3D printed dental restoration precursor with support element and manufacturing process

Abstract

The present invention relates to a 3D-printed dental restoration precursor, a 3D-printed array including a 3D-printed dental restoration precursor, a kit of parts including at least two 3D-printed dental restoration precursors or 3D-printed dental restorations, and a process for manufacturing such a 3D-printed array, 3D-printed dental restoration precursor, or 3D-printed dental restoration. The 3D-printed dental restoration precursor includes at least one crown unit having an outer surface and an inner surface, and at least one support element having a fixing portion. The support element is connected to the outer surface of the crown unit in a specific region via the fixing portion.

Description

[Technical Field]

[0001] The present invention relates to 3D printed dental restoration precursors, 3D printed arrays comprising 3D printed dental restoration precursors, kits of parts comprising at least two 3D printed dental restoration precursors or 3D printed dental restorations, and processes for manufacturing such 3D printed arrays, 3D printed dental restoration precursors, or 3D printed dental restorations.

[0002] The process of producing 3D printed dental restoration precursors can be carried out on an industrial scale or on a smaller scale, for example, in a so-called chairside process in a dental clinic, where 3D printed dental crowns are produced. [Background technology]

[0003] In various technical fields, physical objects or mechanical workpieces are increasingly being produced by additive manufacturing processes.

[0004] Such additive manufacturing processes typically allow an object to be built up into its desired individual shape by successively adding material to create that shape, and are increasingly replacing so-called subtractive processes, in which objects are machined by removing material from a larger blank.

[0005] While additive manufacturing processes are widely used in industry for rapid prototyping, producing final products remains challenging in many areas.

[0006] In particular, the fabrication of dental restorations generally requires the use of materials that are compatible for use in the human body.

[0007] Furthermore, dental restorations produced by a build-up process typically must meet requirements for mechanical stability as well as aesthetic expectations, for example with regard to color and translucency.

[0008] Some additive manufacturing processes are based on stereolithography or digital light processing techniques.

[0009] Stereolithography generally uses light to harden a radiation-curable resin. Computer-aided design and / or computer-aided manufacturing (CAD / CAM)-based data is used to project a light pattern onto a layer of radiation-curable resin. The radiation-sensitive resin typically hardens as a result of exposure to light, forming a layer of hardened resin according to the pattern. By successively stacking layers, a three-dimensional object is created. The pattern is then controlled according to the desired geometry of the three-dimensional object.

[0010] Layer-by-layer manufacturing methods typically require support for each layer on the build platform on which the physical object is built. Naturally, previously built layers can provide support for a new layer. However, if a new layer extends beyond a previously built layer in one or more portions, such portions may not be supported by the previously built layer. Thus, such portions overhang the previously built layer.

[0011] It is common for the overhanging portion to be supported by a support structure that is removed after the object is built up. Typically, the support structure is rod-shaped and is built up during the process of building up the object. Thus, the overhanging portion of a layer is formed directly on the support structure. This means that the previously built-up layer of the overhanging portion is a layer of the support structure.

[0012] The support structure must on the one hand be robust and stable enough for printing and post-processing (e.g., cleaning), but must also be removable once the final object is completed.

[0013] A typical support strategy used in 3D printing requires a certain number of supports to adequately support a three-dimensional object, such as a crown.

[0014] US Patent No. 9,183,325 B2 (Wighton et al.) describes a method for generating a support structure for an object, where the support structure and the object are manufactured by additive manufacturing techniques.

[0015] WO 2017 / 155692 A1 (3M) relates to preformed dental composite crowns characterized by their shape and chemical composition. It is stated that these preformed dental composite crowns can be manufactured by various techniques, for example, using additive manufacturing processes, molding or milling processes.

[0016] German Patent No. 102012108217A1 (DeguDent) describes a process for producing medical molds based on digitized data in a freeform technique, preferably by selective laser melting or sintering, and in a processing device using the digitized data, simultaneously producing a fixed structure derived from the mold, which is fixed to the mold by the fixed structure in the processing device, and post-processing. For producing dental crowns and bridges, it is suggested that each mold has at least three bars, two of which extend from both sides of the mold.

[0017] U.S. Patent Application Publication No. 2009 / 176007 (Uckelmann) relates to a process for layered manufacturing of a product, including applying layers of hardenable material and selectively hardening predetermined areas of the applied layer based on geometric data of the product. During the manufacturing procedure, at least one process parameter is varied to affect the grain size in a first region of the product relative to a second region of the product. In this regard, the publication describes a dental product connected to a base plate by built-up legs and supports, which separate the dental product from the base plate. The supports are laterally fixed to the dental product to prevent undesired distortion of the dental product against forces generated during the layer application procedure.

[0018] US Patent Application Publication No. 2004 / 0031780A1 (Hagemeister et al.) describes a method for producing metal or non-metallic products by free-form laser sintering, in which powder is added vertically onto a substrate in layers and assembled into a product, in which at least one support is fabricated between the substrate and the outer surface of the product. The support is connected to the outer surface of the product via a predetermined breakable area. The product is joined to the substrate plate by the support (or two of them). The support is longitudinal in shape and arranged vertically in the direction in which the powder layers are added. Summary of the Invention

[0019] While existing techniques for building up objects offer certain advantages, there remains a need for methods that minimize the adverse effects that may result from the use of support elements during the building up of an object.

[0020] One of these issues relates to the design and number of support elements required to support a 3D printed article during the printing process, particularly when the 3D printing is performed by stereolithography (SLA) or digital light processing (DLP). Typically, the more complex the shape of the printed article, the more support structure elements are required.

[0021] Another issue relates to the effort required during post-processing of 3D printed articles, for example the need to remove support elements.

[0022] One object of the present invention is to provide a dental restoration that is easily manufactured.

[0023] Another object of the present invention is to provide a dental restoration precursor that is easy to handle during post-processing and use.

[0024] Another object of the present invention is to provide a process that allows for simplified manufacturing of dental restorations or dental restoration precursors.

[0025] One or more of the above objectives are addressed by the inventions described herein.

[0026] In one embodiment, the invention features a 3D printed dental restoration precursor as described herein and claimed, wherein the 3D printed dental restoration precursor comprises: at least one crown unit having an outer surface and an inner surface; at least one support element having a fixing portion; The shape of the crown unit is the molar having an occlusal upper surface and a depending lateral surface; an anterior tooth having an incisal upper edge and a depending side surface; the sides are connected to one another to form a crown neck having a crown margin surrounding a crown opening; The occlusal upper surface or the incisal upper edge defines the plane x; characterized as, The support element is has a direction z directed toward the crown unit through the fixing portion, The support element is In the region adjacent to the occlusal upper surface or the incisal upper edge, preferably at an angle in the range of 20 to 80° formed by the orientation z of the support element and the plane x, or in the region of the crown margin, preferably at an angle in the range of 20 to 80° formed by the orientation z of the support element and the plane x, The crown unit is connected to the outer surface of the crown unit via a fixing portion.

[0027] In another embodiment, the present invention relates to a 3D printed array as described in the present specification and claims, wherein the 3D printed array comprises a support region to which at least one 3D printed dental restoration precursor comprising a crown unit and a support element as described in the present specification and claims is connected via a support element.

[0028] A further embodiment of the present invention is directed to a process for producing a 3D printed dental restoration precursor as described herein and claimed by using an additive manufacturing unit comprising a build platform, the process comprising: forming a support element having a fastening portion and optionally a handle portion from a resin material layer by layer; forming a crown unit layer by layer from a resin material; The crown unit has an outer surface and an inner surface; The shape of the crown unit is the molar having an occlusal upper surface and a depending lateral surface; an anterior tooth having an incisal upper edge and a depending side surface; the sides are connected to one another to form a crown neck having a crown margin surrounding a crown opening; the occlusal upper surface or the incisal upper edge defines the plane x; The support element has a direction z directed toward the outer surface of the crown unit through the fixing portion, The formation process is The support element is In the region adjacent to the occlusal upper surface or the incisal upper edge, preferably at an angle in the range of 20 to 80° formed by the orientation z of the support element and the plane x, or in the region of the crown margin, preferably at an angle in the range of 20 to 80° formed by the orientation z of the support element and the plane x, It is connected to the outer surface of the crown unit via a fixing part. forming a crown unit, Optionally, removing the dental restoration precursor from the additive manufacturing unit; Includes:

[0029] A further embodiment of the present invention is directed to a process for producing a 3D printed dental restoration precursor as described herein and claimed by using an additive manufacturing unit comprising a build platform, the process comprising: producing a 3D printed array comprising a 3D printed dental restoration precursor as described herein; Washing the 3D printed array; Post-curing the 3D printed array; removing the 3d printed dental restoration precursor from the 3d printed array; Includes:

[0030] A further embodiment of the present invention is directed to a process for producing a 3D printed dental restoration by using the additive manufacturing techniques described herein and claimed herein, the process comprising: producing a 3d printed dental restoration precursor comprising a support element and a crown unit as described herein; removing the support element from the crown unit; Optionally, polishing the outer surface of the crown unit at least in the area where the support element is connected to the outer surface of the crown unit; Includes:

[0031] The present invention also relates to a kit of parts comprising at least two 3D printed dental restorations or 3D printed dental restoration precursors as described and claimed herein.

[0032] Unless otherwise defined, as used herein, the following terms have the meanings set forth below.

[0033] "Dental article" means an article used specifically to make dental restorations.

[0034] "Dental restoration" means a dental article used to restore missing tooth structure. Examples of dental restorations include dental crowns, bridges, inlays, onlays, veneers, facings, and copings. Dental articles should not contain components that are harmful to the patient's health and, therefore, are free of harmful and toxic components that may migrate from the dental or orthodontic article.

[0035] "Additive manufacturing" or "3D printing" refers to a process that involves the layer-by-layer creation of an object from digital data. The article can be in almost any shape or configuration and is created from a three-dimensional model or other electronic data source. For purposes of this specification, the term "additive manufacturing" is understood to mean "3D printing."

[0036] There are many 3D printing techniques, one of which is bath polymerization, in which a radiation curing step is used to create three-dimensional articles.

[0037] Examples of bath polymerization techniques include stereolithography (SLA) and digital light processing (DLP).

[0038] "Stereolithography" is an example of an additive manufacturing technique, which typically uses two motors to harden the printing resin by aiming a laser beam across the print area. This process breaks down the design into a series of points, layer by layer.

[0039] "Digital light processing" is another example of an additive manufacturing technique and typically involves the use of a digital projector screen to flash an image of each layer across the building platform of an additive manufacturing unit. The image is typically made up of square pixels, resulting in layers formed from small rectangular bricks called voxels.

[0040] Typically, layers have a particular thickness in a build axis. The build axis typically extends in the dimension in which the layers are stacked on top of each other. In the dimension perpendicular to the build axis, each layer typically has a shape that is derived from the overall three-dimensional shape of the object. Typically, the layers are derived from virtually slicing a three-dimensional computer model of the object into multiple virtual layers. The virtual layers are then used to build up physical layers that correspond in thickness and shape to the virtual layers.

[0041] The expression "light suitable for curing radiation-curable materials" preferably refers to light within a wavelength range of 450 nm to 495 nm (blue light) or light within a wavelength range of 330 nm to 445 nm, preferably 383 nm (ultraviolet light). The light used in the methods described herein can be selected depending on the radiation-curable material used to build up the object.

[0042] As used herein, "a," "an," "the," "at least one," and "one or more" are used interchangeably. Also herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0043] Adding "(s)" to a term means that the term is to include the singular and the plural. For example, the term "additive(s)" means one additive as well as two or more additives (e.g., two, three, four, etc.).

[0044] Unless otherwise indicated, all numbers used in the specification and claims expressing quantities of ingredients, measurements of physical properties, e.g., those set forth below, are to be understood as being modified in all instances by the term "about."

[0045] The terms "comprise" or "contain" and variations thereof do not have a limiting meaning where these terms appear in the specification and claims. The term "comprise" is intended to encompass the terms "consist essentially of" and "consist of."

[0046] "And / or" means either one or both. For example, the phrase component A and / or component B refers to component A only, component B only, or both component A and component B. [Brief explanation of the drawings]

[0047] [Figure 1] FIG. 1 shows a 3D printed dental restoration precursor comprising a crown unit and a support element as described herein, wherein the support element is connected to the crown unit in an area adjacent to the occlusal upper surface of the crown unit. [Figure 2] FIG. 1 shows a 3D printed dental restoration precursor comprising a crown unit and a support element as described herein, wherein the support element is connected to the crown unit in the region of the crown margin. DETAILED DESCRIPTION OF THE INVENTION

[0048] The 3D printed dental restoration precursors described herein have been found to have several advantageous properties.

[0049] 3D printed dental restoration precursors can be easily produced by using additive manufacturing techniques.

[0050] Typically, only one single support structure element is required, eliminating the need to design and print complex multiple different support elements.

[0051] This can also be beneficial with regard to the amount of printing resin material needed during the manufacturing process: only a small amount of printing resin material is typically needed to print just one single support element.

[0052] Surprisingly, it has been found that successful printing of dental restorations (comprising at least one crown unit) with only one single support element is possible if the support element is positioned in a specific area of ​​the crown unit.

[0053] "Good printing" typically means that the 3D printed article (i.e., dental restoration precursor) does not exhibit more than 5% deformation relative to its intended dimensions compared to the desired structure.

[0054] The area where the support element is connected to the crown unit is either adjacent to the upper occlusal surface or the upper incisal edge of the crown unit, or in the area of ​​the crown margin of the crown unit.

[0055] Furthermore, the support elements are arranged at a particular angle relative to the orientation of the crown unit.

[0056] Typically, it has been found that positioning the support elements at an angle in the range of 20 to 80 degrees formed by the orientation z of the support element and the orientation x of the plane defined by the occlusal upper surface or the incisal upper edge of the crown unit is particularly useful as this facilitates printing of the dental restoration precursor in a kind of self-supporting orientation.

[0057] A further advantage relates to the effort required during the post-processing process.

[0058] Removal of support elements is usually time consuming, especially since this step typically cannot be automated, therefore, fewer support structure elements require less post-processing time.

[0059] In the present invention, according to one embodiment, the support structural element is designed to simplify the use and application of the subsequent dental restoration, so that removal of the support element is not even necessary.

[0060] According to the present specification, the support element can be 3D printed and eventually processed together with the dental restoration by the dentist in a chairside procedure and removed before placing the dental restoration on the prepared stump.

[0061] The presence of the support elements described herein can be advantageous for a variety of reasons.

[0062] The effort of removing the support element is reduced or even eliminated, which can be advantageous when dental restorations or dental restoration precursors are produced on an industrial scale.

[0063] Also, if desired, the support element can be used as an adapter for standardized post-processing units. Possible post-processing steps include cleaning steps, post-curing steps, and / or polishing steps.

[0064] The support element may also be used for labeling purposes or to capture patient-related or manufacturing-related data.

[0065] The support element can also simplify handling of the dental restoration precursor during use, especially when the practitioner has to test which dental restoration best fits the prepared stump and situation in the patient's mouth.

[0066] This can be advantageous, particularly if the dental restoration is designed for use by children, as dental restorations are typically small items that are often difficult to manipulate with fingers within a patient's mouth.

[0067] The present invention relates to 3D printed dental restoration precursors.

[0068] The 3D printed dental restoration precursor includes a dental crown unit and a support element.

[0069] According to one embodiment, a 3D printed dental restoration precursor comprises a crown unit and at least one single support element connected to the crown unit.

[0070] However, the 3D printed dental restoration precursor can include more than one crown unit, for example, two, three, four, or five crown units. In such cases, the crown units are typically connected to each other by bridging elements (e.g., pontics), thereby forming the dental bridge precursor.

[0071] In this case, each crown unit is connected to a support element as described herein.

[0072] The crown unit has a convex outer surface and a concave inner surface.

[0073] The crown unit may have different shapes.

[0074] A crown unit typically has an occlusal end and a marginal end. A cavity (crown opening) extends into the crown unit from the marginal end. The crown margin surrounds the crown opening. The cavity forms (or is bounded by) the inner surface of the crown unit.

[0075] The crown unit further has an outer surface that is shaped to resemble the shape of a natural tooth. Typically, the outer surface of the crown unit is the surface that is visible when the dental crown is placed in a patient's mouth.

[0076] Dental crowns used on posterior teeth (eg, molars and premolars) have an occlusal surface and depending buccal, mesial, and distal surfaces, as well as lingual and palatal surfaces, respectively.

[0077] Dental crowns used on anterior teeth (eg, canines and incisors) have a distal upper edge and depending buccal, mesial, and distal surfaces, as well as lingual and palatal surfaces, respectively.

[0078] The occlusal upper surface or the incisal upper edge of the crown unit defines a plane x.

[0079] The plane x may also be characterized by the direction of the plane x extending from that portion of the occlusal upper surface or from the crown edge where the support element is connected to the opposite side of the occlusal upper surface.

[0080] Plane x is typically essentially perpendicular to the depending sides of the crown unit.

[0081] From an anatomical point of view, the plane x, which represents the occlusal plane of the teeth in the patient's mouth, is essentially parallel to the so-called Camper's plane, which, according to the medical dictionary, extends from the tip of the anterior nasal spine to the center of the bony ear canal.

[0082] The crown unit may also be characterized by having an orientation y that extends perpendicularly from the crown opening to the occlusal or incisal upper edge of the crown unit, which orientation y is essentially parallel to the palatal surface of the crown unit and perpendicular to the plane x formed by the occlusal or incisal edge.

[0083] Alternatively, the teeth and respective crowns can also be described by a general tooth coordinate system, as shown, for example, in Figure 3B of U.S. Patent Application Publication No. 2013 / 0289951 A1 (Kuo et al.). Such adjustment systems can be automatically set and / or manually adjusted using conventional techniques for setting coordinate systems of objects known to those skilled in the art.

[0084] The plane x described herein is essentially parallel to the x / y plane of the general tooth coordinate system shown in FIG. 3B of US Patent Application Publication No. 2013 / 0289951 A1.

[0085] The crown unit may also have an undercut region.

[0086] Manufacturing crown units, especially those with undercut regions, is challenging, even when fabricated using additive manufacturing techniques. These regions typically require the addition of additional support elements during the manufacturing process. The present invention allows these additional support elements to be avoided.

[0087] Crown units are typically constructed from hardened dental composite materials.

[0088] 3D printed dental restoration precursors or dental restorations are particularly useful when used in children.

[0089] The 3D printed dental restoration precursor also includes at least one support element per crown unit. "At least one" means that there may be more than one support element connected to a crown unit.

[0090] However, when following the manufacturing process described herein, these additional support elements are typically not required from a manufacturing standpoint, as the support elements are typically constructed from the same resin material from which the crown unit is made.

[0091] According to a preferred embodiment, there is only one support element per crown unit.

[0092] Thus, the 3D printed dental restoration precursor has only one support element per crown unit, and this support element typically serves as a support for the dental restoration precursor during the 3D printing process. When the 3D printed dental restoration precursor includes only one crown unit, according to this preferred embodiment, the 3D printed dental restoration precursor includes only one support element.

[0093] The support element has a fastening portion for fastening the support element to the crown unit.

[0094] The fixing part of the support element has an orientation z. The orientation of the support element z is given by the orientation of the fixing part towards the outer surface of the crown unit to which the support element is fixed.

[0095] The support element is connected to the outer surface of the crown unit via a fastener, either in the region adjacent to the upper occlusal or incisal edge of the crown unit, or in the region of the crown margin.

[0096] The support element is typically connected to the outer surface of the crown unit via fasteners only in the aforementioned areas, but not in the area of ​​the occlusal surface.

[0097] The support element is fixed to the crown unit at a specific angle, preferably within a specific range. The angle is defined as the angle formed by the orientation z of the support element and the plane x, which is defined by the upper occlusal surface or upper incisal edge of the crown unit.

[0098] If the orientation of the support element and the occlusal upper surface are in the same plane, the angle is 0°. If the orientation of the support element and the occlusal upper surface are perpendicular to each other, the angle is 90°.

[0099] According to the present invention, the angle is preferably in the range of 20 to 80°, or 25 to 75°, or 30 to 70°, or 35 to 65°, and in some cases, the range of 30 to 70° or 35 to 65° is preferred.

[0100] By adjusting the angles as described herein, 3D printed dental restorations can be printed in a sort of self-supporting orientation using only one support element, without the need for additional support structures or elements.

[0101] Alternatively, if desired from a geometrical point of view, the angle may be defined by the orientation z of the support element and the orientation of the palatal side of the crown unit extending from the crown opening to the occlusal upper surface or incisal upper edge.

[0102] Furthermore, the orientation z of the support element is typically perpendicular to the orientation of the build platform of the additive manufacturing unit used in the 3D printing process.

[0103] The above orientation has been found to be particularly advantageous when the dental restoration precursor is manufactured by additive manufacturing methods.

[0104] When the support elements and crown units are arranged in this manner, the need for additional support structure elements printed during the manufacturing process is reduced, or in some cases even eliminated.

[0105] Thus, dental restoration precursors can be 3D printed and post-processed in an efficient manner.

[0106] If an angle outside this range is selected, 3D printing of the crown unit may result in undesirable distortion of the crown unit during the 3D printing process, especially if only one support element is used per crown unit.

[0107] The support element includes a fixing portion.

[0108] The fixing portion is a member of the support element attached to the outer surface of the crown unit.

[0109] According to one embodiment, the fixing part is arranged adjacent to the upper occlusal surface of the crown unit, in particular adjacent to the cusp present on the upper occlusal surface of a crown unit having the shape of a molar or premolar.

[0110] Such fixation can be beneficial as it can facilitate post-processing steps such as polishing that can be performed after the support elements are removed.

[0111] Fixing the support element close to the crown edge may be less desirable as there is a risk that the material will chip or break when the support element is removed from the crown unit.

[0112] The fastening portion may include a predetermined break point to facilitate removal of the support element before the crown unit is used, for example before it is fastened to a prepared stump.

[0113] The predetermined break point is preferably located adjacent the outer surface of the crown unit to which the support structural element is connected.

[0114] According to one embodiment, the predetermined breaking point is located at a distance of 0.1 to 0.5 mm relative to the surface of the crown unit.

[0115] Having a predetermined break point located at such a distance can help reduce the risk of the surface of the crown unit being damaged (e.g., the material of the crown unit may be accidentally broken) when the support element is removed.

[0116] The predetermined breaking point may have the shape of a neck or a constriction.

[0117] Alternatively, or in combination, weakening of the structure or support element can also be achieved by including voids during the manufacturing process. After the support structure is separated from the dental crown body, the voids can be opened to release the radiation-curable material contained therein. It has been found that the released radiation-curable material can be dispersed on the fracture surface and used to make the fracture surface shiny after curing.

[0118] If desired, the anchoring portion of the support element can also be characterized by its size and / or volume.

[0119] The fixing part of the support element is 0.1 to 0.5 mm 3 or 0.15 to 0.4 mm 3 The volume (Vf) may be in the range of

[0120] The fixing part may have a cylindrical shape with a diameter in the range of 0.5 to 1.5 mm or 0.6 to 1.2 mm.

[0121] The length of the fixing portion may be in the range of 0.1 to 1 mm, or 0.15 to 0.8 mm, or 0.2 to 0.5 mm.

[0122] The cross-sectional area (Af) of the crown unit at the connection point to the outer surface is 0.3 to 1 mm 2 or 0.4 to 0.8 mm 2 The range may be:

[0123] The volume of the crown unit (Vc) is typically 30 to 150 mm 3 or 35 to 120 mm 3 is within the range.

[0124] The ratio of the volume of the crown unit (Vc) to the volume of the fixing part of the support element (Vf) can be in the range of 100:1 to 700:1, or 150:1 to 600:1, or 200:1 to 550:1. Thus, the volume of the crown unit is much larger than the volume of the fixing part.

[0125] The ratio of the volume of the crown unit (Vc) to the volume of the support element (Vs) may be in the range of 2:1 to 40:1, or 3:1 to 30:1, or 5:1 to 25:1.

[0126] The support element, in particular the fastening part, must have a size and / or volume that allows the support element to perform its function.

[0127] The volume of the crown unit or support element or fastening part means the volume filled with or containing the printing resin.

[0128] If the size and / or volume of the fixing portion of the support element is too small, the support for the crown unit during the printing process may not be sufficient.

[0129] Since the support element must ultimately be removed before the crown unit is inserted into the patient's mouth and is therefore considered waste, if the size and / or volume of the fixing portion of the support element is too large, the manufacturing costs of the crown unit may become too high.

[0130] When the fastening part and the support element are designed as described herein, typically no further predetermined breaking point is necessary, and therefore, according to certain embodiments, the fastening part does not include a predetermined breaking point.

[0131] According to one embodiment, the support element may also include a handle portion in addition to the fixing portion.

[0132] If present, the handle is typically designed to simplify handling of the dental restoration during use, which is particularly advantageous for handling small dental restorations such as pediatric crowns.

[0133] The handle may include a segment that can be used for labeling purposes, where information that can be captured on the segment includes crown size, tooth number, lot number, patient related data, brand, and combinations thereof.

[0134] Examples of 3D printed dental restoration precursors described herein are shown in Figures 1 and 2.

[0135] The present invention also relates to 3d printed arrays.

[0136] The 3D printed array includes a support region to which at least one crown unit is connected via support elements, preferably only one support element per crown unit.

[0137] The support region, support element, and crown unit are typically constructed of the same resin material.

[0138] The 3D printed array may comprise at least 1, or at least 5, or at least 10, or at least 20, or at least 50, as well as up to 500, or 400, or 200 crown units.

[0139] The number of crown units is typically limited by the size of the build platform of the additive manufacturing unit used for production.

[0140] According to one embodiment, the support element of the dental restoration comprises one predetermined break point.

[0141] According to another embodiment, the support element of the dental restoration includes two predetermined break points.

[0142] The one predetermined breaking point can be located at the connection of the fixing part of the support element to the outer surface of the crown unit.

[0143] One predetermined break point can be located at the connection of the support element to the support region of the 3D printed array.

[0144] When the support element includes a handle portion that is connected to the support region of the 3D printed array, the predetermined break point is typically located at the connection of the handle portion to the support region of the 3D printed array.

[0145] If there are two predetermined breaking points, the predetermined breaking points may differ from each other by their breaking resistance.

[0146] For ease of handling, if the 3D printed dental restoration is intended for initial use with a support element, it may be beneficial if the predetermined break point at the connection to the support region is weaker than the predetermined break point at the connection to the crown unit of the dental restoration precursor. Such a structure typically facilitates removal of the dental restoration precursor from the 3D printed array. The risk of accidental removal of the support element is reduced.

[0147] However, if the 3D printed dental restoration is intended to be used without a support element, it may be beneficial if the predetermined break point at the connection to the support region is stronger than the predetermined break point at the connection to the crown unit of the dental restoration precursor. Such a structure typically facilitates removal of the dental restoration from a 3D printed array without a support element.

[0148] The present invention is also directed to a process for producing the 3D printed dental restoration precursors described herein by using an additive manufacturing unit comprising a build platform, the build platform typically having a flat surface area.

[0149] The 3D printed dental restoration is typically secured via support elements to support areas of the 3D printed array, if present, or directly to the build platform.

[0150] The process is forming a support element having a fixing portion from a resin material layer by layer; forming a crown unit layer by layer from a resin material to obtain a 3D printed dental restoration precursor; Optionally, cleaning the 3d printed dental restoration precursor; Optionally, post-curing the 3d printed dental restoration precursor; and Optionally, removing the 3d printed dental restoration precursor from the additive manufacturing unit; and Optionally, polishing an outer surface of the crown unit of the 3d printed dental restoration precursor; Includes:

[0151] During the 3D printing process, the build platform is typically moved upwards, thereby increasing the distance between the vat containing the resin material and the build platform over time.

[0152] Preferably, the forming process is carried out in such a way that the dental restoration precursor can be 3D printed using only one support element, i.e. in a self-supporting orientation.

[0153] If only one support element is formed per crown unit, this may be sufficient.

[0154] In order to reduce the amount of resin required to print the support elements, it may be desirable to choose a 3D printing strategy that allows a short distance between the crown unit and the build platform, preferably the shortest distance reasonably possible.

[0155] The forming process steps are typically performed such that the support elements are connected to the outer surface of the crown unit via fasteners in specific areas and at specific angles.

[0156] This angle is formed by the x orientation of the plane defined by the occlusal upper surface or incisal upper edge of the crown unit and the z orientation of the support element.

[0157] During the molding step, when the support element is connected to the outer surface of the crown unit in the area adjacent to the occlusal upper surface or the incisal edge, the occlusal upper surface or the incisal upper edge of the crown unit is typically oriented toward the build platform of the additive manufacturing unit.

[0158] Thus, according to one embodiment, the crown opening of the crown unit is typically oriented generally away from the build platform.

[0159] Such an orientation can be advantageous, particularly if the build direction is diametric with respect to the x-direction of the support element, as it can facilitate the dropping of residual resin material from the printed crown unit during the 3D printing process.

[0160] Alternatively, during the forming process, if the support element is connected to the outer surface of the crown unit in an area adjacent to the crown marginal area, the occlusal upper surface or incisal upper edge of the crown unit is oriented away from the build platform of the additive manufacturing unit.

[0161] In general, the support element is typically 3d printed before the remainder of the dental restoration precursor is 3d printed.

[0162] After the support element is 3D printed, the 3D printing process proceeds to printing the area adjacent to the occlusal upper surface or incisal upper edge of the final crown unit, or to printing the crown neck.

[0163] The manufacturing process may optionally include further process steps selected from cleaning, post-curing, stripping, polishing the dental restoration precursor, and combinations thereof.

[0164] These process steps are typically performed outside of the additive manufacturing unit, i.e. after the 3d printed object has been removed from the vat containing the radiation curable resin material.

[0165] The additive manufacturing unit used to produce the 3D printed dental restoration precursor or 3D printed array is typically selected from a stereolithography unit or a digital light processing unit.

[0166] In general, the steps to build an object are: providing a layer of radiation curable material; exposing at least a portion of the layer to light suitable for curing the radiation curable material; It is based on sequential execution of

[0167] In this regard, an additive manufacturing unit typically comprises a light-transmitting (preferably transparent) exposure plate for receiving the radiation-curable material, a build platform on which the object and support structure are built up, and a light projector for projecting a light pattern through the exposure plate towards the build platform.

[0168] The exposure plate and the build platform are preferably movable relative to each other in a position-controlled manner. The positions of the exposure plate and the build platform relative to each other and the light pattern are preferably controlled by a computer based on a computer model of the object. The exposure plate may be part of a bath in which the radiation-curable material may be provided. Furthermore, a bath may be provided in addition to the exposure plate.

[0169] During the 3D printing process, the build platform is moved along the build direction: either the vat can be moved downwards towards the build platform, or the build platform can be moved upwards towards the vat.

[0170] For producing the 3D printed dental restoration precursors described herein, it has been found to be more advantageous to move the build platform.

[0171] During the 3D printing process, a tank in an additive manufacturing unit is filled with radiation-curable resin material.

[0172] Radiation curable resin materials are typically -1 1 to 150 Pa at 23° when measured at a shear rate of * s or 20 to 120 Pa * It has a viscosity in the range of s.

[0173] Such a viscosity has been found to be particularly useful when only one support element per crown unit is printed during the 3D printing process.

[0174] Resin materials used in 3D printing processes typically contain a (meth)acrylate component and a photoinitiator suitable for initiating the curing reaction of a radiation-curable composition.

[0175] It may be advantageous if the radiation-curable resin material comprises a radiation-curable (meth)acrylate component that contains at least one urethane moiety.

[0176] Suitable radiation curable resin materials include: A resin matrix comprising: Polymerizable (meth)acrylates that do not contain a urethane moiety, and Contains polymerizable urethane (meth)acrylate, a resin matrix in which a polymerizable (meth)acrylate not containing a urethane moiety is used in excess of a polymerizable urethane (meth)acrylate; A filler matrix comprising: nanocluster(s), and optionally, fumed silica in an amount less than 8 wt. %; a filler matrix, typically present in an amount of 5 to 45 wt. %; An initiator system comprising: photoinitiator(s), and an initiator system comprising an organic dye; The curable composition typically does not contain more than 5% by weight of a softener; Here, "wt%" refers to the weight percent of the total composition. The curable composition was heated at 23°C and 1 s -1 At a shear rate of 150 Pa * It may be characterized as having a viscosity of less than or equal to 1000 .mu.m.

[0177] Suitable radiation-curable resin materials are also described, for example, in PCT / US / 18 / 36025, published as WO 2018 / 231583 A1, the contents of which are incorporated herein by reference.

[0178] The present invention is also directed to a process for producing a 3D printed dental restoration precursor by using an additive manufacturing unit including a build platform, the process comprising: producing a 3d printed array comprising a dental restoration precursor as described herein; Washing the 3D printed array to remove excess resin; Optionally, post-curing the 3d printed array; and Optionally, removing the 3d printed dental restoration precursor from the 3d printed array; and Includes:

[0179] Printing of 3D printed arrays can be beneficial when it is intended to manufacture dental restoration precursors or dental restorations on an industrial scale.

[0180] 3D printing of arrays containing many dental restorations typically facilitates the performance of optional post-processing steps such as cleaning, post-curing, and polishing.

[0181] As described above, according to one embodiment, the support elements included in the 3D printed array may include two predetermined break points, one at the connection with the support region and one at the connection with the dental crown body.

[0182] The predetermined breaking points may differ from one another according to their breaking resistance.

[0183] According to one embodiment, the predetermined breaking point at the connection to the support region is weaker than the predetermined breaking point at the connection to the crown body.

[0184] This can facilitate removal of the 3D printed dental restoration precursor from the 3D printed array and reduces the risk that the support structure elements will also be removed during the removal step.

[0185] The process for manufacturing the 3D printed dental restoration precursor described herein can be carried out either with or without the array described herein.

[0186] As outlined above, the use of arrays for manufacturing can be beneficial when manufacturing is carried out on an industrial scale. In this regard, as a first step, the 3D printed arrays described herein are manufactured.

[0187] As a next step, the 3D printed array is typically removed from the additive manufacturing unit.

[0188] As a further step, if desired, the array is typically washed free of residual resin material.

[0189] As a further step, if desired, a post-cure step of the array is performed to increase the stability of the array.

[0190] As a further step, the 3D printed dental restoration precursor or 3D printed dental restoration is typically removed from the array.

[0191] However, if manufacturing is done only for a small number of items or for single units (eg, chairside in a dental office), it may not be necessary to manufacture an array with support regions.

[0192] In this regard, the process for producing a dental restoration precursor comprises: forming a support element layer-by-layer from a resin material, the support element being connected to a build platform of an additive manufacturing unit; forming a dental restoration including a crown unit layer by layer from a resin material, wherein the crown unit is connected to a support element on an outer surface of the crown unit in an area adjacent to the occlusal upper surface or the incisal upper edge of the crown unit during the manufacturing process, preferably at an angle as described herein.

[0193] The present invention is also directed to a process for manufacturing the 3D printed dental restorations described herein.

[0194] This process is producing a 3d printed dental restoration precursor comprising a support element and a crown unit having an outer surface and an inner surface; removing the support element from the crown unit; Optionally, polishing the outer surface of the crown unit at least in the area where the support element is connected to the concave outer surface.

[0195] In addition to these process steps, the process may include further process steps such as cleaning steps, staining steps, or disinfecting steps.

[0196] Furthermore, the shape of the 3D printed dental restoration precursor can be further adjusted or adapted by grinding or cutting, if desired.

[0197] 3D printed dental restoration precursors or 3D printed dental restorations are typically provided to the practitioner as part of a kit from which the practitioner can select the appropriate restoration.

[0198] The practitioner grasps the 3D printed dental restoration precursor by the handle portion of the support structure element and tests whether the concave inner surface of the crown body fits into the prepared stump.

[0199] Once the concave inner surface of the crown body is fitted, the support structure element is removed and the dental crown body is filled with dental cement and secured to the prepared stump.

[0200] If it does not fit, a different size 3D printed dental restoration precursor is selected or its shape is adapted as desired.

[0201] Accordingly, the present invention also relates to a kit of parts comprising at least two 3D printed dental restoration precursors as described herein.

[0202] According to one embodiment, the at least two 3D printed dental restoration precursors typically differ from each other with respect to one characteristic such as size, shape, color, and combinations thereof.

[0203] According to another embodiment, the 3D printed dental restoration precursors included in the kit are identical.

[0204] The kit can contain up to 10, or up to 8 different shapes of 3D printed dental restoration precursors.

[0205] The kit can contain up to 10 or 8 different sized quantities of each of the different shaped 3D printed dental restoration precursors.

[0206] Thus, a kit can contain up to 100 3D printed dental restoration precursors.

[0207] The 3D printed dental restoration can have the shape of a front tooth or a molar or premolar.

[0208] Typically, 3D printed dental restoration precursors are provided in different tooth colors, which are typically classified according to the Vita™ color code.

[0209] The kit of parts may also include a dental cement suitable for firmly securing the 3D printed dental restoration to the prepared tooth surface.

[0210] A suitable dental cement is a glass ionomer cement (GIZ), particularly a resin-modified glass ionomer cement (RM-GIZ). Glass ionomer cements typically contain the following components: an acid-reactive filler, a polyacid, water, and a complexing agent, but no radiation-curable components.

[0211] The present invention also relates to a kit of parts comprising at least two 3D printed dental restorations as described herein.

[0212] The 3D printed dental restoration includes the crown unit(s) but does not include the support element(s).

[0213] As with the kit of parts comprising at least two 3D printed dental restoration precursors, the at least two 3D printed dental restorations may be identical to or different from one another in terms of size, shape, color, and combinations thereof.

[0214] The kit can contain up to 10 or up to 8 different shapes of 3D printed dental restorations.

[0215] The kits can contain up to 10 or 8 different sized quantities of each of the differently shaped 3D printed dental restorations.

[0216] Thus, a kit can contain up to 100 3d printed dental restorations.

[0217] Figure 1 shows a schematic example of a 3D printed dental restoration precursor in the shape of a dental composite crown. In this embodiment, the support element is connected to the crown unit in the area adjacent to the upper occlusal surface of the crown unit.

[0218] 2 shows a further schematic example of a 3D printed dental restoration precursor having the shape of a dental composite crown. In this embodiment, the support element is connected to the crown unit in the region of the crown margin.

[0219] The following elements are illustrated: Dental Crown Unit(1) Upper occlusal surface (1.1) Crown neck (1.2) Crown margin (1.3) Crown opening (1.4) Support element (2) Fixed part (2.1) Handle (2.2) Build platform of the additive manufacturing unit (3).

[0220] The support element (2) has a direction z (shown by a dashed line) which runs through the support element (2) which has a fixed part (2.1) and a handle part (2.2).

[0221] The occlusal upper surface of the crown unit (1) defines a plane x (shown by a dashed line), which is essentially perpendicular to the side surfaces that form the crown neck.

[0222] The direction z and the direction of the plane x form an angle "α", which is in the range of 20° to 80°.

[0223] The 3D printed dental restoration precursor is fixed to the surface of the build platform (3) of the additive manufacturing unit. In addition to the above-described embodiments, the following aspects will be noted. (Appendix 1) 1. A 3d printed dental restoration precursor, comprising: at least one crown unit having an outer surface and an inner surface; only one support element having a fixing part; Including, The shape of the crown unit is the molar having an occlusal upper surface and a depending lateral surface; an anterior tooth having an incisal upper edge and a depending side surface; the side surfaces are connected to each other to form a crown neck having a crown edge surrounding a crown opening; The occlusal upper surface or the incisal upper edge defines a plane x; characterized as, The support element comprises: a direction z directed through the fixing portion toward the crown unit; The support element comprises: In the region adjacent to the occlusal upper surface or the incisal upper edge, preferably at an angle in the range of 20 to 80° formed by the direction z of the support element and the plane x, or in the region of the crown edge, preferably at an angle in the range of 20 to 80° formed by the orientation z of the support element and the plane x, and connected only to the outer surface of the crown unit via the fixing portion. 3d printed dental restoration precursor. (Appendix 2) 2. The 3D printed dental restoration precursor of claim 1, comprising at least two crown units connected to each other by a bridging element. (Appendix 3) 3. A 3D printed dental restoration precursor as described in Appendix 1 or 2, wherein the fixing portion of the support element includes a predetermined break point, the predetermined break point preferably being located adjacent to the outer surface of the crown unit. (Appendix 4) 3. A 3D printed dental restoration precursor as described in Appendix 1 or 2, wherein the crown unit has a volume Vc and the fixing portion has a volume Vf, and the ratio of Vc to Vf is within the range of 100:1 to 700:1. (Appendix 5) A 3D printed dental restoration precursor described in any one of appendices 1 to 4, wherein the crown unit has a volume Vc and the support portion has a volume Vs, and the ratio of Vc to Vs is within the range of 2:1 to 40:1. (Appendix 6) The fixing portion is 0.3 to 1 mm thick at the connection point of the crown unit to the outer surface. 2 6. A 3D printed dental restoration precursor according to any one of claims 1 to 5, having a cross-sectional area within the range of (Appendix 7) A 3D printed dental restoration precursor described in any one of appendices 1 to 6, wherein the support element further comprises a handle portion. (Appendix 8) 8. The 3D printed dental restoration precursor of claim 7, wherein the handle portion includes a label segment containing information selected from crown size, tooth number, patient-related data, lot number, brand, and combinations thereof. (Appendix 9) A 3D printed array comprising a support region to which at least one 3D printed dental restoration precursor comprising a crown unit and a support element described in any one of appendices 1 to 8 is connected via only said one support element. (Appendix 10) 10. The 3D printed array of claim 9, wherein the support element of the dental restoration precursor comprises one or two predetermined break points, one at the connection of the support element to the support region of the 3D printed array and / or one at the connection of the fixing portion of the support element to the crown unit. (Appendix 11) 10. A process for producing a 3d printed dental restoration precursor, in particular as described in any one of clauses 1 to 8, by using an additive manufacturing unit comprising a build platform, comprising: forming only one support element having a fastening part and optionally a handle part layer by layer from a resin material; forming a crown unit layer by layer from a resin material; the crown unit has an outer surface and an inner surface; The shape of the crown unit is the molar having an occlusal upper surface and a depending lateral surface; an anterior tooth having an incisal upper edge and a depending side surface; the side surfaces are connected to each other to form a crown neck having a crown edge surrounding a crown opening; the occlusal upper surface or the incisal upper edge defines a plane x; The support element has a direction z directed through the fixing portion toward the outer surface of the crown unit, The forming process may include forming the support element: In the region adjacent to the occlusal upper surface or the incisal upper edge, preferably at an angle in the range of 20 to 80° formed by the direction z of the support element and the plane x, or in the region of the crown edge, preferably at an angle in the range of 20 to 80° formed by the orientation z of the support element and the plane x, forming a crown unit, the crown unit being connected only to the outer surface of the crown unit via the fixing portion; Optionally, removing the 3d printed dental restoration precursor from the additive manufacturing unit; and The process includes: (Appendix 12) when the support element is connected to the outer surface of the crown unit in the region adjacent the occlusal upper surface or the incisal upper edge, the occlusal upper surface or the incisal upper edge of the crown unit is oriented towards the build platform of the additive manufacturing unit during the forming process; or, when the support element is connected to the outer surface of the crown unit in the region adjacent to the region of the crown margin, the occlusal upper surface or the incisal upper edge of the crown unit is oriented away from the build platform of the additive manufacturing unit during the forming process; The process described in Appendix 11. (Appendix 13) 10. A process for producing a 3d printed dental restoration precursor, in particular as described in any one of appendices 1 to 9, by using an additive manufacturing unit comprising a build platform, comprising: manufacturing a 3d printed array according to claim 9 or 10, comprising a 3d printed dental restoration precursor according to any one of claims 1 to 8; washing the 3D printed array; Post-curing the 3D printed array; removing the 3d printed dental restoration precursor from the 3d printed array; The process includes: (Appendix 14) 1. A process for manufacturing a 3D printed dental restoration, comprising: producing a 3d printed dental restoration precursor comprising a support element and a crown unit according to appendix 11 or 12; (Appendix 15) removing the support element from the crown unit; Optionally, polishing the outer surface of the crown unit at least in the area where the support element is connected to the outer surface of the crown unit; The process includes: (Appendix 15) 10. A kit of parts comprising at least two 3d printed dental restorations obtainable or obtained by the process described in appendix 14, or 3d printed dental restoration precursors according to any one of appendices 1 to 8, or a combination of 3d printed dental restorations and 3d printed dental restoration precursors, and optionally a dental cement, The at least two 3D printed dental restorations or 3D printed dental restoration precursors are identical or different from each other in terms of size, shape, and / or color; Parts kit.

Claims

1. 1. A 3d printed dental restoration precursor comprising: at least one crown unit having an outer surface and an inner surface; only one support element having a fixing part; Including, The shape of the crown unit is the molar having an occlusal upper surface and a depending lateral surface; an anterior tooth having an incisal upper edge and a depending side surface; the side surfaces are connected to each other to form a crown neck having a crown edge surrounding a crown opening; the occlusal upper surface or the incisal upper edge defines a plane x, the plane x being perpendicular to a direction y extending perpendicularly from the crown opening to the occlusal upper surface or the incisal upper edge of the crown unit; characterized as, The support element comprises: a direction z passing through the longitudinal axis and the geometric center of the support element, through the fixing portion and directed towards the crown unit; The support element comprises: (i) in the region adjacent to the occlusal upper surface or the incisal upper edge, at an angle formed by the orientation z of the support element and the plane x in the range of 20 to 80°; or (ii) in the region of the crown margin, at an angle formed by the orientation z of the support element and the plane x in the range of 20 to 80°, and connected only to the outer surface of the crown unit via the fixing portion. 3D printed dental restoration precursor.

2. 10. The 3d printed dental restoration precursor of claim 1, comprising at least two crown units connected to each other by a bridging element.

3. 2. The 3D printed dental restoration precursor of claim 1, wherein the fixing portion of the support element includes a predetermined break point, the predetermined break point being located adjacent to the outer surface of the crown unit.

4. 3. The 3D printed dental restoration precursor of claim 2, wherein the crown unit has a volume Vc and the fixing portion has a volume Vf, the ratio of Vc to Vf being in the range of 100:1 to 700:

1.

5. 1. A process for producing a 3D printed dental restoration precursor by using an additive manufacturing unit comprising a build platform, comprising: forming only one support element having a fastening portion and optionally a handle portion from a resin material layer by layer; forming a crown unit layer by layer from a resin material; the crown unit has an outer surface and an inner surface; The shape of the crown unit is the molar having an occlusal upper surface and a depending lateral surface; an anterior tooth having an incisal upper edge and a depending side surface; the side surfaces are connected to each other to form a crown neck having a crown edge surrounding a crown opening; the occlusal upper surface or the incisal upper edge defines a plane x, the plane x being perpendicular to a direction y extending perpendicularly from the crown opening to the occlusal upper surface or the incisal upper edge of the crown unit; The support element has a direction z passing through a longitudinal axis and a geometric center of the support element, through the fixing portion, and directed toward the outer surface of the crown unit; The forming process may include forming the support element: (i) in the region adjacent to the occlusal upper surface or the incisal upper edge, at an angle formed by the orientation z of the support element and the plane x in the range of 20 to 80°; or (ii) in the region of the crown margin, at an angle formed by the orientation z of the support element and the plane x in the range of 20 to 80°, forming a crown unit, the crown unit being connected only to the outer surface of the crown unit via the fixing portion; Optionally, removing the 3d printed dental restoration precursor from the additive manufacturing unit; and The process includes:

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