WO2023223250A1

WO2023223250A1 - Remote diagnostic system and method for assessing the alignment of the dental arches and the alveolus-dental morphology of a patient

Info

Publication number: WO2023223250A1
Application number: PCT/IB2023/055111
Authority: WO
Inventors: Tommaso CASTROFLORIO; Mario ALOVISI; Massimo CAROSSA
Original assignee: Universita' Degli Studi Di Torino
Priority date: 2022-05-19
Filing date: 2023-05-18
Publication date: 2023-11-23

Abstract

Remote diagnostic system (1) for assesing the alignment and alveolus-dental morphology of a patient including computer processing and storage resources (4) which can be coupled to a user terminal (2) provided with an image acquisition system (3) and that can be controlled to cause the acquisition, by means of the image acquisition system (3), of sequences (Sim1, Sim2) of two-dimensional images (Imi, Imj ) of casts of dental arches. The computer processing and storage resources (4) are configured to : receive the two-dimensional image (Iim, Imj ) sequences from the user terminal (2); generate, for each dental arch, corresponding three-dimensional images ( I3D1, I3D2) on the basis of the respective sequence of two-dimensional images (Sim1, Sim2); store, for each dental arch, a set of corresponding three- dimensional reference images (Sim1, Sim2); for each dental arch, verify if at least one of the corresponding three-dimensional images (I3D1, I3D2) satisfies a correspondence criterion with at least one of the corresponding reference images ( l3D1rif, l3D2rif)," and generate, for each dental arch, a notification signal if at least one of the corresponding three-dimensional images (I3D1, I3D2) satisfies the correspondence criterion with at least one of the reference images (I3D1rif, l3D2rif).

Description

"REMOTE DIAGNOSTIC SYSTEM AND METHOD FOR ASSESSING THE

ALIGNMENT OF THE DENTAL ARCHES AND THE ALVEOLUS -DENTAL

MORPHOLOGY OF A PATIENT"

CROSS-REFERENCE TO RELATED APPLICATIONS

This Patent Application claims priority from Italian

Patent Application No . 102022000010430 filed on May 19, 2022, the entire disclosure of which is incorporated herein by reference .

TECHNICAL AREA OF THE INVENTION

This invention generally relates to the remote diagnostics field, particularly and without any loss of generality for a remote dental evaluation of a patient .

In more detail, this invention relates to a system and a method of remote diagnostics for the dental evaluation of a patient, in particular for the evaluation of the alignment of the dental arches and the alveolo-dental morphology of a patient .

STATE OF THE ART

As is known, health emergencies, such as the well-know and current pandemic due to the Sars-CoV-2 virus (commonly known as Covid-19) , determine a substantial change in people ’ s daily life; in particular, the Covid- 19 pandemic has led to a substantial and necessary reduction of personal contacts to avoid excessive and potentially uncontrolled spread of the virus .

In particular, in the current pandemic health framework, it was essential to reduce the inflow of non-risk patients to public and private health facilities as much as possible in order to prevent and contain the spread of the virus resulting from merely assembling people at the above health facilities .

The remote administration of medical services (where possible) has thus become increasingly important in the current historical period, as it allows to limit contacts between doctor and patients waiting at the health facility and, therefore, to limit in a non-negligible manner the possible spread of the virus among people . For example, clinical diagnostics underwent considerable developments, some of which allowed doctors and medical staff to diagnose a patient remotely, thus combining medical skills with computer skills . This new type of patient management and diagnosis is commonly known as telemedicine ("telehealth") .

Precisely by virtue of the extraordinary period and, in general, health emergencies, the administration of remote medical services such as telemedicine can play a fundamental role in the patients' management and diagnosis .

In dentistry, in the last twenty years the number of orthodontic patients treated with clear aligners, also known as aligners, has grown significantly; in particular, it is estimated that in 2021 about ten million patients worldwide underwent this type of therapy.

The procedure for the realization of clear aligners provides for a first acquisition, in which an instrument for the acquisition of images is used, specifically an intraoral scanner, in order to acquire a three-dimensional (3D) image relating to an optical imprint of the dental arches and to determine the spatial ratio between these dental arches . In particular, the three-dimensional image is obtained as a combination of several two-dimensional images acquired in sequence at different angles with respect to an axis perpendicular to the extension plane of the considered dental arch.

Following the acquisition procedure, a dedicated software ( for example, the Clincheck® software) pre-loaded on a computer means generates a three-dimensional digital file ( for example, in STL format) representative of the acquired three-dimensional image ; in particular, said three-dimensional digital file allows, once processed by a computing and storage resource, such as e . g. a computer or a computing resource that uses the cloud computing paradigm, to obtain and analyze virtual models of the dental arches and evaluate malocclusion of dental arches, i . e . the presence of misalignments of the patient' s dental arches .

Following, starting from the three-dimensional images of the dental arches, the processed digital file may be used by a manufacturer to create the dental aligners to provide to the patient to start the treatment .

In addition, the processing of the three-dimensional digital file allows, through an appropriate software (e . g. based on artificial intelligence, Al ) to determine a prediction of each phase of the dental alignment process for each patient on the basis of the dental alignment treatment plan planned by the dentist . Therefore, it is possible to break down the treatment in different phases and to predict the intermediate stages, the final result and the time necessary for the alignment procedure to be complete and thus for the dental arches of the patient are correctly aligned. In other words, the processing of the three- dimensional digital file allows to predict what the aligners will be for each phase of the treatment . In fact, each treatment phase corresponds to the production of a corresponding personalized dental aligner, i . e . based on the three-dimensional image acquired when checking the alignment of the dental arches; in particular, each dental aligner is made of transparent thermoplastic material, such as thermoplastic polyurethane (PTU) .

The treatment plan envisages with the use of the first dental aligners ( i . e . produced after the first visit at the dentist) that are delivered to the patient who will take care of changing them according to the deadlines of each individual treatment phase; typically, each dental aligner is replaced after about 7-10 days with new dental aligners, which are produced according to the treatment plan, the prediction, and the evolution of the dental alignment, the latter being verified by means of follow-up visits . The frequency of replacement of the dental aligners is determined on the basis of the fact that the teeth undergo a shift of about 1 mm in 30 days .

As previously discussed, the world pandemic has made it necessary to limit the number of accesses to health facilities, especially in dental clinics, in order to contain the spread of infection. Therefore, it is complex in the current pandemic framework to carry out frequent dental visits to verify the continuation of the dental alignment treatment of a patient . Furthermore, this involves a commitment for the patient in terms of time and costs and for the medical office (i . e . dental practice) that needs to reserve the necessary time and tools .

Systems for remote monitoring of the patients' dental alignment, also defined as remote monitoring systems (RMS) , are known; in particular, these systems use paid devices that allow the correct positioning of a user terminal equipped with a camera, such as a smartphone, at the oral cavity for the taking of images related to the dental occlusion of the patient and readable by the dentist . Through these images, the dentist is able to evaluate the position of the teeth and the real progress state of the treatment .

However, the Applicant observed that these techniques have at least the following drawbacks :

1 ) the complexity of the technique to be performed at home by the patient, who has to adequately frame the smile frontally, with enough light and retracting lips and cheeks so that the view of the dental arches is not compromised;

2 ) the cost of the device charged on the patient or on the dental office, as well as the need for the patient to possess a state-of-the-art user terminal to be able to acquire images of the dental arches correctly and sharply; and

3) the limitation of the qualitative and quantitative analyses that dentists can do by analyzing two-dimensional frontal images of the patient' s smile, since as the dentist is hardly in a position to assess the presence of tooth rotations, extrusions and misalignments of medium and small occlusion, thus making systems of this type unreliable .

SUBJECT AND SUMMARY OF THE INVENTION

In light of the above, the Applicant noted that the current available solutions are liable to change, particularly in relation to making these solutions simpler, efficient and economical to allow both the patient to easily perform the acquisition of the dental arches and the dentist to carry out a first evaluation of the alignment of the dental arches and to assess the need for an in-person visit by the patient .

The aim of this invention is to provide a remote diagnostic system and method for assesing the alignment of the dental arches of a patient that at least partially solves the drawbacks of known art .

According to this invention, a remote diagnostic system and method for assesing the alignment of the dental arches of a patient, as defined in the attached claims .

BRIEF DESRIPTION OF THE DRAWINGS

For a better understanding of the invention, some embodiments are now described, purely as a non-limiting examples, with reference to the attached drawings, in which:

Figure 1 shows a remote diagnostic system for the evaluation of alignment and alveolo-dental morphology of a patient according to the present invention;

- Figure 2 shows a top view of dental alignment reference aligners;

- Figure 3 shows a perspective view of a dental alignment reference aligner scanned and digitally reconstructed by the remote diagnostic system for the evaluation of alignment and alveolo-dental morphology of a patient of Figure 1 ; and

- Figure 4 shows a perspective view of the upper dental arch rebuilt according to a remote diagnostic method in relation to the alignment reference aligner for the evaluation of the alignment and alveolo-dental morphology of a patient according to the present invention.

DESCRIPTION OF THE PREFERRED FORMS OF INVENTION

This invention will now be described in detail with reference to the attached figures to allow an skilled person to realize and use it . Various modifications to the embodiments described herein will be immediately evident to the skilled persons and the generic principles described may be applied to other embodiments and applications without departing from the scope of protection of the present invention, as defined in the attached claims . Therefore, the present invention should not be considered limited to the embodiments described and illustrated herein, but must be accorded the widest scope of protection consistent with the described and claimed features .

Where not otherwise defined, all technical and scientific terms used here have the same meaning commonly used by people of ordinary experience in the field relevant to this invention. In the event of a conflict, this description, including the definitions provided, will be binding. Furthermore, the examples are provided for illustrative purposes only and thus should not be considered limiting. In particular, the block diagrams included in the attached figures described below are not intended to represent the structural characteristics, i . e . constructional limitations, but must be interpreted as representing functional characteristics, i . e . inherent properties of the devices and defined by the obtained effects, i . e . functional limitations and that can be implemented in different ways, so as to protect the functionalities of the same (operating mode) .

In order to facilitate the understanding of the embodiments described herein, reference will be made to some specific embodiments and a precise language will be used to describe them. The terminology used herein is intended to describe only particular embodiments and it is not intended to limit the scope of the present invention.

Figure 1 shows a remote diagnostic system 1 for the evaluation of the alignment and the alveolo-dental morphology of a patient including computer processing and storage resources 4 which can be coupled to a user terminal

2 ; and the user terminal 2. In particular, the user terminal

2 is equipped with an image acquisition system 3.

According to a preferred embodiment of the present invention, the user terminal 2 is a device such as a smartphone or the like; consequently, the image acquisition system 3 is, for example, a camera system integrated in the same user terminal 2. In the following, without any loss of generality, it is assumed that the user terminal 2 is a smartphone equipped with a camera as an image acquisition system 3 configured to acquire n two-dimensional images I_mn, where n is a natural index greater or equal to one .

In addition, the user terminal 2 is provided with a software, in particular an app, and through this it is controllable to cause the acquisition, by the image acquisition system 3, of first and second image sequences

S_Im1, S_Im2 representative of the upper SUP and lower INF dental arches of the patient (shown in Figure 2 ) respectively, the image sequences S_Im1, S_Im2, including i and j two-dimensional images I_mi, I_mj (in which i and j are natural indexes lesser than n) respectively, the sum of the latter being equal to I_mn •

In particular, in order to aid the understanding of this invention, it is assumed that the indices i and j are the same, i . e . that the number of two-dimensional images acquired by the image acquisition system 3 is the same . In other words, according to a preferred aspect of the present invention, the image sequences S_Im1 and S_Im2 include the same number m of two-dimensional images I_mm , in which m is a natural index equal to n/2.

According to further embodiments, not described herein, the two-dimensional images I_mn may be more or less than n; this situation happens, for example, when the user terminal

2 informs the user of the need to acquire more or less I_mn images .

The user terminal 2 is also designed to send notifications, for example sound or textual notifications, to the user by means of the app to notify him/her of the need to carry out a remote check or at the dentist to check the alignment of the upper and lower dental arches SUP, INF of a patient or a result of the analysis carried out regarding the alignment of the same upper and lower dental arches SUP, INF; for example, a notification from user terminal 2 may be related to the need to acquire more image sequences S_Im1, S_Im2 and/or to book a visit with the dentist to evaluate in-person the trend of the alignment therapy of the upper and lower dental arches SUP, INF.

According to an aspect of the present invention, the computer processing and storage resources 4 are of the concentrated type, e . g. in the form of an external server; according to another aspect of the present invention, the computer processing and storage resources 4 are of the distributed type, e . g. on nodes of a network. In the following and without any loss of generality, it is assumed that the computer processing and storage resources 4 are representable as a server implementing the cloud computing paradigm. The computer processing and storage resources 4 are designed to :

- receive the image sequences S_Im1 and S_Im2 from the user terminal 2 ; and generate corresponding three-dimensional images l3D1,

I3D2 for each dental arch based on the respective sequence of two-dimensional images S_Im1, S_Im2.

The computer processing and storage resources 4 are also designed to process three-dimensional images I3D1 and I3D2 of each dental arch to extract data dIm1, dIm2 related to the dental alignment of the teeth of each dental arch SUP and

INF.

The computer processing and storage resources 4 are also designed to store a set of corresponding three-dimensional reference images l3Dlrif , l3D2rif for each dental arch. In particular, according to an aspect of the present invention, the reference images I3D1rif and l3D2rif may be imported into the computer processing and storage resources 4 from an external terminal, provided with a software, such as

ClinCheck®; in detail, said software is designed to predict the dental movement of the SUP and INF dental arches of the patient and to define the phases of the dental alignment therapy according to said predictions .

Moreover, the computer processing and storage resources

4 are designed to : - for each dental arch SUP, INF, verify whether at least one of the obtained three-dimensional images I3D1 , I3D2 satisfies a correspondence criterion with at least one of the corresponding reference images I3D1rif and l3D2rif, and

- for each dental arch SUP, INF, generate a notification signal if at least one of the corresponding three-dimensional images I3D1, I3D2 satisfies the correspondence criterion with at least one of the reference images l3D1rif , l3D2rif .

In particular, it should be noted that in the case at least one of the three-dimensional images I3Dl and I3D2 corresponds with the respective reference image I3D1rif and l3D2rif happens for example when the user mistakenly acquires the three-dimensional images I3D1, I3D2 thus, preventing system

1 from working properly. If, for each dental arch, at least one of the corresponding three-dimensional images I3D1, I3D2 does not satisfy the correspondence criterion with at least one of the corresponding reference images l3D1rif , l3D2rif the computer processing and storage resources 4 are also designed to :

- overlap the three-dimensional image I3D1, I3D2 with the respective reference image l3D1rif , l3D2rif , and determine the misalignment between the three- dimensional image I3D1, I3D2 with the respective reference image l3D1rif , l3D2rif .

In particular, the quantification of misalignment between one or both the three-dimensional image ISDI , ISD2 with the respective reference image l3Dlrif , l3D2rif happens for example by means of a pre-installed algorithm in the computer processing and storage resources 4, which allows to process the images so to determine how much the teeth of the dental arches SUP, INF are deviated from the expected progression in case of evaluation of the dental alignment . For example, the algorithm may be an artificial intelligence algorithm designed to identify and overlap standard landmarks in the three-dimensional images l3D1 , l3D2 and the reference images l3Dlrif , l3D2rif .

Depending on the determined misalignment value (s) , the computer processing and storage resources 4 are designed to transmit a notification, for example a textual notification, to the dentist to warn him of the lack of overlap (and, thus, of deviation from the planned progression due to variations in the alignment of the upper dental arch SUP and/or the lower dental arch INF or variations in the alveolus-dental morphology of the same patient) between one or both three- dimensional image l3D1 , l3D2 with the respective reference image l3D1rif , l3D2rif , in particular, the computer processing and storage resources 4 are designed to quantify the misalignment in numerical terms and indicate in which area of the considered dental arch SUP, INF there is such misalignment and notify the dentist of such misalignment . Depending on said notification, the dentist can decide whether to schedule a visit for the patient or, for example, prescribe the continuation of treatment with the same aligners . In case of scheduling the visit, the computer processing and storage resources 4 are designed to : receive a command from the dentist notifying the scheduling of a dental appointment; and transmit the notification of the scheduling of an appointment for a dental visit to the patient' s user terminal

2 to notify him/her of the need for a visit following verification of the alignment of the upper and/or lower dental arches SUP, INF.

In order to perform such verifications of the upper and lower dental arches SUP, INF , the remote diagnostic system

1 for the evaluation of dental alignment and alveolo-dental morphology of a patient comprises reference dental alignment aligners, also known as passive aligners, 5 ( shown as examples in Figures 2, 3 and 4 ) , which are applicable to the upper dental arch SUP and the lower dental arch INF and are deformable, after being applied to the upper and lower dental arches SUP, INF in order to form corresponding casts of the upper dental arch SUP and the lower dental arch INF respectively of the patient in order to allow the evaluation of the alignment state of the upper and lower dental arches

SUP, INF of a patient under treatment . In particular, according to and aspect of the present invention, the reference dental alignment aligners 5 are disposable . Each reference dental alignment aligner 5 comprises : a support aligner 6; and a layer of impression material 7 carried by the support aligner 6.

In particular, the support aligner 6 is made of plastic material and is designed according to the size and the arrangement of the teeth of the upper and lower arches SUP,

INF of the patient; in this way, each reference dental alignment aligner 5 is adapted to the shape of the upper and lower dental arches SUP, INF of the patient under test . In particular, it is assumed in the following that the reference dental alignment aligners 5 shown in Figure 2 are designed to accommodate a uniform layer of dental impression material inside them and are sent to the patient each time remote control is considered necessary during the therapy, at intervals established according to the characteristics of the treatment ( for example, every 7-10 days, i . e . when replacing the aligners for the treatment) . In fact, following reference dental alignment aligners 5 are produced according to the evaluation of the variation of the dental alignment of the upper and lower dental arches SUP, INF of the patient in the following treatment phases, evaluated on the basis on the casts imprinted on the layer of impression material 7, as also described in more detail below.

The layer of the impression material 7 , once attached to a dental arch (upper SUP or lower INF) , is deformable so as to obtain a cast of the same dental arch, i . e . the malleability of the layer of impression material 7 allows to imprint the shape and the arrangements of the teeth of the considered dental arch on the same layer of impression material 7. The layer of impression material 7 is of malleable material at room temperature; according to an aspect of the invention, the layer of impression material 7 is of thermoplastic material at room temperature, in particular blue plastic wax for dental use, especially prosthetic . The blue wax is non-toxic, it has good dimensional stability at room temperature (i . e . it is able to maintain a consistent shape for a non-negligible period of time ) and does not require any manipulation by the patient . Moreover, the blue wax is economical and has a good stability over time, i . e . its physical properties do not change over time and at different temperatures .

The layer of impression material 7 is also designed to have good adhesion both to the support aligner 6, thus avoiding the presence of an adhesive layer, and to the dental arch of which the cast is wanted .

A remote diagnostics method for assessing the alignment and alveolodental morphology of a patient implemented by the remote diagnostics system 1 according to a preferred embodiment of the present invention is now described.

On the occasion of a first check of the alignment of the upper and lower dental arches SUP, INF of a patient, the user terminal 2 is designed to send a warning notification, for example a sound or textual notification, by means of the app to alert the user of the need to verify the alignment of the upper and lower dental arches SUP, INF. In particular, according to an aspect of the present invention, the notification may give the patient indication to wear the reference dental alignment aligners 5.

Upon receipt of the notification, the user uses the reference dental alignment aligners 5 to obtain an impression of the upper and lower dental arches SUP, INF by wearing them, eventually guided by the user terminal 2 in the procedure; in particular, the user imprints the shape of upper and lower dental arches SUP, INF on the respective reference dental alignment aligners 5, so that the layer of impression material 7 deforms, generating a structure complementary to the shape of the upper and lower dental arches SUP, INF of the patient . In other words, the user generates a cast of his/her upper and lower dental arches

SUP, INF, impressing its shape in the layer of impression material 7.

After generating the cast of the upper and lower dental arches SUP, INF, the user terminal 2 is designed to allow the patient to acquire the first and second image sequences

S_Im1, S_Im2, respectively of the upper and lower dental arches

SUP, INF of the patient imprinted on the layer of impression material 7 of the reference dental alignment aligners 5 through the image acquisition system 3; in other words, the user terminal 2 operates as a scanner, without any acquisition within the mouth of the patient. In particular, each two-dimensional image Imi, Imj is acquired so that it is associated with a corresponding angle, each angle being different for each two-dimensional image Imi, Imojf the first and second image sequence of S_Im1, S_Im2 respectively. In further detail, each angle is determined from respective axes Hi, H2 perpendicular to respective extension planes of the upper and lower dental arch SUP, INF respectively (i.e. the axes Hi, H2 represent perpendicular axes, also known as zenith); according to an aspect of the present invention, said angles are predetermined, i.e. the user terminal 2 is designed to store angular positions associated with the angles at which said user terminal 2 has to be located to allow the app and thus the image acquisition system 3 to acquire the two-dimensional images Imi, Imj. In the following, for simplicity of description and without any loss of generality, it is assumed that the axes Hi,H2 coincide, that is they are identifiable as a single axis H, and the extension plans of the upper and lower dental arches SUP,

INF are parallel with each other and to an XY plane of a

Cartesian reference system XYZ; consequently, the axis H is parallel to the Z axis of the XYZ reference system.

The image acquisition system 3, upon command of the app installed on the user terminal 2, is thus designed to acquire two-dimensional images Imi, Imj , each at a respective angle, so as to allow to have an overview of the upper and lower dental arches SUP, INF and to subsequently rebuild the corresponding three-dimensional images l3D1 , l3D o2f the upper and lower dental arches SUP, INF respectively. It is noted that the two-dimensional images Imi , Imj are images related to the casts reproduced in the layer of impression material

7 of the reference dental alignment aligners 5; in this way, the patient can acquire images of the upper and lower dental arches SUP, INF without using complex acquisition tools to be used for intraoral images ; in other words, the user terminal 2 is controllable to cause the acquisition, by means of the image acquisition system 3, of two-dimensional images

Imi , Imj of the dental arches SUP, INF imprinted in the layer of impression material 7. When acquiring the two-dimensional images Imi, Imj the user terminal 2 is designed to guide the user in acquiring the two-dimensional images Imi, Imj through the app, in particular by providing indications to the user in tilting the terminal 2 according to predetermined angles with respect to the axis H so that the image acquisition system 3 acquires the two-dimensional images Imi, Imj • In particular, the acquisition is such that images Imi subsequent to each other in order of acquisition are angularly distant between each other of an angle comprised between 1 ° and 45° , preferably 20° , i . e . the angular distance between predetermined adj acent angles is equal to an angle comprised between 1 ° and 45° , preferably 20° ; the same applies to images I_mj, i . e . images I_mj subsequent to each other in order of acquisition are angularly distant between each other of an angle comprised between 1 ° and 45° , preferably 20° . It is noted that the choice of this angle allows, compared to the aforementioned known systems, to reduce the number of the acquired two-dimensional images Imi,

Imj while maintaining good efficiency and good accuracy; in other words, this feature allows to have a simple and reliable system for the evaluation of the progression of the therapy.

According to an aspect of the present invention, the number of two-dimensional images Imi, Imj is at least equal to five, preferably greater or equal to twenty or twenty- five .

Subsequently, once the two-dimensional images Imi, Imj have been acquired, the user terminal 2 is designed to transmit the two-dimensional images Imi, Imj to the computer processing and storage resources 4.

Consequently, the computer processing and storage resources 4 are designed to process the acquired image sequences S_Im1, S_Im2 so as to generate the corresponding three- dimensional images ISD1 , ISD2 related to each upper and lower dental arch SUP, INF, in particular the casts embedded in the layer of impression material 7 of the reference dental alignment aligners 5. In particular, the computer processing and storage resources 4 are designed to process the two- dimensional images Imi, Imj of the image sequences S_Im1, S_Im2 to generate the three-dimensional images l3D1 , l3D2. According to an aspect of the present invention, the computer processing and storage resources 4 are designed to : receive two-dimensional images Imi, Imj of the image sequences S_Im1, S_Im2, and combine the two-dimensional images Imi , Imj , respectively of the image sequences S_Im1, S_Im2 in order to generate corresponding three-dimensional images ISDI , ISD2 .

In particular, the combination of the two-dimensional images Imi, Imj, respectively of the image sequences S_Im1, S_Im2 to generate the corresponding three-dimensional images ISDI ,

I3D2 is performed by means of a pre-installed algorithm pre- installed in the computer processing and storage resources

4, such as, e . g. , Pix4D (https : //www.pix4d. com) .

In further detail, the computer processing and storage resources 4 are designed to combine the two-dimensional images Imi of the image sequence S_Im1 to generate the three- dimensional image l3D1 of the upper dental arch SUP; similarly, the user terminal 2 is designed to combine the two-dimensional images Imj of the image sequence Slm2 to generate the three-dimensional image I3D2 of the lower dental arch INF.

Figure 4 schematically shows a three-dimensional reconstruction, i . e . a three-dimensional image ISDI of the upper dental arch SUP of a patient following the acquisition of two-dimensional images Imi and the subsequent processing by the computer processing and storage resources 4.

The computer processing and storage resources 4 are designed to process each three-dimensional image ISDI, ISD2 of the upper and lower dental arches SUP, INF to extract data dIm1, dIm2 related to the dental alignment of the teeth of each dental arch. In particular, the data dimi, dim2 include data related to the position of the teeth of the upper and lower dental arches SUP, INF with respect to a default reference system (e . g. the Cartesian reference system XYZ) , indicated in the following as d_{posr, s , t ,} in which r, s e t are real indexes relating to the position of the teeth of the upper and lower dental arches SUP, INF with respect to the default reference system. It is assumed that the considered reference system is the same used during the acquisition of the image sequences S_Im1, S_Im2, i . e . the Cartesian reference system XYZ and that, thus, the indexes r, s and t refer to the position on X, Y and Z respectively.

Furthermore, the computer processing and storage resources 4 are designed to allow the identification of reference points and to generate corresponding data related to the same reference points identifiable in the upper and lower dental arches SUP, INF, indicated in the following as d_{Posrif, r' , s' ,t'} in which r' , s' e t' are real indexes relating to the position of said reference points in the upper and lower dental arches SUP, INF with respect to the default reference system (here, the Cartesian reference system XYZ) ; for example, the positions of the reference points include the positions of the landmarks, cusps or margins of the teeth of the upper and lower dental arches SUP, INF. In particular, the position of said reference points is determined by the dentist, who, through his/her own terminal ( for example, a computer or a smartphone) , is able to access the three- dimensional images I3D1, I3D2 of the upper and lower dental arches SUP, INF to identify the reference points and, thus, to generate the data dposrif. Said reference points allow, in the following steps of the present method, to verify possible variations in the alignment of the teeth of the upper and lower dental arches SUP, INF following a specific treatment phase . Following, the computer processing and storage resources

4, by means of a proprietary software (e . g. MeshLab) , are designed to overlap the three-dimensional images l3D1 , l3D2 with the reference images l3D1rif , l3D2rif, respectively related to the upper dental arch SUP and the lower dental arch INF.

In particular, the computer processing and storage resources

4 are designed to process the data dposrif,r' ,s' ,t' to find the reference points in the three-dimensional images l3D1 , l3D2 and thus allow the superimposition between the three- dimensional images ISDI, ISD2 and the reference images Isnirif , l3D2rif ; it is noted that the reference images l3D1rif , l3D2rif stored e . g. in the computer processing and storage resources

4 are also associated to corresponding data relating to the positions of the reference points, hereinafter referred to as dposrif, r' , s' , t' * , so that, in the overlapping phase, the three-dimensional images l3D1 , l3D2 and the reference images l3Dlrif , l3D2r±f are correctly superimposed, i . e . the reference points of the three-dimensional images l3D1 , l3D2 and of the reference images l3D1rif , l3D2rif are overlapped with each other .

In this way, it is possible to directly assess whether the dental alignment therapy follows the prediction elaborated by the dentist .

It is noted that, in presence of any discrepancies due, e . g. , to the incorrect use of the dental alignment aligners and that could generate e . g. deviations between the reference points identified in the three-dimensional images l3D1 , l3D2 and in the reference images l3Dlrif , l3D2rif , the computer processing and storage resources 4 are designed to measure such deviations and generate corresponding data for the dentist .

According to an aspect of the present invention, the computer processing and storage resources 4 are further designed to improve the overlap between the three- dimensional images ISDI, ISD2 and the reference images l3D1rif , l3D2rif to optimize it .

Once the three-dimensional images I3D1 , I3D2 are overlapped with the reference images l3D1ref , l3D2rif , the computer processing and storage resources 4 are designed to verify the alignment of the teeth of the upper and lower dental arches SUP, INF according to the position of the teeth and any previously measured deviations, in order to verify that the three-dimensional images ISDI, ISD2 coincide with the reference images Isnirif , l3D2rif . It is noted that, according to an aspect of the present invention, the check of the alignment of the teeth of the upper and lower dental arches

SUP, INF can even be quantified tooth by tooth, in order to monitor the course of therapy accurately; furthermore, the system allows to evaluate the patient' s alveolo-dental morphology, to consider any pathologic aspect in the dental arches SUP, INF. If the verification results positive for at least one of the three-dimensional images l3D1 , l3D2, the computer processing and storage resources 4 are designed to determine that the alignment of the teeth of the upper dental arch SUP and/or of the lower dental arch INF follows the progression expected by the treatment . If either or both of the three- dimensional images l3D1 , l3D2 do not coincide with the respective reference image l 3Dlrif , l3D2rif , the computer processing and storage resources 4 are designed to determine that the alignment of the teeth of the upper dental arch SUP and/or of the lower dental arch INF is not following the progression expected by the treatment . Consequently, the computer processing and storage resources 4 are designed to : overlap one or both three-dimensional images I3D1,

I3D2 with the respective reference image l3D1rif , l3D2rif , and determine the misalignment between the three- dimensional images l3D1 , l3D2 with the respective reference image l3Dlrif , l3D2rif .

Following these verifications, either positive or negative, the computer processing and storage resources 4 are designed to generate output data d_out, indicative of the outcome of the said verifications and transmit them to an external device 10, for example a computer; in this way, the computer processing and storage resources 4 submit the result of the verification to the dentist, so that the same dentist can request the production of new aligners to provide the user for the next phase of the treatment, adapt the treatment plan or require the user to book a visit to check the outcome of the treatment of the dental arches .

The present method and the related system have numerous advantages .

In particular, the present remote diagnostics system 1 for the evaluation of the dental alignment and the alveolusdental morphology of a patient and the related method allow to monitor remotely and accurately the course of the treatment in case of evaluation of the dental alignment, i . e . the deviation og the teeth of the dental arches SUP,

INF and to quantify it at a millimetre scale; furthermore, the system also allows to evaluate the patient' s alveolus- dental morphology, allowing the monitoring of the teeth and the prevention of any pathological situations . Furthermore, this allows in particular to have a greater accuracy in the occlusal vision with respect to the intraoral photographs proposed by systems currently on the market, even more specifically in the occlusal plane to evaluate possible dental intrusions and extrusions .

Furthermore, the present remote diagnostics system 1 for the evaluation of the dental alignment and the alveolusdental morphology of a patient is simple to manufacture and to use for patients and dentists, thanks to the use of the reference dental alignment aligners 5 and the app installed on the user terminal 2 for the acquisition of the two- dimensional images I_mi, I_mj •

In addition, the present remote diagnostics system 1 for the evaluation of the dental alignment and the alveolusdental morphology of a patient and the related method allow to significantly reduce the patients' access to clinics and dental practices .

Furthermore, the present remote diagnostics system 1 for the evaluation of the dental alignment and the alveolusdental morphology of a patient and the related method allow to reduce the travelling costs for the patient and the healthcare facility, as the present system is not a customized device whose costs fall on the patient or on the healthcare facility that is providing it and which would eventually have to dispose of it due to the impossibility of reusing it and to the low possibility of sterilization of the same .

Finally, the present remote diagnostics system 1 for the evaluation of the dental alignment and the alveolus-dental morphology of a patient and the related method allow to have a procedure that is simple to implement by a user and easily reproducible with any portable user terminal equipped with an image capture system, such as a simple camera .

Finally, it is clear that modifications and variants can be made to this device, without departing from the scope of the present invention, as defined by the attached claims .

For example, the present system and the related method can also be applied for applications where fixed or mobile prostheses are used.

Claims

1. A remote diagnostic system (1) for assessing the alignment and alveolus-dental morphology of a patient comprising computer processing and storage resources (4) which can be coupled to a user terminal (2) provided with an image acquisition system (3) and that can be controlled to cause the acquisition, by means of the image acquisition system (3) , of sequences (S_Im1, Si_m2) of two-dimensional images (Imi, Imj ) of casts of dental arches, and wherein the computer processing and storage resources (4) are configured for:

- receiving the two-dimensional image ( I_mi, I_mj) sequences from the user terminal (2) ;

- generating, for each dental arch, corresponding three- dimensional images ( I3D1 , l3D2) on the basis of the respective sequence of two-dimensional images (S_Im1, S_Im2) ;

- storing, for each dental arch, a set of corresponding three-dimensional reference images (I3D1rif, l3D2rif) ;

- for each dental arch, verify if at least one of the corresponding three-dimensional images (l3D1 , l3)D2 satisfies a correspondence criterion with at least one of the corresponding reference images (I3n1rif, l3D2rif) ; and

- generating, for each dental arch, a notification signal if at least one of the corresponding three-dimensional images (l3D1 , l3D)2 satisfies the correspondence criterion with at least one of the reference images (I3D1rif, l3D2rif) .

2. The remote diagnostic system (1) for assessing the alignment and alveolus-dental morphology of a patient according to claim 1, wherein, for each dental arch, if at least one of the corresponding three-dimensional images

( I3D1, I3D2) does not satisfy a correspondence criterion with at least one of the corresponding reference images (I3D1rif, l3D2rif) , the computer processing and storage resources (4) are also designed for: superimposing the three-dimensional image (l3D1 , l3D)2 with the respective reference image (I3D1rif, l3D2rif) ; and determining the misalignment between the three- dimensional image ( I3D1, I3D2) and the respective reference image (I3D1rif, l3D2rif) .

3. The remote diagnostic system (1) for assessing the alignment and alveolus-dental morphology of a patient according to any one of the preceding claims and also comprising said user terminal (2) .

4. The remote diagnostic system (1) for assessing the alignment and alveolus-dental morphology of a patient according to claim 3, wherein the user terminal (2) can be controlled to cause the acquisition, by means of the image acquisition system (3), of each two-dimensional image (Imi,

Imj) according to a corresponding angle, each angle being different for each two-dimensional image ( Imi, Imj) of the first and second sequence of images (S_Im1, S_Im2) , respectively, wherein each angle is determined with respect to respective axes (Hl, H2 ) perpendicular to respective extension planes of the upper dental arch and of the lower dental arch (SUP, INF) , respectively.

5. The remote diagnostic system ( 1 ) for assessing the alignment and alveolus-dental morphology of a patient according to claim 4, wherein, in each sequence of two- dimensional images ( Imi , Imj ) , pairs of successive two- dimensional images have corresponding angles which are distant from one another by an angle comprised between 1 o and 45° .

6. A remote diagnostic method for assessing the alignment and alveolus-dental morphology of a patient comprising the steps of :

- acquiring, by means of an image acquisition system (3) of a user terminal (2 ) , sequences of two-dimensional images

(S_Im1, S_Im2) of casts of dental arches; receiving, at computer processing and storage resources (4 ) , the sequences of two-dimensional images ( Imi,

Imj ) from the user terminal (2 ) ; generating, for each dental arch, by means of the computer processing and storage resources (4 ) , corresponding three-dimensional images ( I3D1 , I 3D2 ) on the basis of the respective sequence of two-dimensional images ( SIm1 , SIm2 ) ; storing, for each dental arch, in the computer processing and storage resources (4) , a set of corresponding three-dimensional reference images (I3D1rif, l3D2rif) ;

- verifying, for each dental arch, by means of the computer processing and storage resources (4) , if at least one of the corresponding three-dimensional images ( I3D1, I3D2) satisfies a correspondence criterion with at least one of the corresponding reference images (I3D1rif, l3D2rif) ; and

- generating, for each dental arch, by means of the computer processing and storage resources (4) , a notification signal if at least one of the corresponding three-dimensional images ( I3D1, I3D2) satisfies the correspondence criterion with at least one of the reference images (I3D1rif, l3D2rif) .

7. The remote diagnostic method for assessing the alignment and alveolus-dental morphology of a patient according to claim 6, wherein, for each dental arch, if at least one of the corresponding three-dimensional images (l3D1 , l3)D2 does not satisfy a correspondence criterion with at least one of the corresponding reference images ( I3D1rif, l3D2rif) , the method also comprises the steps of:

- superimposing, by means of computer processing and storage resources (4) , the three-dimensional image ( I3D1, I3D2) with the respective reference image (I3D1rif, l3D2rif) ; and

- determining, by means of the computer processing and storage resources (4), the misalignment between the three- dimensional image (l3D1 , l3D)2 and the respective reference image ( I3D1rif , l3D2rif ) .

8. The remote diagnostic method for assessing the alignment and alveolus-dental morphology of a patient according to any one of claims 6-7, wherein each two- dimensional image ( I_mi, I_mj) is acquired at a corresponding angle, each angle being different for each two-dimensional image ( I_mi, I_mj) of the first and second sequence of images (S_Im1, S_Im2), respectively, wherein each angle is determined with respect to the respective axes (Hi, H2) perpendicular to respective extension planes of the upper dental arch and of the lower dental arch (SUP, INF), respectively.