Midline positioning ruler for orthognathic surgery and manufacturing method thereof

Abstract

The application discloses a midline positioning ruler for orthognathic surgery and a manufacturing method thereof, and relates to the technical field of medical instruments. The method comprises the following steps: designing a multi-curved positioning ruler main body; drawing a limiting structure and a retaining structure on the positioning ruler main body; virtually designing a buckle and drawing a clamping groove on the buckle; scanning a jaw and face of a target object and manufacturing a hard gypsum tooth model; establishing a virtual three-dimensional craniofacial model, laser scanning the hard gypsum tooth model to obtain virtual dentition data, and replacing dentition data in the jaw and face data with the virtual dentition data; adjusting the positions of the positioning ruler main body and the buckle; virtually connecting the buckle and the intermediate occlusion guide plate to form an integrated whole; and laser cutting the positioning ruler main body and integrally three-dimensionally printing the buckle and the intermediate occlusion guide plate. The midline positioning ruler is used for quickly positioning the position of the maxillary dentition midline in orthognathic surgery, improves the operation precision, saves the operation time, improves the operation efficiency, and reduces the dependence of the operation on the experience of doctors.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a midline positioning ruler for orthognathic surgery and its manufacturing method. Background Technology

[0002] Facial asymmetry is a common and challenging dentofacial deformity in orthognathic surgery. Its main clinical manifestations include bilateral asymmetry of the maxillofacial region relative to the facial midline, with the lower third of the face deviating to one side. It may also be accompanied by malocclusion, midline deviation of the dental arch, deviation of the facial plane, and temporomandibular joint symptoms. Combined orthodontic and orthognathic treatment is a common clinical strategy for treating facial asymmetry. Restoring the consistency between the deviated dental midline and the facial midline, and thereby restoring facial symmetry, is a key aspect of treating facial asymmetry.

[0003] In traditional model-based surgical planning, orthognathic surgeons, based on the degree of maxillary midline deviation observed during clinical examination, move the maxillary midline on a model to align it with the facial midline. This is followed by the fabrication of intermediate and terminal occlusal guides to aid in the positioning of the maxillary and mandibular bone segments. With the widespread application of digital technology in orthognathic surgery, digital design for facial asymmetry has become increasingly common. The basic method is similar to model-based surgical techniques: the surgeon moves the maxillary bone segments within a computer based on the clinically observed deviation of the maxillary midline relative to the facial midline, aligning the maxillary midline with the facial midline. After completing the virtual design of the orthognathic surgical plan, intermediate and terminal occlusal guides are then virtually designed and 3D printed to assist in the surgery. Existing research shows that both traditional model-based surgical techniques and digital design significantly improve all outcome indicators for patients with facial asymmetry. However, compared to traditional surgical planning, virtual design shows significantly greater improvement in facial midline and overall facial symmetry.

[0004] However, regardless of whether the occlusal guide is made using traditional methods or virtual design and 3D printing, although the preoperative midline plan is included in the occlusal guide, the alignment of the maxillary dentition midline with the facial midline still requires careful comparison by the surgeon during orthognathic surgery. Common comparison methods include visual observation or the use of a ruler. Because these guides determine the position of the maxillary tooth bone segments based on the position of the condyles, factors such as bone interference between bone fragments, soft tissue swelling, posterior displacement of the condyles due to general anesthesia, and nasal deviation caused by endotracheal intubation can all affect the orthognathic surgeon's visual judgment of the consistency between the dentition midline and the facial midline.

[0005] Currently, a researcher has designed a digital composite occlusal guide with four indicator rods, based on a digital occlusal guide. The specific method involves designing horizontal rods, anterior midsagittal rods, upward midsagittal rods, and downward midsagittal rods on the occlusal guide after completing the virtual design of the orthognathic surgery and the virtual design of the occlusal guide. These are used to assess parameters such as dental and skeletal midlines, facial soft tissue midlines, and occlusal planes during surgery. The study validated the immediate postoperative maxillary angle and line distance deviations in 17 patients undergoing single-occlusal-plate surgery, with ideal results. However, the indicator rods designed in this method are 7-10 mm in length, limited to the upper and lower lip areas, and cannot be compared with major facial midline landmarks. The accuracy of judging the consistency between the maxillary dentition midline and the facial midline is generally low. Furthermore, a special individualized facebow is required during surgery to determine the jawbone position and dentition midline, making the operation cumbersome and inefficient.

[0006] Therefore, it is necessary to design a midline positioning ruler to assist in determining the position of the midline of the maxillary dentition, so as to improve surgical efficiency and the accuracy of midline determination during surgery. Summary of the Invention

[0007] The main objective of this invention is to provide a midline positioning ruler for orthognathic surgery and its manufacturing method, which aims to assist in determining the position of the midline of the maxillary dentition, improve surgical efficiency, and enhance the accuracy of midline determination during surgery.

[0008] To achieve the above objectives, this invention proposes a method for manufacturing a midline positioning ruler for orthognathic surgery. The midline positioning ruler includes a main body and a clip. The manufacturing method includes the following steps:

[0009] In 3D virtual design software, the contour curve of the right side of the human face is simulated to design the main body of a multi-curved positioning ruler;

[0010] A limiting structure extending the target length in the direction of the face is drawn on the upper end of the positioning ruler body;

[0011] A protruding retention structure is drawn on the main body of the positioning ruler at the position corresponding to the mouth opening;

[0012] A virtual buckle is designed, and a slot that matches the retaining structure is drawn in the middle of the buckle.

[0013] Connect the virtual design of the positioning ruler body to the buckle, and save the design file of the assembled positioning ruler body and buckle;

[0014] A spiral CT scan of the maxillofacial region was performed on the target subject to collect maxillofacial data and to create a hard plaster dental model.

[0015] The maxillofacial data is imported into the craniofacial surgery planning software to establish a virtual three-dimensional craniofacial model. The hard plaster tooth model is then laser-scanned to obtain virtual dentition data, which is then used to replace the dentition data in the maxillofacial data.

[0016] The target surgical type was simulated on a virtual craniomaxillary model, and the target location of the mandibular bone segment was determined based on the terminal occlusion relationship.

[0017] Import the design files of the positioning ruler body and the buckle into the craniofacial surgery planning software, align the lower end of the positioning ruler body with the midline of the maxillary dentition, align the upper end of the positioning ruler body with the midline of the face, and align the height of the buckle position with the occlusal plane.

[0018] Virtual design of intermediate occlusal guide and terminal occlusal guide;

[0019] The buckle and the intermediate engagement guide plate are virtually connected to form a whole to obtain the target design file;

[0020] According to the target design document, the main body of the positioning ruler is laser-cut and manufactured, and the buckle and the intermediate interlocking guide plate are integrally 3D printed.

[0021] Optionally, after importing the design files of the positioning ruler body and the buckle into the craniofacial surgery planning software, aligning the lower end of the positioning ruler body with the midline of the maxillary dentition, aligning the upper end of the positioning ruler body with the midline of the face, and aligning the height of the buckle position with the occlusal plane, the procedure further includes:

[0022] Adjust the distance between the positioning ruler body and the buckle and the facial soft tissue to reserve a safe distance.

[0023] Optionally, in the step of importing the design files of the positioning ruler body and the buckle into the craniofacial surgery planning software, aligning the lower end of the positioning ruler body with the midline of the maxillary dentition, aligning the upper end of the positioning ruler body with the midline of the face, and aligning the height of the buckle position with the occlusal plane, if the maxillofacial data of the target object does not match the positioning ruler body, the length of the positioning ruler body can be stretched or contracted in the virtual design software, or the shape of the positioning ruler body can be modified.

[0024] Optionally, in the step of drawing a limiting structure extending the target length in the direction of the face on the upper end of the positioning ruler body, the length of the limiting structure is 1.8-2.2 cm.

[0025] Optionally, in the step of laser cutting the positioning ruler body according to the target design document and integrally 3D printing the buckle and the intermediate engagement guide plate, the material of the positioning ruler body is medical grade 304 stainless steel.

[0026] Optionally, in the step of laser cutting and fabricating the positioning ruler body according to the target design document, and integrally 3D printing the buckle and the intermediate engagement guide plate, the material of the buckle and the intermediate engagement guide plate is acrylic resin.

[0027] Optionally, in the step of simulating the target surgical type on a virtual craniomaxillary model and determining the target position of the mandibular bone segment based on the final occlusal relationship, the target surgical type includes Le Fort type I osteotomy and mandibular sagittal splitting.

[0028] Optionally, the midline positioning ruler is used to determine the midline of the maxillary dentition in bimaxillary surgery based on a double occlusal guide and to determine the midline of the maxillary dentition in bimaxillary surgery based on a single occlusal guide.

[0029] Optionally, the midline positioning ruler is also used to assist the surgeon in judging the symmetry of the chin during the operation.

[0030] To achieve the above objectives, the present invention also proposes a midline positioning ruler, which is manufactured using the above-described method for manufacturing a midline positioning ruler for orthognathic surgery.

[0031] In the technical solution of this invention, the midline positioning ruler includes a positioning ruler body and a buckle; the method for manufacturing the midline positioning ruler for orthognathic surgery includes the following steps:

[0032] S01. In 3D virtual design software, simulate the contour curve of the right side of the human face and design the main body of the multi-curved positioning ruler.

[0033] S02. Draw a limiting structure extending the target length in the direction of the face on the upper end of the positioning ruler body;

[0034] S03. Draw a protruding retention structure on the main body of the positioning ruler corresponding to the position of the mouth opening;

[0035] S04. Virtually design the buckle and draw a slot in the middle of the buckle that is compatible with the fixing structure.

[0036] S05. Connect the virtual design of the positioning ruler body to the buckle, and save the design file of the assembled positioning ruler body and buckle;

[0037] S06. Perform a spiral CT scan of the maxillofacial region on the target object, collect maxillofacial data, and create a hard plaster dental model.

[0038] S07. Import the maxillofacial data into the craniofacial surgery planning software, establish a virtual three-dimensional craniofacial model, and use laser scanning to scan the hard plaster tooth model to obtain virtual dentition data, and replace the dentition data in the maxillofacial data with it.

[0039] S08. Simulate the target surgical type on a virtual craniofacial model and determine the target location of the mandibular bone segment based on the terminal occlusion relationship.

[0040] S09. Import the design files of the positioning ruler body and the buckle into the craniofacial surgery planning software, align the lower end of the positioning ruler body with the midline of the maxillary dentition, align the upper end of the positioning ruler body with the midline of the face, and align the height of the buckle position with the occlusal plane.

[0041] S10. Virtual design of intermediate occlusal guide and terminal occlusal guide;

[0042] S11. Virtually connect the buckle and the intermediate engagement guide plate to form a whole to obtain the target design file;

[0043] S12. According to the target design document, the positioning ruler body is laser-cut and manufactured, and the buckle and the intermediate interlocking guide plate are integrated into a 3D printing process.

[0044] It is understood that the midline positioning ruler of this invention, manufactured using the above-described method, assists in determining the position of the maxillary dentition midline. The ruler's length covers a wide facial area, allowing for comparison with key facial midline landmarks, thus saving surgical time, improving surgical efficiency, enhancing the accuracy of intraoperative midline determination, and reducing the reliance on the surgeon's experience. During surgery, the midline positioning ruler of this invention can effectively assist surgeons in transferring the preoperative computer-generated surgical plan to intraoperative implementation, ensuring that the maxillary dentition midline aligns with the facial midline.

[0045] The midline positioning ruler of this invention maintains a safe distance from the patient's side profile, avoiding pressure on the patient's facial soft tissues.

[0046] The midline positioning ruler of this invention has a multi-curved contour shape, which is suitable for the facial profile of most patients. For a very small number of patients whose profiles are not suitable, the length of the midline positioning ruler can be stretched or shrunk, or its shape can be appropriately fine-tuned, in virtual design software. Using resin 3D printing to produce individualized midline positioning rulers also helps to improve the fit with the patient's profile.

[0047] In this invention, the buckle and the intermediate occlusal guide are integrated and 3D printed. During the operation, the intermediate occlusal guide is fixed between the upper and lower dentitions, and its position is stable, thereby keeping the buckle in a stable position and making the midline positioning ruler more stable.

[0048] In this invention, the positioning ruler body and the buckle of the midline positioning ruler are designed separately. After the midline positioning is completed, the midline positioning ruler can be easily removed without interfering with subsequent surgical procedures.

[0049] In this invention, the main body of the centerline positioning ruler is made of 304 stainless steel sheet by laser cutting, which allows the main body of the positioning ruler to be sterilized at high temperature and high pressure and reused, thus helping to save patients' medical expenses.

[0050] The midline positioning ruler of this invention is not only applicable to determining the midline of the maxillary dentition in bimaxillary orthognathic surgery based on a double occlusal guide, but can also be integrally printed with the snap-fit ​​device and the terminal occlusal guide for determining the midline of the maxillary dentition in bimaxillary surgery based on a single occlusal guide. In other words, the midline positioning ruler of this invention is also applicable to orthognathic surgery prioritizing mandibular surgery, as the snap-fit ​​device and the terminal occlusal guide are integrally three-dimensionally printed, allowing for the determination of the midline position of the maxillary dentition during orthognathic surgery prioritizing mandibular surgery.

[0051] The midline positioning ruler of this invention can also be used to assist surgeons in judging the symmetry of the chin during surgery. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0053] Figure 1 This is a flowchart illustrating an embodiment of the method for manufacturing a midline positioning ruler for orthognathic surgery according to the present invention.

[0054] Figure 2 This is a schematic diagram of a structure of an embodiment of the midline positioning ruler for orthognathic surgery of the present invention;

[0055] Figure 3 This is a schematic diagram of the main body of the positioning ruler in one embodiment of the midline positioning ruler for orthognathic surgery of the present invention;

[0056] Figure 4 This is a schematic diagram of the buckle structure in one embodiment of the midline positioning ruler for orthognathic surgery of the present invention;

[0057] Figure 5 This is a schematic diagram of the structure of the buckle and the intermediate occlusal guide plate in one embodiment of the midline positioning ruler for orthognathic surgery of the present invention;

[0058] Figure 6 This is a schematic diagram illustrating the clinical application of a midline positioning ruler for orthognathic surgery according to an embodiment of the present invention. Figure 1;

[0059] Figure 7 This is a schematic diagram illustrating the clinical application of a midline positioning ruler for orthognathic surgery according to an embodiment of the present invention. Figure 2 .

[0060] Explanation of icon numbers:

[0061] 100. Centerline positioning ruler; 10. Positioning ruler body; 20. Buckle; 101. Limiting structure; 102. Fixing structure; 20a. Slot; 30. Intermediate interlocking guide plate.

[0062] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0063] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0064] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0065] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0066] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. The word "and / or" throughout the text means including three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. The technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0067] Facial symmetry is one of the fundamental characteristics of facial aesthetics, and symmetrical faces are generally considered more attractive. One important component of facial symmetry is the coordination between the dental midline and the facial midline; the consistency between the facial midline and the maxillary dental midline is important for both facial and smile aesthetics.

[0068] Facial asymmetry is a common and challenging dentofacial deformity in orthognathic surgery. Its main clinical manifestations include bilateral asymmetry of the maxillofacial region relative to the facial midline, with the lower third of the face deviating to one side. It may also be accompanied by malocclusion, midline deviation of the dental arch, deviation of the facial plane, and temporomandibular joint symptoms. Combined orthodontic and orthognathic treatment is a common clinical strategy for treating facial asymmetry. Restoring the consistency between the deviated dental midline and the facial midline, and thereby restoring facial symmetry, is a key aspect of treating facial asymmetry.

[0069] In traditional model-based surgical planning, orthognathic surgeons, based on the degree of maxillary midline deviation observed during clinical examination, move the maxillary midline on a model to align it with the facial midline. This is followed by the fabrication of intermediate and terminal occlusal guides to aid in the positioning of the maxillary and mandibular bone segments. With the widespread application of digital technology in orthognathic surgery, digital design for facial asymmetry has become increasingly common. The basic method is similar to model-based surgical techniques: the surgeon moves the maxillary bone segments within a computer based on the clinically observed deviation of the maxillary midline relative to the facial midline, aligning the maxillary midline with the facial midline. After completing the virtual design of the orthognathic surgical plan, intermediate and terminal occlusal guides are then virtually designed and 3D printed to assist in the surgery. Existing research shows that both traditional model-based surgical techniques and digital design significantly improve all outcome indicators for patients with facial asymmetry. However, compared to traditional surgical planning, virtual design shows significantly greater improvement in facial midline and overall facial symmetry.

[0070] However, regardless of whether the occlusal guide is made using traditional methods or virtual design and 3D printing, although the preoperative midline plan is included in the occlusal guide, the alignment of the maxillary dentition midline with the facial midline still requires careful comparison by the surgeon during orthognathic surgery. Common comparison methods include visual observation or the use of a ruler. Because these guides determine the position of the maxillary tooth bone segments based on the position of the condyles, factors such as bone interference between bone fragments, soft tissue swelling, posterior displacement of the condyles due to general anesthesia, and nasal deviation caused by endotracheal intubation can all affect the orthognathic surgeon's visual judgment of the consistency between the dentition midline and the facial midline.

[0071] Currently, a researcher has designed a digital composite occlusal guide with four indicator rods, based on a digital occlusal guide. The specific method involves designing horizontal rods, anterior midsagittal rods, upward midsagittal rods, and downward midsagittal rods on the occlusal guide after completing the virtual design of the orthognathic surgery and the virtual design of the occlusal guide. These are used to assess parameters such as dental and skeletal midlines, facial soft tissue midlines, and occlusal planes during surgery. This method was validated in 17 patients undergoing single-occlusal-plate surgery, showing ideal results in immediately postoperative maxillary angle and line distance deviations. However, the indicator rods designed in this method are 7-10 mm in length, limited to the upper and lower lip areas, and cannot be compared with major facial midline landmarks. Furthermore, a special individualized facebow is required during surgery to determine the position of the jawbone and the dental midline.

[0072] One researcher designed a method using a laser to assist in determining the dental and facial midlines during surgery. Before surgery, the patient's facial midline was assessed using a laser, and points were marked on the face before entering the operating room. After general anesthesia, the laser was set up, and the facial midline was assessed again, with punctures made at the corresponding points. After osteotomy of the maxilla and mandible, the laser was used again to align the dental and facial midlines, and the maxilla and mandible were fixed. Three months post-surgery, a clinical examination using a laser showed satisfactory consistency between the facial and dental midlines. However, this treatment method is relatively cumbersome, requiring multiple laser treatments before, during, and after surgery, resulting in high time and cost.

[0073] In response, this invention proposes a method for manufacturing a midline positioning ruler for orthognathic surgery, aiming to assist in determining the position of the midline of the maxillary dentition, improve surgical efficiency, and enhance the accuracy of midline determination during surgery.

[0074] Reference Figures 1 to 7 In one embodiment of the present invention, the centerline positioning ruler 100 includes a positioning ruler body 10 and a buckle 20; the manufacturing method of the centerline positioning ruler 100 includes the following steps:

[0075] S01. In 3D virtual design software, simulate the contour curve of the right side of the human face and design the main body of the multi-curved positioning ruler.

[0076] In this step, the 3D virtual design software can be FreeForm V11.0 from a certain company.

[0077] like Figure 2 and Figure 3 As shown, the outline of the multi-curved positioning ruler body 10 is basically consistent with the right side profile outline curve of the three-dimensional face of a person without facial asymmetry deformity, which helps to improve the accuracy of positioning the midline of the maxillary dentition.

[0078] Before this step, you can first take a three-dimensional picture of an object with a standard human face (facial symmetry) and import the three-dimensional face file into the three-dimensional virtual design software.

[0079] S02. Draw a limiting structure 101 extending the target length in the direction of the face on the upper end of the positioning ruler body 10.

[0080] In this step, such as Figure 3 As shown, the limiting structure 101 is used to limit the distance between the ruler body and the face to avoid compressing facial soft tissue. The length of the limiting structure 101 can be 1.8-2.2 cm, preferably 2.0 cm, but is not limited here.

[0081] S03. Draw a protruding retaining structure 102 on the positioning ruler body 10 corresponding to the position of the mouth opening.

[0082] In this step, such as Figure 2 and Figure 3 As shown, the retaining structure 102 is used to connect with the retaining snap 20 described below.

[0083] S04. Virtually design the buckle 20, and draw the slot 20a in the middle position of the buckle 20 to be matched with the retaining structure 102.

[0084] In this step, such as Figures 2 to 4 By setting the slot 20a, the subsequently manufactured buckle 20 can be engaged with the positioning ruler body 10, which facilitates disassembly and assembly, helps improve the efficiency of the procedure, and allows the positioning ruler body 10 to be reused, which helps reduce the treatment cost for patients.

[0085] S05. Connect the virtual design positioning ruler body 10 with the buckle 20, and save the design file of the assembled positioning ruler body 10 and buckle 20.

[0086] In this step, such as Figure 2 As shown, two separate structural components are assembled together to provide a retaining force for the positioning ruler body 10.

[0087] S06. Perform a spiral CT scan of the maxillofacial region on the target object, collect maxillofacial data, and create a hard plaster dental model.

[0088] In this step, the target is the patient's frontal face to be treated. The purpose of creating a hard plaster dental model is to prepare for obtaining three-dimensional virtual dental data from the patient.

[0089] S07. Import the maxillofacial data into the craniofacial surgery planning software, establish a virtual three-dimensional craniofacial model, and use laser scanning to scan the hard plaster tooth model to obtain virtual dentition data, and replace the dentition data in the maxillofacial data with it.

[0090] In this step, the maxillofacial data can be in DICOM format. Laser scanning can obtain virtual dentition data in STL format, which replaces the dentition data in CT scans, resulting in higher accuracy of the dentition data.

[0091] S08. Simulate the target surgical type on a virtual craniofacial model and determine the target location of the mandibular bone segment based on the terminal occlusal relationship.

[0092] In this step, the target surgical types include Le Fort I osteotomy and mandibular sagittal splitting.

[0093] Specifically, Le Fort I osteotomy of the maxilla and sagittal split of the mandible can be simulated on a virtual craniomaxillary model. The maxillary bone segment is moved to the target position according to the surgical plan, and then the target position of the mandibular bone segment is determined based on the final occlusal relationship.

[0094] S09. Import the design files of the positioning ruler body 10 and the buckle 20 into the craniofacial surgery planning software. Align the lower end of the positioning ruler body 10 with the midline of the maxillary dentition, align the upper end of the positioning ruler body 10 with the midline of the face, and ensure that the height of the buckle 20 is consistent with the occlusal plane.

[0095] In this step, the STL files of the positioning ruler body 10 and the buckle 20 of the midline positioning ruler are imported into the craniomaxillofacial surgery planning software, and then the position of the positioning ruler body 10 is adjusted, combined with... Figure 2 , Figure 6 and Figure 7 This ensures that the lower end of the positioning ruler body 10 is aligned with the midline of the maxillary dentition, the upper end is aligned with the midline of the face, and the height of the buckle 20 is aligned with the occlusal plane.

[0096] This step can also be included after this step:

[0097] Adjust the distance between the positioning ruler body 10 and the buckle 20 and the facial soft tissue to reserve a safe distance.

[0098] Specifically, on the right-side view, the distance between the positioning ruler body 10 and the buckle 20 and the facial soft tissue can be adjusted to leave a certain safe distance to avoid compressing the facial soft tissue.

[0099] S10, virtual design of intermediate occlusal guide plate 30 and terminal occlusal guide plate.

[0100] In this step, an intermediate occlusal guide 30 and a terminal occlusal guide can be designed to fit the face of the person to be corrected based on CT data. The intermediate occlusal guide 30 is a routine clinical device, so the specific design and manufacturing method will not be described in this article.

[0101] S11. Virtually connect the buckle 20 and the intermediate engagement guide plate 30 into one unit to obtain the target design file.

[0102] In this step, such as Figure 5 As shown, the final snap-fit ​​20 is assembled with the intermediate engagement guide plate 30 in the software, thus obtaining the final product design file, i.e., the target design file, including... Figure 3 The drawing file of the positioning ruler body 10 shown and Figure 5 The drawing file showing the buckle 20 and the intermediate engagement guide plate 30 is shown.

[0103] S12. According to the target design documents, the positioning ruler body 10 is laser-cut and manufactured, and the buckle 20 and the intermediate interlocking guide plate 30 are integrated into a 3D printed buckle.

[0104] In this step, the material of the positioning ruler body 10 is preferably medical-grade 304 stainless steel. The materials of the buckle 20 and the intermediate engagement guide plate 30 are preferably acrylic resin, but are not limited here.

[0105] Specifically, the drawing file of the positioning ruler body 10 is imported into the laser equipment to make the positioning ruler body 10, and the drawing files of the buckle 20 and the intermediate interlocking guide plate 30 are imported into the 3D printing equipment to make the buckle 20 and the intermediate interlocking guide plate 30, thus completing the production of the entire centerline positioning ruler 100.

[0106] It is understood that the midline positioning ruler 100 manufactured using the above-described method in this invention assists in determining the position of the maxillary dentition midline. The midline positioning ruler 100 has a wide facial coverage area, allowing for comparison with key facial midline landmarks, thus improving surgical efficiency, saving surgical time, increasing the accuracy of intraoperative midline determination, and reducing the reliance on the surgeon's experience. During surgery, the midline positioning ruler 100 of this invention can effectively assist the surgeon in transferring the preoperative computer-generated surgical plan to the intraoperative implementation, ensuring that the maxillary dentition midline aligns with the facial midline.

[0107] The midline positioning ruler 100 of the present invention maintains a safe distance from the patient's side profile, thus avoiding pressure on the patient's facial soft tissues.

[0108] The midline positioning ruler 100 of this invention has a multi-curved contour shape, which is suitable for the facial profile of most patients. Furthermore, the midline positioning ruler 100 is manufactured using resin 3D printing, which also helps to improve its adaptability to the patient's profile.

[0109] In this invention, the buckle 20 and the intermediate occlusal guide plate 30 are integrated and 3D printed. During the operation, the intermediate occlusal guide plate 30 is fixed between the upper and lower dentitions and is in a stable position, thereby making the buckle 20 in a stable position, and the fixed position of the midline positioning ruler 100 that is engaged with it is also more stable.

[0110] In this invention, the positioning ruler body 10 and the buckle 20 of the midline positioning ruler 100 are designed separately. After the midline positioning is completed, the midline positioning ruler 100 can be easily removed without interfering with subsequent surgical procedures.

[0111] In this invention, the positioning ruler body 10 of the centerline positioning ruler 100 is made of 304 stainless steel sheet by laser cutting, which allows the positioning ruler body 10 to be sterilized at high temperature and high pressure and reused, thus helping to save patients' medical expenses.

[0112] The midline positioning ruler 100 of this invention is not only applicable to determining the midline of the maxillary dentition in bimaxillary orthognathic surgery based on a double occlusal guide, but can also be integrally printed with the snap fastener 20 and the terminal occlusal guide for determining the midline of the maxillary dentition in bimaxillary surgery based on a single occlusal guide. In other words, the midline positioning ruler 100 of this invention is also applicable to orthognathic surgery prioritizing mandibular surgery, i.e., by integrally three-dimensionally printing the snap fastener 20 and the terminal occlusal guide, it can be used to determine the position of the midline of the maxillary dentition during orthognathic surgery prioritizing mandibular surgery.

[0113] The midline positioning ruler 100 of the present invention can also be used to assist surgeons in judging the symmetry of the chin during surgery.

[0114] In some embodiments, in step S10, when importing the design files of the positioning ruler body 10 and the buckle 20 into the craniofacial surgery planning software, aligning the lower end of the positioning ruler body 10 with the midline of the maxillary dentition, aligning the upper end of the positioning ruler body 10 with the midline of the face, and aligning the height of the buckle 20 with the occlusal plane, if the maxillofacial data of the target object does not match the positioning ruler body 10, the length of the positioning ruler body 10 is stretched or contracted in the virtual design software, or the shape of the positioning ruler body 10 is modified.

[0115] The midline positioning ruler 100 of this invention may not fit the profile of a very small number of patients, but this can be quickly resolved. If a mismatch is found during the alignment process between the design file and CT scan data, the length of the midline positioning ruler 100 can be stretched or contracted, or its shape can be appropriately fine-tuned, in virtual design software.

[0116] In clinical application, combined with Figures 2 to 7 After completing the maxillary Le Fort I osteotomy during orthognathic surgery, the upper and lower jaws are placed in the intermediate occlusal guide plate 30, and the occlusion is fixed by intermaxillary ligation. The retention structure 102 of the positioning ruler body 10 is inserted into the slot 20a of the clip 20, so that the upper end of the midline positioning ruler 100 passes through the midpoint of the line connecting the inner canthi and is perpendicular to the line connecting the inner canthi, which means that the dental midline is consistent with the facial midline. After measuring other parameters of the jawbone position to ensure they meet the surgical design, a firm internal fixation is performed to complete the maxillary Le Fort I osteotomy.

[0117] This invention also proposes a midline positioning ruler 100 for orthognathic surgery. The midline positioning ruler 100 includes a ruler body 10 and a snap fastener 20, with the ruler body 10 and snap fastener 20 engaging. This midline positioning ruler 100 is manufactured using the aforementioned method. The midline positioning ruler 100 proposed in this invention encompasses all embodiments of the aforementioned manufacturing method, and therefore possesses at least the same technical effects as the aforementioned midline positioning ruler 100, which will not be elaborated upon here.

[0118] This invention, based on the virtual design of orthognathic surgery plans for facial asymmetry, designs a midline positioning ruler 100 for determining the consistency between the maxillary dentition midline and the facial midline during orthognathic surgery. The midline positioning ruler 100 consists of a main body 10 and a clip 20. The main body 10 is made of medical-grade 304 stainless steel using laser cutting and can be sterilized under high temperature and pressure. The clip 20 is integrated with the virtually designed intermediate occlusal guide 30 and manufactured using 3D printing. During orthognathic surgery, after the intermediate occlusal guide 30 is ligated between the maxillary and mandibular dentitions, the retention structure 102 of the main body 10 is inserted into the slot 20a of the clip 20, which can then be used to assist in determining the position of the maxillary dentition midline. This midline positioning ruler 100 helps improve surgical efficiency, reduce surgical time, and improve the accuracy of midline determination during surgery, representing a new method with certain clinical application value.

[0119] The present invention also provides a computer device that can be directly or indirectly electrically connected to all devices or apparatuses that can be controlled by signals in the above-described method for manufacturing the centerline positioning ruler 100, or the computer device can be composed of the host of one of the devices or apparatuses used in the above-described method. This computer device is used to control the operation of each device or apparatus and execute relevant manufacturing steps to automatically complete the manufacturing of the centerline positioning ruler 100.

[0120] The computer device includes one or more processors, memory, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other using different buses and can be mounted on a common motherboard or otherwise installed as needed. The processor can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on an external input / output device (such as a display device coupled to the interface). In some embodiments, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system).

[0121] The processor can be a central processing unit, a network processor, or a combination thereof. The processor may further include hardware chips. These hardware chips can be application-specific integrated circuits (ASICs), programmable logic devices (PLDs), or combinations thereof. The programmable logic devices can be complex programmable logic devices (CLPs), field-programmable gate arrays (FPGAs), general-purpose array logic (GDAs), or any combination thereof.

[0122] The memory stores instructions executable by at least one processor to cause the at least one processor to perform a method for manufacturing the centerline positioning ruler 100 shown in the above embodiments.

[0123] The memory may include a stored program area and a stored data area, wherein the stored program area may store the operating system and application programs required for at least one function; the stored data area may store data created based on the use of the computer device, etc. Furthermore, the memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory may include memory remotely located relative to the processor, and these remote memories may be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0124] The memory may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory may also include a combination of the above types of memory.

[0125] The computer device also includes input and output devices. The processor, memory, input and output devices can be connected via a bus or other means.

[0126] Input devices can receive input numerical or character information and generate key signal inputs related to user settings and function control of the computer device, such as touchscreens, keypads, mice, trackpads, touchpads, joysticks, one or more mouse buttons, trackballs, joysticks, etc. Output devices may include display devices, auxiliary lighting devices (e.g., LEDs), and haptic feedback devices (e.g., vibration motors). The aforementioned display devices include, but are not limited to, liquid crystal displays, light-emitting diodes, displays, and plasma displays. In some embodiments, the display device may be a touchscreen.

[0127] The present invention also provides a computer-readable storage medium. The method for manufacturing the centerline positioning ruler 100 according to the embodiments of the present invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the method described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that a computer, processor, microprocessor controller, or programmable hardware includes a storage component capable of storing or receiving software or computer code, which, when accessed and executed by the computer, processor, or hardware, implements the method shown in the above embodiments.

[0128] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for manufacturing a midline positioning ruler for orthognathic surgery, characterized in that, The centerline positioning ruler includes a positioning ruler body and a buckle; the manufacturing method includes the following steps: In 3D virtual design software, the contour curve of the right side of the human face is simulated to design the main body of a multi-curved positioning ruler; A limiting structure extending the target length in the direction of the face is drawn on the upper end of the positioning ruler body; A protruding retention structure is drawn on the main body of the positioning ruler at the position corresponding to the mouth opening; A virtual buckle is designed, and a slot that matches the retaining structure is drawn in the middle of the buckle. Connect the virtual design of the positioning ruler body to the buckle, and save the design file of the assembled positioning ruler body and buckle; A spiral CT scan of the maxillofacial region was performed on the target subject to collect maxillofacial data and to create a hard plaster dental model. The maxillofacial data is imported into the craniofacial surgery planning software to establish a virtual three-dimensional craniofacial model. The hard plaster tooth model is then laser-scanned to obtain virtual dentition data, which is then used to replace the dentition data in the maxillofacial data. The target surgical type was simulated on a virtual craniomaxillary model, and the target location of the mandibular bone segment was determined based on the terminal occlusion relationship. Import the design files of the positioning ruler body and the buckle into the craniofacial surgery planning software, align the lower end of the positioning ruler body with the midline of the maxillary dentition, align the upper end of the positioning ruler body with the midline of the face, and align the height of the buckle position with the occlusal plane. Virtual design of intermediate occlusal guide and terminal occlusal guide; The buckle and the intermediate engagement guide plate are virtually connected to form a whole to obtain the target design file; According to the target design document, the main body of the positioning ruler is laser-cut and manufactured, and the buckle and the intermediate interlocking guide plate are integrally 3D printed.

2. The method for manufacturing a midline positioning ruler for orthognathic surgery as described in claim 1, characterized in that, After importing the design files of the positioning ruler body and the buckle into the craniofacial surgery planning software, aligning the lower end of the positioning ruler body with the midline of the maxillary dentition, aligning the upper end of the positioning ruler body with the midline of the face, and ensuring the height of the buckle position is consistent with the occlusal plane, the procedure further includes: Adjust the distance between the positioning ruler body and the buckle and the facial soft tissue to reserve a safe distance.

3. The method for manufacturing a midline positioning ruler for orthognathic surgery as described in claim 1, characterized in that, In the step of importing the design files of the positioning ruler body and the buckle into the craniofacial surgery planning software, aligning the lower end of the positioning ruler body with the midline of the maxillary dentition, aligning the upper end of the positioning ruler body with the midline of the face, and aligning the height of the buckle position with the occlusal plane, if the maxillofacial data of the target object does not match the positioning ruler body, then the length of the positioning ruler body is stretched or contracted, or the shape of the positioning ruler body is modified, in the virtual design software.

4. The method for manufacturing the midline positioning ruler for orthognathic surgery as described in claim 1, characterized in that, In the step of drawing a limiting structure extending the target length towards the face on the upper end of the positioning ruler body, the length of the limiting structure is 1.8-2.2 cm.

5. The method for manufacturing a midline positioning ruler for orthognathic surgery as described in claim 1, characterized in that, In the steps of laser cutting and fabricating the positioning ruler body according to the target design document, and integrally 3D printing the buckle and the intermediate interlocking guide plate, the material of the positioning ruler body is medical grade 304 stainless steel.

6. The method for manufacturing a midline positioning ruler for orthognathic surgery as described in claim 1 or 5, characterized in that, In the step of laser cutting and fabricating the positioning ruler body according to the target design document, and integrally 3D printing the buckle and the intermediate engagement guide plate, the material of the buckle and the intermediate engagement guide plate is acrylic resin.

7. The method for manufacturing the midline positioning ruler for orthognathic surgery as described in claim 1, characterized in that, In the step of simulating the target surgical type on a virtual craniomaxillary model and determining the target position of the mandibular bone segment based on the terminal occlusion relationship, the target surgical type includes Le Fort type I osteotomy and mandibular sagittal splitting.

8. The method for manufacturing a midline positioning ruler for orthognathic surgery as described in claim 1, characterized in that, The midline positioning ruler is used to determine the midline of the maxillary dentition in bimaxillary surgery based on a double occlusal guide and to determine the midline of the maxillary dentition in bimaxillary surgery based on a single occlusal guide.

9. The method for manufacturing a midline positioning ruler for orthognathic surgery as described in claim 1, characterized in that, The midline positioning ruler is also used to assist the surgeon in judging the symmetry of the chin during surgery.

10. A centerline positioning ruler, characterized in that, The midline positioning ruler is manufactured using the method described in any one of claims 1-9 for manufacturing a midline positioning ruler for orthognathic surgery.

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