A positioning device for apical surgery and a preparation method thereof

Abstract

The present invention relates to the field of dental equipment, and in particular to a positioning device for apical surgery and a preparation method thereof. In order to reduce the risk of apical surgery, improve the quality of treatment, and improve the long-term prognosis, the present invention proposes a positioning device for apical surgery, wherein the outer edge side of the support plate is an outer convex arc surface; the positioning plate is located on the top surface of the support plate and close to the outer edge side of the support plate, and a positioning through groove is provided on the positioning plate, and the positioning through groove is close to or located at the positioning end of the positioning plate away from the support plate; the positioning accessory is clamped in the positioning through groove, and the positioning accessory is provided with a positioning guide through hole that passes through the inner wall and the outer wall of the positioning accessory; when in use, the support plate is located between the upper and lower teeth of the patient, the positioning accessory is pressed against the affected tooth, and the positioning guide through hole is located at the resection position of the root apex of the affected tooth. Using the positioning device for apical surgery of the present invention can reduce surgical risks, improve treatment quality, and be conducive to a good long-term prognosis.

Description

Technical Field

[0001] The invention relates to the field of dental equipment, and in particular to a positioning device for apical surgery and a preparation method thereof. Background Art

[0002] Root canal treatment is the first choice treatment for chronic apical periodontitis. However, when root canal treatment fails and root canal retreatment is not suitable or root canal retreatment fails, or when there are serious root canal anatomical variations in the affected tooth, or when exploratory surgery is needed to confirm the diagnosis, apical surgery is often required. That is, surgical methods are used to scrape away the periapical diseased tissue and remove the infected root apex, process the apical stump, and use blood clot organization to deposit calcified substances to promote the healing of the apical disease. These surgical methods include apex resection, apical scaling, and retrograde root filling.

[0003] When using apical surgery to treat periapical lesions that cannot be cured by some root canal treatment and retreatment, the amount of bone removed during surgery and the length of the root apex of the affected tooth need to be determined based on the structure, direction, depth and periapical lesions of the affected tooth root. During the operation, the amount of bone removed, the length of the root apex of the affected tooth and the degree of damage to the soft and hard tissues in the apical area have a significant impact on the quality and long-term prognosis of apical surgery. Therefore, when using apical surgery to treat periapical lesions, the length and angle of the root apex of the affected tooth need to be accurately located. However, currently, the structure, direction, depth and periapical lesions of the tooth root of the affected tooth are usually preliminarily understood through preoperative Cone beam CT (CBCT for short, i.e., cone CT), but the length and angle of the root apex of the affected tooth cannot be accurately located, which leads to certain risks in apical surgery, affecting the quality of treatment and the long-term prognosis. Summary of the invention

[0004] In order to reduce the risk of apical surgery, improve the quality of treatment, and improve the long-term prognosis, the present invention proposes a positioning device for apical surgery, the positioning device comprising a support plate, a positioning plate and a positioning accessory, the outer edge side of the support plate is an outward convex arc surface; the positioning plate is located on the top surface of the support plate and close to the outer edge side of the support plate, a positioning through groove is provided on the positioning plate, and the positioning through groove is close to or located at the positioning end of the positioning plate away from the support plate; the positioning accessory is clamped in the positioning through groove, and the positioning accessory is provided with a positioning guide through hole that passes through the inner wall and the outer wall of the positioning accessory; when in use, the support plate is located between the upper and lower teeth of the patient, the inner wall of the positioning accessory is pressed against the affected tooth, and the positioning guide through hole on the positioning accessory is located at the resection position of the root apex of the affected tooth.

[0005] When performing apical surgery on a patient's affected tooth, first place the support plate in the positioning device for apical surgery of the present invention between the patient's upper and lower teeth, and make the inner wall of the positioning end of the positioning plate adhere to the gums of the patient's affected tooth; then use a bone removal tool to pass through the positioning slot to remove bone tissue to expose the root of the affected tooth; then insert the positioning accessory into the positioning slot and make the inner wall of the positioning accessory press against the patient's affected tooth, and use the long-handled split drill inserted into the positioning guide hole to remove the root apex of the affected tooth, thereby removing the root apex of the affected tooth. In this way, when performing apical surgery on a patient's affected tooth, using the positioning device for apical surgery of the present invention, the bone removal range can be limited by the positioning slot on the positioning plate, thereby reducing the amount of bone removal; the resection position, direction, depth and angle of the long-handled split drill can be accurately limited by the positioning guide hole on the positioning accessory, thereby accurately removing the root apex of the affected tooth and reducing the damage to the soft and hard tissues in the root apex area when removing the root apex of the affected tooth. It can be seen that when performing apical surgery on a patient's affected tooth, using the positioning device for apical surgery of the present invention can effectively reduce the amount of bone removal, accurately remove the root apex of the affected tooth, reduce damage to the soft and hard tissues in the root apex area of ​​the affected tooth, reduce the risk of apical surgery, improve the quality of treatment, and be conducive to a positive long-term prognosis.

[0006] Preferably, the positioning guide through hole is a countersunk hole, and the aperture of the positioning guide through hole at the outer wall of the positioning accessory is larger than the aperture of the positioning guide through hole at the inner wall of the positioning accessory. In this way, the depth of the countersunk groove of the positioning guide through hole at the outer wall of the positioning accessory can be adjusted as needed to control the resection depth of the long-shank fissure drill, thereby preventing the long-shank fissure drill from causing damage to the patient due to excessive penetration during the resection process, thereby affecting the treatment and long-term prognosis.

[0007] Preferably, the support plate is a ring-sector plate. In this way, the support plate and the patient's tongue can be prevented from interfering with each other, which may affect the positioning effect of the positioning plate and the positioning accessories. Furthermore, the top and bottom surfaces of the support plate are provided with limiting grooves for accommodating the tooth tips. In this way, the tooth tips of the patient's teeth can be stuck in the limiting grooves during use, which may prevent the support plate from shifting during the operation and affecting the quality of surgical treatment.

[0008] Preferably, the positioning device further comprises a supporting protrusion, which is located on the positioning end of the positioning plate away from the supporting plate. In this way, when in use, the supporting protrusion can be used to support the patient's lips to prevent the patient's lips from obstructing the operation and affecting the quality of treatment.

[0009] Preferably, the positioning accessory is made of titanium alloy material. Such a positioning accessory has good wear resistance, can reduce possible wear errors, and further improve the accuracy of the operation.

[0010] In addition, the present invention also provides a method for preparing a positioning device for apical surgery, the method comprising the following steps:

[0011] Step S1: obtaining a dental model of the patient by plaster model scanning or oral scanning;

[0012] Step S2: Using a cone beam CT device to perform circular digital projection on the patient's head to obtain a CBCT image of the patient's affected tooth, and clarifying the location, nature, degree, and range of the periapical lesions of the affected tooth, the changes in the surrounding alveolar bone, and whether the adjacent important anatomical structures are affected by the affected tooth based on the CBCT image; importing the CBCT image into Mimics Research software, and using a threshold segmentation method to distinguish the soft tissue, bone tissue, and tooth body in the CBCT image, and establishing a three-dimensional reconstruction model of the bone destruction area of ​​the periapical disease of the patient's affected tooth;

[0013] Step S3: importing the dentition model and the CBCT image into Geomagic Studio software, segmenting the upper and lower jaws in the CBCT image using Geomagic Studio software, and registering and fusing the jaw where the patient's affected teeth are located with the dentition model to reconstruct a three-dimensional model of the patient's jaw-dentition;

[0014] Step S4: importing the three-dimensional reconstruction model of the bone destruction area of ​​the periapical disease and the three-dimensional model of the jaw-dentition into the Freeform Plus software, using the Freeform Plus software to measure the maximum diameter and volume of the periapical lesions of the patient's affected teeth, the distance between the periapical lesions and important anatomical structures, the crown length and the root length, and establishing a visualized three-dimensional model of the periapical lesions;

[0015] Step S5: Determine the outer edge size of the support plate in the positioning device and select an outer convex arc surface for the outer edge side according to the outer edges of the crowns of the upper and lower teeth in the mandibular-dentition three-dimensional model; determine the shape, size and position of the positioning plate in the positioning device on the support plate according to the visualized three-dimensional model of the periapical lesion; determine the position and size of the positioning groove on the positioning plate, the shape and size of the positioning accessory installed in the positioning groove, and the position, size and direction of the positioning guide through hole on the positioning accessory according to the visualized three-dimensional model of the periapical lesion;

[0016] Step S6: inputting the shape and size of the positioning device determined in step S5 into a 3D printer, and printing the positioning device by the 3D printer.

[0017] When the positioning device for apical surgery is prepared by the preparation method of the positioning device for apical surgery of the present invention, the patient's dentition model obtained by scanning the plaster model or the mouth scan has high accuracy, so it can be matched and fused with the obtained CBCT graphics to establish a high-precision jaw-dentition three-dimensional model, and then the outer edge size and the shape of the outer edge side of the support plate in the positioning device for apical surgery can be accurately determined according to the outer edges of the crowns of the upper and lower teeth in the jaw-dentition three-dimensional model; after the CBCT image of the patient's affected tooth is obtained by projection using a cone beam CT device, the CBCT image of the patient's affected tooth can be anatomized from different angles and levels, the morphological structure of the root canal can be clearly observed, the location, nature, degree, range of the periapical lesions and the changes in the surrounding alveolar bone, as well as whether the adjacent important anatomical structures are involved, are clearly determined, so as to facilitate the establishment of a three-dimensional reconstruction model of the bone destruction area of ​​the periapical disease of the patient's affected tooth, and then The invention is convenient for determining the surgical scope during surgical treatment; the maximum diameter and volume of the periapical lesions of the patient's affected teeth, the distance between the periapical lesions and important anatomical structures, the crown length and the root length are measured according to the three-dimensional reconstruction model of the bone destruction zone of the periapical disease and the three-dimensional model of the jaw-dentition, so as to establish a visualized three-dimensional model of the periapical lesions, and then the shape, size and position of the positioning plate on the support plate, the setting position and size of the positioning groove on the positioning plate, the shape and size of the positioning accessory installed in the positioning groove, and the position, size and direction of the positioning guide hole on the positioning accessory can be accurately determined according to the visualized three-dimensional model of the periapical lesions, so as to facilitate medical staff to use the positioning device for apical surgery prepared by the preparation method in combination with a long-handled fissure drill to accurately remove the root apex of the affected tooth, reduce the amount of bone removed during the root apex resection of the affected tooth, and reduce the damage to the soft and hard tissues in the root apex area when removing the root apex of the affected tooth.

[0018] Preferably, in step S1, when obtaining the patient's dental arch model by plaster model scanning, firstly, the patient's dental arch impression is made by 3M ESPE silicone rubber impression material, then the patient's dental arch plaster model is obtained by plaster casting, and finally, the dental arch plaster model is scanned by 3Shape laser scanner to obtain the dental arch model; when obtaining the patient's dental arch model by oral scanning, the patient's dental arch model is scanned by 3shape Trios intraoral scanner. When the patient's dental arch model is obtained by these two methods, the accuracy of the obtained dental arch model can be further improved.

[0019] Preferably, in step S2, the threshold used when segmenting the CBCT image using the threshold segmentation method is set to 226-3071HU. In this way, the threshold used when segmenting the CBCT image using the threshold segmentation method is set to 226-3071HU, that is, the bone tissue threshold, which can easily segment tissues with obvious gray value differences in the CBCT image, such as soft tissue, bone tissue and tooth body, and thus quickly and accurately reconstruct the patient's jaw-dentition three-dimensional model.

[0020] Preferably, in step S5, the inner edge shape and size of the support plate of the annular sector plate are determined according to the inner edges of the crowns of the upper and lower teeth in the three-dimensional model of the jaw-dentition; the position and size of the limiting grooves on the top and bottom surfaces of the support plate for accommodating the tooth tips are determined according to the crowns of the upper and lower teeth in the three-dimensional model of the jaw-dentition. In this way, when a positioning device for apical surgery is printed using a 3D printer, the support plate can be printed as an annular sector plate, and limiting grooves for accommodating the tooth tips of the patient's teeth can be printed on the top and bottom surfaces of the support plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of a positioning device for apical surgery of the present invention;

[0022] Figure 2 for Figure 1 The schematic diagram of the structure of the positioning device for apical surgery shown in FIG. 1 when the positioning accessories are removed;

[0023] Figure 3 for Figure 2 The schematic diagram of the structure of the positioning device for apical surgery shown in another angle. DETAILED DESCRIPTION

[0024] Next, combine Figure 1-3 The invention provides a positioning device for apical surgery and a method for preparing the same.

[0025] like Figures 1 to 3 As shown, the positioning device for apical surgery of the present invention includes a support plate 1, a positioning plate 2, a positioning accessory 3 and a support protrusion 4. Among them, the outer edge side surface 11 of the support plate 1 is an outward convex arc surface, so that it can be placed in the patient's mouth and located between the patient's upper and lower teeth when in use. Preferably, the support plate 1 is an annular fan-shaped plate. In this way, it can be avoided that the support plate 1 and the patient's tongue interfere with each other and affect the positioning effect of the positioning plate 2 and the positioning accessory 3. Preferably, the top surface 12 and the bottom surface (not shown in the figure) of the support plate 1 are provided with a limiting groove (not shown in the figure) for accommodating the tooth tip. In this way, when in use, the tooth tip of the patient's tooth can be stuck in the limiting groove to avoid the displacement of the support plate 1 during the operation and affect the quality of surgical treatment.

[0026] The positioning plate 2 is located on the top surface 12 of the support plate 1 and close to the outer edge side surface 11 of the support plate 1. A positioning slot 21 is provided on the positioning plate 2, and the positioning slot 21 is close to or located at the positioning end of the positioning plate 2 away from the support plate 1. Preferably, the positioning plate 2 is an arc-shaped plate, so that the inner wall 22 of the positioning plate 2 is attached to the jaw surface where the patient's affected tooth is located during use, to avoid shaking or dislocation during surgery, which affects the treatment effect.

[0027] The positioning accessory 3 is clamped in the positioning groove 21 on the positioning plate 2, and the positioning accessory 3 is provided with a positioning guide through hole 32 that passes through the inner wall (not shown in the figure) and the outer wall 31 of the positioning accessory 3. Preferably, the positioning guide through hole 32 is a countersunk hole, and the aperture of the positioning guide through hole 32 at the outer wall 31 of the positioning accessory 3 is larger than the aperture of the positioning guide through hole 32 at the inner wall of the positioning accessory 3. In this way, the depth of the countersunk groove of the positioning guide through hole 32 at the outer wall 31 of the positioning accessory 3 can be adjusted as needed to control the resection depth of the long-shank fissure drill, thereby avoiding the long-shank fissure drill from causing damage to the patient due to excessive depth during the resection process, affecting the treatment and long-term prognosis. Preferably, the positioning accessory 3 is made of titanium alloy material. Such a positioning accessory 3 has good wear resistance, can reduce possible wear errors, and further improve the accuracy of the operation.

[0028] The support protrusion 4 is located on the positioning end of the positioning plate 2 away from the support plate 1. In this way, when in use, the support protrusion 2 can be used to support the patient's lips to prevent the patient's lips from obstructing the operation and affecting the treatment quality.

[0029] When in use, the support plate 1 is placed in the patient's mouth and located between the patient's upper and lower teeth, the positioning accessory 3 is located in the positioning slot 21 on the positioning plate 2 and pressed against the affected tooth, and the positioning guide hole 32 on the positioning accessory 3 is located at the resection position of the root apex of the affected tooth. When performing apical surgery on the patient's affected tooth, first place the support plate 1 in the positioning device for apical surgery of the present invention between the patient's upper and lower teeth, and make the inner wall of the positioning end of the positioning plate 2 attached to the gums of the patient's affected tooth; then use a bone removal tool to pass through the positioning slot 21 to remove bone tissue to expose the root of the affected tooth; then insert the positioning accessory 3 into the positioning slot 21 and make the inner wall of the positioning accessory 3 press against the patient's affected tooth, and use the long-handled crack drill inserted into the positioning guide hole 32 to resect the root apex of the affected tooth, thereby resecting the root apex of the affected tooth. In this way, when performing apical surgery on the patient's affected tooth, the positioning device for apical surgery of the present invention is used, and the bone removal range can be limited by the positioning groove 21 on the positioning plate 2, thereby reducing the amount of bone removal; the resection position, direction, depth and angle of the long-handled fissure drill can be accurately limited by the positioning guide hole 32 on the positioning accessory 3, so as to accurately remove the root apex of the affected tooth and reduce the damage to the soft and hard tissues in the apical area when removing the root apex of the affected tooth. It can be seen that when performing apical surgery on the patient's affected tooth, the positioning device for apical surgery of the present invention is used, which can effectively reduce the amount of bone removal, accurately remove the root apex of the affected tooth, reduce the damage to the soft and hard tissues in the apical area of ​​the affected tooth, reduce the risk of apical surgery, improve the quality of treatment, and is conducive to a good long-term prognosis.

[0030] When preparing the positioning device for apical surgery, the specific preparation method is as follows:

[0031] First, the patient's dental model is obtained by plaster model scanning or oral scanning. Preferably, when the patient's dental model is obtained by plaster model scanning, the patient's dental impression is first made by 3M ESPE silicone rubber impression material, and then the patient's dental plaster model is obtained by plaster casting, and finally the dental plaster model is scanned with a 3Shape laser scanner to obtain the patient's dental model; when the patient's dental model is obtained by oral scanning, the patient's dental model is scanned with a 3shape Trios intraoral scanner. When the patient's dental model is obtained by these two methods, the accuracy of the obtained dental model can be further improved.

[0032] Then, a cone beam CT device is used to perform circular digital projection on the patient's head to obtain a CBCT image of the patient's affected tooth, and the location, nature, degree, and range of the periapical lesions of the affected tooth, the changes in the surrounding alveolar bone, and whether the adjacent important anatomical structures are affected by the affected tooth are clarified based on the CBCT image, and the CBCT image is imported into the Mimics Research software, and the soft tissue, bone tissue, and tooth body in the CBCT image are distinguished by the threshold segmentation method to establish a three-dimensional reconstruction model of the bone destruction area of ​​the periapical disease of the patient's affected tooth. Preferably, the threshold used when segmenting the CBCT image using the threshold segmentation method is set to 226-3071HU. In this way, the threshold used when segmenting the CBCT image using the threshold segmentation method is set to 226-3071HU, that is, the bone tissue threshold, which is easy to segment the tissues with obvious gray value differences in the CBCT image, such as soft tissue, bone tissue, and tooth body, and the image segmentation is convenient and fast, and then the patient's jaw-dentition three-dimensional model can be quickly and accurately reconstructed. Among them, the MimicsResearch software can preferably be 19.0 and later versions. In addition, for adjacent structures with similar grayscale values ​​in CBCT images that are difficult to distinguish through threshold segmentation methods, image segmentation tools such as 3D magnetic lasso, morphological operations, Boolean operations, cavity filling, editing masks, multi-layer editing, and mask 3D editing can be used for local fine-tuning to further improve the accuracy of the reconstructed patient's jaw-dentition 3D model.

[0033] Next, the acquired patient's dental arch model and CBCT image were imported into Geomagic Studio software, and the maxilla and mandible in the CBCT image were segmented using Geomagic Studio software, and the jawbone and dental arch model where the patient's affected teeth were located were registered and fused to reconstruct the patient's jaw-dentition 3D model. If the patient's affected teeth were upper teeth, the patient's maxilla was registered and fused with its dental arch model; if the patient's affected teeth were lower teeth, the patient's mandible was registered and fused with its dental arch model.

[0034] Then, the three-dimensional reconstruction model of the bone destruction area of ​​the periapical disease and the three-dimensional model of the jaw-dentition were imported into the Freeform Plus software. The maximum diameter and volume of the periapical lesions of the patients' teeth, the distance between the periapical lesions and important anatomical structures, the crown length, the root length, and the root length supported by the alveolar bone were measured by Freeform Plus software, and a visual three-dimensional model of the periapical lesions was established. In addition, the maximum diameter and volume of the periapical lesions of the patients' teeth can be measured to evaluate the range of the periapical lesions of the patients' teeth; the distance between the periapical lesions of the patients' teeth and important anatomical structures (maxillary sinus and incisor canal) can be measured to evaluate the risk of surgical operation on the patients' teeth and remind them to operate during the operation, thereby reducing the risk of surgery; the crown length, root length, and root length supported by the alveolar bone of the patients can be measured, and the crown length and root length can be combined to analyze the root-crown ratio of the patients' teeth and calculate the root-crown ratio after surgery, thereby evaluating the retention value of the patients' teeth.

[0035] Finally, the outer edge size of the support plate 1 in the positioning device for apical surgery and the outer edge side surface 11 are determined to be an outer convex arc surface according to the outer edges of the upper and lower tooth crowns in the three-dimensional model of the jaw-dentition; the shape, size and position of the positioning plate 2 in the positioning device for apical surgery on the support plate 1 are determined according to the visualized three-dimensional model of periapical lesions; the position and size of the positioning slot 21 on the positioning plate 2 and the shape and size of the positioning accessory 3 installed in the positioning slot 21 and the position, size and direction of the positioning guide through hole 32 on the positioning accessory 3 are determined according to the visualized three-dimensional model of periapical lesions. The shape and size of the positioning device for apical surgery are input into the 3D printer, and the positioning device for apical surgery is printed by the 3D printer. Preferably, the inner edge shape and size of the support plate 1 of the annular sector plate are determined according to the inner edges of the crowns of the upper and lower teeth in the three-dimensional model of the jaw-dentition; the position and size of the limiting grooves (not shown in the figure) on the top and bottom surfaces of the support plate 1 for accommodating the tooth tips are determined according to the crowns of the upper and lower teeth in the three-dimensional model of the jaw-dentition. In this way, when the positioning device for apical surgery is printed using a 3D printer, the support plate 1 can be printed as an annular sector plate, and the limiting grooves for accommodating the tooth tips of the patient's teeth can be printed on the top and bottom surfaces of the support plate 1. During the specific implementation, in the visualized three-dimensional model of the periapical lesion, after the undercut operation is performed using the crown part in the jaw-dentition three-dimensional model, a support plate 1 is established through the stretching function; a positioning plate 2 whose inner wall fits the bone surface of the jaw where the patient's affected tooth is located is formed through the convex function; a contour projection of the periapical lesion on the surface of the cortical bone is established in the visualized three-dimensional model of the periapical lesion, and the form (shape and size) of the bone removal guide part, i.e., the positioning groove 21, is established according to the boundary of the contour projection, and then a positioning accessory 3 is formed at the positioning groove using the convex function; the long axis of the patient's affected tooth is determined in the visualized three-dimensional model of the periapical lesion, because the diameter of the long-handled fissure drill used for bone removal is 1 mm, and the resection length of the root apex is generally 3 mm, a plane perpendicular to the long axis of the patient's affected tooth is made 2 mm away from the root apex, so that the position, size and direction of the positioning guide hole on the positioning accessory 3 are determined using the plane. In order to ensure the apical resection effect, the positioning guide through hole 32 is set as a countersink, and the aperture of the positioning guide through hole 32 at the outer wall 31 of the positioning accessory 3 is larger than the aperture of the positioning guide through hole 32 at the inner wall of the positioning accessory 3, so that the depth of the countersink of the positioning guide through hole 32 at the outer wall 31 of the positioning accessory 3 can be adjusted as needed to control the resection depth of the long-shank fissure drill, so as to avoid the long-shank fissure drill causing damage to the patient due to excessive depth during the resection process, affecting the treatment and long-term prognosis. In addition, a support protrusion 4 can be set on the positioning end of the positioning plate 2 away from the support plate 1, so as to use the support protrusion 4 to support the patient's lips, so as to avoid the patient's lips hindering the operation and affecting the quality of treatment. Preferably, the thickness of the support protrusion 4 can be set to 7 mm to facilitate supporting the patient's lips.

[0036] When the positioning device for apical surgery is prepared by the method for preparing the positioning device for apical surgery of the present invention:

[0037] The patient's dental arch model obtained by plaster model scanning or oral scanning has high accuracy, so it can be fused with the acquired CBCT images to establish a high-precision jaw-dentition three-dimensional model, and then the outer edge size and shape of the outer edge side of the support plate in the positioning device for apical surgery can be accurately determined based on the outer edges of the upper and lower tooth crowns in the jaw-dentition three-dimensional model;

[0038] After the CBCT images of the patient's affected teeth are obtained by projection using a cone beam CT device, the CBCT images of the patient's affected teeth can be anatomized from different angles and levels to clearly observe the morphological structure of the root canals of the patient's affected teeth, clarify the location, nature, degree, range of periapical lesions and changes in the surrounding alveolar bone, and whether the adjacent important anatomical structures are involved, so as to facilitate the establishment of a three-dimensional reconstruction model of the bone destruction area of ​​the periapical disease of the patient's affected teeth, and then facilitate the determination of the surgical scope when surgical treatment is used;

[0039] Based on the three-dimensional reconstruction model of the bone destruction area of ​​the periapical disease and the three-dimensional model of the jaw-dentition, the maximum diameter and volume of the periapical lesions of the patient's affected teeth, the distance between the periapical lesions and important anatomical structures, the crown length and the root length are measured, so that a visualized three-dimensional model of the periapical lesions can be established, and then the shape, size, and position of the positioning plate 2 on the support plate 1, the setting position and size of the positioning groove 21 on the positioning plate 2, the shape and size of the positioning accessory 3 installed in the positioning groove 21, and the position, size and direction of the positioning guide hole 32 on the positioning accessory 3 can be accurately determined according to the visualized three-dimensional model of the periapical lesions, so that medical personnel can use the positioning device for apical surgery prepared by the preparation method in combination with a long-handled fissure drill to accurately resect the root apex of the affected tooth, reduce the amount of bone removed during root apex resection of the affected tooth, and reduce the damage to the soft and hard tissues in the root apex area when resecting the root apex of the affected tooth.

Claims

1. A positioning device for apical surgery, characterized in that: The positioning device comprises a support plate, a positioning plate and a positioning accessory, wherein the outer edge side surface of the support plate is an outer convex arc surface; the positioning plate is located on the top surface of the support plate and close to the outer edge side surface of the support plate, a positioning through groove is provided on the positioning plate, and the positioning through groove is close to or located at the positioning end of the positioning plate away from the support plate; the positioning accessory is clamped in the positioning through groove, and a positioning guide through hole penetrating the inner wall and the outer wall of the positioning accessory is provided on the positioning accessory; when in use, the support plate is located between the upper and lower teeth of the patient, the inner wall of the positioning accessory is pressed against the affected tooth, and the positioning guide through hole on the positioning accessory is located at the resection position of the root apex of the affected tooth; The positioning device further comprises a supporting protrusion, which is located on a positioning end of the positioning plate away from the supporting plate; The resection position, direction, depth and angle of the long-shank fissure drill are precisely limited through the positioning guide through hole on the positioning accessory, thereby precisely resecting the root apex of the affected tooth and reducing damage to the soft and hard tissues in the root apex area when resecting the root apex of the affected tooth.

2. The positioning device for apical surgery according to claim 1, characterized in that: The positioning guide through hole is a countersunk hole, and the hole diameter of the positioning guide through hole at the outer wall of the positioning accessory is larger than the hole diameter of the positioning guide through hole at the inner wall of the positioning accessory.

3. The positioning device for apical surgery according to claim 1 or 2, characterized in that: The support plate is a ring sector plate.

4. The positioning device for apical surgery according to claim 3, characterized in that: The top and bottom surfaces of the support plate are provided with limiting grooves for accommodating tooth tips.

5. The positioning device for apical surgery according to claim 1 or 2, characterized in that: The positioning fitting is made of titanium alloy material.

6. A method for preparing a positioning device for apical surgery according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: Step S1: obtaining a dental model of the patient by plaster model scanning or oral scanning; Step S2: Using a cone beam CT device to perform circular digital projection on the patient's head to obtain a CBCT image of the patient's affected tooth, and clarifying the location, nature, degree, and range of the periapical lesions of the affected tooth, the changes in the surrounding alveolar bone, and whether the adjacent important anatomical structures are affected by the affected tooth based on the CBCT image; importing the CBCT image into Mimics Research software, and using a threshold segmentation method to distinguish the soft tissue, bone tissue, and tooth body in the CBCT image, and establishing a three-dimensional reconstruction model of the bone destruction area of ​​the periapical disease of the patient's affected tooth; Step S3: importing the dentition model and the CBCT image into Geomagic Studio software, segmenting the upper and lower jaws in the CBCT image using Geomagic Studio software, and registering and fusing the jaw where the patient's affected teeth are located with the dentition model to reconstruct a three-dimensional model of the patient's jaw-dentition; Step S4: importing the three-dimensional reconstruction model of the bone destruction area of ​​the periapical disease and the three-dimensional model of the jaw-dentition into the Freeform Plus software, using the Freeform Plus software to measure the maximum diameter and volume of the periapical lesions of the patient's affected teeth, the distance between the periapical lesions and important anatomical structures, the crown length and the root length, and establishing a visualized three-dimensional model of the periapical lesions; Step S5: Determine the outer edge size of the support plate in the positioning device and select an outer convex arc surface for the outer edge side surface according to the outer edges of the crowns of the upper and lower teeth in the mandibular-dentition three-dimensional model; determine the shape, size and position of the positioning plate in the positioning device on the support plate according to the visualized three-dimensional model of the periapical lesion; determine the position and size of the positioning groove on the positioning plate, the shape and size of the positioning accessory installed in the positioning groove and the position, size and direction of the positioning guide through hole on the positioning accessory according to the visualized three-dimensional model of the periapical lesion; a supporting protrusion is provided on the positioning end of the positioning plate away from the support plate; Step S6: inputting the shape and size of the positioning device determined in step S5 into a 3D printer, and printing the positioning device by the 3D printer.

7. The method for preparing a positioning device for apical surgery according to claim 6, characterized in that: In step S1, when obtaining the patient's dental model by plaster model scanning, firstly, a dental impression of the patient is made by 3M ESPE silicone rubber impression material, then a dental plaster model of the patient is obtained by plaster casting, and finally, a 3Shape laser scanner is used to scan the dental plaster model to obtain the dental model; when obtaining the patient's dental model by oral scanning, a 3shape Trios intraoral scanner is used to scan and obtain the patient's dental model.

8. The method for preparing a positioning device for apical surgery according to claim 7, characterized in that: In the step S2, the threshold used when segmenting the CBCT image using the threshold segmentation method is set to 226-3071HU for bone.

9. The method for preparing a positioning device for apical surgery according to claim 8, characterized in that: In step S5, the inner edge shape and size of the support plate of the annular fan-shaped plate are determined according to the inner edges of the crowns of the upper and lower teeth in the jaw-dentition three-dimensional model; the position and size of the limiting grooves on the top and bottom surfaces of the support plate for accommodating the tooth tips are determined according to the crowns of the upper and lower teeth in the jaw-dentition three-dimensional model.

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