SYSTEM AND METHOD FOR MANUFACTURING DENTAL WORKPIECE

A system is disclosed for manufacturing a dental workpiece. The system may have a subtractive machine configured to manufacture a base of a dental device from a material blank, and an additive machine configured to manufacture a top of the dental device by adding material onto a surface of the base. The system may also have a controller in communication with the subtractive machine and the additive machine. The controller may be programmed to receive digital data corresponding to a mouth of a particular patient, and to control operation of the subtractive machine to customize the base based on the digital data.

TECHNICAL FIELD

The present disclosure relates generally to a manufacturing system and, more particularly, to a system and method for manufacturing dental workpieces including prostheses, support structures, and drill or surgical templates.

BACKGROUND

Additive manufacturing is a process of creating three-dimensional components by depositing overlapping layers of material, typically under the guided control of a computer. One technique of additive manufacturing is known as direct metal laser sintering (DMLS). The DMLS technique uses a laser to direct a high-energy beam into a powdered metal medium at precise locations corresponding to features and dimensions of the component to be manufactured. As the energy beam contacts the powdered metal, the powdered metal is caused to melt and weld together and to previously melted layers of the component.

In some situations, a component created only via DMLS is complete and in final form. In other situations, however, for example in situations where tight tolerances on size and/or form are required, other manufacturing steps (e.g., subtractive steps) may be taken. These steps can include creation of a base component (e.g., via milling and/or lathing) on which the printed component can subsequently be fabricated. The base component may have tight external tolerances in critical areas that cannot be achieved via additive manufacturing.

DMLS and conventional subtractive manufacturing operations have been used together to create dental prostheses. For example, U.S. Pat. No. 8,778,443 of Uckelmann et al. that issued on Jul. 15, 2014 (“the '443 patent”) describes a method for manufacturing an abutment for a dental implant. The method includes mounting a generic base member previously prefabricated via milling onto a platform. The method then includes laser-sintering a customized main body onto the base member in a layer-by-layer manner.

Although, the method described in the '443 patent may be used to produce high-quality dental prostheses, the method may still be less than optimal in some circumstances. For example, because the method of the '443 patent uses a generic base member, the completed implant abutment may not match well the contours of a specific patient's mouth. This may be particularly true when the implant abutment spans multiple tooth sites. An abutment that does not match the contours of the patient's mouth may be uncomfortable, unhygienic, and unreliable.

The disclosed system and method are directed to overcoming one or more of the problems set forth above and/or other problems of the prior art. In particular, the invention is directed towards a system according to claim1, a method according to claim8and dental device according to claim15. Advantageous embodiments are the subject of the dependent claims. They may be combined freely unless the context clearly indicates otherwise.

SUMMARY

In one aspect, the present disclosure is directed to a system for manufacturing a dental device. The system may include a subtractive machine configured to manufacture a base of the dental device from a material blank, and an additive machine configured to manufacture a top of the dental device by adding material onto a surface of the base. The system may also include a controller in communication with the subtractive machine and the additive machine. The controller may be programmed to receive digital data corresponding to a mouth of a particular patient, and to control operation of the subtractive machine to customize the base based on the digital data.

In yet another aspect, the present disclosure is directed to a method for manufacturing a dental device. The method may include receiving digital data corresponding to a mouth of a particular patient and, based on the digital data, subtractively manufacturing from a material blank a base of the dental device. The method may also include additively manufacturing a top of the dental device on a surface of the base.

In particular, a system for manufacturing a dental device comprises:

a subtractive machine configured to manufacture a base of the dental device from a material blank;
an additive machine configured to manufacture a top of the dental device by adding material onto a surface of the base; and
a controller in communication with the subtractive machine and the additive machine, the controller being programmed to:
receive digital data corresponding to at least one of a mouth of a particular patient and the dental device; and
control operation of the subtractive machine to customize the base based on the digital data.

In an embodiment of the system the controller is further configured to control operation of the additive machine to customize the top based on the digital data.

In another embodiment of the system the controller is further configured to:determine in a virtual model of the dental device a first location of at least one feature having geometry that can be fabricated by the subtractive machine;determine in the virtual model of the dental device a second location of at least one feature having geometry that can be fabricated by the additive machine; and determine in the virtual model a location of a plane separating the first location from the second location, wherein the plane forms a virtual boundary at least partially defining the base and the top.

In another embodiment of the system the plane passes through multiple features of the dental device.

In another embodiment of the system:

the plane is a first plane; and
the controller is further configured to:
determine in the virtual model of the dental device a third location of at least one feature having geometry that can be fabricated by the subtractive machine;
determine in the virtual model of the dental device a fourth location of at least one feature having geometry that can be fabricated by the additive machine; and
determine in the virtual model a location of a second plane separating the third location from the fourth location, wherein the second plane forms a virtual boundary at least partially defining the base and the top.

In another embodiment of the system the first location corresponds with tight-tolerance and high-precision; and

the second location corresponds with complex freeform geometry.

In another embodiment of the system the dental device is one of a superstructure, a substructure used for mounting of the superstructure, and a template used to install the superstructure or substructure in a mouth of a particular patient.

In another embodiment of the system the subtractive machine is configured to manufacture a reference feature associated with the material blank for use in at least one of placing the base of the dental device inside the additive machine and detecting an orientation of the base of the dental device inside the additive machine.

In another embodiment of the system it further includes a transfer machine configured to transfer the base from the subtractive machine to the additive machine based on a location of the reference feature.

In another embodiment of the system the additive machine is configured to sinter the top from a powdered metal.

In another embodiment of the system select surfaces of the base correspond to one of an implant abutment face, a threaded bore, or a cusp surface.

In particular, a method for manufacturing a dental device comprises: receiving digital data corresponding to at least one of a mouth of a particular patient and the dental device; subtractively manufacturing from a material blank a base of the dental device based on the digital data; and additively manufacturing a top of the dental device on a surface of the base.

In an embodiment of the method, additively manufacturing the top of the dental device includes additively manufacturing the top based on the digital data.

In another embodiment the method further includes: determining in a virtual model of the dental device a first location of at least one feature having geometry that can be fabricated by subtractive manufacturing;

determining in the virtual model of the dental device a second location of at least one feature having geometry that can be fabricated by additive manufacturing; and
determining in the virtual model a location of a plane separating the first location from the second location, wherein the plane forms a virtual boundary at least partially defining the base and the top.

In another embodiment of the method the plane passes through multiple features of the dental device.

In another embodiment of the method the plane is a first plane and the method further includes:

determining in the virtual model of the dental device a third location of at least one feature having geometry that can be fabricated by subtractive manufacturing;
determining in the virtual model of the dental device a fourth location of at least one feature having geometry that can be fabricated by additive manufacturing; and
determining in the virtual model a location of a second plane separating the third location from the fourth location, wherein the second plane forms a virtual boundary at least partially defining the base and the top.

In another embodiment of the method the first location corresponds with tight-tolerance and high-precision; and the second location corresponds with complex freeform geometry.

In another embodiment of the method the dental device is one of a superstructure, a substructure used for mounting of the superstructure, and a template used to install the dental device in a mouth of a particular patient.

In another embodiment the method further includes subtractively manufacturing a reference feature associated with the material blank for use in placement of the base prior to additively manufacturing the top.

In another embodiment of the method additively manufacturing the top includes sintering the top from a powdered metal.

In another embodiment of the method select surfaces of the base correspond to one of an implant abutment face, a threaded bore, or a cusp surface.

The invention is also directed towards a dental device manufactured via a method according to the invention.

DETAILED DESCRIPTION

FIGS. 1, 2, and 3illustrate different dental devices10that can be manufactured by an exemplary system12, which is shown inFIG. 4and described in detail below. Dental devices10ofFIGS. 1-3may be manufactured from any type of material to have any desired shape. For example, dental devices10may be manufactured from a metal, such as titanium, a titanium/aluminum/vanadium alloy, a titanium/aluminum/niobium alloy, a titanium/zirconium alloy, a cobalt/chromium alloy, or another similar alloy. It is also contemplated that dental devices10could alternatively be manufactured from a non-metallic material, for example from a ceramic, a plastic, or a composite, as desired. Dental devices10may include, among other things, superstructures (e.g., bridges, crowns, dentures, and other prostheses)14, substructures (e.g., abutments, bars, implants, screws, and other similar structures)16that are configured to provide mounting for superstructures14, and templates (e.g., drill and/or surgical templates)18that are used to prepare a patient's mouth for receiving the other types of dental devices10. It should be noted that most dental devices10are uniquely designed (e.g., sized, shaped, contoured, and/or finished) for a particular patient based on x-rays of the patient's underlying bone structure and/or 3-D scans of the patient's mouth. Accordingly, the x-rays, scan images, and other similar digital data may at least partially define dental devices10, and care should be taken to manufacture dental devices10as close to the digital data as possible.

FIG. 4illustrates system12as having multiple machines that cooperate during the manufacture of dental devices10(referring toFIGS. 1-3). These machines may include, among other things, a subtractive machine (“machine”)20, an additive machine (“machine”)22, a transfer machine24, and a controller26in communication with each of the other machines. As will be explained in more detail below, machine20may use the digital data associated with a particular dental device10to machine down a material blank27and produce a high-precision 3D base28that is unique to a particular patient (e.g., that matches the size, shape, contour, and/or surface texture of the patient's mouth and, in particular, that includes any connecting interfaces to existing implants). Machine22may then build upon base28a corresponding 3-D top29also using the digital data in order to produce the particular dental device10. Transfer machine24may automatically move base28from machine20to machine22; and controller26may store the digital data and/or control operations of machines20-24. It is contemplated that transfer machine24could be omitted in some embodiments, if desired, and base28manually transferred between machines20and22. It is also contemplated that, instead of a centralized controller26, each of machines20-24could have its own dedicated controller26. Finally, it is contemplated that, instead of utilizing two separate fabrication machines20,22and a transfer machine24to transport base28between the machines, a single fabrication machine (e.g., a machine having both additive and subtractive capabilities) could instead be used to make dental devices10, if desired.

Machine20may embody any type of machine known in the art that is used to remove (i.e., “subtract”) material from select surfaces of material blank27. In the disclosed exemplary embodiment, machine20is a general or specific-use milling machine having a computer-controlled rotary cutter44that is configured to cut away chips of material from surfaces of material blank27. In particular, one or more actuators46may be connected to cutter44and configured to spin cutter44about its own axis while also advancing teeth (not shown) of cutter44into the surfaces of material blank27at desired locations. The relative spinning and/or translating between cutter44and material blank27may be precisely controlled (e.g., via controller26) based on the digital data defining dental device10, material blank27, and/or cutter44. It is contemplated that machine20could form a portion of a larger machining center, if desired, and have access to one or more automatic tool changers, tool carousels, coolant systems, debris collection, and/or enclosures. It is contemplated that another type of machine, for example a laser ablation or milling machine could also or alternatively be used to remove material from the surfaces of material blank27, if desired.

In the disclosed exemplary embodiment, machine20includes a holder48configured to receive and secure material blank27during the material-removal process performed by cutter44and described above. In the disclosed example, a recess50is formed within holder48and designed to receive material blank27of a standard size, shape, and/or configuration. In the disclosed exemplary embodiment, recess50is shown as a generally cylindrical socket having a diameter and depth specifically associated with material blank27and/or the manufacture of dental devices10. Recess50may be accessible to cutter44from one side or opposing sides, as desired. For example, holder48may have windows therein that allow cutter44to pass through and access material blank27over a large area and/or from a wide range of angles. Holder48may be movable to allow the desired access (e.g., holder48may be configured to flip over) and/or cutter44may be moved to the side(s) of material blank27requiring cutting, as desired. A flange53, clamp, fastener, clip, or other similar device may be used to retain material blank27inside recess50of holder48.

Machine22may take many different forms. In the disclosed exemplary embodiment, machine22is a sintering type of machine having a build chamber30, a material chamber32, a recoater34, and an energy source36. Recoater34may be configured to push powdered material from material chamber32into build chamber30(in a direction indicated by an arrow38) and on top of base28, and energy source36may be selectively activated to sinter (e.g., to melt) a pattern in the powder (e.g., by way of a laser beam39) and thereby produce layers of solidified material on base28that form top29. After each layer of material is solidified, a platform40in build chamber30(along with base28and any already fabricated layers of top29) may be incrementally lowered; a platform42in material chamber32(along with the powdered material) may be incrementally raised; and recoater34may push a new layer of powdered material over the solidified layer for sintering of a new layer of top29. It is contemplated that machine22could embody another type of additive machine (e.g., a vat photo-polymerization machine, a material jetting machine, a binder jetting machine, a material extrusion machine, a directed energy deposition machine, or another machine), if desired.

The placement of material blank27(or at least knowledge of the placement) inside of holder48may affect material removal from blank27and/or subsequent material additions to base28. For example, cutter44of machine20may be guided by controller26based on known geometry of material blank27and also based on a known or assumed relative location between cutter44and material blank27. For this reason, machine20may be equipped with a way to locate and/or detect the location of material blank27during and/or after placement within recess50. This may include, for example, one or more reference features54formed in material blank27and/or holder48(e.g., within and/or around recess50) that are configured to engage material blank27in a particular manner so as to precisely locate and/or orient material blank27. Alternatively or additionally, a scanner, imaging device, and/or measurement probe (not shown) may be used by machine20to detect the location of feature(s)54and/or material blank27after placement within holder48. In one example, reference feature54is a cylindrical depression or hole formed at a center of material blank27. Reference feature(s)54may be prefabricated within material blank27or machined into material blank27by machine20during manufacture of base28. It is contemplated that feature(s)54may be used in one or both of machines20,22to properly position, orient, machine, and/or build up layers of dental devices10. Other methods may also be used, if desired.

In the disclosed exemplary embodiment ofFIG. 4, transfer machine24is a robotic arm capable of retrieving base28from machine20(e.g., from within recess50after machining) and placing base28inside of build chamber30in preparation for subsequent layer buildup. In an alternative exemplary embodiment (not shown), transfer machine24may be an overhead gantry capable of moving base28in the same manner described above. Other embodiments may also be possible. It is contemplated that, in addition to moving base28from machine20into machine22, machine24may also move holder48between machines20,22while base28remains secured within recess50. This may help to improve the placement accuracy of base28inside build chamber30, in some instances. It is also contemplated that in some applications, transfer machine24, in addition to moving base28and/or holder48, may also be configured to perform one or more additional processes (e.g., cleaning away of machined material chips, detecting base location and/or orientation, etc.) during movement of base28, if desired.

Controller26may embody a single processor or multiple processors that include a means for controlling an operation of system12. Numerous commercially available processors may perform the functions of controller26. Controller26may include or be associated with a memory for storing data such as, for example, the digital data associated with dental device10and/or blank27, operating conditions of machines20-24, design limits, performance characteristics or specifications, operational instructions, etc. Various other known circuits may be associated with controller26, including power supply circuitry, signal-conditioning circuitry, solenoid driver circuitry, communication circuitry, and other appropriate circuitry. Moreover, controller26may be capable of communicating with other components of system12(e.g., with each of machines20-24) via either wired or wireless transmission and, as such, controller26could be connected directly to machines20-24or alternatively disposed in a location remote from machines20-24and indirectly connected (e.g., wirelessly).

In some exemplary embodiments, controller26may rely on sensory information when regulating operations of machines20-24. This sensory information may include, for example, a detected location and/or orientation of material blank27within recess50of work holder48, a detected location and/or orientation of base28within build chamber30, and a tracked location and/or orientation of transfer machine24(e.g., a grasping hand of machine24). The sensory information may be provided by way of one or more sensors52, for example a proximity sensor, an actuator sensor, a measurement probe, a camera, etc. Signals generated by sensor(s)52may be directed to controller26for processing.

As described above and shown in the exemplary embodiment ofFIG. 5, dental device10may include at least two primary components that are fabricated together as a single integral part. These components include base28and top29. It should be noted that, when material blank27is initially cut by machine20, only base28may be fabricated. That is, after completion of the cutting processes by machine20, dental device10may not yet have a final size, shape, and/or contour necessary for use within the patient's mouth. Base28of dental devices10may still require extra material at select locations where machine22will perform the additive processes described above.

Base28and top29may be fabricated by different machines and/or processes due to the specific tolerances and geometric requirements of each of these components. For example, base28may include features intended to engage other devices or existing dentistry in the patient's mouth and, therefore, requires tighter tolerances and/or finer surface finishes that are best achieved by machine20. These features may include, for example, abutment faces, threaded bores, and/or cusp surfaces (not shown). Abutment faces may mate tightly against faces of corresponding implants and, accordingly, accurate contours at these faces may be required for proper engagement. Threaded bores may receive screws or other fasteners that are used to anchor dental devices within the patient's mouth. Accordingly, proper alignment of the bores and crisp threading may be required to ensure a desired placement in relation to existing contours surrounding dental devices10. The cusp surfaces may need to be accurate in order to ensure that damage to dental devices10and/or the surrounding dentistry does not occur during use. Top29may be additively manufactured by machine22to create complex geometries not otherwise possible via traditional subtractive processes and/or rougher surfaces that can improve bonding with cosmetic veneers or other similar outer covers. The complex geometries can include, for example, curving passages and imbedded fasteners.

A virtual model of dental device10may be created for a particular patient (e.g., based on the digital data described above), and then divided into base28and top29along at least one plane56. In the embodiment ofFIG. 5, plane56passes through every feature (e.g., every tooth site) of dental device10and is located such that a majority (e.g., all) of the high-precision, tight-tolerance features of dental device10are positioned to one side (e.g., the lower side shown inFIG. 5) of plane56, while a majority (e.g., all) of the complicated, free-form features are positioned to an opposing side (e.g., the upper side shown inFIG. 5). Plane56may be generally perpendicular to a center axis passing through material blank27(referring toFIG. 4) or oriented at another desired angle. The digital data associated with each divided portion of the virtual model of dental device10(e.g., associated with base28and top29) may then be sent to controller26and used to regulate fabrication via the respective machines20,22.

Dividing the virtual model of dental device10into base28and top29may allow use of a thinner material blank27, as compared to subtractively producing the entirety of dental device10. This may reduce the amount of material to be subtractively removed, saving manufacturing time and reducing waste. Such waste may not be recyclable in all cases, leading to increased cost of a fully subtractively manufactured dental device10.

In an alternative embodiment shown inFIGS. 6 and 7, plane56does not pass through every feature of dental device10. In contrast, plane56ofFIGS. 6 and 7passes through a limited number of features and is located only where the high-precision and tight-tolerances or complicated and free-form features are required. In particular, plane56could pass through a single feature (e.g., a single tooth site) of dental device10, such that a majority of dental device10is subtractively manufactured or the majority of dental device10is additively manufactured. In the example ofFIGS. 6 and 7, the majority of dental device10is subtractively manufactured by machine20, with only a complex curving passage58being subsequently manufactured by machine22. It is contemplated that any number of separate planes56could be used to define base28and top29within a single dental device10. In these embodiments, the different planes56could be aligned with each other or located at different elevations and orientations.

In some embodiments, during subtractive manufacturing, machine20may co-form a support structure with base28from material blank27. The support structure may include, for example, an outer frame60(shown only inFIG. 4, inside of build chamber30of machine22) that at least partially surrounds base28, and one or more connectors (not shown) that extend between outer frame60and base28. In these embodiments, outer frame60and the connectors support base28during transfer between machines20and22, function as an adapter for use in placing dental devices10inside machines22and24, and securely mounts base28inside of machine22during the addition of top29. In some exemplary embodiments, outer frame60and the associated connectors may also function as a shipping container during transport of dental devices10to a final-use destination (e.g., to a dentist's or oral surgeon's office) after the additive processes of machine22are complete. Outer frame60may be removed before installation of dental device10, for example by cutting away of the associated connectors.

It is contemplated that a single dental device10or multiple dental devices10may be fabricated inside a single outer frame60. For example, multiple dental devices10may be nested inside each other and inside of outer frame60. By fabricating multiple dental devices10inside the same outer frame60, greater efficiencies may be achieved. In some exemplary embodiments, the particular dental devices10formed within the same outer frame60may correspond with the same patient and/or the same surgical procedure. For example, a kit may be created by co-forming one or more superstructures14, substructures16, and/or templates18(referring toFIGS. 1-3) for a single patient within the same outer frame60. In this way, all parts of the kit may be fabricated at the same time, in the same location, from the same materials, and/or by the same machines, thereby providing for ease of part handling and inventory tracking, improved efficiency, enhanced accuracy, and better assembly fit. In some instances, the parts of a particular kit may even be transported together within outer frame60to the final-use destination.

INDUSTRIAL APPLICABILITY

The disclosed system and method may be used to manufacture a wide range of well-fitting dental devices in an accurate manner. The dental devices manufactured by the disclosed system may conform well to a patient's mouth because most (if not all) parts of each dental device are customized for each patient. Accuracy may be achieved through the combined use of subtractive and additive manufacturing processes, such that areas of high-precision and also areas of high-complexity can be produced within required tolerances. Operation of system12will now be described in detail.

At a start of a manufacturing event, digital data regarding a dental device10to be produced may be electronically loaded into controller26(referring toFIG. 4). This digital data may include a shape, a size, a contour, a location and/or orientation of plane56, etc. associated with the particular dental device10, as well as specifications of the associated material blank27that is to be used. Material blank27may then be physically loaded into holder48of machine20, and controller26may use the digital data to regulate operation of cutter44. In particular, cutter44may be controlled to remove material from select surfaces of material blank27, thereby creating base28upon which top29can be subsequently added.

Once machining of base28has been completed, any chip material around base28may be removed (e.g., brushed away, vacuumed up, etc.). Transfer machine24may then transport base28from machine20to machine22, and place base28in a desired location inside of build chamber30. In some exemplary embodiments, base28may need to be oriented in a particular way before sintering can begin. This may include, for example, aligning particular reference features54of base28(and/or holder48) with corresponding features in build chamber30. In another example, base28may be loaded into build chamber30in any desired manner, but the resulting location and/or orientation may need to be detected thereafter.

The digital data described above may then be used to control operation of build chamber30, material chamber32, recoater34, and energy source36. For example, platform40may be lowered in an amount corresponding to a desired thickness of a first layer of top29on base28. At about the same time, platform42may be raised by at least this same thickness. Thereafter, recoater34may be driven by associated actuator(s) to push material protruding from material chamber32above a lower edge of the corresponding recoater into build chamber30and on top of base28. The material may be spread across platform40in a relatively consistent and well-distributed manner. Thereafter, energy source36may be activated to sinter the powdered material in a pattern corresponding to the size, shape, and/or contour of top29at the particular height above platform40. Platform40may then be lowered by a thickness of a second layer of top29, and the process may be repeated. It should be noted that, in some embodiments (e.g., embodiments, where plane56passes through only a single feature of dental device10and is surrounded by other taller features), a different method of additive manufacturing (e.g., vat photo-polymerization, material jetting, binder jetting, material extruding, or directed energy depositing) may be required. Once all layers of top29have solidified, any powdered material around dental device10may be removed (e.g., brushed away, vacuumed up, etc.). Dental device10may thereafter be installed within the corresponding patient's mouth. In some embodiments, outer frame60and/or the associated connectors may first need to be cut away from dental device10prior to installation.

It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed system and method. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed system and method. For example, when referring the “mouth” of a particular patient, such reference is intended to encompass only part (e.g., only soft tissue, only hard tissue, a particular combination of soft and hard tissues, etc.) or all of the mouth. It is intended that the specification and examples be considered as exemplary only.