JP5955798B2 - Addressable matrix / cluster blank for dental CAD / CAM system and its optimization - Google Patents

Description

Reference to related applications

  This application claims the priority of US Patent Application No. 60 / 935,006 filed on July 20, 2007 and US Patent Application No. 61 / 024,935 filed on January 31, 2008. Are incorporated herein by reference.

  The present invention is directed to a computer-aided system for the design and manufacture of dentures and dental restorations. The present invention also relates to the use of cluster mill blanks and cluster mill blanks in dental CAD / CAM systems, expanding the range of systems that fit a given blank; making the mill blank compatible with other systems; A wider variety of mill blanks are available for use; maximize system versatility, material selection and work efficiency. According to certain features, the present invention is also directed to techniques and methods related to the cluster blank described above.

  The following discussion refers to certain structures and / or methods. However, the following references should not be construed as an admission that these structures and / or methods constitute prior art. Applicant expressly reserves the right to indicate that these structures and / or methods are not considered prior art.

  Today in dentistry, both dental offices (chairs) and dental laboratories (laboratories) tend to use automated techniques for treatment planning, virtual treatment, orthodontics, and design and manufacture of dental restorations. It is gradually increasing. This trend, sometimes referred to as the “digital revolution”, is most evident in the rapid increase in CAD / CAM technology on the laboratory side. The number of CAD / CAM systems available to dental laboratories has increased nearly tenfold over the last decade. Currently, there are a substantial number of copy milling systems that use more than 25 dental CAD / CAM systems and mill blanks of various shapes and sizes. Blank shapes vary from simple shapes such as rectangular, cylindrical or hexagonal to more complex shapes such as smart blanks described in US Pat. No. 6,979,496. No. 6,979,496 is incorporated herein by reference in its entirety. Blank dimensions range from about 0.5 "to about 4" length or diameter. There are a total of four types of materials in mill blanks: metals, polymers (resins, plastics), ceramics and composite materials. Ceramic mill blanks include feldspar (white nepheline, sanidine or feldspar) blanks, glass ceramic (lithium silicate, mica, etc.) blanks, and (sintered or sufficiently dense) alumina and / or zirconia Can be classified into three large categories of crystalline ceramic blanks based on the above. All three ceramic categories and composite blanks already have a variety of colors or will be available soon. Accumulating a list of the required tones for each given type of blank puts economic pressure on the equipment operating the CAD / CAM system.

  A conventional disc-shaped zirconia blank 100 having a diameter of 4 inches is shown in FIGS. 1 and 2. As shown in these drawings, a plurality of milled shapes 110 are formed on the zirconia blank 100. Since the blank 100 is made entirely of zirconia, it is quite expensive. As shown in FIG. 2, using this blank 100 to form a plurality of milled shapes 110 results in a substantial amount of wasted intervening block regions 120 defined between the milling envelopes 112.

  CAD / CAM technology offers dental laboratories the opportunity to improve quality, reproducibility, and eliminate human error, while most CAD / CAM systems are for milling soft sintered zirconia, As such, it is inadequate in terms of selecting competitive materials in a rapidly supersaturated market. The price of CAD / CAM systems depends on the manufacturer and structure, but costs between $ 50,000 and $ 500,000, so only the largest laboratories and outsourcing centers can run multiple systems to select materials Can only be expanded. Most CAD / CAM system manufacturers do not manufacture their own blocks, but rather have Ivoclar, Vita, and Metoxit with core technologies established in the development and manufacture of dental or advanced materials. Buy blocks from such suppliers. Of course, CAD / CAM materials are quite expensive, substantially increasing the cost of operating the CAD / CAM system. For example, ceramic mill blank prices range from about $ 0.60 to $ 4.50 per gram of material. The output per blank described in US Pat. No. 6,979,496 is rather small, most of which is wasted.

  The first CAD / CAM system consisting of a milling device for use on the chair side or laboratory side, such as Serec (Sirona) or Lava (3M / ESPE) was a closed system. In that system, the mill blank is attached to a stub retainer, projection, mandrel, holder or carrier and is described in US Pat. Nos. 6,485,305 and 6,769,912. Unique patent shape and can be protected by a bar code, preventing compatibility with other (CAD / CAM) systems. Various workpieces (milling parts) on the stub assembly are also described in US Pat. Nos. 7,214,435, 6,669,875, 6,627,327, It is described in US Pat. No. 6,482,284, US Pat. No. 6,224,371, US Pat. No. 6,991,853 and US Pat. No. 6,660,400. The advent of open structure systems not only enabled blank compatibility between systems, but became highly desirable. Currently, the market is dominated by closed systems, while open systems are steadily penetrating the market. At least 5 or 6 out of 25 commercial CAD / CAM systems utilize the same D-250 dental 3D scanner and DentalDesigner (R) dental CAD software (3Shape A / S, Copenhagen, Denmark) ing. In an open structure system, the blank is not protected by a bar code and any blank can be used as long as it fits the existing housing (blank holder, chuck, collector, support) of the milling device.

  Not all types of blanks can be economically manufactured in all shapes and dimensions. For example, zirconia and alumina blocks can be formed in a predetermined shape and size to meet the demand for larger containers that can be milled from larger blanks. On the other hand, large feldspar and glass ceramic blanks are less desirable due to numerous mechanical and economic constraints.

  US 2006/0115794 teaches a system for the continuous production of denture parts such as crown cores, crowns and the like. The system utilizes rotation and milling of zirconia bar stock that is automatically fed to the machine in a live central computer numerically controlled CNC machine. Multiple parts are cut from the continuous bar stock one after another. This patent application further teaches the use of multiple machines, each machine supplying different stocks of shapes and / or dimensions. The central controller produces the part by obtaining the specifications of the part to be cut, selecting the machine, and determining the bar stock that requires the least amount of cutting. In addition to the above-mentioned economic and processing difficulties of manufacturing and milling long bar stock from materials other than fully dense zirconia, many machines are of a given type, given the cost of CNC machines. It is much more advantageous to be able to mill all containers with a single machine than to be provided for each container.

  U.S. Patent No. 7,234,938 discloses a multiple blank holder or workpiece container configured as an elongated strip with a plurality of holes to embed a plurality of identical blanks or workpieces. The present invention relates to a milling / grinding machine, characterized in that a workpiece container or a milling blank holder is provided with a plurality of holes arranged along its longitudinal axis to accommodate the workpiece or blank. The present invention also includes a molding embedding material disposed within the through hole to hold the workpiece within the through hole. Further disclosed is a milling / grinding machine including an embedding device for automatic embedding of the workpiece in a workpiece container.

  US 2006/0106485 describes forming a plurality of manufacturing features using a virtual blank corresponding to the physical blank being processed. The application further teaches provisional machining of each of the plurality of manufacturing features into a virtual blank, wherein each manufacturing feature indicates an association with a coordinate system. A manufacturing specification is created for manufacturing an actual part by machining a plurality of manufacturing features into a blank. Such a method was developed in the automotive industry and is described in US Pat. Nos. 6,775,581; 7,024,272; 7,110,849 and US Patent Application Publications. No. 2006/0106485, which are hereby incorporated by reference in their entirety. It is also described in the white paper: “Horizontal Modeling and Digital Process Design”. A method for electronically designing a product consisting of a collection of parts is described in US Patent Application Publication No. 2007/0136031, which is incorporated herein by reference in its entirety. Again, this document is not about dentistry.

  Therefore, there is a technical need to provide compatibility for blanks, maximize yield per blank, and reduce material waste to maximize system versatility, material selection and work efficiency. It would also be desirable to reduce the operating costs associated with commercial CAD / CAM systems by reducing blank lists.

  The present invention provides techniques and apparatus that can optionally address one or more of the above-mentioned drawbacks associated with existing CAD / CAM systems. According to one aspect, the present invention provides a mill blank by a method that provides a cluster blank and software for its efficient use.

  As used herein, “cluster blank” refers to a framework (transport) that can be adapted with minimal or no modification to the existing housing (blank holder, chunk, collect, support) of the milling machine. (Unit body, housing, holding yoke) are defined as a plurality of blank assemblies consisting of at least two, preferably four or more individual blanks. The cluster blank is thus a kind of milling machine or CAD / CAM system that can minimize the waste and material removal, maximize compatibility and flexibility and efficiently blank milled compacts. Form a blank addressable matrix. Thus, the terms “cluster blank” and “addressable matrix” can be used interchangeably herein.

  Various cluster blanks can be formed from individual blanks using off-the-shelf or custom-made frameworks, allowing the individual blanks to be used in as many systems as possible. Cluster blanks can include the same individual blanks having the same dimensions and tone, or the same size and type of blanks with different tones. Cluster blanks can also include various dimensions and colors of the same blank mold (material), and "composite" by assembling various different types of blanks from one or different manufacturers on the same framework. A cluster blank can be produced. In order to maximize the impact of cluster blanks on system efficiency, the present invention also provides the use of nesting software and system optimization software based on a digital process design (DPD) methodology using a virtual blank method.

  Accordingly, the present invention provides a cluster mill blank comprising a framework configured to cooperate with a blank holder of an existing CAD / CAM system and a plurality of sub-blanks attached to the framework.

  According to a further feature, from a milling machine, a blank holder, a cluster milling blank comprising a framework configured to cooperate with the blank holder, and a plurality of sub-blanks attached to the framework A configured CAD / CAM system and nesting software having at least primary functionality are provided.

According to yet another aspect, the present invention provides a method for milling an object using the above-described CAD / CAM system, which uses nesting software to perform actual milling on history. Analyzing the data, or analyzing the data corresponding to the milling object, thereby obtaining a distribution of dimensions and shapes with respect to the milling envelope and the correlation with a particular type of dental product; Select a group of containers corresponding to the object to be milled by selecting the corresponding electronic data, and the number, type , dimensions, arrangement , volume and number of sub-blanks selected to mill the group of containers. Or optimize the color tone and assemble one or more sub-blanks on one or more frameworks using one or more molds To produce a raster blank; and an object to milling to each sub-blanks.

  In the present specification, the present invention will be described mainly with reference to denture machining, but the present invention is not limited thereto. For example, the principles of the present invention are generally applicable to medical devices (eg, implants, replacement joints, skeletal replacements, etc.). According to its broad features, the present invention is capable of milling or shaping that is essential for three-dimensional objects. Examples of (but not limited to) three-dimensional objects include coping, pontic, framework, denture teeth, gap retention devices, tooth replacement orthodontic appliances, orthodontic retainers, dentures, posts, facets, Sprints, cylinders, pins, connectors, crowns, partial crowns, veneers, onlays, inlays, bridges, fixed partial dentures, implants or abutments.

It is a conventional disk-shaped blank. The waste material produced by milling the blank of FIG. 1 is shown. 1 is a cluster blank formed according to the first embodiment of the present invention. It is a cluster blank formed according to the second embodiment of the present invention. Figure 6 is a cluster blank formed according to a further embodiment of the present invention. 6 is a cluster blank formed according to yet another embodiment of the present invention. Figure 6 is a cluster blank formed according to a further additional embodiment of the present invention. 1 shows a conventional CAD / CAM milling machine in an open position consisting of two disc mill blank holders. 1 shows a conventional CAD / CAM milling machine in a closed position consisting of two disc mill blank holders. It is the schematic of the original template of the cluster blank formed by the principle of this invention. FIG. 10 illustrates an improved version of the original mold of FIG. 9 constructed in accordance with an embodiment of the present invention. FIG. 10 shows an improved version of the original mold of FIG. 9 constructed in accordance with another embodiment of the present invention. It is a graph of the dimension distribution of a milling process envelope. It is an upper surface perspective view of the sub blank attached to the framework concerning one embodiment of the present invention. It is an upper surface perspective view of the sub blank attached to the framework concerning one embodiment of the present invention. It is a fragmentary perspective view of the sub blank attached in the framework which concerns on one Embodiment of this invention. It is a fragmentary perspective view of the sub blank attached in the framework which concerns on one Embodiment of this invention. It is a fragmentary perspective view of the sub blank attached in the framework which concerns on one Embodiment of this invention. It is a fragmentary perspective view of the sub blank attached in the framework which concerns on one Embodiment of this invention. FIG. 19 is a cross-sectional view of a sub-blank mounted in the framework cut at line 19-19 in FIG. It is an upper surface perspective view of the sub blank attached to the framework concerning one embodiment of the present invention. It is a side upper surface perspective view of the sub blank attached to the framework concerning one embodiment of the present invention. It is a side view of the framework in FIG. FIG. 23 is a front view of the framework of FIG. 21 including a partial cross-sectional view taken along line 23-23 of FIG. FIG. 23 is a top perspective view of the framework of FIG. 21 including a partial cross-sectional view taken along line 24-24 of FIG. It is a fragmentary perspective view of the cluster blank which concerns on one Embodiment of this invention. It is a top view of the cluster blank which concerns on one Embodiment of this invention. FIG. 27 is an exploded view of the cluster blank assembly of FIG. 26. FIG. 27 is a cross-sectional view of the cluster blank of FIG. 26 taken along line 28-28 of FIG. FIG. 27 is a cross-sectional view of the cluster blank of FIG. 26 taken along line 29-29 of FIG. It is an enlarged view of the sub blank attached in FIG. FIG. 27 is a cross-sectional view of the cluster blank of FIG. 26 taken along line 31-31 of FIG. It is a perspective view of the sub blank in the container which concerns on this invention. FIG. 33 is a partial view of the sub-blank of FIG. 32.

  In accordance with one optional feature of the present invention, a variety of cluster blanks are formed from individual blanks using off-the-shelf or custom-made frameworks, thereby using individual blanks in as many systems as possible. It becomes possible to do. Hereinafter, individual blanks assembled into cluster blanks are referred to as sub-blanks. The cluster blank can include sub-blanks of the same size and color, or sub-blanks of different color, size and / or type. For example, a cluster blank can include a variety of dimensions and tones of the same sub-blank mold, and a variety of different types of sub-blanks from one or different manufacturers can be assembled into the same framework to create a “mixed” "A cluster blank is formed. For example, e. maxCAD MO and / or LT blank (Ivoclar) could potentially be processed by a robust CAD / CAM system with software that utilizes wet milling techniques to design full contour restorations is there. Examples of systems with such capabilities (but not yet capable of milling “blue blocks”) are the Zeno® Tec system (Veeland), in particular the above mentioned 3Shape DentalDesigner ( ZENO (R) 4820 and ZENO (R) 3020 milling equipment compatible with trademark software.

  The sub-blanks can be placed in an addressable matrix, whereby the addressable matrix is designed from parameters obtained from the history before milling work or before work work. The sub-blank has characteristics related to parameters obtained from the history before the milling work or the work. These characteristics may include material type, material characteristics, sub-blank dimensions, sub-blank shape, and / or sub-blank color tone. Parameters from the pre-milling history include container type, material selection parameters, dental product dimensions, dental product shape, dental product color, optimal tool path, milling parameters, and dental product manufacture The statistics of the milling envelope used in An example of a milling envelope statistic is the correlation of the milling envelope between the shape and dimensions of the milling envelope and a particular type of dental product. Examples of milling parameters include tool type, cutting depth, feed rate, number of revolutions per minute (rpm) and / or linear velocity. Examples of tool types include cutting, grinding or polishing surfaces. The tool may vary depending on the material, shape, and / or tool dimensions. Examples of cutting, grinding or polishing surfaces include diamond, carbide, hardened steel or ceramic. Examples of the shape of the tool include, but are not limited to, a cylindrical shape, a conical shape, a disk shape, a spherical shape, or a wave shape. The dimensions of the tool may depend on the diameter and length. An example of the diamond tool is diamond grit. The cutting depth of the tool can vary in size from microns to millimeters. Furthermore, examples of milling parameters include post-milling parameters such as painting, polishing, or heat treatment parameters. Examples of the parameters relating to the history before the work work include a list used, a remaining list, and a container history.

  Examples of cluster blanks formed according to the present invention are shown in FIGS. 3-6. A first cluster blank 10 formed according to a particular embodiment of the present invention is shown in FIG. As shown in FIG. 3, the cluster blank 10 includes a plurality of sub-blanks 12. According to the illustrated embodiment, two different types of sub-blanks 12 are included in the cluster blank 10. That is, according to the illustrated embodiment, the plurality of first cluster blanks 14 are normally arranged in the center of the cluster blank 10 and the second plurality of sub-blanks 16 are in accordance with the non-binding example. Provided along the periphery of the cluster blank 10, the first plurality of cluster blanks includes a C14 blue block, and the second plurality of sub-blanks includes a B32 blue block. Each sub-blank 12 may be attached to the shared part 18 or may be integrated with the shared part 18. The framework 18 can be formed from any suitable material. For example, the framework 18 can be constructed from a metal such as steel or aluminum alloy, a plastic or polymer such as PMMA, or a composite material such as Paradigm® MZ100 manufactured by 3M Company. The framework can also include a fixed part or a movable part.

  As described in the exemplary embodiment above, the cluster blanks 10, 20 are optionally composed of a plurality of blue blocks and may be customized for use with the above-described Zeno® Tec System.

  An improved version of the embodiment shown in FIG. 3 is shown in FIG. This embodiment is similar to the embodiment illustrated in FIG. 3 except for the placement and type of sub-blank 12 that couples to the framework 18. According to the embodiment illustrated in FIG. 4, the sub-blanks 14 each have the same structure, for example, each having the same dimensions, color and / or formed from the same material. According to one optional embodiment, each sub-blank 14 is substantially identical to one another.

  The framework can be in any form including 2D and 3D. The framework can be mass produced (factory produced) or can be customized for each desired combination of system and mill blank. The sub-blank is mechanically attached (fixed) to the framework, or alternatively adhesively bonded (glued) to the framework, or formed as an integral part of the framework. Sub-blanks can also be attached to openings in the framework using castable attachment materials, modeling materials, polymer composites and other curable materials. The framework for the cluster blank can be designed for multiple uses and / or for disposable instruments. Furthermore, the framework of the cluster blank can include an integral single part or can include an assembly of multiple parts or components. In the latter case, the parts or components of the framework assembly may be non-removable or removably attached to each other. The framework assembly can also be included in the moving part. For example, a movable part can be used to rotate or change the position of the sub-blank within the cluster blank before, during or after milling. This movement is manually or automated and controlled by the same means as the CNC milling device.

  Cluster blanks 30, 40 and 50 formed according to further embodiments of the present invention are illustrated in FIGS. 5-7, respectively.

  As shown in FIG. 5, the cluster blank 30 includes a plurality of sub-blanks 32 arranged in a polygonal framework 34. According to a non-limiting and illustrative embodiment, the sub-blank each includes nine circular blocks arranged in three rows of three blocks, and the framework 34 is substantially square. Block 32 and framework 34 may be formed of any of the materials previously described herein.

  As shown in FIG. 6, a cluster blank 40 formed in accordance with an alternative embodiment of the present invention is different from the characteristics of at least one sub-blank having a first characteristic and at least one first sub-blank 42. A plurality of second sub-blanks 44 having two characteristics are included. According to a non-limiting and illustrative example, the first sub-blank 42 includes a substantially circular block, and the plurality of second sub-blanks 44 are arranged symmetrically around the first sub-blank 42. Polygonal or substantially square blanks. The first and second sub-blanks 42, 44 are attached to the polygonal framework 46. According to a non-limiting illustrative embodiment, the framework 46 is substantially square. Both the sub-blanks 42, 44 and the framework 46 can be formed from any of the materials described above.

FIG. 7 shows a cluster blank 50 that forms an addressable 4 × 4 matrix (SBij) that includes 16 sub-blanks 52 with various dental tones that are fitted into the framework 54. According to one illustrative embodiment, if each sub-blank 52 represents one Vita Classic tone, this 4 × 4 addressable matrix covers the full Vita Classic tone range. be able to. In general, each and every individual sub-blank position in a given cluster blank / addressable matrix will have an index (number) based on a specific method and the nesting described in the CAD / CAM system software or below. An algorithm is assigned for the method to be processed by the optional software of the central processing facility such as a software type. For example, each sub-blank has at least one number corresponding to an individual position / slot in a given cluster blank where the sub-blank is placed, and a host cluster blank identification number or job queue, ie a group to be milled Is assigned at least a second number corresponding to its position. In this case, the cluster blank / addressable matrix of FIG. 7 is represented by the vector SB _km . Here, k corresponds to the position of the cluster blank in the job queue, and m varies from 1 to 16 with respect to the total number of 16 sub-blank positions in a given cluster blank. By running the software, other vectors such as those related to specific sub-blank materials, dimensions, shapes, tones and milling parameters and container details are added to the addressable matrix. Thus, each physical cluster blank / addressable matrix is represented by at least the same size or larger “virtual” matrix in the working memory of the CPU and CAD / CAM system. The CAD / CAM system or milling center processes the addressable matrix with its operational software or other means of automating operations, saving time and money and minimizing waste. Therefore, the required optimization can be performed by well-known methods used in operational research and image processing such as factor analysis based on eigenvectors and eigenvalues.

  Almost all dental CAD / CAM systems can mill plastic (eg, PMMA) or composite materials, so the framework formed from those materials can be milled to the same milling equipment and blank. Milling can be performed using the nesting software used for processing and can be improved or optimized. Furthermore, the framework can be reused, making manufacturing in the same milling machine more economical. Compared to mounting on a stub or mandrel, such as in a Sirona system, mounting along the entire circumference of the blank reduces stress during milling, thus reducing the strength and stiffness requirements for the framework material, and thus PMMA. Or it makes it feasible to select a polymer composite for the cluster blank framework.

  Furthermore, the open structure system is not limited to CNC milling machines specifically designed for dental use, but can actually utilize a rugged 3-axis or higher CNC machine. More and more commercial CNC machines are improved for dental use, ie mounted in blank holders and adapted with open-structure scanners such as 3Shape's D-250, in large laboratories and milling centers In use, dental products such as zirconia frameworks and custom implant abutments are primarily produced commercially. With respect to custom-made systems, the cluster blank method has the greatest advantage of allowing the existing range of blocks to be “coupled” to a given milling device without significantly improving the hardware of the machine.

  According to another aspect, the present invention provides nesting software for use with cluster blanks. Nesting software adds features related to sub-blank molds and other characteristics, milling subroutine and / or algorithm optimized tool path, tool selection, cutting depth, feed rate, RPM, linear velocity and other milling operations By assigning parameters, a physical m-unit addressable matrix (including m sub-blanks) can be transformed into a multidimensional matrix. If the addressable matrix is automatically assembled, one of the features added to indicate the addressable matrix to the computer can be an assembly instruction. If necessary, cluster blank sub-blanks and / or frameworks are marked with an exponent or alphanumeric code, a bar code or other identification form in a computer readable form. Alternatively, the cluster blank framework includes a magnetic strip, microelectronic chip or other rewritable data storage microdevice that carries identification information and other information related to the milling and processing of a given cluster blank. This is particularly useful when the CAD / CAM system does not include nesting software.

  An example of a first order nesting software (defined below) is described in US Pat. No. 5,662,566, which is hereby incorporated by reference in its entirety. Currently, nesting software is rarely used in dental CAD / CAM systems, and is limited to mapping parts that are milled into individual large blanks (milling jobs), so that the average per blank The output is maximized. The average yield per blank is characterized by being calculated by dividing the weight of the final restoration by the weight of the blank before being formed by material removal. The cluster blank of the present invention allows the nesting software to be used more extensively with the actual cluster blank, and in certain embodiments the nesting software can also use a virtual blank.

  Nesting software is essential for systems that allow milling of large blanks. Nesting software has become more essential for milling cluster blanks. To illustrate embodiments of the present invention relating to the application of nesting software with cluster blanks, an a4 "diameter disk-shaped blank can be advantageously converted to a cluster blank as a typical example of a large single blank. Blanks, and the latter are called equivalent cluster blanks These blanks made from soft-sintered zirconia change from 10-15 milling jobs up to 10-15 or a circular house of up to 14 units from a single unit. (See Figure 5A) Figures 1 and 2 show what the blank looks like after milling, and the milling job layout is Not optimized and actual output is much less than 50% of the blank material The holes left after milling the individual containers define the milling envelopes for these containers, the term milling envelopes describing the various features of the present invention regarding the use of nesting software. A milling envelope is defined by its maximum length (MEL) and maximum width (MEW) if its depth is equal to the thickness of the blank.

  Although 4 "circular zirconia blanks were used in the examples to illustrate large blanks (precursor blanks) that are transformed into equivalent cluster blanks, the present invention provides a plurality of small and millable sizes that can be milled into single or multiple unit frameworks. It should be noted that zirconia is not the only dental material that can be manufactured in large shapes, for example, lithium silicate glass ceramics can be transformed into a dental product without excessive wear of the milling tool. Can be easily processed by machining and then converted into a lithium disilicate restoration showing high strength up to about 800 MPa, as well as a single unit of dental restoration It is also useful for dental restorations, where glass ceramics are formed in the glassy state, and in any glass formation. Glass molding technology can potentially be used for these materials, in addition to strong dental materials that can be molded into any shape and are suitable for milling into multi-unit dental products. Examples include dental alloys: zirconia, glass ceramics and alloys are simple shapes (rectangular, cylindrical, disc-shaped or polygonal), or complex shapes of any size ("smart" or near net shape) Can be manufactured as. The driving force to reduce waste is equally strong for all these materials. When nesting software is used, material waste is much less than that shown in FIGS. Alternatively, sub-blanks can be assembled into cluster blanks, possibly further reducing waste by as much as 10 times compared to applying the primary nesting software to one or several large blanks. Further waste reduction achieved by the present invention is brought about by co-use of cluster blanks in combination with higher order nesting software, as described in the following embodiments.

  The nesting software predicts the dimensions and shape of the milling envelope corresponding to the milling job in the job queue based on prior statistics or the electronic data of the container, calculates the required number of sub-blanks and frameworks, Apply blank and framework assemblies to the required number of cluster blanks and optionally distribute milling jobs between sub-blanks and cluster blanks to minimize material waste and tone listings.

  With respect to the present invention, existing and future nesting software modules can be classified based on the level of intelligence and the number of containers they can process simultaneously, ie, using an “N / n” ratio. Here, “N” is the number of containers that are “optimized” at the same time (characteristic batch size), and “n” is the average number of individual devices per blank. The function of the nesting software maximizes the average output per blank and hence optimizes “n” (not necessarily maximized). That is, the number of blanks used to mill the container eigenvalue N associated with the operation of a given CAD / CAM facility is optimized (and not necessarily minimized). In terms of use in embodiments of the present invention, nesting software is classified as primary, secondary, and tertiary based on the ability to process small or large (queue) containers simultaneously, ie, N / n ratio. . Examples of “n” are 7 or more, 10 or more, and 30 or more.

  The primary nesting software is N / n <10 and can maximize output from a given blank, i.e., placing a continuous milling job within the milled blank to dispose of waste Can be minimized. A related procedure would be to distribute a milling job to be stacked in a cue assigned for one or a set of new blanks installed in a mill fixture material fixture or cartridge. In other words, the primary nesting software matches a limited number of individual containers to the blank volume. Since the milling job queue is small and different each time, the result is also different every time and the type cannot be revealed. That is the current industry. Currently, holders that can accommodate large multi-container blanks are limited to carry up to two blanks at a time (see, eg, FIG. 8). For example, N / n is 0.55 and 0.35 for the blanks of FIGS. 1 and 2, respectively. When both blanks are milled in a system using a combination of nesting software and milling equipment with two blank holders, the resulting average number of devices per blank is 26.5. And the relevant N / n ratio is 0.87 (see Table 1 below). From the analysis of the data in Table 1, it was concluded that approximately 30 was a good estimate of the “optimal” average number of milling equipment per 4 ″ circular blank.

  Primary nesting software is used to guide the milling job to a known position in the cluster blank and the corresponding sub-blank is placed, ie corresponding to each milling job in the appropriate sub-blank of the cluster blank To accurately place the milling envelope. This function is called a placement function. Thus, waste is limited to two components. 1) material removed during milling of the sub-blank; and 2) volume difference between the material to be disposed of, ie the actual milling envelope and the corresponding cluster blank sub-blank. Most waste is now avoided by using cluster blank frameworks or molds. The second component of the waste is minimized through the use of higher order nesting software shown below.

  The secondary nesting software is N / n = 10-100 and can maximize output from a fairly large amount of blanks, and the dimensions of batch N are relevant to the operation, i.e. given CAD / Related to the characteristic time sufficient to obtain statistically significant data determined by the size and equipment of the CAM equipment. Hereinafter, N is referred to as a characteristic batch size when N is related to work, that is, when it is defined by the operating equipment and market requirements of a given milling center. For example, in steady state operation, the number of containers received each business day (daily input) is equal to the number of containers delivered to the consumer (daily output). The average residence time of containers in the milling center or the transit time of containers leaving the milling center from containers entering the milling center is limited by market conditions. Currently, in order for a milling center to be successful, the rotation time needs to be less than one week, that is, the customer needs to receive the container in less than a week, so the container residence time in the milling center , 3-5 business days regardless of container complexity. Therefore, every day, the number of containers in a given milling center pipeline is 3-5 times the daily input / output. Therefore, the characteristic batch size is at least equal to the number of containers in the daily job queue for high-productivity CNC milling machines, and the total daily container load, i.e. the pipeline of a given milling center at all stages. Alternatively, it can be the same size or larger than all containers of the daily job queue for the entire milling center. Examples of a high-productivity CNC milling machine particularly suitable for a large-scale milling center include a ZENO (registered trademark) 6400L milling machine having four material holders and an Etcon HSC (high-speed cutting) machine.

  The small and medium milling center processes 100 to 500 containers per day or 500 to 3000 containers per week. If a 4 "circular blank is used in such a milling center, assuming an" optimized "n value of 30, the resulting N / n ratio is in the range of 17-100. The secondary nesting software does not just match the limited number of individual containers in the same large blank volume as the primary nesting software. The secondary nesting software also optimizes the placement and type of sub-blanks assembled within the cluster blank mold range for a given prototype, thus minimizing waste and color listings for much larger containers .

  A possible prototype blank 60 for a cluster blank corresponding to a prototype framework or a 4 "circular precursor blank is shown in FIG. 9. This mold 60 includes an outer ring 62 and an inner core 64, the outer ring 62 being 66. Or 68 large sub-blanks and the inner core holds small sub-blanks 70, 72. The overall dimensions of these molds are the same and specific as the given prototype, The number and size of the openings (shown by dashed lines in the illustrative embodiment) may be different for each mold, for example, the mold shown in Fig. 9 is 4 to 6 units in the outer ring according to one shape. The largest sub-blank 66 for one of the frameworks, or a medium-sized sub-blank 68 for two to three units of framework in an outer ring according to other shapes. The inner core can also have different arrangements of fairly small sub-blanks, for example, the inner core 64 'can have a first polygonal sub-blank 70' and a second as shown in FIG. The inner core 64 ′ has two relatively large polygonal blanks 70 ′ and four relatively small circular or oval blanks, according to the illustrated example. In addition, an alternative configured internal core 64 "is shown in FIG. As shown in FIG. 11, the arrangement of the inner core 64 "may include the arrangement of a first polygonal sub-blank 70" and a second circular or oval sub-blank 72 ". According to the illustrated example. The inner core 64 "includes an arrangement of two relatively large polygonal blanks 70" and two relatively small circular or oval blanks 72 ". Any type of sub-blank arrangement can be used, for example, a large sub-blank for producing 2 to 3 units of product or a small sub-blank for producing single-unit dental products.

  The maximum number of sub-blanks depends on the structure and diameter of the mold and also depends on the arrangement, shape and dimensions of the sub-blanks that make up. Based on feedback from the secondary nesting software, some, but not necessarily all, available positions on the mold are occupied, or necessarily with sub-blanks of the same tone.

  In one aspect of the invention, the method is provided and a CAD / CAM system with nesting software collects data and determines the type of sub-blank required for future work. At the beginning of the process, a sufficient amount of time, a 4 "circular zirconia precursor blank is milled more than the cluster blank, and the nesting software serves as the first simultaneous collection statistic on the size distribution of the milling envelope. Based on the actual milling of the blank, a dimensional distribution chart, histogram, curve or surface group is generated for the milling envelope corresponding to the posterior and anterior single dental units and the multi-unit dental framework. Figure 12 shows one curve portion of the two-dimensional "frequency vs. MEL" where the milling envelope is characterized in the most simplified way by maximum length (MEL) and maximum width (MEW). Even in this simple concept, the resulting size distribution becomes a complex surface group in a coordinated 3D system and is schematically illustrated in FIG. The dimension distribution curve shows peaks and valleys, the physical meaning of which is shown in Table 2 below.

* The most frequent value of MEL for a type of container, for example the most frequent milling envelope length (MEL) for a 3 unit bridge framework is about 35 mm.
** Intermediate values correspond to the largest n unit container that rarely occurs and the smallest (n + 1) unit container that rarely occurs. For example, the holes (milling envelope) left after milling of almost all 3 unit frameworks are shorter than 40 mm, whereas the holes for 4 unit frameworks are almost larger than 40 mm. Therefore, the 40mm x 22mm sub-blank is compatible with most 3 unit frameworks.

The milling envelope dimensional distribution shown in FIG. 12 is a cylindrical sub-blank with a diameter of about 15-18 mm or a rectangular sub-blank with a cross section of 15 × 18 mm ² for the front single unit, 19 × 28 mm for the rear single unit. ² sub-blanks, logically select between the 23 × 55 mm ² sub-blanks for 22 × 40 mm ² sub-blanks for 3 units frameworks, and 4 units framework. With more accurate statistics corresponding to large volume containers, these dimensions can be further subcategories for front and back multi-unit frameworks. These sub-blanks are also required for at least two different thicknesses to minimize zirconia waste, particularly the second component of the waste, and the nesting software can be used for example for the outer ring / inner core shown in FIG. It is necessary to operate with at least 8 different sub-blank dimensions to be placed in the mold.

  Statistical analysis of the size and shape distribution for the milling envelope yields the optimal sub-blank size. If 1) the sub-blank shape and dimensional diversity is consistent with the number of characteristic features of the milling envelope dimension distribution curve (eg, MEL and MEW peaks or valleys), and 2) the raw material used If the number of mold improvements available matches the placement of these characteristic shapes and dimensions with a group of containers related to a given operation in a nearly optimal manner, the second component of waste is reduced, The list of colors is also reduced. The optimal number of shapes and dimensions for the sub-blank can be logically solved by analyzing the data provided by the secondary nesting software. The secondary nesting software can also achieve the required minimization for waste and color listings by recommending a minimum number of sub-blank dimensions. However, the original mold cannot be designed or redesigned to create the number of improvements required. The latter task requires tertiary nesting software that can use a virtual blank method instead of the actual statistics obtained during milling.

  The tertiary and highest nesting software is N / n> 100 and can be deployed in large central processing facilities and milling centers that process more than 1,000 containers per day. The potential savings in scale in such facilities justify custom sub-blank types and custom cluster blank designs. Designs need to change regularly to meet changing market demands. These facilities are large enough to direct their parameters to sub-blanks, CAD / CAM units and / or software manufacturers. Nesting software suitable for such equipment has design capabilities built into the process feedback loop and can improve the size and shape range with respect to construction sub-blanks and corresponding mold designs based on actual feedback data And For example, tertiary nesting software can improve mold volume, number, size, shape and sub-blank placement within the mold, as well as cluster blank mold and cluster blank housing / holder volumes can be supported by CNC machines. Optimal tone distribution can also be selected if it is designed parametrically within the design envelope given by the volume.

  Prior to milling, all the milling jobs are represented in CAD files, STL files or other standard digital representations of composite 3D objects, so the optimization function described above is before actual milling or simultaneously with milling Can be implemented. For example, the size and shape distribution for the milling envelope can be predicted, i.e., derived or estimated from multiple CAD files to be milled. This data can also be used to assemble, design and process sub-blanks and mold / framework for cluster blanks. This and other capabilities and functions of different dimensions of nesting software are compared in the table below.

  The nesting software features summarized in the table above optimize the placement of sub-blanks in a cluster blank assembly by providing a way to use the nesting software for effective use, design and assembly of cluster blanks. And minimize waste and color listings. The method may optionally include system optimization software based on CAD / CAM manufacturing configured horizontally using a digital process design (DPD) procedure, in particular a virtual blank method. The method includes one or more of the following operations in any combination and order.

1) Analyze the historical milling data provided by the nesting software for the placement of the units on the precursor blank to obtain the size and shape distribution for the milling envelope.
2) Select the (design) range of the cluster blank mold that matches the optimal range of the set of containers and sub-blanks associated with the milled operation represented by the corresponding CAD, STL or equivalent file.
3) By using higher-order nesting software instead of 1), “virtual statistics” that estimates the distribution of the size and shape of the milling envelope based on the CAD file or the equivalent digital representation of the milled container "I will provide a.
4) Determine the optimal number, shape and volume of sub-blanks based on actual or virtual statistical analysis of multiple milling envelopes associated with the operation.
5) Assemble the selected sub-blanks in the selected mold to produce a cluster blank and mill the container as instructed by the nesting software.
6) Re-acquire actual or virtual statistics on milling envelope and output.
7) Improve or redesign the mold based on the criteria of maximum average output, minimum waste per sub-blank, and minimum sub-blank color scheme.
8) Mill the modified or redesigned mold from the plastic precursor blank using the same CAD / CAM system.
9) Alternatively, mass production of molds can be carried out using special equipment or outsourced.
10) Assemble the cluster blank and mill a group of containers related to the next operation as instructed by the nesting software.
11) Alternatively, at least some of the operations 5) to 10) are automated by the third nesting software and can be executed by robot control.

  When operations 5) to 10) are automated by the tertiary nesting software, it effectively functions as a manufacturing platform, specifically a digital manufacturing platform. At present, milling centers will probably have an advantage in operating different types of CAD / CAM systems, but any type will increase as the demand for standardization increases and the market penetration of open structure systems increases. The propulsive force of operating one type, one platform system, which can be milled, increases gradually. The need for such manufacturing platforms for large central processing facilities and milling centers, along with further development of the digital revolution in dentistry, greatly increases the emergence of impressionless dental and web-based processing centers.

  Figures 13 to 24 illustrate the sub-blank attached to the framework by various attachment means. FIGS. 13 and 14 illustrate different embodiments of the present invention comprising circular frameworks 80 and 82. The framework 80 has a circular shape including sub-blanks arranged along the periphery of the framework 80. The framework 82 has a set of sub-blanks arranged in two rows on opposite sides of the framework. Each sub-blank 84 is attached to a support 86 having a flange 88 attached to a shaft 90 having a longitudinal axis attached to the framework 80. The sub-blank 84 may be glued or glued to the flange 88. The shaft 90 may have a cross-sectional shape such as a hexagon or an octagon, but preferably has a circular cross-section. Shaft 90 may be fitted into frameworks 80 and 82. Alternatively, the shaft 90 may contain a set screw or other structure including a groove extending around it.

  Figures 15 and 16 show sub-blanks 92 and 94, respectively, attached to frameworks 96 and 98, respectively. In FIG. 15, the sub-blank 92 is nested within the framework 96 by the support 100. FIG. 16 shows a sub-blank 94 having a notch 102 on which a framework 98 is mounted.

  FIGS. 17-19 show a rectangular framework 104 having two rows of sub-blanks 106 attached to both sides of the framework 104. A sub-blank 106 is attached to the support 108 and the support 108 is shown attached to the framework 104. The support 108 includes a flange 110 and a shaft 112 and is attached to the framework 104.

  20-24 further illustrate another embodiment of a cluster blank 120 comprising a rectangular framework 122 with a set of sub-blanks 124 attached along opposite sides of the framework 122. FIG. The sub-blank 124 is attached to a support 126 that is coincident with the framework 122. The support 126 includes a flange portion 128 and a shaft 130 that extend into the frame 122. In this example, the milled portion of the sub-blank is placed completely outside the framework.

  FIGS. 25-27 illustrate a cluster blank 140 with a sub-blank 142 into which a circular framework 144 is inserted and attached. The cut-away view in FIG. 25 illustrates a sub-blank mounted or snugly fitted in a container 146 that matches the framework 144 in the appropriate position.

  FIG. 27 illustrates an exploded view of the cluster blank 140 and shows the top 148 and bottom 150 of the framework 144. The sub blank 142 is disposed on the bottom 150 and the top 148 is disposed on the sub blank 142 and the bottom 150 to hold the sub blank 142 in place during milling. Bolts 152 or similar securing means are inserted into the series of top and bottom openings to simultaneously secure and hold that portion.

  28 to 33 show cross-sectional views of the sub-blank 142 disposed on the framework 144. Each sub-blank is shown attached to a holder 146 located on the bottom 150. The top 148 fits over the bottom 150 and a bolt 152 or similar means holds the top and bottom simultaneously. As clearly shown in FIG. 30, the acute angle portion of the holder 146 is pushed into the framework unit 148. 32 and 33 more clearly show the acute angle of the holder 146 that fits within the framework 148. The sub-blank 142 may be glued or similarly attached to the holder 146, the latter completely including the sub-blank and can function as a compression fitting, i.e. pushed by the top and / or bottom. The arrangement of the sub-blanks within the framework 148 may be any shape, including those shown in FIGS. 3-7 and 9-11. The holder 146 may be made of a flexible, elastic or rubber material. Furthermore, the holder may be attached to the cluster blank by a clasp connection or a compression connection. In all embodiments, the sub-blank may be attached directly to the framework or attached to an intermediate material attached to the framework.

  The following examples show increased output and reduced material waste. This can be brought about by replacing one disk or blank with a cluster blank formed according to the present invention.

Two dimensions of separate ZirCAD blocks—C14 and B40 (e.maxCAD) are used as sub-blanks. A Charly4dent CNC milling machine 56 (see, eg, FIG. 8) (available from Charlybot, Cruzeles, France) for continuous production of dentures is used. Charly4dental is equipped with a disk fixing system that can accommodate two 100mm (~ 4 ") or small disks 58. Mainly for dry milling of soft sintered zirconia and resin disks (such as PMMA) Designed: A first 100 mm PMMA disk is used to produce a framework for a cluster blank using the same milling machine, 4 contrasts with dimensions of 25 × 20 mm ² and 45 × 20 mm ² The rectangular opening located in the mill is milled in a PMMA disk, then 2ZirCAD C15 and two C40 zirconia blanks are available from the opening and the LECOSET 100 castable mounting material (LECO, product number 812-125) ) In the resulting uniform gap, two 3-unit bridges and two molars are milled into a sub-blank.If one 100 mm zirconia disk is used, the remaining zirconia is as shown in FIG. In the case of a cluster blank, the remainder of the sub-blank is removed and the PPMA framework can be reused to assemble the next cluster blank.

  All numbers representing quantities or parameters used herein are additionally modified by the word “about” in all cases. Despite the numerical ranges and parameters described, the broad range of subject matter presented herein is an approximation, and the numerical values described are shown as accurately as possible. For example, any numerical value may inherently contain certain errors, as will be apparent from the standard deviation or rounding error and error associated with each measurement technique.

  Although the invention has been described with reference to preferred embodiments, those skilled in the art can make additions, deletions, modifications and substitutions not specifically described without departing from the spirit and scope of the invention as defined in the appended claims. .

Claims (9)

A framework configured to work with blank holders of existing CAD / CAM systems;
A plurality of sub-blanks attached to the framework,
A portion of the sub-blank is a cluster mill blank for manufacturing a dental product that is milled into a dental product,
The sub-blanks are arranged in an addressable matrix, and the addressable matrix is designed from parameters obtained from a history before milling work or pre-work work, and from a history before milling work or pre-work work A characteristic associated with the resulting parameter, the characteristic including a material type, material characteristic, sub-blank dimension, sub-blank shape, and / or sub-blank color tone, wherein the parameter Including mold type, material selection parameters, dental product dimensions, dental product shape, dental product color, optimal tool path and milling parameters,
A cluster mill blank for manufacturing a dental product, characterized in that the milled portion of the sub-blank is located completely outside the framework.   The dental products include coping, pontic, framework, denture teeth, gap retention device, tooth replacement orthodontic appliance, orthodontic retainer, denture, post, facet, splint, cylinder, pin, connector, crown The cluster mill blank according to claim 1, comprising: a partial crown, a veneer, an onlay, an inlay, a bridge, a fixed partial denture, an implant or an abutment.   The cluster mill blank according to claim 1, wherein the framework is circular, elliptical, or polygonal.   The cluster mill blank according to claim 1, wherein the sub blank is disposed on both sides of the framework.   The cluster mill blank according to claim 1, wherein the sub blanks are arranged in a row.   The cluster mill blank according to claim 1, wherein the sub-blank is directly attached to the framework.   The cluster mill blank according to claim 1, wherein the sub-blank is attached to a shaft, and the shaft is directly attached to the framework.   The cluster mill blank according to claim 1, wherein the sub-blanks are made of the same size, color, and / or material.   The cluster mill blank according to claim 1, wherein the sub blank is made of different sizes, colors, and / or materials.

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