# US 10,368,960 B2 · Tooth movement measurement by automatic impression matching > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,368,960 B2 - Document ID: US10368960B2 - Status: Granted - Kind: B2 - Application number: 14/865,479 - Filed: 2015-09-25 - Published: 2016-01-14 - Granted: 2019-08-06 - Earliest claimed: 2008-12-12 - Assignees: Align Technology, Inc. - Applicants: Align Technology, Inc. - Inventors: Fuming Wu; Vadim Matov; Jihua Cheng - Web page: https://patentgrep.com/patent/US10368960B2 ## CPC - A61C 7/00: Orthodontics, i.e. obtaining or maintaining the desired position of teeth, e.g. by straightening, evening, regulating, separating, or by correcting malocclusions - A61C 7/002: {Orthodontic computer assisted systems} - A61C 7/08: Mouthpiece-type retainers {or positioners, e.g. for both the lower and upper arch (arch-shaped medicament applicators for teeth or gums A61C19/063; mouthguards for protecting the teeth of sportsmen A63B71/085)} - A61C 9/00: Impression cups, {i.e. impression trays}; Impression methods {(computer-assisted sizing A61C13/0004; instruments for determining occlusion A61C19/05)} - A61C 9/0006: {Impression trays} - A61C 9/0053: {Optical means or methods, e.g. scanning the teeth by a laser or light beam} - G06F 18/22: Matching criteria, e.g. proximity measures - G06T 7/0014: {using an image reference approach} - G06T 7/60: Analysis of geometric attributes - G06T 7/74: {involving reference images or patches} - G06T 2207/30036: Dental; Teeth - 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) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract The present invention relates to systems and methods for detecting deviations from an orthodontic treatment plan. One method includes receiving a tracking model, performing a matching step between individual teeth in a plan model and the tracking model, comparing the tracking model with the plan model, and detecting one or more positional differences. ## Claims ### Claim 1 A system for performing an alignment between digital models of a patient's teeth for improved detection of deviations from an orthodontic treatment plan, the system comprising: a data processing system comprising at least one processor; and a storage subsystem associated with the data processing system, wherein the storage subsystem comprises a memory subsystem, the memory subsystem comprising instructions that, when executed by the at least one processor, cause the system to: obtain, by the data processing system, a first digital model of the patient's teeth in a first arrangement and a second digital model of the patient's teeth in a second arrangement, detect, by the data processing system, in each of the first and second digital models, a partial region extending beyond and excluding one or more tooth crowns, the detecting being based on a polygon formed in part from identified cementoenamel junction (CEJ) points on a plurality of teeth and connecting the CEJ points of the plurality of teeth to enclose and define the partial region, and perform, by the data processing system, an alignment between the first and second digital models using the partial regions such that one or more stationary elements of each of the first and second digital models are aligned with one another. ### Claim 2 (depends on 1) The system of claim 1, wherein the instructions, when executed by the at least one processor, further cause the system to detect one or more positional differences between the first and second arrangements of the patient's teeth. ### Claim 3 (depends on 1) The system of claim 1, wherein the first arrangement comprises an actual arrangement of the patient's teeth after the orthodontic treatment plan has begun for the patient and the second arrangement comprises a pre-determined planned arrangement of the patient's teeth. ### Claim 4 (depends on 3) The system of claim 3, wherein the first digital model comprises a non-segmented model of the patient's teeth in the actual arrangement and the second digital model comprises a previously segmented model of the patient's teeth. ### Claim 5 (depends on 1) The system of claim 1, wherein the alignment is performed by at least: calculating, by the data processing system, an alignment transform using the partial regions; and wherein the alignment between the first and second digital models is based at least in part on the calculated alignment transform. ### Claim 6 (depends on 1) The system of claim 1, wherein the partial regions include one or more of a gingiva shape, palatine rugae, or hard plate. ### Claim 7 (depends on 1) The system of claim 1, wherein the partial regions in each of the first and second digital models are located on one or more of a lingual side or a buccal side of the plurality of teeth. ### Claim 8 (depends on 1) The system of claim 1, wherein the one or more stationary elements are located within the partial regions. ### Claim 9 A method for performing an alignment between digital models of a patient's teeth for improved detection of deviations from an orthodontic treatment plan, the method comprising: obtaining, by a storage subsystem associated with a data processing system, a first digital model of the patient's teeth in a first arrangement and a second digital model of the patient's teeth in a second arrangement, wherein the storage subsystem comprises a memory subsystem, the memory subsystem having one or more machine-readable instructions; detecting, by at least one processor in communication with the storage subsystem, in each of the first and second digital models, a partial region extending beyond and excluding one or more tooth crowns, the detecting being based on a polygon formed in part from identified cementoenamel junction (CEJ) points on a plurality of teeth and connecting the CEJ points of the plurality of teeth to enclose and define the partial region; and performing, by the at least one processor, an alignment between the first and second digital models using the partial regions such that one or more stationary elements of each of the first and second digital models are aligned with one another. ### Claim 10 (depends on 9) The method of claim 9, wherein the method further comprises detecting one or more positional differences between the first and second arrangements of the patient's teeth. ### Claim 11 (depends on 9) The method of claim 9, wherein the first arrangement comprises an actual arrangement of the patient's teeth after the orthodontic treatment plan has begun for the patient and the second arrangement comprises a pre-determined planned arrangement of the patient's teeth. ### Claim 12 (depends on 11) The method of claim 11, wherein the first digital model comprises a non-segmented model of the patient's teeth in the actual arrangement and the second digital model comprises a previously segmented model of the patient's teeth. ### Claim 13 (depends on 9) The method of claim 9, wherein performing the alignment comprises: calculating an alignment transform using the partial regions; and wherein the alignment between the first and second digital models is based at least in part on the calculated alignment transform. ### Claim 14 (depends on 9) The method of claim 9, wherein the partial regions include one or more of a gingiva shape, palatine rugae, or hard plate. ### Claim 15 (depends on 9) The method of claim 9, wherein the partial regions in each of the first and second digital models are located on one or more of a lingual side or a buccal side of the one or more teeth. ### Claim 16 (depends on 9) The method of claim 9, wherein the one or more stationary elements are located within the partial regions. ### Claim 17 (depends on 9) The method of claim 9, wherein the obtaining, detecting, and performing steps are performed with aid of the at least one processor. ### Claim 18 One or more non-transitory computer-readable storage media having stored thereon executable instructions that, when executed by at least one processor of a data processing system for performing an alignment between digital models of a patient's teeth for improved detection of deviations from an orthodontic treatment plan, cause the data processing system to: obtain, by a storage subsystem associated with a data processing system, a first digital model of the patient's teeth in a first arrangement and a second digital model of the patient's teeth in a second arrangement; detect, by at least one processor in communication with the storage subsystem, in each of the first and second digital models, a partial region extending beyond and excluding one or more tooth crowns, the detecting being based on a polygon formed in part from identified cementoenamel junction (CEJ) points on a plurality of teeth and connecting the CEJ points of the plurality of teeth to enclose and define the partial region; and perform, by the at least one processor, an alignment between the first and second digital models using the partial regions such that one or more stationary elements of each of the first and second digital models are aligned with one another.