A method for analyzing coordination of maxillary and mandibular dental arches based on oral cone beam CT

Abstract

The application discloses a kind of upper and lower jaw alveolar arch coordination analysis method based on oral cone beam CT, specific steps are as follows: collecting patient cone beam examination data, it is exported as DICOM format, three-dimensional reconstruction is carried out using software;Head position calibration is carried out in software, and three-dimensional reference plane is established;Four quadrant of dental arch is positioned and marked, and four quadrant first molar impedance center point is positioned;Determine alveolar arch measurement plane;Determine four quadrant alveolar arch width measurement mark point;Mark point is projected to the same coronal reference plane, and is connected to form upper and lower jaw alveolar arch width coordination angle respectively, and the angle of upper and lower jaw alveolar arch width coordination angle is measured respectively;According to the angle of upper and lower jaw alveolar arch width coordination angle, whether the upper and lower jaw alveolar arch coordination is judged.The angle of measured double jaw alveolar arch width coordination angle can more accurately reflect the position relationship of upper and lower jaw first molar alveolar arch in horizontal direction;It has guiding significance to judge whether left and right alveolar arch is symmetrical.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of orthodontics, in particular to a method for analyzing the coordination of upper and lower dental arches based on oral cone beam CT. BACKGROUND

[0002] With the development of society, people's requirements for the appearance of the face and the function of the oral cavity have gradually increased, thus putting forward higher demands for orthodontic treatment. Orthodontics has thus gained more applications and better development. One of the purposes of orthodontic treatment is to establish a stable occlusion in three dimensions, i.e., sagittal, vertical and horizontal directions. In the horizontal direction, individualized dental arches should be established on the basis of width-coordinated upper and lower dental arches. In order to achieve this goal, orthodontists need to make accurate diagnoses and treatment plans before orthodontic treatment.

[0003] In intermaxillary transverse analysis, traditional two-dimensional images and traditional plaster registration models have certain limitations. Head posteroanterior radiographs are easily affected by factors such as head position deviation during shooting, difficulty in distinguishing overlapping structures during point setting, and image magnification, thus deviating from the true situation. Plaster registration models can only reflect the surface of teeth and periodontal tissues, and cannot accurately analyze the internal structure relationship of the roots and alveolar bones. The application of oral cone beam CT (CBCT) has gradually increased in recent years, which has the advantages of three-dimensional imaging, accurate reconstruction and precise measurement, and has opened up a new angle for transverse analysis of the maxillofacial region.

[0004] The current known intermaxillary transverse analysis methods are as follows:

[0005] Ricketts transverse analysis method: using head posteroanterior radiographs to measure and analyze the width of the jaw and the width between the molars;

[0006] Andrews analysis method: using the WALA ridge width to calculate the width of the upper and lower dental arches and the alveolar arch;

[0007] CBT analysis method: using CBCT to measure the distance between the palatal (lingual) cortical bone as the width of the alveolar arch, calculate the width difference of the upper and lower alveolar bones, and measure the inner side angle between the long axis of the upper and lower molars and the horizontal reference plane (functional occlusion plane) as the basis for judging the degree of buccal and lingual inclination of the upper and lower molars;

[0008] CWRU transverse analysis method: using CBCT to measure the inclination angle of each tooth in the four quadrants, as well as the angle between the upper and lower incisors and the upper and lower molars;

[0009] Yonsei transverse index: part of which uses CBCT to measure the width of the upper and lower dental arches by taking the center of tooth resistance as the CBCT alveolar arch width measurement marker point, and calculates the difference.

[0010] Among the various existing methods mentioned above, some methods focus on measuring the width of the alveolar arch. However, due to the variability in the transverse width of the maxillofacial region among different individuals, simply using the reference range of the absolute width value is insufficient to diagnose horizontal coordination between jaws. Other methods focus on measuring the tilt angle of the teeth, but when performing alveolar bone analysis, the degree of tooth tilt cannot be used as the most direct expression of the alveolar arch, a bony structure.

[0011] Therefore, in order to assist doctors in correctly diagnosing the transverse relationship between the jaws, it is necessary to study a method for analyzing the coordination of the maxillary and mandibular alveolar arches. Summary of the Invention

[0012] To address the shortcomings of the existing technology, this invention provides a method for analyzing the coordination of the maxillary and mandibular alveolar arches based on oral cone-beam CT, aiming to assist doctors in correctly diagnosing the transverse relationship between the jaws, thereby formulating accurate orthodontic treatment plans.

[0013] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0014] A method for analyzing the coordination of the maxillary and mandibular alveolar arches based on oral cone-beam computed tomography (CBCT) includes the following steps:

[0015] S1. Collect the patient's cone-beam ultrasound data, export it in DICOM format, and use software to perform three-dimensional reconstruction;

[0016] S2. Perform head position calibration in the software and establish three-dimensional reference planes, including the horizontal reference plane, the sagittal reference plane, and the coronal reference plane;

[0017] S3. Mark the four quadrants of the dental arch: the upper right dental arch is marked as UR, the upper left dental arch as UL, the lower right dental arch as LR, and the lower left dental arch as LL; locate the impedance center points of the first molars in the four quadrants and mark them as UR6, UL6, LR6, and LL6, respectively.

[0018] S4. Determine the alveolar arch measurement planes PU6 and PL6 based on the center points of the first molar impedance in the four quadrants;

[0019] S5. Determine the alveolar arch width measurement markers in the four quadrants. The alveolar arch width measurement markers are the alveolar bone center points of each tooth position on PU6 and PL6.

[0020] S6. Project the four alveolar arch width measurement markers in the four quadrants onto the same coronal reference plane, connect them to form the coordination angle of the upper and lower alveolar arch widths, and measure the angles of the coordination angles of the upper and lower alveolar arch widths respectively.

[0021] S7. Determine the coordination of the maxillary and mandibular alveolar arches based on the aforementioned coordination angle of the width of the alveolar arches.

[0022] Furthermore, the horizontal reference plane is set as a functional occlusal plane that evenly divides the bilateral posterior tooth occlusal contact points; the sagittal reference plane passes through the palatal plane and is perpendicular to the horizontal reference plane; the coronal reference plane is perpendicular to both the horizontal and sagittal reference planes.

[0023] Furthermore, in step S3, the center point of the first molar impedance in the four quadrants is the center point between the roots located 1 mm below the root bifurcation.

[0024] Preferably, in step S4, when the impedance center point UR6 of the upper right first molar and the impedance center point UL6 of the upper left first molar are located on the same horizontal plane, the method for determining the alveolar arch measurement plane is as follows: the plane where the impedance center point UR6 of the upper right first molar and the impedance center point UL6 of the upper left first molar are located is the working plane for measuring the width of the alveolar arch of the maxillary first molar.

[0025] In another preferred embodiment, in step S4, when there is a difference in the vertical position between the impedance center point of the upper right first molar and the impedance center point of the upper left first molar, the method for determining the alveolar arch measurement plane is as follows: the plane that bisects the height between UR6 and UL6 is the working plane for measuring the width of the alveolar arch of the maxillary first molar.

[0026] Preferably, in step S5, when the buccal and palatal cortex of the tooth root is tightly wrapped, the method for determining the alveolar arch width measurement marker is as follows: the center point of the root of the first molar on both sides on the PU6 plane is the alveolar arch width measurement marker.

[0027] In another preferred embodiment, in step S5, when there is a gap between the tooth root and the buccal or palatal cortex, the method for determining the alveolar arch width measurement marker is as follows: draw a line connecting the minimum distance between the inner surfaces of the buccal and palatal cortex of the tooth position through the center point of the root of the first molar on both sides of the PU6 plane, and take the midpoint of the line as the alveolar arch width measurement marker.

[0028] Furthermore, in step S7, determining the coordination of the maxillary and mandibular alveolar arches includes analyzing the horizontal positional relationship of the maxillary and mandibular first molar alveolar arches and determining whether the width coordination angle of the bimaxillary alveolar arches is symmetrical.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] 1) The method for analyzing the coordination of the maxillary and mandibular alveolar arches based on oral cone-beam CT of the present invention uses the alveolar bone center point located at the height of the molar impedance center as the reference point for measuring the width of the maxillary and mandibular alveolar arches. It projects the alveolar arches onto the horizontal reference plane of the maxilla and mandible respectively, reducing the error caused by the vertical position difference. The measured bimaxillary alveolar arch width coordination angle can more accurately reflect the horizontal positional relationship of the alveolar arches of the first molars of the maxilla and mandible.

[0031] 2) The method for analyzing the coordination of the maxillary and mandibular alveolar arches based on oral cone-beam CT of the present invention measures the coordination angle of the left and right bimaxillary alveolar arches respectively, which is of guiding significance for judging whether there is asymmetry between the two sides. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart illustrating an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the horizontal reference plane in an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the horizontal and sagittal reference planes in an embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of a three-dimensional reference plane in an embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram showing the positions of the center points of the first molar impedance in the four quadrants in an embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram showing the positions of the four quadrant alveolar arch width measurement markers in one embodiment of the present invention;

[0039] Figure 7 This is a schematic diagram showing the positions of the four quadrant alveolar arch width measurement markers in another embodiment of the present invention;

[0040] Figure 8 This is a schematic diagram of the maxillary alveolar arch width coordination angle according to an embodiment of the present invention; Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0042] like Figure 1 As shown, a method for analyzing the coordination of the maxillary and mandibular alveolar arches based on oral cone-beam CT includes the following steps:

[0043] S1. Collect the patient's cone-beam ultrasound data, export it in DICOM format, and use software to perform three-dimensional reconstruction.

[0044] S2. Perform head positioning calibration in the software and establish a three-dimensional reference plane: Wherein:

[0045] Horizontal reference plane: set as the functional occlusal plane that evenly divides the bilateral posterior tooth occlusal contact points, such as... Figure 2 The X-plane shown;

[0046] Sagittal reference plane: passing through the palatal plane and perpendicular to the horizontal reference plane, such as... Figure 3 The Y-plane is shown.

[0047] Coronal reference plane: A plane that is perpendicular to both the horizontal and sagittal reference planes, such as... Figure 4 The Z-plane is shown.

[0048] S3. Mark the four quadrants of the dental arch: UR for the upper right arch, UL for the upper left arch, LR for the lower right arch, and LL for the lower left arch; locate the impedance center point of the first molar in each quadrant as the interroot center point located 1 mm below the root bifurcation, and label them UR6, UL6, LR6, and LL6 respectively. Figure 5 As shown.

[0049] S4. Determine the alveolar arch measurement plane: Keep the head in the calibrated position in the software without rotation, and move the horizontal reference plane vertically. This plane should always remain parallel to the functional occlusal plane. Taking the maxillary first molar as an example, when UR6 and UL6 are on the same horizontal plane, this plane is the working plane for measuring the alveolar arch width of the maxillary first molar, denoted as PU6. When there is a difference in the vertical position of UR6 and UL6, take the plane that bisects the height between UR6 and UL6 as the measurement working plane PU6. Use the same method to obtain the mandibular measurement working plane, denoted as PL6.

[0050] S5. Determine the center point of the alveolar bone at each position on PU6 and PL6 as the marker point for measuring the alveolar arch width; taking the maxillary first molar as an example, when the buccal and palatal cortex of the root is tightly wrapped, such as Figure 6 As shown, the center points of the roots of the bilateral first molars on the PU6 plane are the marking points for measuring the alveolar arch width, denoted as UR6' and UL6'; when there is a cancellous bone gap between the tooth root and the buccal or palatal cortex, such as Figure 7 As shown, draw the minimum distance between the inner surfaces of the buccal and palatal cortical bones of the tooth position through the center point of the tooth root. The midpoint of this line is used as the measurement mark point for the alveolar arch width, denoted as UR6' and UL6'. The same method is used to obtain the measurement reference point for the alveolar arch of the mandibular first molar and mark it as LR6' and LL6'.

[0051] S6. After completing the positioning of UR6', UL6', LR6', and LL6', use the software function to return to the head in an orthostatic position and project the above four markers onto the same coronal reference plane; connect LR6'-UR6'-UL6' to form the right angle ∠R, and connect LL6'-UL6'-UR6' to form the left angle ∠L, as shown. Figure 8 As shown, measure the angles ∠R and ∠L, record and calculate the average value of the left and right sides, and record it as the bimaxillary alveolar arch width coordination angle.

[0052] S7. The measured alveolar arch width coordination angle is used to analyze the horizontal positional relationship of the alveolar arches of the first molars of the upper and lower jaws, determine whether the alveolar arches on both sides are symmetrical, assist the doctor in diagnosing the transverse relationship between the jaws, and formulate an accurate orthodontic treatment plan.

[0053] The present invention will be described with reference to a specific embodiment. The method of the present invention is carried out through the following steps:

[0054] 124 patients with skeletal Class III malocclusion, posterior crossbite, and a few normal occlusions were selected from the Department of Orthodontics. CBCT data were collected from all subjects before treatment, and 3D model reconstruction was performed using Dolphin Imaging. After correcting head position on the virtual model, a 3D reference plane was established, alveolar arch landmarks and working planes were determined, and alveolar arch width measurement markers were identified in the four quadrants. These markers were projected onto the same coronal reference plane, and lines were drawn to form the coordination angles of the maxillary and mandibular alveolar arch widths. The coordination angles of the maxillary and mandibular alveolar arch widths were measured separately. The coordination angles of the maxillary and mandibular alveolar arch widths of patients with skeletal Class III malocclusion and a few normal occlusions were imported into SPSS statistical software for pairwise comparisons. Statistical differences were found in the coordination angles of the alveolar arch widths of patients with skeletal Class III malocclusion and a few normal occlusions, providing a basis for dentists to diagnose intermaxillary transverse relationships and develop precise orthodontic treatment plans.

[0055] The method for analyzing the coordination of the maxillary and mandibular alveolar arches based on cone-beam CT of the present invention uses the center point of the alveolar bone located at the height of the molar impedance center as the reference point for measuring the width of the maxillary and mandibular alveolar arches. This point is projected onto the horizontal reference plane of the maxilla and mandible respectively, reducing the error caused by vertical positional differences. The measured bimaxillary alveolar arch width coordination angle can more accurately reflect the horizontal positional relationship of the maxillary and mandibular first molar alveolar arches. The bimaxillary alveolar arch width coordination angle of the present invention can be measured separately on the left and right sides, which is of guiding significance for judging whether there is asymmetry between the two sides.

[0056] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A method for analyzing the coordination of the maxillary and mandibular alveolar arches based on oral cone-beam computed tomography (CBCT), characterized in that: The specific steps are as follows: S1. Collect the patient's cone-beam ultrasound data, export it in DICOM format, and use software to perform three-dimensional reconstruction; S2. Perform head position calibration in the software and establish three-dimensional reference planes, including the horizontal reference plane, the sagittal reference plane, and the coronal reference plane; S3. Mark the four quadrants of the dental arch: the upper right dental arch is marked as UR, the upper left dental arch as UL, the lower right dental arch as LR, and the lower left dental arch as LL. Locate the impedance center points of the first molars in the four quadrants. The impedance center points of the first molars in the four quadrants are the interroot center points located 1 mm below the root bifurcation, and are marked as UR6, UL6, LR6, and LL6, respectively. S4. Determine the alveolar arch width measurement working plane based on the impedance center point of the first molar in the four quadrants. Record the alveolar arch width measurement working plane of the maxillary first molar as PU6 and the alveolar arch width measurement working plane of the mandibular first molar as PL6. S5. Determine the alveolar arch width measurement markers in the four quadrants. The alveolar arch width measurement markers are the alveolar bone center points of each tooth position on PU6 and PL6. S6. Project the four alveolar arch width measurement markers in the four quadrants onto the same coronal reference plane, connect them to form the coordination angle of the upper and lower alveolar arch widths, and measure the angles of the coordination angles of the upper and lower alveolar arch widths respectively. S7. Determine the coordination of the maxillary and mandibular alveolar arches based on the aforementioned coordination angle of the width of the alveolar arches.

2. The method for analyzing the coordination of the maxillary and mandibular alveolar arches based on oral cone-beam CT according to claim 1, characterized in that: The horizontal reference plane is set as a functional occlusal plane that evenly divides the occlusal contact points of both posterior teeth; the sagittal reference plane passes through the palatal plane and is perpendicular to the horizontal reference plane; the coronal reference plane is perpendicular to both the horizontal and sagittal reference planes.

3. The method for analyzing the coordination of the maxillary and mandibular alveolar arches based on oral cone-beam CT according to claim 1, characterized in that: In step S4, when the impedance center point UR6 of the upper right first molar and the impedance center point UL6 of the upper left first molar are located on the same horizontal plane, the method for determining the working plane for measuring the alveolar arch width is as follows: the plane where the impedance center point UR6 of the upper right first molar and the impedance center point UL6 of the upper left first molar are located is the working plane for measuring the alveolar arch width of the maxillary first molar.

4. The method for analyzing the coordination of the maxillary and mandibular alveolar arches based on oral cone-beam CT according to claim 1, characterized in that: In step S4, when there is a difference in the vertical position between the impedance center point of the upper right first molar and the impedance center point of the upper left first molar, the method for determining the alveolar arch width measurement working plane is as follows: the plane that bisects the height between UR6 and UL6 is the alveolar arch width measurement working plane of the maxillary first molar.

5. The method for analyzing the coordination of the maxillary and mandibular alveolar arches based on oral cone-beam CT according to claim 3 or 4, characterized in that: In step S5, when the buccal and palatal cortex of the tooth root is tightly wrapped, the method for determining the alveolar arch width measurement marker is as follows: the center point of the root of the first molar on both sides on the PU6 plane is the alveolar arch width measurement marker.

6. The method for analyzing the coordination of the maxillary and mandibular alveolar arches based on oral cone-beam CT according to claim 3 or 4, characterized in that: In step S5, when there is a gap between the tooth root and the buccal or palatal cortex, the method for determining the alveolar arch width measurement marker is as follows: draw the minimum distance between the inner surfaces of the buccal and palatal cortex of the tooth position through the center point of the root of the first molar on both sides of the PU6 plane, and take the midpoint of the line as the alveolar arch width measurement marker.

7. The method for analyzing the coordination of the maxillary and mandibular alveolar arches based on oral cone-beam CT according to claim 1, characterized in that: In step S7, determining the coordination of the maxillary and mandibular alveolar arches includes analyzing the horizontal positional relationship of the alveolar arches of the first molars of the mandible and mandible, and determining whether the width coordination angle of the bimaxillary alveolar arches is symmetrical.

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