Digital design of dental matrices with improved and customized interproximal contacts

Abstract

Disclosed are systems and techniques for designing a digital dental matrix with improved interproximal contacts, including generating a digital three-dimensional model of a patient's desired future dental structure, where the future dental structure represents the intended shape of at least one tooth of the patient; selecting one or more pairs of adjacent teeth within the 3D model; for each selected pair of teeth, determining a position and orientation within the interproximal space of the adjacent teeth to insert a digital 3D geometric shape having one or more initial parameters; and inserting the digital 3D geometric shape at the determined position and orientation.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to dental restorative devices for reshaping teeth. [Background technology]

[0002] Dentists often utilize a variety of dental appliances to reshape or restore a patient's dental structure. The appliances can be either stock designs that the dentist fits to each individual patient, or custom devices constructed from a model of the patient's dental structure and expanded to the desired dental structure. The model can be a physical model or a digital model. Historically, it has proven difficult to construct a model that forms a tight yet flossable contact in one step. Instead, dentists employ a process that is time-consuming and can be uncomfortable for the patient, to separate the formed contacts using blades, saws, and other tools. Summary of the Invention

[0003] The present disclosure relates to a technique for designing dental restorations with improved and customized interproximal contacts to reduce or eliminate the need for separating interproximal contacts. In a first aspect, a first method includes generating a digital three-dimensional (3D) model of a patient's desired future dental structure, where the future dental structure represents the intended shape of at least one of the patient's teeth; selecting one or more pairs of adjacent teeth in the 3D model; and, for each selected pair of teeth, determining a position and orientation of the adjacent teeth within the interproximal space to insert a digital 3D geometric shape having one or more initial parameters; and inserting the digital 3D geometric shape at the determined position and orientation. The one or more initial parameters of the digital 3D geometric shape may include at least one thickness greater than 100 microns and less than 500 microns. Furthermore, determining the position and orientation within the interproximal space may include offsetting the adjacent teeth to intersect the respective geometric shapes of the adjacent teeth, determining a Boolean intersection result for the adjacent teeth, and determining a best-fit plane based on the Boolean intersection result. Additionally, determining the position and orientation within the interproximal space may include determining contact points between adjacent teeth, determining a landmark coordinate system for each of the adjacent teeth, determining an average of the landmark coordinate systems based on the landmark coordinate systems for each of the adjacent teeth, determining an orientation based on the determined average of the landmark coordinate systems, and determining a position based on the contact points between the adjacent teeth. The method may further include refining the digital 3D geometry. Refining the digital 3D geometry may include subdividing the 3D geometry into one or more portions between a lingual end and a facial end of the 3D geometry, and translating one or more portions of the 3D geometry relative to the digital 3D model to adjust the resulting 3D geometry within the digital 3D model.Refining the 3D digital geometry can also include positioning a predefined 3D geometry at a position and orientation relative to the 3D model and scaling the predefined 3D geometry based on one or more parameters of the 3D model. Refining the digital 3D geometry can also include orthogonalizing the 3D geometry to at least the first portion and the second portion and adjusting one or more parameters of each individual portion to adjust the resulting 3D geometry in the digital 3D model. The parameters can include at least one of a first thickness along the mesial-distal axis, a distance along the gingival-occlusal axis, and an offset of each individual portion. The parameters of each individual portion can be different for each portion. The method can further include generating a file representing a 3D dimensional physics matrix including the 3D model and the refined 3D geometry and generating the physics matrix from the representation. Generating the physics matrix from the representation can include constructing the physics matrix from the representation using a 3D printer. Additionally, refining the 3D geometric shape may include adding an egg-shaped cylinder to each instance of the digital 3D geometric shape, where the egg-shaped cylinder is bisected by the respective digital 3D geometric shape; for each added egg, aligning the respective egg-shaped cylinder midplane to the respective digital 3D geometric shape; for each digital 3D geometric shape, determining an angle between the respective dividing plane and the respective 3D digital geometric shape; and for each digital 3D geometric shape, rotating the respective digital 3D geometric shape based on the respective determined angle to match the respective egg to the tooth inclination of the respective tooth.

[0004] In a second aspect, a second method includes generating a digital three-dimensional (3D) model of a patient's desired future dental structure, the future dental structure representing the intended shape of at least one tooth of the patient; selecting one or more pairs of teeth in the 3D model, the teeth in the pairs being adjacent; for each selected pair of teeth, determining a position and orientation within the interproximal space of the adjacent teeth to insert a digital 3D geometric shape having one or more initial parameters; inserting the digital 3D geometric shape at the determined position and orientation; refining the digital 3D geometric shape; generating a file representing a 3D dimensional physical matrix including the 3D model and the refined 3D geometric shape; and generating the physical matrix from the representation.

[0005] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a block diagram illustrating an exemplary system for designing and manufacturing dental appliances with improved and customized interproximal contacts for restoring a patient's dental structure, according to various aspects of the present disclosure.

[0007] [Figure 2] FIG. 1 is a flow diagram illustrating an exemplary technique for generating a digital model of a dental appliance with improved and customized interproximal contacts, according to various aspects of the present disclosure.

[0008] [Figure 3A] 1A-1C are conceptual diagrams illustrating an exemplary technique for determining the position and orientation of an inserted interproximal geometry using Boolean intersection results, according to various aspects of the present disclosure. [Figure 3B]1A-1C are conceptual diagrams illustrating an exemplary technique for determining the position and orientation of an inserted interproximal geometry using Boolean intersection results, according to various aspects of the present disclosure.

[0009] [Figure 4] 1A-1C are conceptual diagrams illustrating exemplary techniques for optimizing contact geometry, according to various aspects of the present disclosure.

[0010] [Figure 5] FIG. 10 is a conceptual diagram illustrating how a landmarking coordinate system can be used to calculate the orientation and position of interproximal geometries, according to various aspects of the present disclosure.

[0011] [Figure 6A] 1A-1C are conceptual diagrams illustrating placement of interproximal geometries with the option to offset features along the mesial-distal axis, according to various aspects of the present disclosure. [Figure 6B] 1A-1C are conceptual diagrams illustrating placement of interproximal geometries with the option to offset features along the mesial-distal axis, according to various aspects of the present disclosure.

[0012] [Figure 7] 1A-1D are conceptual diagrams illustrating an example technique for placing an egg-shaped cylinder within a 3D model, in accordance with various aspects of the present disclosure.

[0013] [Figure 8A] 1A-1C are conceptual diagrams illustrating exemplary techniques for orienting an oval cylinder, according to various aspects of the present disclosure. [Figure 8B] 1A-1C are conceptual diagrams illustrating exemplary techniques for orienting an oval cylinder, according to various aspects of the present disclosure. [Figure 9A] 1A-1C are conceptual diagrams illustrating exemplary techniques for orienting an oval cylinder, according to various aspects of the present disclosure. [Figure 9B] 1A-1C are conceptual diagrams illustrating exemplary techniques for orienting an oval cylinder, according to various aspects of the present disclosure.

[0014] [Figure 10A] FIG. 10 is a flow diagram illustrating an exemplary technique for determining the position and orientation of interproximal geometry, according to various aspects of the present disclosure. [Figure 10B] FIG. 10 is a flow diagram illustrating an exemplary technique for determining the position and orientation of interproximal geometry, according to various aspects of the present disclosure.

[0015] [Figure 11A] FIG. 1 is a flow diagram illustrating an exemplary technique for refining digital 3D geometry to customize interproximal geometry, according to various aspects of the present disclosure. [Figure 11B] FIG. 1 is a flow diagram illustrating an exemplary technique for refining digital 3D geometry to customize interproximal geometry, according to various aspects of the present disclosure. [Figure 11C] FIG. 1 is a flow diagram illustrating an exemplary technique for refining digital 3D geometry to customize interproximal geometry, according to various aspects of the present disclosure. [Figure 11D] FIG. 1 is a flow diagram illustrating an exemplary technique for refining digital 3D geometry to customize interproximal geometry, according to various aspects of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0016] 1 is a block diagram illustrating an exemplary system 100 for designing and manufacturing dental appliances for restoring a patient's dental structure, in accordance with various aspects of the present disclosure. In the example of FIG. 1, the system 100 includes a clinic 104, an appliance design facility 108, and a manufacturing facility 110.

[0017] The physician 106 may treat the patient 102 at the clinic 104. For example, the physician 106 may create a digital model of the patient's 102's current dental structure. The dental structure may include any portion of the crown or root of one or more teeth in a dental arch, gums, periodontal ligament, alveolar bone, cortical bone, implants, artificial crowns, bridges, veneers, dentures, orthodontic appliances, or any structure that may be considered part of the dentition before, during, or after treatment. In one example, the digital model of the current dental structure includes a three-dimensional (3D) model of the patient's current dental structure. The 3D model may be generated using an intraoral scanner, a cone beam computed tomography (CBCT) scan (i.e., 3D X-ray), optical coherence tomography (OCT), magnetic resonance imaging (MRI), or any other 3D imaging system. In some examples, the computing device 190 stores a digital model of the patient's 102 current dental structure.

[0018] The computing device 190 at the clinic 104 can store a digital model of the patient's future dental structure. The future dental structure represents the intended shape of the dental structure resulting from the application of dental appliances, such as the dental appliance 101. In one example, the doctor 106 may create a physical model of the future dental structure or may utilize an imaging system (e.g., as described above) to create a digital model of the future dental structure. In another example, the doctor 106 may modify the digital model of the patient's 102's current structure (e.g., by adding material to the surface of one or more teeth in the dental structure) to generate the digital model of the future dental structure. In yet another example, the computing device 190 may modify the digital model of the current dental structure to generate the model of the future dental structure. In another example, modifications to the patient's dental structure may be performed off-site by a third-party provider. Such modifications may be prescribed, reviewed, and modified by or under the direction of the doctor 106. The dental structure may be designed in a digital environment, or alternatively, a physical rendering of the initial dentition may be physically modified using traditional dental laboratory techniques (e.g., applying wax). This physical model of the teeth may be digitized via a 3D scanner.

[0019] In one scenario, computing device 190 outputs a digital model representing the (e.g., current and / or future) dental structure of patient 102 to another computing device, such as computing device 150 and / or computing device 192. As shown in FIG. 1 , in some examples, computing device 150 at design facility 108, computing device 190 at clinic 104, and computing device 192 at manufacturing facility 110 may be communicatively coupled to each other via network 114. Network 114 may include a wired or wireless network, such as via WIFI, BLUETOOTH, 3G, 4G LTE, 5G, etc.

[0020] 1, design facility 108 includes a computing device 150 configured to automatically design dental appliances for reshaping dental structures of patient 102. In one example, computing device 150 includes one or more processors 172, one or more user interface (UI) devices 174, one or more communication units 176, and one or more storage devices 178.

[0021] UI device 174 may be configured to receive user input and / or output information, also referred to as data, to a user of computing device 150. One or more input components of UI device 174 may receive input. Examples of input include tactile input, voice input, kinetic input, and optical input, to name just a few. For example, UI device 174 may include a mouse, keyboard, voice response system, video camera, buttons, control pad, microphone, or any other type of device for sensing input from a human or machine. In some examples, UI device 174 may be a presence-aware input component, which may include a presence-aware screen, a touch-sensitive screen, etc.

[0022] One or more output components of UI device 174 can generate output. Examples of output include data output, tactile output, audio output, and video output. In some examples, the output component of UI device 174 includes a display device (e.g., a presence sensing screen, a touch screen, a liquid crystal display (LCD) display, a light-emitting diode (LED) display, an optical head-mounted display (HMD), a light-emitting diode, a speaker, among others) or any other type of device for generating output to a human or a machine.

[0023] Processor 172 represents one or more processors, such as a general-purpose microprocessor, a specially designed processor, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a collection of discrete logic circuits, or any type of processing device capable of performing the techniques described herein. In one example, storage device 178 may store program instructions (e.g., software instructions or modules) that are executed by processor 172 to perform the techniques described herein. In another example, the techniques may be performed by specially programmed circuitry in processor 172. In these or other approaches, processor 172 may be configured to perform the techniques described herein.

[0024] Also, in some examples, storage device 178 may include one or more computer-readable storage media. Storage device 178 may be configured to store more data than volatile memory. Storage device 178 may also be configured as non-volatile memory space for long-term storage of data, retaining data after activation / deactivation cycles. Examples of non-volatile memory include solid state drives (SSDs), hard disk drives (HDDs), flash memory, or forms of electrically programmable memories (EPROMs) or electrically erasable and programmable memories (EEPROMs). Storage device 178 may store program instructions and / or data associated with software components 182-189 and / or operating system 180.

[0025] In the example of FIG. 1 , storage device 178 includes appliance feature library 164, model library 166, and doctor preference library 168. Libraries 164, 166, and 168 may include relational databases, multidimensional databases, maps, hash tables, or any data structure for storing data. In one example, model library 166 includes 3D models of the patient's current and / or future dental structures. As described in more detail below, libraries 164, 166, and 168 may include representations of interproximal 3D geometry. In some cases, libraries 164, 166, and 168 may be stored locally on computing device 150 or accessed via networked file shares, cloud storage, or other remote data stores.

[0026] Computing device 150 can execute software components 182-189 using one or more processors 172. Computing device 150 can execute any of components 182-189 as or within a virtual machine running on the underlying hardware. In one example, any of components 182-189 can be implemented as part of operating system 180.

[0027] According to the techniques of the present disclosure, the computing device 150 automatically or semi-automatically generates a digital model of the dental appliance 101 for restoring the dental structure of the patient 102 based on the digital model of the patient's future dental structure. The preprocessor 181 can preprocess the digital model of the patient's future dental structure. In one example, the preprocessor 181 performs preprocessing to identify one or more teeth in the patient's future dental structure. In some cases, the preprocessor 181 can identify a local coordinate system for each individual tooth and a global coordinate system that includes each tooth in the future dental structure. As another example, the preprocessor 181 can preprocess the digital model of the future dental structure and identify the root structure of the dental structure. In another example, the preprocessor 181 can identify the gingiva. In this manner, the preprocessor 181 can determine the portion of the future dental structure that includes the gingiva and the portion of the future dental structure that includes the tooth. As yet another example, the preprocessor 181 can preprocess the digital model of the future dental structure by extending the root and identifying the apical surface of the root of each individual tooth.

[0028] The landmark identifier 182 can determine one or more landmarks of the future dental structure. Exemplary landmarks include a slice, a midpoint, a gingival border, a nearest point between two adjacent teeth (e.g., a contact point or closest point (or nearest point) between adjacent teeth), a convex hull, a center of mass, or other landmarks. A slice refers to a cross-section of the dental structure. A tooth midpoint refers to the geometric center (also called the geometric midpoint) of a tooth in a given slice. A gingival border refers to the boundary between the gingiva and one or more teeth of the dental structure. A convex hull refers to a polygon whose vertices include a subset of vertices in a given set of vertices, and the boundary of the subset of vertices circumscribes the full set of vertices. A tooth center of mass refers to the midpoint, center, centroid, or geometric center of the tooth. In some cases, the landmark identifier 182 determines landmarks in the local coordinate system of each tooth.

[0029] In some examples, the landmark identifier 182 determines multiple slices of the patient's future dental structure. In one example, the thickness of each slice is the same. In some cases, the thickness of one or more slices is different from the thickness of another slice. The thickness of a given slice may be predefined. In one example, the landmark identifier 182 automatically determines the thickness of each slice. In another example, the thickness of each slice may be user-defined.

[0030] In some examples, the landmark identifier 182 determines the midpoint of each tooth. In one example, the landmark identifier 182 determines the midpoint of a particular tooth by calculating the extrema of the geometry of the particular tooth based on the entire particular tooth (e.g., without dividing the dental structure into slices) and determining the midpoint of the particular tooth based on the extrema of the geometry of the tooth.

[0031] In some examples, the landmark identifier 182 determines the midpoint of each tooth for each slice. The landmark identifier 182 may determine the midpoint of a particular slice for a particular tooth by calculating the center of mass of the arrangement of vertices around the edge of the particular tooth for that slice. In some cases, the midpoint of a particular tooth for a particular slice may be biased toward one edge of the tooth (e.g., if one edge has more points than another edge).

[0032] In another example, the landmark identifier 182 may determine the midpoint of a particular tooth in a particular slice based on the convex hull of the particular tooth in the particular slice. For example, the landmark identifier 182 may determine the convex hull of the set of edge points of the teeth in a given slice. In some cases, the landmark identifier 182 determines the geometric center from the convex hull by performing a fill operation on the area circumscribed by the convex hull and calculating the center of mass of the filled convex hull.

[0033] In some examples, landmark identification module 182 determines the nearest point between two adjacent teeth. The nearest point between two adjacent teeth may be a point of contact or a point of closest approach. In one example, landmark identification module 182 determines the nearest point between two adjacent teeth for each slice. In another example, landmark identification module 182 determines the nearest point between two adjacent teeth based on the entire adjacent teeth (e.g., without dividing the dental structure into slices).

[0034] A spline refers to a curve that passes through multiple points or vertices, such as a piecewise polynomial parametric curve. A mold parting surface refers to a 3D mesh that bisects two sides of one or more teeth (e.g., separating the facial side of one or more teeth from the lingual side of one or more teeth). A gingival trim surface refers to a 3D mesh that trims a surrounding shell along the gingival margin. A shell refers to an object with a nominal thickness. In some examples, the inner surface of the shell coincides with the surface of the dental arch, and the outer surface of the shell is a nominal offset of the inner surface. A facial ribbon refers to a reinforcing rib with a nominal thickness that is facially offset from the shell. A window refers to an aperture that provides access to the tooth surface so that a dental composite can be placed on the tooth. A door refers to a structure that covers the window. An incisal ridge reinforces the incisal edge of the dental appliance 101 and can be derived from the dental arch form. Case frame sparing refers to connectable material that couples components of the dental appliance 101 (e.g., the lingual portion of the dental appliance 101, the facial portion of the dental appliance 101, and its subcomponents) to the manufacturing case frame. In this manner, the case frame sparing can bond components of the dental appliance 101 to the case frame during manufacturing, protecting various components from breakage or loss and / or reducing the risk of component mix-up.

[0035] In some examples, the custom feature generator 184 generates one or more splines based on landmarks. The custom feature generator 184 may generate splines based on midpoints of multiple teeth and / or nearest points between adjacent teeth (e.g., contact points between adjacent teeth or nearest points between adjacent teeth). In some cases, the custom feature generator 184 generates one spline for each slice. In one example, the custom feature generator 184 generates multiple splines for a given slice. For example, the custom feature generator 184 may generate a first spline for a first subset of teeth (e.g., right molars), a second spline for a second subset of teeth (e.g., left molars), and a third spline for a third subset of teeth (e.g., front teeth).

[0036] The appliance feature library 164 includes a set of predefined appliance features that can be included in the dental appliance 101. The appliance feature library 164 may include a set of predefined appliance features that define one or more functional characteristics of the dental appliance 101. Examples of predefined appliance features include, among others, vents, rear snap clamps, door hinges, door snaps, incisal alignment features, center clips, custom labels, manufacturing case frames, and interdental matrix handles. Each vent is configured to allow excess dental composite to flow out of the dental appliance 101. The rear snap clamps are configured to couple a facial portion of the dental appliance 101 to a lingual portion of the dental appliance 101. Each door hinge is configured to pivotally couple a respective door to the dental appliance 101. Each door snap is configured to secure a respective door in a closed position. In some examples, the incisal alignment features include a pair of male and female tabs on the incisal edge of the dental appliance 101 (e.g., along the midsagittal plane). In one example, an incisal alignment feature is used to maintain vertical alignment between a facial portion of the dental appliance 101 and a lingual portion of the dental appliance 101. Each center clip is configured to provide vertical alignment between a lingual portion of the dental appliance 101 and a facial portion of the dental appliance 101. Each custom label includes data identifying a part of the dental appliance 101. A manufacturing case frame is configured to support one or more parts of the dental appliance 101. For example, the manufacturing case frame can removably couple the lingual portion of the dental appliance 101 and the facial portion of the dental appliance 101 to one another for safe handling and transportation of the dental appliance 101 from the manufacturing facility 110 to the clinic 104.

[0037] According to other implementations, the appliance feature library 164 can be configured to include one or more interproximal geometries to be inserted between adjacent teeth. The predefined geometries may include library portions, scaled geometries, and / or parametric geometries, to name a few. For example, the appliance feature library 164 may include 3D fins of uniform thickness. As another example, the appliance feature library 164 may include 3D fins that are subdivided so that each subdivision has a distinct thickness, which can be varied to better accommodate the spacing and orientation of adjacent teeth. Generally, the fins can have an initial thickness of 100 to 500 microns, according to certain implementations. For example, in one implementation, a fin with a uniform thickness of 150 microns is stored in the appliance feature library 164. In yet another example, the appliance feature library 164 may include an oval cylinder that can be placed in the interproximal space between adjacent teeth. Techniques for placing and refining interproximal geometries are described in more detail below.

[0038] The feature manager 186 determines parameters of one or more predefined appliance features included in the predefined appliance feature library 164. In one example, the predefined appliance features are configured to perform the function of the dental appliance 101. The parameters of the predefined appliance features may include the size, shape, scale, position, and / or orientation of the predefined appliance feature. The feature manager 186 may determine the parameters of the predefined appliance features based on one or more rules. The rules may be pre-programmed or machine-generated, for example, by machine learning.

[0039] In some cases, feature manager 186 determines the placement of the posterior snap clamps based on rules. In one example, feature manager 186 places two posterior snap clamps along the arch form at opposite ends of the arch form (e.g., placing a first snap clamp at one end and a second snap clamp at the other end). In some examples, feature manager 186 places the posterior snap clamp one tooth past the outermost tooth to be restored. In some examples, feature manager 186 places the female part of the posterior snap clamp on the lingual side of the parting surface and the male part of the posterior snap clamp on the facial side.

[0040] In some examples, the feature manager 186 determines the placement of the vent based on rules. In one example, the feature manager 186 places the vent at the centerline of the corresponding door on the incisal side of the dental appliance 101.

[0041] In some scenarios, feature manager 186 determines the placement of door hinges based on rules. In one scenario, feature manager 186 places each door hinge on the centerline of its corresponding door. In another scenario, feature manager 186 places the female part of the door hinge to secure to the facial side of dental appliance 101 (e.g., toward the incisal edge of the tooth) and the male part of the door hinge to secure to the exterior surface of the door.

[0042] In one example, feature manager 186 determines the placement of door snaps based on rules by placing the door snaps along the centerline of the corresponding door. In one example, feature manager 186 places the female part of the door snap to be secured to the exterior surface of the door and extend downward toward the gums. In another example, feature manager 186 places the male part of the door snap to be secured to the gum side of the facial ribbon. For example, the door snap can secure the door in a closed position by clipping the male part of the door snap to the facial ribbon.

[0043] In other examples, feature manager 186 may determine the initial placement, orientation, and thickness of one or more interproximal geometries, according to the present disclosure.

[0044] The feature manager 186 may determine parameters of predefined appliance features based on the preferences of the physician 102. The physician preference library 168 may include data indicating various physician 102 preferences. In one example, the physician preferences directly influence the parameters of one or more appliance features. For example, the physician preference library 168 may include data indicating preferred sizes of various appliance features, such as the size of a vent. In such an example, a larger vent may allow the pressure of the dental composite or resin to reach equilibrium more quickly during the door seating process, but may result in a larger ridge to be finished after curing. In another example, the physician preference library 168 may include data indicating a preferred initial size or shape of an interproximal geometry.

[0045] As another example, physician preferences indirectly influence appliance feature parameters. For example, physician preference library 168 may include data indicating a preferred stiffness of an appliance or a preferred tightness of a self-clamping feature. Such preference selections may also influence more complex design modifications to the cross-sectional thickness of the matrix and / or the degree of activation of the clamp geometry. Feature manager 186 may determine appliance feature parameters by applying physician preferences to one or more rules, simulations (e.g., Monte Carlo), or finite element analysis. Feature parameters can also be derived from the nature of the material used in the matrix, such as the type of composite the dentist prefers to use in the appliance.

[0046] The model assembler 188 generates a digital 3D model of the dental appliance 101 that is used to reshape the dental structure (e.g., into a future dental structure) in response to determining parameters for the custom appliance features and the predefined appliance features. The digital model of the dental appliance 101 may include a point cloud, a 3D mesh, NURBS, or other digital representation of the dental appliance 101. In some cases, the model assembler 188 stores the digital model of the dental appliance 101 in the model library 166.

[0047] The model assembler 188 can output a digital model of the dental appliance 101. For example, the model assembler 188 can output the digital model of the dental appliance 101 to a computing device 192 at the manufacturing facility 110 (e.g., via the network 114), which manufactures the dental appliance 101. In another example, the computing device 150 sends the digital model of the dental appliance 101 to a computing device 190 at the clinic 104 for manufacturing at the clinic 104. In some implementations, the model assembler 188 generates a computer-readable file containing data describing the digital model of the dental appliance 101. This file may be stored in the storage device 164, and the file may be referenced in the future by the system 100 to refine a previous digital model or by the manufacturing system 194 to manufacture a physical matrix of the digital model.

[0048] The refinement module 189 can be used to refine the digital model of the dental appliance 101. For example, the refinement module 189 can be used to modify one or more parameters of the digital model. In some implementations, the modifications to the digital model include modifying one or more parameters of the inserted interproximal geometry. The refinement module 189 can be configured to incrementally modify the digital model in response to user input received (e.g., from the practitioner 106), or can be configured to automatically refine the digital geometry using predefined rules or based on machine learning techniques.

[0049] In some implementations, the refinement module 189 can also graphically present incremental refinements in real time as parameters of the digital model are changed. For example, when the thickness or position of an interproximal fin is modified according to received user input, the refinement module 189 can update the parameters of the modified interproximal fin and indicate any changes to the interproximal fin relative to the digital model in real time via the UI device 174. In other implementations, the refinement module 189 can graphically present a final refinement that is automatically calculated using predefined rules or machine learning.

[0050] An advantage of presenting the refinement graphically (either incrementally or upon completion of the refinement) is that a user of the system 100 (e.g., the practitioner 106) can visually inspect the digital model of the dental appliance 101 before the model is provided to the manufacturing system 194. In some implementations, one or more aspects of the digital model of the dental appliance 101 can be provided to the refinement module 189 before the system 100 provides the digital model to the model assembler 188.

[0051] The computing device 192 may transmit the digital model of the dental appliance 101 to a manufacturing system 194. The manufacturing system 194 manufactures the dental appliance 101 according to the digital model of the dental appliance 101. The manufacturing system 194 may form the dental appliance 101 using any number of manufacturing techniques such as 3D printing, chemical vapor deposition (CVD), thermoforming, injection molding, lost-wax casting, milling, machining, laser cutting, among others.

[0052] The dentist 106 can receive the dental appliance 101 and utilize it to reshape one or more teeth of the patient 102. For example, the doctor 106 can apply dental composite to the surface of one or more teeth of the patient 102 through one or more doors of the dental appliance 101. Excess dental composite can be removed through one or more vents. In some circumstances, the presence of an interproximal geometry in the dental appliance 101 allows the doctor 106 better control the amount of dental composite or bonding material used during the patient's 102 filling procedure. In general, advantages of using the techniques described herein include significantly reducing the doctor's 106's need to remove excess dental composite. This can reduce the time spent treating the patient 102 using the dental appliance 101 and limit the doctor's 106's use of saws, blades, and other tools to separate the interproximal dental composite after it has hardened.

[0053] In some examples, the model assembler 188 generates the digital model of the dental appliance 101 based on an existing digital model (e.g., stored in the model library 166). In one example, the model library 166 may include data indicating appliance success criteria associated with each completed dental appliance 101, indicative of the appliance success criteria, manufacturing print yield, feedback or evaluation from a doctor and / or customer, or a combination thereof. For example, the model assembler 188 can utilize an existing digital model to generate a new or updated digital model of the dental appliance 101 in response to determining that the appliance success criteria of a previous dental appliance 101 meets a threshold criteria (e.g., a manufacturing yield threshold or a doctor evaluation threshold). In one example, the existing digital model is a template or reference digital model. In such an example, the model assembler 188 can generate the digital model of the dental appliance 101 based on a template digital model. For example, the template digital model may be associated with different characteristics of a patient's original dental structure, such as a patient with small teeth or who cannot open their mouth widely.

[0054] In one example, the model assembler 188 generates the digital model 101 of the dental appliance based on an existing digital model by utilizing one or more morphing algorithms. For example, the model assembler 188 can utilize a morphing algorithm to interpolate the geometry of the appliance features. In one example, the model assembler 188 can generate a new digital model of the dental appliance 101 based on a design of the existing digital model. In one example, the design features of the existing digital model can include a window inset from the periphery to enable the model assembler 188 to morph the geometry of the existing digital model based on landmarks of different dental structures.

[0055] The techniques of the present disclosure may enable a computing device to automatically determine the shape of the dental appliance 101 and the placement of various appliance features. In this way, the computing device can generate the digital model 101 of the dental appliance more accurately and more quickly. More accurately determining the shape of the dental appliance 101 and the placement of the appliance features can increase the effectiveness of the dental appliance 101 and tooth restoration. More quickly determining the shape of the dental appliance 101 and the placement of the appliance features can allow a practitioner to correct a patient's teeth earlier, which can improve the appearance and / or function of the patient's teeth, thereby potentially improving the patient experience. Furthermore, reducing the time required to generate the digital model of the dental appliance 101 can reduce production costs, making treatment affordable to a wider range of patients.

[0056] Although computing device 150 is described as automatically generating the digital model of dental appliance 101 based on a digital model of the patient's future dental structure, in some examples, computing device 150 may utilize a digital model of the patient's current, unrestored state of the dental structure to generate all or part of the digital model of dental appliance 101. For example, computing device 150 may utilize the digital model of the current dental structure to determine the location of snap clamps (which may be placed on teeth that will not be restored) or to generate facial ribbons (e.g., because the gingival margin may not change during restoration).

[0057] 2 is a flow diagram illustrating an exemplary technique 200 for generating a digital model of a dental appliance, according to various aspects of the present disclosure. FIG. 2 is described in the context of the system 100 shown in FIG.

[0058] In step 202, the computing device 150 receives a digital 3D model of the patient's 102's future (i.e., desired) dental structure. In one example, the computing device 150 receives the digital model of the future dental structure from another computing device, such as the computing device 190 at the clinic 104. The digital model of the patient's future dental structure may include a point cloud or a 3D mesh of the future dental structure. A point cloud includes a collection of points that represent or define an object in three-dimensional space. A 3D mesh includes multiple vertices (also called points) and geometric faces (e.g., triangles) defined by the vertices. In one example, the physician 106 creates a physical model of the future dental structure and uses an imaging system to create a digital model of the future dental structure. In another example, the physician 106 modifies the digital model of the patient's 102's current structure (e.g., by adding material to the surface of one or more teeth in the dental structure) to generate the digital model of the future dental structure. In some cases, selective removal of tooth structure may be planned. In other embodiments, the designed future structure may take into account the dentist's preferences for subsequent treatment steps, for example, where tooth embrasures may be overcontoured in the digital model because the dentist prefers to be able to manually adjust them during subsequent finishing. In yet another example, the computing device 190 may modify the digital model of the current dental structure and generate a model of the future dental structure. Instead of a doctor or computer or appliance manufacturer creating the future dental structure, third-party laboratories and technicians may perform all or part of the dentition design work.

[0059] In step 204, the computing device 150 selects one or more pairs of teeth in the 3D model. For example, the computing device 150 may perform a search on the digital model to identify portions of the 3D mesh that represent teeth present in the 3D model and Portions of the 3D mesh corresponding to adjacent tooth pairs can be automatically selected. In other implementations, teeth can be selected in response to user input. For example, a user can draw a bounding box around portions of the mesh representing the teeth, and computing device 150 can select those teeth in response to the user input. In other words, one or more teeth can be selected by computing device 150 using manual techniques (e.g., in response to user input highlighting particular elements of the 3D mesh that belong to adjacent tooth pairs) or automatic techniques (e.g., detecting curvature changes between adjacent mesh elements representing tooth boundaries, or applying tooth templates to the 3D mesh and determining tooth segmentation based on the applied template). Additionally, various combinations of automatic tooth segmentation, landmark identification, and / or tooth identification algorithms can be used. Additional deep learning algorithms can be used to assess confidence in automatically selected and flagged tooth pairs for further consideration.

[0060] In step 206, for each pair of selected teeth, computing device 150 determines the position and orientation within the interproximal space between the selected adjacent teeth for inserting the digital 3D geometric shape. There are several techniques that computing device 150 can use to determine the position and orientation. In one example, computing device 150 uses a Boolean intersection of the offsets between adjacent teeth to determine a best fit plane. The use of Boolean intersection is described in more detail, for example, with reference to FIGS. 3A and 3B. In another example, computing device 150 uses a landmark coordinate system to determine the position and orientation. The use of a landmark coordinate system is described in more detail elsewhere, for example, with reference to FIGS. 4 and 5.

[0061] In step 208, the computing device 150 inserts the digital 3D geometric shape at the determined position and orientation. For example, 3D fins can be inserted between 3D meshes representing adjacent teeth based on the determined position and orientation.

[0062] At step 210, the computing device 150 refines the digital 3D geometry using a refinement module 189. For example, the refinement module 189 may receive user input and, in response to the received user input, modify thickness parameters of one or more portions of the 3D fin. As another example, in response to the user input, the refinement module 189 may translate one or more portions of the 3D fin to reposition the respective portions within the interproximal space between adjacent teeth. Such a refinement module may also refine the shape and cross-section of the 3D fin to generate slopes or curves to improve, for example, local strength, flexibility, alignment to adjacent tooth structure, or the fin's ability to create a desired geometry in a restoration while maintaining mechanical integrity through the molding, curing, and removal processes.

[0063] In step 212, computing device 150 generates a file representing the 3D dimensional dental appliance (such as dental appliance 101) including the 3D model and the refined 3D geometry. For example, computing device 150 can generate the file specifying the 3D model using any number of conventional techniques.

[0064] In step 214, computing device 150 generates dental appliance 101 from the representation. For example, computing device 150 can send the file to manufacturing system 194, which can generate dental appliance 101 using any number of techniques, including 3D printing, CVD, thermoforming, injection molding, lost-wax casting, milling, machining, and laser cutting, among others.

[0065] 3A and 3B are conceptual diagrams illustrating an example technique for determining the position and orientation of an inserted interproximal geometry using Boolean intersection results, according to various aspects of the present disclosure. The conceptual diagrams are described in the context of system 100. For example, FIGS. 3A and 3B are described in the context of computing device 150.

[0066] According to a particular implementation, the computing device 150 offsets or translates the 3D meshes representing adjacent teeth 302a and 302b to intersect the 3D meshes. The intersection 304 of adjacent teeth 302a and 302b can be of various widths. For example, in one implementation, the 3D meshes are offset so that they result in an intersection 304 of no more than 100 microns. Specifically, in this example, each 3D mesh representing adjacent teeth 302a and 302b is individually offset by 50 microns, resulting in an intersection of 100 microns. The computing device 150 then determines a Boolean intersection result of the overlapping meshes. For example, using a Boolean intersection technique, the computing device 150 identifies and retains portions of the 3D meshes that overlap and discards portions of the 3D meshes that do not overlap.

[0067] After the computing device 150 performs the Boolean intersection, the computing device 150 can also determine a best-fit plane 306 of the remaining 3D meshes corresponding to adjacent teeth 302a and 302b. There are various techniques for determining the best-fit plane 306. For example, an iterative process can be used, whereby a plane is generated and its position is refined until the average distance between each vertex of the intersection mesh and the generated plane is minimized. Once the best-fit plane 306 is determined, the computing device 150 can thicken the plane. For example, as shown in FIG. 3A , the plane 308 is of a uniform thickness, such as 150 microns. To complete the refinement of the model, the computing device 150 can perform a Boolean subtraction to generate a mode refinement that includes an interproximal space 310 into which a 3D geometric shape can be inserted. This separates the 3D meshes corresponding to adjacent teeth 302a and 302b by a selected thickness in the model.

[0068] FIG. 3B illustrates a technique similar to that shown in FIG. 3A. The primary difference is that, as shown in FIG. 3B, the plane is subdivided into regions (or zones) 508a, 508b, and 508c, allowing the computing device 150 to specify different parameters for each subdivision. For example, the computing device 150 can specify a first thickness for region 508a relative to a first distance along the mesial-distal axis and the gingival-occlusal axis. This allows the computing device 150 to generate a better fit for the interproximal geometry to be inserted into the interproximal spaces 310a-310c. Although FIG. 3B illustrates the best-fit plane being subdivided into three regions, it should be understood that the best-fit plane can be subdivided into any number of regions to refine the model according to the needs of the patient 102. It should also be understood that thicknesses may be zero and / or include values ​​below the resolution limit of the fabrication device. In other examples, the geometry can be controlled to be larger than the minimum demonstrated resolution of the fabricated device to ensure that all of the device's features can be repeatedly fabricated, inspected, and carried forward to clinical use, regardless of day-to-day process variations of the fabricated device.

[0069] FIG. 4 is a block diagram illustrating an exemplary technique for optimizing contact geometry according to various aspects of the present disclosure. In some situations, the intersection or contact area between teeth may not occur in a convenient location relative to the digital representation of the dental appliance 101. FIG. 4 illustrates an example of an exemplary method for mapping an initially determined position to a more ideal location. In the disclosed technique, the initial position is modified to more closely align with the mold parting surface, although other optimization techniques are possible. As shown in FIG. 4, for a particular tooth represented by a 3D mesh 402, the computing device 150 can calculate a CG point 404 of the "contact body." Referring back to FIG. 3, 304 represents an exemplary contact body. That is, as used herein, a "contact body" is defined as the volume created by intersecting offsetting teeth. As used herein, a "CG point" refers to the center of gravity of a contact body (here, an adjacent tooth). For example, the CG point can be represented by the mathematical center of the contact body and can be determined using conventional techniques.

[0070] The computing device 150 can also introduce a mold parting plane 406 that refers to a 3D mesh that bisects two sides of one or more teeth (e.g., separating the facial side of one or more teeth from the lingual side of one or more teeth), as described above. For example, the mold parting plane 406 can be generated using anatomical landmarks from within the patient's dentition. In one embodiment, the geometry of the mold parting plane 406 can be created to pass through the midpoint of each of a series of slices or other subdivisions of a tooth. Other embodiments and formulations are possible.

[0071] For example, in other implementations, mold parting surface 406 may be generated using one or more neural networks, such as a generative adversarial neural network (GAN), a graph convolutional neural network (GraphCNN), or a combination of these and other networks.

[0072] The computing device 150 then maps the CG point 404 to the intersection of the mold parting surface 406 and the contact plane, which is the best-fit plane for the intersecting tooth. For example, referring back to FIG. 3 , the computing device 150 can determine the location where the contact plane intersects the mold parting surface, which designates the best-fit plane 306. After the computing device maps the CG point 404, the computing device can generate a parametric oval at a new point 408. For example, in some implementations, the CG point 404 can be translated in the XY plane to determine the location of the new point 408. The computing device 150 can also determine the size of the parametric oval based on one or more parameters of the adjacent teeth. For example, the size of the parametric oval may be determined based on some combination of the average anatomical contact size of the adjacent teeth and which particular teeth are adjacent. As a result, for example, incisors, canines, and molars may all have contacts of different shapes and sizes, according to certain implementations.

[0073] FIG. 5 is a conceptual diagram illustrating how landmark coordinate systems can be used to calculate the orientation and position of interproximal geometries, according to various aspects of the present disclosure. In the illustrated example, the computing device 150 identifies or otherwise determines a first set of landmark coordinate systems 502a for a first 3D mesh representing the tooth 302a. For example, the first landmark coordinate system can be represented by X, Y, and Z axes defined for the 3D mesh representing the first tooth 302a. Similarly, the computing device 150 identifies or otherwise determines a second set of landmark coordinate systems 502b for a second 3D mesh representing the tooth 302b. According to certain implementations, the landmark coordinate systems 502a and 502b can be automatically determined based on features present in the digital 3D model. In other implementations, a user can manually adjust the landmark coordinate systems 502b based on the user's expertise until the landmark coordinates visually reflect the desired result of the adjustments. However, it should be understood that landmark coordinates 502a and 502b may be determined in other ways as well.

[0074] The computing device 150 may then average the first landmark coordinate systems 502a and 502b to calculate an average landmark coordinate system 512. For example, the computing device 150 may calculate the average of the X origin, Y origin, and Z origin of each of the first landmark coordinate system 502a and the second landmark coordinate system 502b such that the distance 508 between the first landmark coordinate system 502a and the average landmark coordinate system 512 is the same as or substantially similar to the distance 510 between the second landmark coordinate system 502b and the average landmark coordinate system 512.

[0075] The computing device 150 can also calculate the orientation angle of the landmark coordinate system. According to a particular implementation, the first landmark coordinate system axis 502a and the second landmark coordinate system axis 502b are surface normals. That is, the landmark coordinate system axes 502a and 502b form imaginary lines oriented at a 90-degree angle relative to the surfaces of the teeth 302a and 302b, respectively. In other words, the landmark coordinate system axis 502a forms an imaginary line perpendicular to the 3D mesh representing the tooth 302a, and the landmark coordinate system axis 502b forms an imaginary line perpendicular to the 3D mesh representing the tooth 302b. Using the surface normals, the computing device 150 can calculate the orientation angle of the average landmark coordinate system axis 512. For example, according to a particular implementation, the orientation angle for the average landmark coordinate system axis 512 can be determined by the computing device 150 such that the angle 504 with the first landmark coordinate system axis 502a is the same as the angle 506 with the second landmark coordinate system axis 502b. In other words, the computing device 150 can determine the orientation angle of the mean landmark coordinate system axis 512 by determining the angle 504 between the surface normal represented by the landmark coordinate system axis 502a and the mean landmark coordinate system axis 512 that is the same as the angle 506 between the surface normal represented by the second landmark coordinate system axis 502b and the mean landmark coordinate system axis 512.

[0076] After computing device 150 calculates the orientation angle of mean landmark coordinate system axis 512, computing device 150 can translate the mean landmark coordinate system to point 514. In some implementations, point 514 represents a point where the 3D meshes representing teeth 302a and 302b intersect. For example, in one implementation, point 514 can be determined by generating a pair of points (one from each tooth mesh 302a and 302b) with the smallest distance and calculating the midpoint between them. In other implementations, point 514 can represent a point within the interproximal space between adjacent teeth, whereby the teeth are at their closest points without intersecting.

[0077] 6A and 6B are conceptual diagrams illustrating an example technique for refining interproximal geometries according to various aspects of the present disclosure. Generally, the concepts illustrated in FIGS. 6A and 6B represent refinements to a 3D model. For example, FIGS. 6A and 6B illustrate a 3D model after one or more 3D geometric shapes (e.g., 3D fins 602a-602g) have been inserted into their respective interproximal spaces. Accordingly, FIGS. 6A and 6B are described in the context of a computing device 150 that can use refinement module 189 to perform the operations described herein.

[0078] As shown in Figures 6A and 6B, it may be advantageous to subdivide the interproximal 3D geometry 602a-602g into facial portions 604a-604g and lingual portions 606a-606g, for example, by bisecting the interproximal 3D geometry using a calculated mold dividing plane, such as mold dividing plane 406. This allows the facial portion, represented by subdivisions 604d and 604e, and the lingual portion, represented by subdivisions 606d and 606e, of the interproximal 3D geometry to be independently moved to refine the placement of the 3D interproximal geometry. For example, as shown in Figure 6B, facial subdivisions 604d and 604e and lower subdivisions 606d and 606e can be displaced in response to input received by refinement module 189 to reposition each subdivision to improve the fit of the interproximal 3D geometry to the 3D mesh representing the adjacent teeth. In other words, refinement module 189 can translate any of subdivisions 604d, 604e, 606d, and 606e relative to their respective adjacent teeth to adjust the profile of the interproximal 3D geometry and refine the amount of contact between adjacent teeth or the level of tightness when flossing.

[0079] 7, 8A, 8B, 9A, and 9B are conceptual diagrams illustrating an exemplary technique for refining interproximal geometry using an oval cylinder. According to a particular implementation, the oval cylinder is first positioned as shown in FIG. 7. The orientation of the oval cylinder is then modified as shown in FIGS. 8A, 8B, 9A, and 9B. Consequently, FIGS. 7, 8A, 8B, 9A, and 9B are described in the context of a computing device 150 that can perform the operations described herein using a refinement module 189.

[0080] 7 is a conceptual diagram illustrating an example technique for placing an egg-shaped cylinder within a 3D model, according to various aspects of the present disclosure. The refinement module 189 can use the techniques described herein to place contact planes 704a-704k between the 3D meshes representing the teeth 702a-702l. For example, according to a particular implementation, the refinement module 189 can determine the locations of the contact planes 704a-704k by calculating the best fit plane 306, as described in connection with FIGS. 3A and 3B.

[0081] The refinement module 189 can then generate one or more egg-shaped cylinders, such as the exemplary egg-shaped cylinder depicted as egg-shaped cylinder 710. For example, according to certain implementations, the egg-shaped cylinder can be a stock egg-shaped cylinder stored in the appliance feature library 164. In other implementations, the egg-shaped cylinder can be a scaled version of a stock egg-shaped cylinder stored in the appliance feature library 164. In other implementations, egg-shaped cylinders can be generated. For example, the egg-shaped cylinder can be generated by scaling the cylinder along the Z-axis and / or Y-axis to modify the cylinder into an egg-shaped shape. As another example, the egg-shaped cylinder can be generated based on a parametric equation according to the dimensions of the interproximal space between adjacent teeth. In other examples, the egg-shaped cylinder can be based on a shape measured in a contact structure study. In such situations, the cross-section of the cylinder can technically differ from an egg shape where the anatomical contact is known to be, for example, kidney-shaped. In other examples, the rules for generating the structural contacts can differ for each tooth pair. For example, an oval in a tooth pair with existing contacts between untreated teeth may be treated differently than a tooth gap or tooth pair where only occlusal extension is performed during treatment. One or more oval cylinders, such as one or more of oval cylinders 710, can be used to insert contact windows, such as contact window 706, into the 3D model. For example, according to certain implementations, refinement module 189 can define one or more contact planes 704a-704k such that the center of contact plane 704a-704k bisects a respective oval cylinder, such as one of the oval cylinders shown as oval cylinder 710. Stated differently, refinement module 189 can use inter-plane alignment to position the oval cylinders at their respective interproximal contacts. For example, the oval cylinders can be positioned at the interproximal contacts such that the mid-plane of the cylinder matches a contact plane, such as contact planes 704a-704k. One example of using inter-plane alignment is shown for the position of the orientation of contact window 706, although other positions and orientations are possible.

[0082] By arranging the oval cylinders as described, the oval geometry defines contact windows, such as contact window 706, that pass through individual contact planes. For example, each of the oval cylinders can be subtracted (e.g., using Boolean subtraction techniques) from the respective interproximal fins to generate the contact windows. This allows the 3D model to include contact windows with configurable sizes and shapes. Configurable contact windows also enable the generation of dental appliances that create precise and tight interproximal contacts with minimal bonding between the teeth, and may provide filling procedures that are quicker to separate adjacent teeth after the restorative material has hardened and less reliant on saws, blades, and other tools.

[0083] 8A, 8B, 9A, and 9B are conceptual diagrams illustrating an exemplary technique for orienting an oval cylinder according to various aspects of the present disclosure. As shown in FIGS. 8A and 8B, refinement module 189 can orient oval cylinders 802a-802g to account for the varying tip angles of teeth 804a-804j. For example, according to certain embodiments, the angle between the mold parting surfaces at each of contact planes 704a-704k can be calculated by determining an intersection curve where the mold parting surfaces and the contact planes intersect. According to certain implementations, a line can be best-fit to this intersection curve, and the angle between the best-fit line and the Z-axis (i.e., the vertical axis) can be determined.

[0084] The resulting angles for each of contact planes 704a-704k can then be used to rotate one or more oval geometric shapes, such as one or more oval cylinders shown as oval cylinder 710, so that the resulting contact windows match the orientation of the respective teeth. For example, an oval cylinder positioned relative to contact plane 704g can be rotated by an amount equal to the calculated angle between the mold parting plane measured at contact plane 704g and the Z-axis (i.e., vertical axis). The oval cylinder can then be subtracted (e.g., using Boolean subtraction techniques) from the interproximal fin inserted between teeth 702g and 702h to generate contact windows at orientation angles that reflect the tooth inclination of teeth 702g and 702h.

[0085] Once the orientations of the cylinders 802a-802g are corrected, the refinement module 189 can place the reoriented cylinders 802a-802g in their respective positions relative to the contact planes 704a-704k. It should be appreciated that, after rotation, the contact windows defined by the oval cylinders 802a-802g present a natural, aligned, and parameterized contact definition for the 3D mesh representing the teeth 804a-804j, as shown in FIG. 8B.

[0086] 9A and 9B show different conceptual views of the oval cylinder 802c relative to the 3D mesh representing the tooth 804c. As shown and described, the orientation angle of the oval cylinder 802c here corresponds to the tilt of the 3D mesh representing the tooth 804c. According to certain implementations, as described above, each of the oval cylinders can be subtracted from its respective interproximal fin to generate a contact window. It may also be advantageous to further refine one or more oval cylinders before generating the individual contact windows. For example, according to some implementations, as shown by FIG. 9B, before subtraction, the oval cylinder 802c can be subdivided into a lingual component 902a and a facial component 902b, respectively. For example, the refinement module 189 can subdivide the oval cylinder 802c using a mold parting surface of the tooth 804c (e.g., a mold parting surface like mold parting surface 406). In one implementation, the refinement module 189 can position the parting plane so that it bisects the oval cylinder 802c to create the lingual component 902a and the facial component 902b. This allows for greater design control of the contact window. For example, instead of modifying only the position and orientation of the entire oval cylinder 802c, the refinement module 189 can modify the position and orientation of either the lingual component 902a or the facial component 902b.

[0087] 10A and 10B are flow diagrams illustrating an exemplary technique for determining the position and orientation of interproximal geometry in step 206 of technique 200. For clarity, the exemplary techniques in FIGS. 10A and 10B are described individually, but it should be understood and appreciated that the disclosed techniques can be used in combination.

[0088] Referring to FIG. 10A , at step 1002, the computing device 150 offsets or translates the 3D meshes representing adjacent teeth to intersect the 3D meshes. For example, as shown and described in connection with FIGS. 3A and 3B , the computing device 150 may translate the 3D meshes representing teeth 302a and 302b. In one implementation, the 3D meshes are offset so that they intersect by no more than 50 microns. At step 1004, the computing device 150 determines a Boolean intersection result of the overlapping meshes. For example, the computing device 150 may determine the intersection 304 shown and described in connection with FIGS. 3A and 3B . Step 1004 is generally performed using conventional techniques. For example, using Boolean intersection techniques, the computing device 150 identifies and retains portions of the 3D meshes that overlap and discards portions of the 3D meshes that do not overlap.

[0089] In step 1006, computing device 150 determines a best fit plane based on the Boolean intersection results. For example, computing device 150 may use conventional techniques to calculate best fit plane 306 shown and described in connection with Figures 3A and 3B based on the Boolean intersection results.

[0090] 10B, a technique for determining the position and orientation using the landmark coordinate systems of adjacent teeth will be described. In step 1012, the computing device 150 determines the contact point between the adjacent teeth. For example, as shown and described in FIG. 5, the computing device 150 can determine point 514 by determining the intersection of the 3D meshes representing teeth 304a and 304b.

[0091] In step 1014, computing device 150 determines a landmark coordinate system for each of the adjacent teeth. For example, as shown and described in FIG. 5, computing device 150 can determine the landmark coordinate system based on morphology present in the digital 3D model, based on received user input, and using other techniques.

[0092] In step 1016, the computing device 150 determines the average of the landmark coordinate systems for each of the adjacent teeth. For example, as shown and described with reference to FIG. 5 , the computing device 150 may calculate the average of the X, Y, and Z coordinate axes of each of the first landmark coordinate system 502 a and the second landmark coordinate system 502 b such that the distance 508 between the first landmark coordinate system 502 a and the average landmark coordinate system 512 is the same as or substantially similar to the distance 510 between the second landmark coordinate system 502 b and the average landmark coordinate system 512.

[0093] In step 1018, computing device 150 determines an orientation based on the determined average of the landmark coordinate systems. For example, as shown and described in Figure 5, an orientation angle for the average landmark coordinate system 512 can be determined by computing device 150 such that angle 504 with first landmark coordinate system axis 502a is the same as angle 506 with second landmark coordinate system axis 502b.

[0094] In step 1020, computing device 150 determines a position based on the contact points between adjacent teeth. For example, as described with reference to FIG. 5, computing device 150 may translate the mean landmark coordinate system to point 514. In other words, according to a particular implementation, the calculated mean landmark coordinate system 512 is modified by the value of point 514 to determine the position.

[0095] 11A-11D are flow diagrams illustrating an exemplary technique for refining a digital 3D geometry in step 210 of technique 200, according to various aspects of the present disclosure. In certain implementations, this includes customizing interproximal geometry, according to various aspects of the present disclosure. For clarity, the exemplary techniques of FIGS. 11A-11D are described independently, but it should be understood and appreciated that one or more of the techniques illustrated in FIGS. 11A-11D can be used in combination to refine a digital 3D model, such as a digital 3D model representing a dental appliance 101.

[0096] 11A, in step 1102, refinement module 189 subdivides the 3D geometric shape into one or more portions between the lingual end and the facial end of the 3D geometric shape. For example, as shown and described in FIGS. 6A and 6B, refinement module 189 can use mold dividing planes to subdivide 3D fins 602a-602g into lingual ends 606a-606g and facial ends 604a-604g.

[0097] In step 1104, refinement module 189 translates one or more portions of the 3D geometry relative to the digital 3D model to adjust the resulting 3D geometry in the digital 3D model. For example, as shown and described in FIG. 6B , refinement module 189 can translate facial portions 604d and / or 604e and tongue portions 606d and / or 606e to adjust the fit of 3D fins 602d and / or 602e, respectively.

[0098] 11B, in step 1112, refinement module 189 vertically subdivides the 3D geometric shape into at least a first portion and a section portion. For example, as shown and described with reference to FIG. 3B, refinement module 189 may subdivide the 3D fin into a plurality of zones 308a-308c.

[0099] In step 1114, refinement module 189 adjusts one or more parameters of each individual portion to adjust the resulting 3D geometry in the digital 3D model. The parameters may include the relative position of each of the respective portions, the thickness of each portion, and other parameters. For example, as shown and described with reference to FIG. 3B, refinement module 189 may modify the thickness of zone 308a to have a different thickness than zones 308b and 308c. Similarly, refinement module 189 may modify the thickness of zones 308b and / or 308c.

[0100] 11C, in step 1122, refinement module 189 places a predefined 3D geometric shape at a position and orientation relative to the digital 3D model. For example, as shown and described with reference to FIG. 3A, refinement module 189 can place a predefined plane 306 at the intersection of 3D meshes representing adjacent teeth 302a and 302b. As another example, as shown and described with reference to FIGS. 5 and 6A, refinement module 189 can insert a 3D fin at point 514 with an orientation equal to landmark axis 512.

[0101] In step 1124, refinement module 189 scales the pre-defined 3D geometric shape based on one or more parameters of the 3D model. For example, as shown and described with reference to FIG. 3A , refinement module 189 may increase the thickness of best fit plane 306 to generate 3D fin 308. As another example, refinement module 189 may scale any of 3D fins 602a-602g to promote an improved interproximal fit between the 3D meshes representing adjacent teeth.

[0102] 11D , at step 1132, refinement module 189 adds an oval cylinder to each instance of the digital 3D geometric shape. For example, as shown and described in connection with FIG. 7 , refinement module 189 may insert one or more oval cylinders into the contact planes 704a-704k within the interproximal spaces of the 3D mesh representing teeth 702a-702l. Furthermore, according to certain implementations, the inserted 3D geometric shapes are bisected by the respective digital 3D geometric shapes. For example, as shown and described with reference to FIG. 7 , refinement module 189 positions an oval cylinder (e.g., oval cylinder 710) such that the oval cylinder bisects the contact plane that creates contact window 706.

[0103] In step 1134, refinement module 189 aligns the individual oval cylinder mid-planes to the individual digital 3D geometric shapes. For example, as shown and described in connection with Figures 8A and 8B, the individual oval cylinder mid-planes can be aligned to any tilt present in each tooth of the 3D model.

[0104] In step 1136, refinement module 189 determines angles between the respective parting planes and the respective digital 3D geometric shapes. For example, as shown and described with reference to FIGS. 8A-9B , angles between the mold parting planes in each of contact planes 704a-704k can be calculated. In other words, determining angles between the respective parting planes may include determining angles between the occlusal-gingival axes of the teeth and the respective 3D digital geometric shapes. The resulting values ​​can then be used to rotate one or more oval geometric shapes, such as one or more oval cylinders represented by oval cylinder 710, so that the resulting contact windows match the orientation of the teeth.

[0105] In step 1138, refinement module 189 rotates the respective digital 3D geometric shapes based on the respective determined angles to match the respective oval shapes to the tooth inclination of each adjacent tooth. For example, as shown and described in FIG. 9A , the orientation of oval cylinder 802c matches the orientation of the 3D mesh representing tooth 804c. In some implementations, refinement module 189 can subdivide the respective digital 3D geometric shapes to further refine the placement and orientation of the geometric shapes. For example, as shown and described in FIG. 9B , a mold splitting plane can be applied to oval cylinder 802c to bisect cylinder 802c into lingual portion 1002a and facial portion 1002b.

Claims

1. 1. A computer-implemented method for digitally designing interproximal geometry, comprising: generating a digital three-dimensional (3D) model of a patient's future dental structure, the future dental structure representing an intended shape of at least one tooth of the patient; selecting one or more pairs of teeth in the 3D model, the teeth in the pairs being adjacent; determining, for each selected pair of teeth, a position and orientation within the interproximal space of said adjacent teeth for inserting a digital 3D geometric shape having one or more initial parameters; inserting the digital 3D geometric shape at the determined position and orientation; 11. A computer-implemented method comprising:

2. The computer-implemented method of claim 1 , wherein the one or more initial parameters of the digital 3D geometric shape include at least one thickness that is greater than 100 microns and less than 500 microns.

3. Determining the position and orientation within the interproximal space includes: offsetting the adjacent teeth from one another to intersect the geometric shapes of each of the adjacent teeth; determining a Boolean intersection result of the adjacent teeth; determining a best fit plane based on the Boolean intersection results; The computer-implemented method of claim 1 , comprising:

4. Determining the position and orientation within the interproximal space includes: determining contact points between the adjacent teeth; determining a landmark coordinate system for each of the adjacent teeth; determining, for each of the adjacent teeth, an average of the landmark coordinate system based on the landmark coordinates; determining the orientation based on the determined average of the landmark coordinate system; and determining the position based on the contact points between the adjacent teeth; The computer-implemented method of claim 1 , comprising:

5. refining said digital 3D geometry; The computer-implemented method of claim 1 further comprising:

6. The elaboration may comprise: subdividing the 3D geometric shape into one or more portions between a lingual end and a facial end of the 3D geometric shape; translating one or more portions of the 3D geometry relative to the digital 3D model to adjust the resulting 3D geometry within the digital 3D model; The computer-implemented method of claim 5 , comprising:

7. The elaboration may comprise: vertically subdividing the 3D geometric shape into at least a first portion and a second portion; adjusting one or more parameters of each of the individual portions to adjust the resulting 3D geometry in the digital 3D model; The computer-implemented method of claim 5 , comprising:

8. The computer-implemented method of claim 7 , wherein the parameters include at least one of a first thickness along a mesial-distal axis, a distance along a gingival-occlusal axis, and an offset of each of the individual portions.

9. The computer-implemented method of claim 8 , wherein the parameters of each of the individual portions are different for each of the respective portions.

10. The elaboration may comprise: placing a predefined 3D geometric shape at a position and orientation relative to the 3D model; scaling the predefined 3D geometric shape based on one or more parameters of the 3D model; The computer-implemented method of claim 5 , comprising:

11. generating a file representing a 3D dimensional physics matrix including the 3D model and the refined 3D geometry; generating the physical matrix from the representation; The method of claim 10 further comprising:

12. The computer-implemented method of claim 11 , wherein generating the physics matrix from the representation comprises constructing the physics matrix from the representation using a 3D printer.

13. The elaboration may comprise: adding an egg-shaped cylinder to each instance of the digital 3D geometric shape, the egg-shaped cylinder being bisected by the individual digital 3D geometric shape; for each added egg cylinder, aligning the respective egg cylinder mid-plane to said respective digital 3D geometric shape; determining, for each digital 3D geometric shape, an angle between a respective split plane and said respective digital 3D geometric shape; for each digital 3D geometric shape, rotating the individual digital 3D geometric shape based on the individual determined angle to match the individual oval shape to the tooth inclination of the respective adjacent tooth; The computer-implemented method of claim 5 , comprising:

14. 1. A computer-implemented method for digitally designing interproximal geometry, comprising: generating a digital three-dimensional (3D) model of a patient's future dental structure, the future dental structure representing an intended shape of at least one tooth of the patient; selecting one or more pairs of teeth in the 3D model, the teeth in the pairs being adjacent; determining, for each selected pair of teeth, a position and orientation within the interproximal space of said adjacent teeth for inserting a digital 3D geometric shape having one or more initial parameters; inserting the digital 3D geometric shape at the determined position and orientation; refining the digital 3D geometry; generating a file representing a 3D dimensional physics matrix including the 3D model and the refined 3D geometry; generating the physical matrix from the representation; 11. A computer-implemented method comprising:

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