3D dentofacial system and method

Patent metadata

Field	Value
Publication number	US-9808326-B2
Application number	US-201514661820-A
Country	US
Kind code	B2
Filing date	Mar 18, 2015
Priority date	Mar 18, 2014
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

A reference standard or reference system for dental feature location and orientation can include evaluating the facial appearance of one or more subjects based on aesthetic criteria and selecting a subset of subjects. The reference standard further includes constructing 3D representations, (e.g., a 3D virtual model), of the facial and dental features of the subset of subjects, from photographs of the face and mouth of each subject and determining the location and/or orientation of one or more dental features for each subject. The location and/or orientation values for each subject can be used to produce an average value and a standard deviation that forms the basis for a reference standard as part of reference system for evaluating patients. The method and system further includes constructing 3D representations (e.g., a 3D virtual model) of the facial and dental features of a patient from photographs of the face and mouth of the patient and determining the location and/or orientation of one or more dental features of the patient in order to compare them to the reference standard and develop a treatment plan for the subject based on differences between the patient's measurements and reference standard. The reference standard can use the pupils (e.g., in the natural head position orientation) as a landmark for registration and scaling of the reference standard to the patient under evaluation.

First claim

What is claimed is:

1. A method for determining a reference standard diagnostic tool comprising:
selecting a set of subjects meeting a first set of aesthetic criteria;
determining a 3 dimensional (3D) representation of a head and mouth of each subject from two or more photographic images of the head and mouth of each subject, the 3D representation including an indication a central point of a left pupil and a right pupil of each subject;
wherein the 3D representation of the head and mouth is determined by indexing a first photographic image to a second photographic image by marking an area in the first photographic image and searching for an area in the second photographic image having a substantially same curvature as the marked area in the first photographic image;
identifying at least one dental feature and at least one facial feature in the 3D representation of the head and mouth of each subject;
identifying at least one landmark on the at least one dental feature and at least one landmark on the at least one facial feature in the 3D representation of the head and mouth of each subject;
defining in the 3D representation of the head and mouth of each subject a mid-axial plane extending horizontally through the central point of both pupils of each subject;
defining in the 3D representation of the head and mouth of each subject a mid-coronal plane extending vertically through the central point of both pupils of each subject;
defining in the 3D representation of the head and mouth of each subject a left sagittal plane extending vertically through the left pupil of each subject;
defining in the 3D representation of the head and mouth of each subject a right sagittal plane extending vertically through the right pupil of each subject;
determining a first dental landmark distance from at least one of the mid-axial plane, the mid-coronal plane, the left sagittal plane, and the right sagittal plane to the at least one landmark on the at least one dental feature; and
determining a first facial landmark distance from at least one of the mid-axial plane, the mid-coronal plane, the left sagittal plane, and the right sagittal plane to the at least one landmark on the at least one facial feature.

2. The method according to claim 1 wherein the at least one dental feature includes a tooth and the at least one landmark is a point along a facial axis of a clinical crown of the tooth.

3. The method according to claim 1 wherein the at least one facial feature includes a location on the face of the subject and the at least one landmark is a point midway between the pupils of the subject.

4. The method according to claim 1 wherein the first dental landmark distance is determined as a perpendicular distance from one of the mid-axial plane, the mid-coronal plane, the left sagittal plane, and the right sagittal plane.

5. The method according to claim 1 wherein the first facial landmark distance is determined as a perpendicular distance from one of the mid-axial plane, the mid-coronal plane, the left sagittal plane, and the right sagittal plane.

6. The method according to claim 1 wherein the 3D representation of the head and mouth is determined only using the two or more photographic images.

7. The method according to claim 1 wherein the first photographic image shows a facial image of the subject at rest and the second photographic image shows a smiling facial image of the subject, and the first photographic image is superimposed over the second photograph image by matching the marked area of the first photographic image to the area in the second photographic image having a substantially same curvature as the marked area in the first photographic image, such that when the first photograph image is made transparent any teeth shown in the second transparent image are visible with respect to the facial image of the subject at rest.

8. A method for determining an orthodontic patient treatment plan from reference standard comprising:
determining a 3 dimensional (3D) representation of a head and mouth of the patient from two or more photographic images of the head and mouth of the patient, the 3D representation including an indication a central point of a left pupil and a right pupil of the patient;
wherein the 3D representation of the head and mouth is determined by indexing a first photographic image to a second photographic image by marking an area in the first photographic image and searching for an area in the second photographic image having a substantially same curvature as the marked area in the first photographic image;
identifying at least one dental feature and at least one facial feature in the 3D representation of the head and mouth of the patient;
identifying at least one landmark on the at least one dental feature and at least one landmark on the at least one facial feature in the 3D representation of the head and mouth of the patient;
defining in the 3D representation of the head and mouth of the patient a mid-axial plane extending horizontally through the central point of both pupils of the patient;
defining in the 3D representation of the head and mouth of the patient a mid-coronal plane extending vertically through the central point of both pupils of the patient;
defining in the 3D representation of the head and mouth of the patient a left sagittal plane extending vertically through the left pupil of the patient;
defining in the 3D representation of the head and mouth of the patient a right sagittal plane extending vertically through the right pupil of the patient;
determining a first dental landmark distance from at least one of the mid-axial plane, the mid-coronal plane, the left sagittal plane, and the right sagittal plane to the at least one landmark on the at least one dental feature of the patient;
comparing the first dental landmark distance with a corresponding reference standard distance to determine a deviation from the reference standard distance;
and
determining a patient treatment plan as a function of the determined deviation from the reference standard distance.

9. The method according to claim 8 wherein the at least one dental feature includes a tooth and the at least one landmark is a point along a facial axis of a clinical crown of the tooth.

10. The method according to claim 8 wherein the first dental landmark distance is determined as a perpendicular distance from one of the mid-axial plane, the mid-coronal plane, the left sagittal plane, and the right sagittal plane.

11. The method according to claim 8 further comprising determining a first dental axis as a line intersecting at least one dental landmark and determining a dental landmark angle as an angle between the first dental axis and one of the mid-axial plane, the mid-coronal plane, the left sagittal plane, and the right sagittal plane.

12. The method according to claim 8 wherein the 3D representation of the head and mouth is determined only using the two or more photographic images.

13. The method according to claim 8 wherein the first photographic image shows a facial image of the subject at rest and the second photographic image shows a smiling facial image of the subject, and the first photographic image is superimposed over the second photograph image by matching the marked area of the first photographic image to the area in the second photographic image having a substantially same curvature as the marked area in the first photographic image, such that when the first photograph image is made transparent any teeth shown in the second transparent image are visible with respect to the facial image of the subject at rest.

14. A method for determ

Assignees

• Harvard College
• Univ Boston

Inventors

• Masoud Mohamed I

Classifications

• G16H30/40

  for processing medical images, e.g. editing · CPC title

• A61B2034/105

  Modelling of the patient, e.g. for ligaments or bones · CPC title

• A61B34/10

  Computer-aided planning, simulation or modelling of surgical operations · CPC title

• A61C7/002 Primary

  Orthodontic computer assisted systems · CPC title

• A61B2576/02

  specially adapted for a particular organ or body part · CPC title