# US 11,998,422 B2 · Processing CT scan of dental impression > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,998,422 B2 - Document ID: US11998422B2 - Status: Granted - Kind: B2 - Application number: 18/069,473 - Filed: 2022-12-21 - Published: 2023-04-27 - Granted: 2024-06-04 - Earliest claimed: 2019-06-25 - Assignees: James R. Glidewell Dental Ceramics, Inc. - Applicants: James R. Glidewell Dental Ceramics, Inc. - Inventors: Sergey Nikolskiy; Fedor Chelnokov - Web page: https://patentgrep.com/patent/US11998422B2 ## CPC - A61C 9/0053: {Optical means or methods, e.g. scanning the teeth by a laser or light beam} - A61B 6/032: {Transmission computed tomography [CT]} - A61B 6/466: {adapted to display 3D data} - A61B 6/5217: {extracting a diagnostic or physiological parameter from medical diagnostic data} - A61C 9/0006: {Impression trays} - A61C 9/0046: {Data acquisition means or methods} - A61C 13/0004: {Computer-assisted sizing or machining of dental prostheses} - G06T 17/20: Finite element generation, e.g. wire-frame surface description, {tesselation} - A61B 6/51: for dentistry - G06T 2210/56: Particle system, point based geometry or rendering - A61C: DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE (non-driven toothbrushes A46B; {tongue scrapers A61B17/24;} preparations for dentistry A61K6/00; preparations for cleaning the teeth or mouth A61K8/00, A61Q11/00) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract A computer-implemented method and system of determining a material surface from a volumetric density file includes generating a density frequency distribution of a volumetric density file of a dental impression and determining an iso-value of density between air and a particular material in the density frequency distribution. A computer-implemented method and system of creating a digital model from a CT scan of a physical dental impression includes selecting an iso-value of density for a digital volumetric density file having one or more voxels, generating one or more digital surface points in virtual 3D space for each of one or more voxels, and selecting a subset of digital surface points from the one or more digital surface points. A computer-implemented method and system of optimizing a digital surface includes moving one or more digital surface points to satisfy a criteria of optimum digital surface selection. ## Claims ### Claim 1 A computer-implemented method of determining a material surface from a volumetric density file, comprising: generating a density frequency distribution of a volumetric density file of a dental impression; and determining an iso-value of density between air and a particular material in the density frequency distribution, wherein the density frequency distribution comprises a plurality of voxel count peaks separated by valleys, wherein determining the iso-value of density comprises selecting an iso-value of density value between a highest voxel count density range and a second highest voxel count density range. ### Claim 2 (depends on 1) The method of claim 1, wherein the particular material comprises an impression material. ### Claim 3 (depends on 2) The method of claim 2, wherein the dental impression comprises Titanium and wherein the computer-implemented method provides an iso-value of density of the Titanium. ### Claim 4 (depends on 1) The method of claim 1, wherein the highest voxel count density range comprises an air density range and a second highest voxel count density range comprises a particular material density range. ### Claim 5 (depends on 1) The method of claim 1, wherein the highest voxel count density range comprises a particular material density range and a second highest voxel count density range comprises an air density range. ### Claim 6 (depends on 1) The method of claim 1, wherein determining the iso-value of density comprises selecting an iso-value of density value between one or more density subranges of a highest voxel count peak and one or more density subranges of a second highest voxel count peak. ### Claim 7 (depends on 6) The method of claim 6, wherein the one or more density subranges comprising the highest voxel count peak comprises an air density range and the one or more density subranges comprising second highest voxel count peak comprises a particular material density. ### Claim 8 (depends on 6) The method of claim 6, wherein the one or more density subranges comprising the highest voxel count peak comprises a particular material density range and the one or more density subranges comprising second highest voxel count peak comprises an air density. ### Claim 9 (depends on 1) The method of claim 1, wherein generating the density frequency distribution further comprises detecting contaminants in the dental impression. ### Claim 10 A computer-implemented system of automatic detection of iso-value of density, comprising: a processor; a computer-readable storage medium comprising instructions executable by the processor to perform steps comprising: generating a density frequency distribution of a volumetric density file of a dental impression; and determining an iso-value of density between air and a particular material in the density frequency distribution, wherein the density frequency distribution comprises a plurality of voxel count peaks separated by valleys, wherein determining the iso-value of density comprises selecting an iso-value of density value between a highest voxel count density range and a second highest voxel count density range. ### Claim 11 (depends on 10) The system of claim 10, wherein the particular material comprises an impression material. ### Claim 12 (depends on 10) The system of claim 10, wherein determining the iso-value of density comprises selecting an iso-value of density value between one or more density subranges of a highest voxel count peak and one or more density subranges of a second highest voxel count peak. ### Claim 13 (depends on 10) The system of claim 10, wherein the dental impression comprises Titanium and wherein the computer-implemented method outputs an iso-value of density of the Titanium. ### Claim 14 (depends on 10) The system of claim 10, wherein generating the density frequency distribution further comprises detecting contaminants in the dental impression.