MEDICAL IMAGING TOOTH DISPLACEMENT SYSTEMS AND METHODS

Abstract

The present disclosure relates to systems, computer programs, and methods employing oral cavity image capture for determining tooth displacement (e.g., for identifying patients with, or at risk for, periodontal disease). In certain embodiments, a medical imaging device or system (e.g., an intraoral scanner or other scanner) is employed to generate baseline and test scan images of at least one tooth, where the test scan is performed when the tooth in engaged with an opposing tooth in a chewing action, or is being pushed by an outside force, and the images are processed by a computer program to determine the amount of displacement of the tooth in at least one direction.

Claims

1. A method of determining tooth displacement comprising: a) performing a first scan of at least a portion of the oral cavity of a subject using an intraoral scanner to generate baseline scan data, wherein said baseline scan data comprises a baseline image of a first tooth, and wherein said first scan is performed when said first tooth: i) is not engaged with an opposing tooth in a chewing action, and ii) is not being pushed by an outside force; b) performing a second scan of at least a portion of said oral cavity of said subject using an intraoral scanner to generate first test scan data, wherein said first test scan data comprises a first test image of said first tooth, wherein said second scan is performed when said first tooth is: i) engaged with said opposing tooth in a chewing action, or ii) is being pushed by an outside force; and c) processing said baseline scan data and said first test scan data with a processing system to thereby determine an amount of displacement of said first tooth in at least one direction, wherein said processing system comprises: i) a computer processor, and ii) non-transitory computer memory comprising one or more computer programs, wherein said one or more computer programs, in conjunction with said computer processor, is/are configured to align said baseline image and said first test image and calculate said amount of displacement of said first tooth in said at least one direction.

2. The method of claim 1, further comprising: performing a third scan of at least a portion of said oral cavity of said subject using an intraoral scanner to generate second test scan data, wherein said second test scan data comprises a second test image of said first tooth, wherein said third scan is performed when said first tooth is: i) engaged with said opposing tooth in a chewing action, or ii) is being pushed by an outside force.

3. The method of claim 2, further comprising: processing said baseline scan data and said second test scan data with said processing system to thereby determine an amount of displacement of said first tooth in at least one direction.

4. The method of claim 3, further comprising: performing a fourth scan of at least a portion of said oral cavity of said subject using an intraoral scanner to generate third test scan data, wherein said third test scan data comprises a third test image of said first tooth, wherein said fourth scan is performed when said first tooth is: i) engaged with said opposing tooth in a chewing action, or ii) is being pushed by an outside force.

5. The method of claim 4, further comprising: processing said baseline scan data and said third test scan data with said processing system to thereby determine an amount of displacement of said first tooth in at least one direction.

6. The method of claim 1, wherein said baseline scan data further comprises a first reference point image from a first location in said oral cavity, and wherein said first test scan data further comprises a first corresponding reference point image from said first location in said oral cavity.

7. The method of claim 6, wherein said one or more computer programs employ said first reference point image and said first corresponding reference point image to align said baseline image and said first test image.

8. The method of claim 7, wherein said baseline scan data further comprises a second reference point image from a second location in said oral cavity, and wherein said first test scan data further comprises a second corresponding reference point image from said second location in said oral cavity.

9. The method of claim 1, wherein said amount of displacement of said first tooth in a generally horizontal direction is at least 0.05 millimeters, wherein said processing system further comprises a display component or is linked to a display component, and wherein the method further comprises: d) reporting that said subject has, or is at elevated risk for, periodontal disease on said display component.

10. The method of claim 1, wherein said amount of displacement of said first tooth in a generally horizontal direction is at least 1.1 millimeters, wherein said processing system further comprises a display component or is linked to a display component, and wherein the method further comprises: d) reporting that said subject has, or is at elevated risk for, periodontal disease on said display component.

11. The method of claim 1, wherein said first tooth is being pushed by an outside force selected from the group consisting of: a human finger, a dental mirror, and a rod.

12. The method of claim 1, wherein said first tooth is a type of tooth selected from the group consisting of: cuspid, incisor, molar, premolar, and third molar.

13. The method of claim 1, wherein said baseline image of said first tooth, and said test image of said first tooth, are both 3-D images.

14. The method of claim 1, wherein said first tooth is pushed in a general buccal direction.

15. The method of claim 1, wherein said first tooth is pushed in a general lingual direction.

16. The method of claim 1, wherein said at least one direction is selected from the group consisting of: generally buccal, generally lingual, generally apical, generally coronal, generally mesial, and generally distal.

17. The method of claim 1, wherein said at least one direction is at least two different directions selected from the group consisting of: generally, buccal, generally lingual, generally apical, generally coronal, generally mesial, and generally distal.

18. The method of claim 1, wherein said at least one direction is at least three different directions selected from the group consisting of: generally, buccal, generally lingual, generally apical, generally coronal, generally mesial, and generally distal.

19. The method of claim 1, wherein said amount of displacement of said first tooth is the amount of displacement of the crown of said first tooth.

20. The method of claim 19, wherein said amount of displacement of said crown of said first tooth is the amount of displacement of at least one of the following: i) the cervical area of said crown, ii) the middle area of said crown, and iii) the occlusal area of said crown.

21. The method of claim 21, wherein said amount of displacement of said crown of said first tooth is the average amount of displacement of the cervical area, the middle area, and the occlusal area of said crown.

22. The method of claim 1, wherein said first tooth is being pushed by an outside force comprises at least 0.05 N of force applied to said first tooth.

23. The method of claim 1, wherein said first tooth is being pushed by an outside force comprises between 0.05 and 25 N of force is applied to said first tooth.

24. The method of claim 1, wherein said second scan is performed when said first tooth is engaged with said opposing tooth in a chewing action.

25. The method of claim 1, wherein said second scan is performed when said first tooth is being pushed by an outside force.

26. The method of claim 1, wherein said subject is suspect of having periodontal disease.

27. A processing system comprising: a) a computer processor, and b) non-transitory computer memory comprising one or more computer programs, wherein said one or more computer programs, in conjunction with said computer processor, is/are configured to process baseline scan data and first test scan data with a processing system to thereby determine an amount of displacement of a first tooth in at least one direction, wherein said baseline scan data is generated from a first scan of at least a portion of the oral cavity of a subject using an intraoral scanner, wherein said baseline scan data comprises a baseline image of said first tooth, wherein said first scan is performed when said first tooth: i) is not engaged with an opposing tooth in a chewing action, and ii) is not being pushed by an outside force, wherein said first test scan data is generated from a second scan of at least a portion of said oral cavity of said subject using an intraoral scanner, wherein said first test scan data comprises a first test image of said first tooth, wherein said second scan is performed when said first tooth is: i) engaged with said opposing tooth in a chewing action, or ii) is being pushed by an outside force; and wherein said one or more computer programs, in conjunction with said computer processor, is/are further configured to align said baseline image and said first test image and calculate said amount of displacement of said first tooth in said at least one direction.

28. The system of claim 27, wherein the one or more computer programs are further configured to process the baseline scan data and second scan data with a processing system to thereby determine an amount of displacement of said first tooth in at least one direction, wherein said second scan data is generated from a third scan of at least a portion of the oral cavity of said subject using an intraoral scanner, wherein said second test scan data comprises a second test image of said first tooth, wherein said third scan is performed when said first tooth is: i) engaged with said opposing tooth in a chewing action, or ii) is being pushed by an outside force.

29. The system of claim 28, wherein the one or more computer programs are further configured to process the baseline scan data and third scan data with a processing system to thereby determine an amount of displacement of said first tooth in at least one direction, wherein said third scan data is generated from a fourth scan of at least a portion of the oral cavity of said subject using an intraoral scanner, wherein said third test scan data comprises a third test image of said first tooth, wherein said fourth scan is performed when said first tooth is: i) engaged with said opposing tooth in a chewing action, or ii) is being pushed by an outside force.

30. The system of claim 27, wherein said non-transitory computer memory further comprises a database, wherein said database comprises a periodontal disease algorithm, and wherein said one or more computer programs is configured to apply said amount of displacement of said first tooth to said periodontal disease algorithm and determine if said subject has, or is at elevated risk for, periodontal disease.

31. The system of claim 30, wherein said periodontal disease algorithm comprises an operation that finds periodontal disease is present in said subject if said amount of displacement of said first tooth in a generally horizontal direction is at least 0.05 millimeters.

32. The system of claim 30, wherein said periodontal disease algorithm comprises an operation that finds periodontal disease is present in said subject if said amount of displacement of said first tooth in a generally horizontal direction is at least 1.1 millimeters.

33. The system of claim 27, wherein said baseline scan data further comprises a first reference point image from a first location in said oral cavity, and wherein said first test scan data further comprises a first corresponding reference point image from said first location in said oral cavity.

34. The system of claim 33, wherein said one or more computer programs is further configured to employ said first reference point image and said first corresponding reference point image to align said baseline image and said first test image.

35. The system of claim 34, wherein said baseline scan data further comprises a second reference point image from a second location in said oral cavity, and wherein said first test scan data further comprises a second corresponding reference point image from said second location in said oral cavity.

36. The system of claim 27, further comprises a display component or is linked to a display component.

37. The system of claim 27, wherein said first tooth is being pushed by an outside force selected from the group consisting of: a human finger, a dental mirror, and a rod.

38. The system of claim 27, wherein said first tooth is a type of tooth selected from the group consisting of: cuspid, incisor, molar, premolar, and third molar.

39. The system of claim 73, wherein said baseline image of said first tooth, and said test image of said first tooth, are both 3-D images.

40. The system of claim 27, wherein said first tooth is pushed in a general buccal direction when said first test scan data is generated.

41. The system of claim 27, wherein said first tooth is pushed in a general lingual direction when said first test scan data is generated.

42. The system of claim 27, wherein said at least one direction is selected from the group consisting of: generally buccal, generally lingual, generally apical, generally coronal, generally mesial, and generally distal.

43. The system of claim 27, wherein said at least one direction is at least two different directions selected from the group consisting of: generally, buccal, generally lingual, generally apical, generally coronal, generally mesial, and generally distal.

44. The system of claim 27, wherein said at least one direction is at least three different directions selected from the group consisting of: generally, buccal, generally lingual, generally apical, generally coronal, generally mesial, and generally distal.

45. The system of claim 27, wherein said amount of displacement of said first tooth is the amount of displacement of the crown of said first tooth.

46. The system of claim 45, wherein of displacement of said crown of said first tooth is the amount of displacement of at least one of the following: i) the cervical area of said crown, ii) the middle area of said crown, and iii) the occlusal area of said crown.

47. The system of claim 45, wherein of displacement of said crown of said first tooth is the average amount of displacement of the cervical area, the middle area, and the occlusal area of said crown.

48. The system of claim 27, wherein said first tooth is being pushed by an outside force comprises at least 0.05 N of force applied to said first tooth when said first test scan data is generated.

49. The system of claim 27, wherein said first tooth is being pushed by an outside force comprises between 0.05 and 25 N of force applied to said first tooth when said first test data is generated.

50. The system of claim 27, wherein said second scan is performed when said first tooth is engaged with said opposing tooth in a chewing action.

51. The system of claim 27, wherein said second scan is performed when said first tooth is being pushed by an outside force.

52. A non-transitory computer memory comprising one or more computer programs, wherein said one or more computer programs is/are configured to process baseline scan data and first test scan data with a processing system to thereby determine an amount of displacement of a first tooth in at least one direction, wherein said baseline scan data is generated from a first scan of at least a portion of the oral cavity of a subject using an intraoral scanner, wherein said baseline scan data comprises a baseline image of said first tooth, wherein said first scan is performed when said first tooth: i) is not engaged with an opposing tooth in a chewing action, and ii) is not being pushed by an outside force, wherein said first test scan data is generated from a second scan of at least a portion of said oral cavity of said subject using an intraoral scanner, wherein said first test scan data comprises a test image of said first tooth, wherein said second scan is performed when said first tooth is: i) engaged with said opposing tooth in a chewing action, or ii) is being pushed by an outside force; and wherein said one or more computer programs is/are further configured to align said baseline image and said first test image and calculate said amount of displacement of said first tooth in said at least one direction.

53. The system of claim 52, wherein the one or more computer programs are further configured to process the baseline scan data and second scan data with a processing system to thereby determine an amount of displacement of said first tooth in at least one direction, wherein said second scan data is generated from a third scan of at least a portion of the oral cavity of said subject using an intraoral scanner, wherein said second test scan data comprises a second test image of said first tooth, wherein said third scan is performed when said first tooth is: i) engaged with said opposing tooth in a chewing action, or ii) is being pushed by an outside force.

54. The system of claim 53, wherein the one or more computer programs are further configured to process the baseline scan data and third scan data with a processing system to thereby determine an amount of displacement of said first tooth in at least one direction, wherein said third scan data is generated from a fourth scan of at least a portion of the oral cavity of said subject using an intraoral scanner, wherein said third test scan data comprises a third test image of said first tooth, wherein said fourth scan is performed when said first tooth is: i) engaged with said opposing tooth in a chewing action, or ii) is being pushed by an outside force.

55. A method of scanning an oral cavity of a subject comprising: a) performing a first scan of at least a portion of the oral cavity of a subject using an intraoral scanner to generate baseline scan data, wherein said baseline scan data comprises a baseline image of a first tooth, and wherein said first scan is performed when said first tooth is not being pushed by an outside force; b) pushing on said first tooth to cause displacement of said tooth in at least one direction, and c) performing a second scan of at least a portion of said oral cavity of said subject using an intraoral scanner to generate test scan data, wherein said test scan data comprises a first test image of said first tooth, and wherein said second scan is performed when said first tooth is being pushed in step b).

Description

BRIEF DESCRIPTION OF THE FIGURES

[0021] FIG. 1 shows an exemplary tooth mobility evaluation process, which includes: a) a representation of a tooth in the mouth at baseline with no displacement; b) a representation of a tooth in the mouth with no displacement at baseline with three reference points in the crown (occlusal, middle, and cervical) for tracking movement, and a medical imaging device or system (e.g., an intraoral scanner or other scanner) pointed at the tooth; c) a representation of a tooth in the mouth where displacement is observed via a dental mirror exerting force on the tooth; and d) a representation of a tooth in the mouth with a position different than the baseline. Displacement can be calculated, for example, on any one, or all three, reference points compared to baseline values.

[0022] FIG. 2 shows an exemplary tooth or teeth mobility evaluation process, which includes: a) a representation of teeth in the mouth at baseline with no displacement; b) a representation of teeth in the mouth with no displacement at baseline with three reference points in the crown (occlusal, middle, and cervical) for tracking movement, and a medical imaging device or system (e.g., an intraoral scanner or other scanner) pointed at the teeth; c) a representation of teeth in the mouth where displacement is observed when the teeth are engaged with opposing teeth in a chewing action; and d) a representation of teeth in the mouth with a position different than the baseline due to the displacement promoted when teeth are engaged in a chewing action. Displacement can be calculated, for example, on any one, or all three, reference points compared to baseline values.

[0023] FIG. 3 shows an image of a typodont oral cavity model, shown with the handle of a dental mirror pushing on one of the teeth in the model.

[0024] FIG. 4 shows an alignment of the two digital models obtained by intra-oral scanning from Example 1. Three coincident areas were employed as reference in each model for alignment.

[0025] FIG. 5 shows a 3D comparison of the two digital models aligned. Different colors indicate amount of deviation between the models.

[0026] FIG. 6 shows how a grid tool and axis references were used to standardize image position for analysis.

[0027] FIG. 7 shows three different reference points that were chosen to measure the linear movement in millimeters in the 3 different axis.

[0028] FIG. 8 shows the X, Y, Z axes direction in relation to the buccal-lingual, coronal-apical and mesio-distal planes.

[0029] FIG. 9 shows a scatter plot of the data in microns obtained, in Example 1, at different axes showing a limited dispersion of the data in the different reference points for mobility 1 and 2. Value reported in p.m, n=30.

[0030] FIG. 10 shows that different mobility was observed and reported in microns, in Example 1, along the cervical, middle and occlusal points. (**)=p<0.001, #=0.02, @=0.04, and the proportional change observed between the selected reference points, such as:

[0031] cervical-middle and cervical-occlusal in different axis, reported as percentage.

[0032] FIG. 11 shows an exemplary 3D scan of an intraoral cavity with a tooth being pushed by the end of the handle of a dental mirror.

[0033] FIG. 12 shows the results of Example 2 wherein two operators measured 3 different mobilities (A, B, and C) that were measured in microns at three different heights on the crown (occlusal, middle, and cervical) in the typodont. The three mobilities were generated by changing the level of attachment of the plastic tooth. FIG. 11A shows results for mobility A; FIG. 11B shows results for mobility B; and FIG. 11C shows results for mobility C.

[0034] FIG. 13 shows the results of Example 2 where five measurements were obtained by a single operator at each of occlusal, middle, and cervical reference points.

[0035] FIG. 14 shows the results in microns of Example 2 where 5 operators measured tooth mobility at each reference point occlusal, middle, and cervical.

[0036] FIG. 15 shows results of Example 2 where 5 operators employed 5 scans and measured tooth mobility in microns at occlusal (FIG. 15A), middle (FIG. 15B) and cervical (FIG. 15C) reference points.

[0037] FIG. 16 shows an exemplary tooth mobility evaluation in a patient without periodontal disease using a computer-aided diagnostic system, which includes: a) scan image of the mouth at baseline with no force applied; b) scan image of the mouth when a force is applied by the handle of a dental mirror on the first right maxillary tooth; c) tooth displacement values obtained after a) and b) were processed generating linear displacement in the three different axis in three reference points. Mean values calculated from three operators are represented in FIG. 16D. The overall displacement on the three reference points in all three axes below 15 microns indicates stable periodontium tissues compatible with absence of disease.

[0038] FIG. 17 shows an exemplary tooth mobility evaluation in a patient with periodontal disease using a computer-aided diagnostic system, which includes: a) scan image of the mouth at baseline with no force applied; b) scan image of the mouth when a force is applied by the handle of a dental mirror on the first mandibular left molar; c) tooth displacement values obtained after a) and b) were processed generating linear displacement in the three different axis at three reference points. Mean values calculated from three operators are represented in FIG. 17D. The displacement observed in the occlusal, middle and cervical points in the buccal direction (dx) ranging from 100 microns to 150 microns indicates unstable periodontium tissues compatible with the presence of disease.

[0039] FIG. 18 shows an exemplary tooth displacement in a typodont simulating the forces transmitted by an antagonist tooth during the movement of the mandible, such as chewing. Two scan files of tooth #30 and #6 were obtained without and with contact with the antagonist teeth. The two scan files were then processed and the 3D analysis used to establish the deviation at pre-determined points between the first and second scan. Three reference points at the tooth were chosen with the tool create annotations, providing the 3D deviation by linear deviation of each of the 3 axes (x, y, z) associated to a mandibular right first molar (FIG. 18A) and maxillary right canine (FIG. 18B). The mean values obtained by two operators in the cervical, middle and cervical reference points were determined in the three axes (x, y, z) (FIG. 18C). The data demonstrates a deviation to the lingual direction in the mandibular right first molar and to the buccal direction in tooth maxillary right canine during contact with the opposing teeth when a normal chewing contact is simulated.

Definitions

[0040] As used herein, the term “diagnosis” “diagnosis” can encompass determining the nature of disease in a subject, as well as determining the severity and probable outcome of disease or episode of disease and/or prospect of recovery (prognosis). “Diagnosis” can also encompass diagnosis in the context of rational therapy, in which the diagnosis guides therapy, including initial selection of therapy, modification of therapy (e.g., adjustment of dose and/or dosage regimen or lifestyle change recommendations), and the like. In certain embodiments, a subject is diagnosed with periodontal disease supported on the tooth mobility methods and systems described herein.

[0041] The terms “individual,” “host,” “subject,” and “patient” are used interchangeably herein, and generally refer to a mammal, including, but not limited to, primates, including simians and humans, equines (e.g., horses), canines (e.g., dogs), felines, various domesticated livestock (e.g., ungulates, such as swine, pigs, goats, sheep, and the like), as well as domesticated pets and animals maintained in zoos. In some embodiments, the subject is specifically a human subject (e.g., a human at risk of periodontitis).

[0042] As used herein, the phrase “periodontal disease” also known as “gum disease,” is a set of inflammatory conditions affecting the tissues surrounding the teeth. In its early stage, called gingivitis, the gums become swollen, red, and may bleed. In its more serious form, called periodontitis, the gums can pull away from the tooth, bone can be lost, and the teeth may loosen or fall out.

DETAILED DESCRIPTION OF THE INVENTION

[0043] The present disclosure relates to systems, computer programs, and methods employing oral cavity image capture for determining tooth displacement (e.g., for identifying patients with, or at risk for, periodontal disease). In certain embodiments, a medical imaging device or system (e.g., an intraoral scanner or other scanner) is employed to generate baseline and test scan images of at least one tooth, where the test scan is performed when the tooth in engaged with an opposing tooth in a chewing action, or is being pushed by an outside force, and the images are processed by a computer program to determine the amount of displacement of the tooth in at least one direction.

[0044] Provided herein are methods, systems, and software to determine tooth mobility based on intra-oral scanner measurements. In certain embodiments, such systems, software and methods provide reliable 3D quantitative oral health outcomes for physiological and non-physiological movements of the tooth. In some embodiments, provided herein are three-dimensional (3D) measuring techniques that utilize intra-oral scanners to capture the tooth position under different physiological and non-physiological function, providing: i) a systematic approach to collect reference points of the moving tooth or teeth, ii) a systematic approach to collect reference points of non-moving oral tissues, and iii) a tooth mobility calculation system which determine mobility of the tooth on the basis of the difference of the baseline output values compared to the outputs obtained during a single or multiple dental visits. In certain embodiments, the overall displacement of the tooth is provided as a quantitative outcome to be used for diagnosis, planning, assessing tooth prognosis, determining the need for intervention, and/or evaluating patients' progress with and without treatment.

[0045] The present disclosure provides, in certain embodiments, an accurate and reliable quantitative assessment of tooth displacement that can be used to measure tooth mobility by comparing different measurements using defined reference points of the moving tooth and non-moving tissues in the oral cavity. The measurement, in some embodiments, is obtained with an intra-oral scanner based measurements of the oral cavity structures generating accurate 3D mapping of the oral cavity structures which includes the tooth, or teeth, of interest, and the neighboring teeth. This provides a non-invasive technique that will collect data of tooth mobility without the need to intervene with invasive analog tools, such as periodontal or exploratory probes, minimizing the impact of the operator technique and experience on the outcome measure.

[0046] In certain embodiments, provided herein are tooth mobility assessment methods, that include: i) an integrated approach to determine reference points of the oral cavity structures, including the tooth of interest and neighboring tissues, ii) a minimum number of points at the tooth surface of interest to be considered to calculate tooth mobility at varying time points according to the outcome measurement of interest, iii) a minimum number of points or surfaces to be used as reference throughout the evaluations allowing accurate alignment of the oral cavity scans, iv) an internal check to indicate errors during measurement to inform the operator the need to redo the scan enabling scans comparison; and/or v) at least one main displacement outcome measurement along the 3-axis to be considered by the dental team during evaluation based on the disease or condition of interest. In certain embodiments, the tooth mobility data is incorporated into a subject's electronic oral and/or medical health records.

[0047] Image capturing sensors that will record the geometry of oral tissues based on passive or active light emission are known in the art. In general, the object is recorded as a single image or a video compiling data points of the region of interest to generate the three-dimensional digital reconstructions. Particular image capturing technologies available are: passive or active triangulation (AT), confocal laser scanning microscopy, accordion fringe interferometry (AFI), active wavefront sampling (AWS), and stereophotogrammetry. Exemplary commercial devices are displayed in Table 3.

TABLE-US-00001 TABLE 3 SCANNER TECHNOLOGY(IES) PRIMEScan (Dentsply Sirona) AT and CLSM CEREC AC Omnicam (Dentsply Sirona) AT and CLSM CEREC AC BlueCam (Dentsply Sirona) AT and CLSM MIA 3D (Densys Ltd.) AT stereophotogrammetry DirectScan (HINT - ELS GMBH) AT stereophotogrammetry Virtuo Vivo (Dental Wings) AT stereophotogrammetry Condor (Condor Technologies) AT stereophotogrammetry iTero element (Align Technology) CLSM CS 3700 (Carestream Dental) CLSM Trios (3shape) CLSM Lythos (Digital Impressions, Ormco Corp) AFI Medit i500 (Medit) AT Midmark True definition (Midmark) AWS Planmeca Emerald S (Planmeca) CLSM Aadva IOS 200 (GC) CLSM ZFX IntraScan (Zfx GmbH) CLSM and AFI

EXAMPLES

[0048] The following examples are for purposes of illustration only and are not intended to limit the scope of the claims.

Example 1

Quantitative Tooth Mobility Evaluation Based on Intra-Oral Scanning

[0049] This Example employs an intraoral scanner to quantitatively test tooth mobility.

Material and Methods

Images Acquisition

[0050] The method in this Example is based on the 3D comparison of digital models obtained with an intra-oral scanner (Trios, 3hape, Denmark). A first digital impression of the typodont (SM-PVR-860, Columbia Dentoform, Long Island City, N.Y.), as shown in FIG. 1, with its original configuration was obtained with the scanner and defined as the baseline. A series of digital impressions of the typodont was taken with the operators pushing the typodont's tooth to be analyzed into a buccal direction. The force was applied with the tip of the handle of a dental mirror placed in the lingual surface. The goal was to promote a movement in the tooth that simulates a dental mobility commonly associated with periodontitis.

[0051] A typodont model was used to simulate the clinical environment and two different degrees of tooth mobility were created by changing the tightness of the screw holding tooth #16. Each operator was asked to push the tooth into a buccal position to promote the movement, with the use of the handle of a dental mirror. An example of this is shown in the image in FIG. 2. The operator was asked also to hold the instrument at the final position of tooth movement while a second operator performed the scanning. Three experienced periodontists evaluated two mobility and repeated the measurements 10 times. The operators were asked to simulate the same force and direction used in a clinical setting. No instructions were provided to the operators regarding direction and magnitude of the force during the experiment.

Mobility Evaluation

[0052] Digital impressions of the models were obtained with the scanner and the .stf files were exported from the software TRIOS (3shape, Denmark). The images were compared in the Geomagic Qualify software (3dsystems, North Carolina, USA). For the different evaluations, one baseline digital impression was obtained as reference and the different tested scenarios compared to generate the deviations at different pre-determined points in the crown (#16). The two models for each evaluation were then aligned using surfaces in the image not affected by the force applied to #16 (FIG. 3). Once the models were aligned and the fit confirmed, a 3D analysis tool was used to establish the deviation at pre-determined points between the reference and test models (FIG. 4). The image was positioned setting the buccal surface of the tooth in the screen and aligned 90° with the ground plane using regions not affected by the displacement of #16 (FIG. 5). For the displacement analysis, three reference points at the buccal surface of the tooth were chosen to determine by linear deviation in the 3 axis (x, y, z). The 3 areas chosen were in the cervical, middle and occlusal third of the tooth crown (FIG. 6). The linear measurements of the movement in the 3 different axes were collected for statistical analysis. The x, y and y axes represent the bucco-lingual, apical-coronal, and mesio-distal directions of the tooth anatomy. It was determined that a positive sign during the analysis represented a change to the buccal, apical, and mesial for the present evaluation, and a negative sign would relate to the lingual, coronal and distal, respectively (FIG. 7).

Statistical Analysis

[0053] The statistics analysis was performed to evaluate (1) reliability; (2) differences form mobility 1 and mobility 2, and (3) the variation in the different regions (cervical, middle, and occlusal). The reliability was analyzed by intraclass correlation coefficient (ICC). ICC estimates and their 95% confident intervals were calculated using SPSS statistical package version 24 (IBM, Chicago, Ill.). Based on the 95% confident interval of the ICC estimate, values less than 0.5, between 0.5 and 0.75, between 0.75 and 0.9, and greater than 0.90 are indicative of poor, moderate, good, and excellent reliability, respectevely.sup.ll. Data from mobility 1 and 2 was analyzed by t-test for each examiner or pooled to support a comprehensive interpretation. Data analysis among the cervical, middle and occlusal points was performed by one-way analysis of variance (ANOVA). Significance level was set at 95%. Tooth displacement was calculated in microns (pm).

Results

Reliability

[0054] Table 1a and 1b shows the mean +SD, inter-item correlation, Cronbach's alpha, Cronbach's alpha confidence interval CI (95%), and the F test for the ICC analysis.

TABLE-US-00002 TABLE 1A Mobility 1 Cervical Middle Inter-Item C's CI F Inter-Item Axis Examiners Mean + SD Correlation α (95%) Test Mean + SD Correlation x 1 124.3 + 7.2  1-2 = .986 .850 .559-.959 .000 178.9 + 17.3 1-2 = .961 2 132.4 + 25.7 1.3 = .933 149.5 + 21.2 1-3 = .929 3 132.7 + 13.3 2-3 = .901 178.4 + 15.0 2-3 = .953 y 1 32.8 + 4.7 1-2 = .944 .931 .798-.981 .000  −7.1 + 11.5 1-2 = .963 2 35.6 + 9.4 1-3 = .976 −16.4 + 12.7 1-3 = .791 3 33.6 + 5.2 2-3 = .958 −19.2 + 23.8 2-3 = .900 z 1 −61.1 + 7.9  1-2 = .982 .954 .866-.988 .000  −46.2 + .17.8 1-2 = .859 −59.4 + 12.9 1-3 = .931 −41.7 + 12.5 1-3 = .969 3 −63.0 + 7.9  2-3 = .950 −47.8 + 15.3 2-3 = .913 Mobility 1 Middle Occlusal C's CI F Mean Inter-Item C's CI F Axis Examiners α (95%) Test + SD Correlation α (95%) Test x 1 .972 .918-.992 .000 211.3 + 26.0 1-2 = .912 .966 .902-.991 .000 2  145.2 + .20.1 1-3 = .960 3 221.2 + 22.1 2-3 = .885 y 1 .891 .681-.971 .000  −35.5 + .11.7 1-2 = .961 .982 .946-.995 .000 2 −.24.3 + 14.4  1-3 =.987 3 −38.0 + 12.3 2-3 = .934 z 1 .961 .885-.989 .000 −17.8 + 21.0 1-2 = .963 .942 .829-.984 .000  −1.5 + 13.9 1-3 = .848 3  −4.3 + 13.1 2-3 = .905

TABLE-US-00003 TABLE 1b Mobility 2 Cervical Middle Inter-Item C's CI F Inter-Item Axis Examiners Mean + SD Correlation α (95%) Test Mean + SD Correlation x 1 192.0 + 33.7 1-2 = .848 .949 .852-.986 .000 291.1 + 28.7 1-2 = .847 2 202.1 + 26.7 1-3 = .836 265.4 + 19.1 1-3 = .692 3 215.4 + 30.7 2-3 = .949 270.2 + 24.9 2-3 = .917 y 1 49.7 + 9.0 1-2 = .728 .933 .803-.982 .000  10.5 + 15.6 1-2 = .843 2 52.7 + 8.4  1-3 = c.819 −10.4 + 21.2 1-3 = .838 3 51.3 + 8.6 2-3 = .928 −18.0 + 14.1 2-3 = .856 2 1 −100.9 + 18.1  1-2 = .807 .940 .825-.984 .000 −98.8 + 33.0 1-2 = .860 2 −102.3 + 14.1  1-3 = .899 −79.8 + 16.0 1-3 = .884 3 — 2-3 = .881 −60.4 2-3 = .882 Mobility 2 Middle Occlusal C's CI F Inter-Item C's CI F Axis Examiners α (95%) Test Mean + SD Correlation α (95%) Test x 1 .910 .737-.976 .000 362.8 + 36.1 1-2 = .857 .937  .816-.983 .000 2 299.8 + 30.8 1-3 = .945 3 268.0 + 54.6 2-3 = .916 y 1 .931 .799-.981 .000 −54.0 + 8.8  1-2 = .953 .976 .928-993 .000 2 −45.1 + 7.6  1-3 =.928 3 −45.9 + 10.1 2-3 = .968 2 1 .892 .685-.971 .000 −35.1 + 33.6 1-2 = .876 .906 .724-975 .000 2 −24.9 + 18.7 1-3 = .759 3 −18.9 2-3 = .926
The reliability of the technique is supported by the high Cronbach's alpha on the x, y and z axis for both mobility tested that scored above 0.9 in all groups, except for mobility 1 cervical x (0.850), mobility 1 middle y (0.891), and mobility 2 middle z (0.892). The analysis of the correlation between the examiners demonstrated excellent (above 0.90) or good (between 0.75 and 0.90) consistency of the measurements, except for mobility 1 cervical on they axis between examiners 1-2 (.728), and mobility 1 middle in the x axis between examiners 1-3 (0.692). A graphic representation of the data demonstrates the consistency of the measurements obtained in the different axis (FIG. 8).

Mobility 1×Mobility 2

[0055] Significant changes were detected in all axis at the three reference points comparing mobility 1 and 2 (Table 2).

TABLE-US-00004 TABLE 2 Δ M2 − M1 Axis Point (μm) Direction p-value X Cervical 73 Buccal p < 0.001 Middle 107 Buccal p < 0.001 Occlusal 121 Buccal p < 0.001 Y Cervical 17 Apical p < 0.001 Middle 8 Apical P = 0.002 Occlusal −16 Coronal p < 0.001 Z Cervical −43 Distal p < 0.001 Middle −34 Distal p < 0.001 Occlusal −18 Distal p < 0.001
Change observed to mobility 1 and mobility 2 in the three axis and three points evaluated. The mean value and resulted magnitude Δ(m2 −m1) and direction of the displacement is reported.

[0056] For the x axis, higher displacement of towards the buccal (P<0.001) was observed to mobility 2 compared to mobility 1 in the cervical, middle and occlusal points. The y axis showed a significant displacement to the apical at the cervical (P<0.001) and middle (p=0.002), whereas the displacement (P<0.001) at the occlusal was to the coronal direction, indicating a shift in resulting direction from mobility 1 to mobility 2 in the occlusal compared to the cervical and middle points. For the z axis, a displacement (P<0.001) at all points was observed to the distal.

Cervical x Middle X Occlusal

[0057] The data reporting the values calculated in the different points along the x, y, z axes is summarized in FIG. 9. The x axis demonstrated a gradual increase for both mobility in the middle compared to cervical (p<0.001), and for occlusal compared to middle for mobility 1 (p=0.02) and mobility 2 (p=0.04). For they axis, increase displacement to the coronal was observed to M compared to C (P<0.001) and 0 compared to M (P<0.001) for mobility 1 and 2. The z axis demonstrated higher displacement to the mesial for M compared to C (P<0.001) and 0 compared to M (P<0.001) for both mobility 1 and 2. Despite a significant difference in the values observed in mobility 1 compared to mobility 2, a similar change in percentages was observed between the cervical-middle and cervical-occlusal points, indicating a consistent movement in all points in all axes.

[0058] As shown in Table 1, excellent reliability was obtained testing different mobility as demonstrated by a high Cronbach's alpha above 0.9, and an inter-examiner correlation between 0.75>x<0.9 (good) or above 0.9 (excellent). Previous evaluation of mobility data was obtained based on a categorical data using 5.sup.12 or 2.sup.13 scores. The data was reported lower Cohen's k varying from poor (0.4) to moderate (0.6) between 2 examiners with 19 patients.sup.13. Higher values between 2 examiners based on the Pearson's correlation coefficient of 0.86 was obtained with the first set of 26 patients and 0.98 with 24 patients after recalibration.sup.12. The agreement of the data reported by the analysis of correlation should be done with cautious, since the coefficient shows the magnitude of the relationship, not the agreement. The reliability of the measurement depends on (1) the clarity of the criteria, (2) number of categories and (3) training of the examiners.sup.13. This Example demonstrates an objective measurement excluding the factors 1 and 2 that will generate an outcome restricted to the magnitude and the direction of the force applied by the operator.

[0059] Persson & Svensson (1980) in a clinical study associated greater tooth mobility measurements in periodontally compromised individuals, using a loading/sensing device. The apparatus utilized at the time was complex and presented several limitations like one dimensional recording possibility and no access to posterior teeth.sup.14. Schulte et al. (1992) examined the relationship between tooth mobility, assessed by means of the Periotest® (PVscore) and some clinical parameters of periodontal disease. The results showed that the percentage of bone loss was the parameter which was most highly correlated (r−=0.55) to the PVscore. Periotest instrument was also used in other studies, but a major limitation of this device is its restriction to only measure damping characteristics with a predefined frequency15, 16. Increased tooth mobility at baseline of periodontal treatment was one of the factors strongly associated with high levels of additional attachment loss during maintenance.sup.4, 5. Since tooth mobility could be a factor affecting severity, progression and therapeutic outcome of periodontal disease.sup.3, 17, accurate measurement is important.

[0060] In this example, a significant difference in mobility from 8 μm in the y axis in the middle up to 121 μm in the x axis in the occlusal was successfully characterized. The displacement was significantly different within each examiner and with the data pooled (Table 2). This Examples provides an accurate alternative for the measurement that could be correlated to periodontal clinical parameters allowing a more comprehensive evaluation of periodontally compromised patients.

[0061] Different approaches to monitor tooth mobility and to understand the behavior of the

[0062] PDL were reported in previous studies. The majority of the methods described were limited to in vitro application only, and in vivo studies are scarce.sup.18-20. Other studies implemented newly developed measurement systems in their investigations.sup.21, 22. Konermann et al. 2017.sup.21 developed a new device for in vivo measurement of tooth mobility. The authors demonstrated precision and validity in clinical use of the device, however it requires the construction of an individual splint for the upper jaw of each patient for intraoral fixation of the device. The technique used in this Example, and in this application, does not require a splint. Moreover, the measurement performance demanded high precision from the investigator in terms of splint adaption and patient supervision to avoid unwanted movements potentially impacting the measurement results. This Example demonstrates a user-friendly non-invasive technique that can be performed by the dentist and the dental hygienist.

Example 2

Oral Health Quantitative Outcomes for Physiologic and Non-Physiologic Tooth Displacement

[0063] This Example describes a method based on the 3D comparison of digital models obtained by digital impressions with an intra-oral scanner device (Trios, 3hape, Denmark). A first digital impression of the typodont on its original configuration was obtained and defined as the baseline. A second digital impression of the typodont was taken with the operator pushing the typodonts tooth to be analyzed, into a buccal direction. The force was applied with the tip of a dental mirror placed in the lingual surface. The goal was to promote a movement in the tooth that simulates a dental mobility commonly associated to periodontitis.

[0064] Digital impressions of the models were obtained and the stf files compared in Geomagic Qualify software (3dsystems, North Carolina, USA). For the different experiments, one baseline digital impression was obtained as reference and the different tested scenarios compared to generate the deviations at different pre-determined points in the crown. The two models were then aligned using the best-fit surface alignment tool of the software (fig. B). Once the models are aligned and the fit confirmed, a 3D analysis is used to establish the deviation at pre-determined points between the reference and test models. The grid tool and axis were used as reference to standardize image position. Three reference points at the tooth were chosen with the tool create annotations, providing the 3D deviation by linear deviation of each of the 3 axis (x, y, z). The 3 areas chosen were in the half part of the buccal surface and in the cervical, middle and occlusal third of the tooth crown. The linear measurement of the movement in the 3 different axis was collected for statistical analysis.

Tooth Mobility Simulating Periodontitis

[0065] A series of tests was performed. A typodont model was used to simulate the clinical environment. Different mobility were created by changing the tightness of the screw holding tooth #16. All values reported in microns. Different scenarios were tested to evaluate the reliability:

Test 1

[0066] Intra-Examiner (2 Operators) with Three Different Mobilities

[0067] Two operators measured 3 different mobilities (A, B, and C) that were measured at three different heights on the crown (occlusal, middle, and cervical) in the typodont. The three mobilities were generated by changing the level of attachment of the plastic tooth. This was done by unscrewing the screw that holds the tooth, as one can change how firm the tooth is placed in the plastic model. This was done to mimic progression of the periodontal disease with increased mobility overtime. This was also done to show resolution measurement variations below 50 microns. Mean values (D, Dx, Dy, and Dz) reported by examiner (Opl and Op2) at each reference point (occlusal, middle, and cervical). Results are shown in FIG. 11A-C.

Test 2

Intra-Examiner 5 Scans

[0068] Five measurements obtained by a single operator. Mean values (D, Dx, Dy, and Dz) reported by each scan at occlusal, middle, and cervical reference points, as shown in FIG. 12.

Test 3

[0069] A. 5 Inter-Examiner 5 Scans Mean Values

[0070] 5 measurements obtained by 5 operators. Mean values (D, Dx, Dy, and Dz) reported by examiner at each reference point (occlusal (FIG. 13A), middle (FIG. 13B), and cervical (FIG. 13C)).

[0071] B. 5 Inter-examiner 5 scans scatter-plot

[0072] 5 measurements obtained by 5 operators. Measurements: 1-5 operator 1; 6-10 operator 2; 11-15 operator 3; 16-20 operator 4; 21-25 operator 5. Values (Dx, Dy and Dz) calculated at occlusal (FIG. 14A), middle (FIG. 14B) and cervical (FIG. 14C) reference points.

Example 3

Computer-Aided Diagnosis System for Tooth Displacement in Patients without Periodontal Disease

[0073] This Example is a clinical demonstration of the steps described in Example 1 using a computer-aided diagnosis system based on an intra-oral scanner device. A first digital impression of a patient without periodontal disease was obtained and defined as the baseline (16A). A second digital impression of the patient was taken with an operator pushing tooth #3 into a buccal direction (16B). The force was applied with a handle of a dental mirror placed in the lingual surface. The goal was to promote a movement in the tooth that simulates a dental mobility commonly associated to periodontitis.

[0074] Digital files of the first scan (baseline, (16A)) and of the second scan (pushed tooth, (16B)) were generated and the stf files compared in a comprehensive metrology software (Geomagic Control X (3D Systems). The two scan files were then processed and the 3D analysis used to establish the deviation at pre-determined points between the first and second scan. Three reference points at the tooth were chosen with the tool create annotations, providing the 3D deviation by linear deviation of each of the 3 axes (x, y, z) (16 C). Three reference points at the tooth were chosen with the tool create annotations, providing the 3D deviation by linear deviation of each of the 3 axes (x, y, z). Mean values calculated from three operators are represented in FIG. 16D. The overall displacement on the three reference points in all three axes below 15 microns indicates stable periodontium tissues compatible with absence of disease.

Example 4

Computer-aided Diagnosis System for Tooth Displacement in Patients with Periodontal Disease

[0075] This Example is a clinical demonstration of the steps described in Example 1 using a computer-aided diagnosis system based on an intra-oral scanner device. A first digital impression of a patient with periodontal disease was obtained and defined as the baseline (17A). A second digital impression of the patient was taken with an operator pushing tooth #20 into a buccal direction (17B). The force was applied with a handle of a dental mirror placed in the lingual surface. The goal was to promote a movement in the tooth that simulates a dental mobility commonly associated to periodontitis.

[0076] Digital files of the first scan (baseline, (17A)) and of the second scan (pushed tooth, (17 B)) were generated and the stf files compared in a comprehensive metrology software (Geomagic Control X (3D Systems). The two scan files were then processed and the 3D analysis used to establish the deviation at pre-determined points between the first and second scan. Three reference points at the tooth were chosen with the tool create annotations, providing the 3D deviation by linear deviation of each of the 3 axes (x, y, z) (17C). Mean values calculated from three operators are represented in FIG. 17D. The displacement observed in the occlusal, middle and cervical points in the buccal direction (dx) ranging from 100 microns to 150 microns indicates unstable periodontium tissues compatible with the presence of disease.

Example 5

Computer-aided Diagnosis System for Tooth Displacement during Chewing

[0077] This Example is the final output obtained as described in FIG. 2. A first digital impression of a typodont with no displacement was aligned with a second scan with the mandibular right first molar and the maxillary right canine in a position different than the baseline due to the displacement promoted when teeth are engaged in a chewing action. Digital files of the first scan (no force from the antagonist tooth) and a second (with contact receiving force from the antagonist) were generated and the stf files compared in a comprehensive metrology software. The two scan files were then processed and the 3D analysis used to establish the deviation at pre-determined points between the first and second scan. Three reference points at the tooth were chosen with the tool create annotations, providing the 3D deviation by linear deviation of each of the 3 axes (x, y, z) associated to the mandibular right first molar (FIG. 18A) and maxillary right canine (FIG. 18B). The mean values obtained by three operators in the cervical, middle and cervical reference points were determined in in the three axes (x, y, z) (FIG. 18C). The data demonstrates a deviation to the lingual direction associated to the tooth located in the mandible and to the buccal direction in the teeth located in the maxilla during contact with the opposing teeth when a normal chewing contact is simulated.

REFERENCE

[0078] 1. Miller S C. Textbook of Periodontia. Philadelphia: The blakiston Co.; 1938. [0079] 2. Ramfjord S P, J Periodontol 1967; 38:Supp1:602-610. [0080] 3. Fleszar et al., J Clin Periodontol 1980; 7:495-505. [0081] 4. Ismail et al., 1959-87. J Dent Res 1990; 69:430-435. [0082] 5. Wang et al., J Periodontol 1994; 65:25-29. [0083] 6. Burgett et al., J Clin Periodontol 1992; 19:381-387. [0084] 7. Parfitt G J, J Dent Res 1960; 39:608-618. [0085] 8. Muhlemann HR, Oral Surg Oral Med Oral Pathol 1951; 4:1220-1233. [0086] 9. Ferris R T, J Periodontol 1966; 37:190-197. [0087] 10. Rateitschak KH, Journal Periodontology 1963; 34:540. [0088] 11. Koo et al., J Chiropr Med 2016; 15:155-163. [0089] 12. Feldman et al., J Periodontal Res 1982; 17:80-89. [0090] 13. Mojon et al., J Clin Periodontol 1996; 23:56-59. [0091] 14. Persson R, J Clin Periodontol 1980; 7:506-515. [0092] 15. Tanaka et al., Angle Orthod 2005; 75:101-105. [0093] 16. Nakago et al., Am J Orthod Dentofacial Orthop 1994; 105:92-96. [0094] 17. Giargia et al., J Clin Periodontol 1997; 24:785-795. [0095] 18. Pedersen et al., Eur J Orthod 1991; 13:65-74. [0096] 19. Hinterkausen et al., Med Eng Phys 1998; 20:40-49. [0097] 20. Kawarizadeh et al., Eur J Orthod 2003; 25:569-578. [0098] 21. Konermann et al., Clin Oral Investig 2017; 21:1283-1289. [0099] 22. Yoshida et al., Med Eng Phys 2000; 22:293-300.

[0100] Although only a few exemplary embodiments have been described in detail, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this disclosure. Accordingly, all such modifications and alternative are intended to be included within the scope of the invention as defined in the following claims. Those skilled in the art should also realize that such modifications and equivalent constructions or methods do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.