainty. During milling, lubricant fluid <NUM> may be added to the injection and sealing apparatus <NUM>, in this case through the injection flow path <NUM>, and may alternatively be provided through a separate flow path. During milling, exhaust fluid <NUM> may flow out of the vent <NUM>, and may alternatively be exhausted through a separate flow path. The mould <NUM> defines a profile around which the flowable injection material <NUM> may be injected and may set around the anchor point <NUM>. During milling, the mill <NUM> may be rotated relative to the mould <NUM> by translating the repositionable milling input <NUM> relative to the injection body <NUM> both axially and radially, as is shown in <FIG>.

<FIG> shows the mill <NUM> angled downward relative to the injection body <NUM> with the repositionable milling input <NUM> for milling a lower portion of the mould <NUM>. Positional certainty is maintained based on the defined orientation maintained between the injection body <NUM> and the mill <NUM>, and positional certainty is maintained between the injection body <NUM> and the mould <NUM>.

<FIG> shows the mill <NUM> translated downward and rotated about the mould <NUM> relative to the injection body <NUM> with the repositionable milling input <NUM> for milling a lower portion of the mould <NUM>. Positional certainty is maintained based on the defined orientation maintained between the injection and sealing apparatus <NUM> and the mill <NUM>.

Maintaining a connection between the mould <NUM> and the sealing and injection apparatus <NUM>, through injection and setting of flowable injection material <NUM>, and also through milling, allows positional certainty to be maintained during both injection and milling while maintain sealing between the injection apparatus <NUM> and the blank <NUM> or the mould <NUM>. The injection apparatus <NUM> and the mill <NUM> may each be connected with the injection apparatus <NUM> throughout the method, or may be disconnected when not required for a given step.

<FIG> shows the compound stock <NUM> removed from the injection and sealing apparatus <NUM>. The compound stock <NUM> is prepared when the flowable injection material <NUM> sets into the set material <NUM>.

<FIG> shows the mill <NUM> milling the set material <NUM> down to the dentition <NUM>, providing the restoration <NUM>. The dentition <NUM> is prepared from the set material <NUM>. The dentition <NUM> is anchored to the attachment point <NUM> by the anchor point <NUM> that was machined into the mould <NUM>. The attachment point <NUM> provides positional certainty by anchoring to a milling machine or to a holder that is connected with the mill <NUM>. The anchor point <NUM> may be a custom abutment machined into the blank <NUM> when preparing the mould <NUM>. The restoration <NUM> is connected to the unmilled portions of the mould <NUM> through the flash <NUM>. The flash <NUM> may be cut, broken or otherwise disrupted to remove the restoration <NUM> from any remaining first material <NUM>.

<FIG> shows the restoration <NUM>, which includes the dentition <NUM>, which is prepared from the set material <NUM> and connected with the anchor point <NUM>, which is prepared from the first material <NUM>. The attachment point <NUM> allows the restoration <NUM> to be connected with a broader restoration, such as a denture or bridge. The restoration <NUM> may also be used as a crown. In some cases, the blank <NUM>, and as a result the anchor point <NUM> and the attachment point <NUM>, may be prepared from a metal such as titanium and the set material <NUM> may be a lithium disilicate or other material suitable for preparing the dentition <NUM>.

<FIG> shows a cross-sectional plan view of a blank <NUM> in a holder <NUM>. The holder <NUM> includes grooves <NUM> outwardly extending into the walls of the holder <NUM>.

<FIG> shows the blank <NUM> after material has been provided to the grooves <NUM> and cured to bond with the blank <NUM>, resulting in ridges <NUM>. Once the material has cured and bonded with the blank <NUM>, the resulting ridges <NUM> pair with the grooves <NUM> and prevent the blank <NUM> from rotating relative to the holder <NUM>, providing positional certainty of the blank <NUM> with respect to the holder <NUM>. The material may be flowable injection material that cures or otherwise hardens into the ridges <NUM>.

<FIG> shows a cross-sectional plan view of a blank <NUM> in a holder <NUM>. The holder <NUM> includes the grooves <NUM> outwardly extending into the walls of the holder <NUM>. The blank <NUM> includes ridges <NUM> that pair with the grooves <NUM>, preventing the blank <NUM> from rotating relative to the holder <NUM>, providing positional certainty of the blank <NUM> with respect to the holder <NUM>.

<FIG> shows a cross-sectional plan view of a blank <NUM> in a holder <NUM>. The holder <NUM> includes ridges <NUM> inwardly extending into the walls of the holder <NUM>. The blank <NUM> includes grooves <NUM> that pair with the ridges <NUM>, preventing the blank <NUM> from rotating relative to the holder <NUM>, providing positional certainty of the blank <NUM> with respect to the holder <NUM>.

In the preceding description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the embodiments. However, it will be apparent to one skilled in the art that these specific details are not required. In other instances, well-known electrical structures and circuits are shown in block diagram form in order not to obscure the understanding. For example, specific details are not provided as to whether the embodiments described herein are implemented as a software routine, hardware circuit, firmware, or a combination thereof.

Embodiments of the disclosure may be represented as a computer program product stored in a machine-readable medium (also referred to as a computer-readable medium, a processor-readable medium, or a computer usable medium having a computer-readable program code embodied therein). The machine-readable medium may be any suitable tangible, non-transitory medium, including magnetic, optical, or electrical storage medium including a diskette, compact disk read only memory (CD-ROM), memory device (volatile or non-volatile), or similar storage mechanism. The machine-readable medium may contain various sets of instructions, code sequences, configuration information, or other data, which, when executed, cause a processor to perform steps in a method according to an embodiment of the disclosure. Those of ordinary skill in the art will appreciate that other instructions and operations necessary to implement the described implementations may also be stored on the machine-readable medium. The instructions stored on the machine-readable medium may be executed by a processor or other suitable processing device, and may interface with circuitry to perform the described tasks.

Claim 1:
A method of manufacturing a dental restoration comprising:
securing an initial mould (<NUM>,<NUM>);
injecting initial flowable material into the initial mould;
setting the initial flowable material, resulting in an initial compound stock (<NUM>,<NUM>); and
applying subtractive manufacturing to the initial compound stock for providing the dental restoration,
characterized in that:
the initial mould (<NUM>,<NUM>) is secured in an orientation;
the method further comprises sealing the initial mould (<NUM>,<NUM>) against an injection surface;
the initial flowable material is injected into the initial mould (<NUM>,<NUM>) through the injection surface;
setting the initial flowable material results in the initial compound stock which is secured in the orientation; and
the substractive manufacturing is applied to the initial compound stock (<NUM>,<NUM>) while the initial compound stock (<NUM>,<NUM>) is secured in the orientation.