A detachable maxillary skeletal expander and method of designing the same

Abstract

The application discloses a detachable maxillary skeletal expander and a design method thereof. The maxillary skeletal expander comprises a pair of mirror image arranged and connected expander units. Each expander unit comprises an expander body, a band for fixing to a patient's tooth crown, and a connecting rod detachably connected to the expander body and the band. The expander body of each expander unit is connected and used for fixing to the patient's upper palate by a micro-implant. The detachable assembly of the application adopts a "fixing part-sleeve-screw" structure. In the maintenance stage after the completion of the expander treatment, the band can be easily detached by rotating out the screw, the operation process is greatly simplified, the chair-side time is significantly shortened, the clinical work efficiency is improved, the grinding operation is avoided, the vibration and noise interference is eliminated, the risk of soft tissue injury is reduced, and the comfort and safety of the patient in the treatment process are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of orthodontic tools, and more particularly to a detachable maxillary skeletal expander and its design method. Background Technology

[0002] Maxillary transverse deficiency (MTD) is a common problem in orthodontic clinics, mainly manifested as a narrow maxillary arch, disproportionate width between the maxillary and mandibular arches and basal bones, often accompanied by symptoms such as anterior crowding, posterior crossbite, and high palatal arch. Maxillary expansion is a classic method for treating MTD, using orthodontic forces to widen the mid-palatal suture to coordinate the width relationship between the maxilla and mandible and provide interdental space. However, traditional expansion methods have a high relapse rate, and their effectiveness is limited in late adolescence and adult patients whose mid-palatal suture has been fully ossified.

[0003] The introduction of Micro-implant Assisted Rapid Palatal Expansion (MARPE) technology has provided an effective approach for non-surgical orthodontic treatment of adult patients with maxillary temporomandibular joint disorder (MTD). Unlike traditional expanders, MARPE applies orthodontic force directly to the micro-implants rather than the teeth or periodontal tissues, significantly increasing skeletal effects and reducing dental side effects. It offers advantages such as simple operation, minimal trauma, less soft tissue irritation, and less root resorption. As an important implementation of MARPE, the Maxillary Skeletal Expander (MSE) implants four micro-implants into the double-layered cortical bone of the posterior palate, providing stable and reliable skeletal anchorage for late adolescence and adult MTD patients, resulting in significant clinical orthodontic outcomes.

[0004] Existing maxillary skeleton expanders (MSEs) employ a monolithic welded structure, with the connecting rod, band, and expander body fixed as a non-removable unit. After expansion treatment, to remove the band while preserving the expander body and maintaining therapeutic efficacy, clinicians must manually grind down the connecting rod to separate the components. This procedure is not only cumbersome and prolongs chairside time, but the vibration and noise generated during grinding also increase patient discomfort. More importantly, the high-speed grinding operation poses a safety risk of accidentally injuring oral soft tissues, contradicting the "minimally invasive and highly safe" design philosophy of the MARPE technique.

[0005] In summary, the non-removable structure of existing bony expanders has become a key bottleneck restricting their clinical convenience and safety. Therefore, there is an urgent need for a maxillary bony expander with easily detachable connecting rods, which, while ensuring structural stability during treatment, allows for easy removal of the band, thereby optimizing clinical procedures and improving the patient's treatment experience. Summary of the Invention

[0006] This invention provides a detachable maxillary bony expander and its design method to solve the technical problem in the prior art of how to easily remove the band of the maxillary bony expander while ensuring structural stability during treatment, so as to optimize the clinical operation process and avoid the risk of soft tissue injury.

[0007] In view of the above technical problems, the present invention provides a detachable maxillary skeletal expander, comprising a pair of expander units arranged in mirror and connected, each expander unit comprising an expander body, a band for fixing to the patient's crown, and a connecting rod detachably connected to the expander body and the band. The expander bodies of each expander unit are connected and used for fixing to the patient's palate with micro-implants.

[0008] The first end of the connecting rod is welded to the belt ring, and the second end of the connecting rod is connected to the bow expander body through a detachable component. The detachable component includes a fixing member disposed at the second end of the connecting rod, a sleeve disposed on the bow expander body, and a screw. The fixing member is provided with a threaded hole, the inner hole of the sleeve is provided with an internal thread, and the screw passes through the threaded hole on the fixing member and is threadedly connected to the sleeve.

[0009] Optionally, the number of connecting rods is set to 2, and the number of sleeves is adapted to the number of connecting rods.

[0010] Optionally, the head of the screw is provided with a notch that matches the screwdriver, the outer diameter of the screw shank matches the specification of the internal thread of the sleeve, and the screw thread direction is opposite to the disassembly direction.

[0011] Optionally, the inner diameter of the threaded hole on the fastener is larger than the outer diameter of the screw shank and smaller than the outer diameter of the screw head.

[0012] Optionally, the bow expander body is also provided with support nail holes for installing micro implants.

[0013] Optionally, the bow expander body is also provided with a connecting block, and two mirror-arranged bow expander bodies are connected by the connecting block. The connecting block has a built-in bow expander screw, and the lateral distance between the two bow expander bodies can be adjusted by rotating the bow expander screw.

[0014] In this invention, a three-part threaded connection structure consisting of a fastener, sleeve, and screw cleverly resolves the technical contradiction between "stable connection during treatment" and "convenient disassembly after treatment." During treatment, the thread preload ensures stable transmission of the expansion force, providing reliable support for the orthodontic process. After treatment, simply unscrewing the screw allows for non-destructive separation of the band and the expander body, completely overcoming the technical bias of traditional integral welded structures where "stability equals permanence, disassembly equals destruction." In particular, setting the screw's thread direction opposite to the disassembly direction effectively resists the loosening tendency caused by external forces generated during oral functional movements such as chewing and speech during treatment, preventing screw loosening and ensuring long-term stability throughout the treatment period. Furthermore, the stepped hole design of the fixation piece (the inner diameter of the threaded hole is larger than the outer diameter of the screw shank but smaller than the outer diameter of the head) balances assembly feasibility and locking reliability. Combined with the bony anchorage design of the expander body, it achieves an optimal configuration for both expansion treatment and efficacy maintenance. After treatment, the expander body continues to be placed through micro-implants to maintain efficacy, while the band can be easily removed. This ensures the high efficiency of bony expansion and avoids the difficulties in oral hygiene maintenance caused by long-term band placement, significantly improving the patient's treatment experience and orthodontic results. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention 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 these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the overall structure of a detachable maxillary expander according to an embodiment of the present invention;

[0017] Figure 2 This is a partial structural schematic diagram of a detachable maxillary expander according to an embodiment of the present invention;

[0018] Figure 3 This is a partial structural schematic diagram of a detachable maxillary expander according to another embodiment of the present invention.

[0019] The reference numerals in the accompanying drawings are as follows:

[0020] 1-Bow expander body, 11-Anti-nailing nail hole, 12-Connecting block, 2-Ring, 3-Connecting rod, 31-Fixing component, 4-Sleeve. Detailed Implementation

[0021] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0022] In the description of this invention, it should be understood that the terms "longitudinal," "radial," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0023] In the description of this invention, it should 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.

[0024] like Figures 1 to 3 As shown, one embodiment of the present invention provides a detachable maxillary skeletal expander, comprising a pair of mirror-arranged and connected expander units. Each expander unit includes an expander body 1, a band 2 for fixing to the patient's crown, and a connecting rod 3 detachably connected to the expander body 1 and the band 2. The expander bodies 1 of each expander unit are connected and used for fixing to the patient's palate with micro-implants.

[0025] The first end of the connecting rod 3 is welded to the ring 2, and the second end of the connecting rod 3 is connected to the bow expander body 1 through a detachable component. The detachable component includes a fixing member 31 at the second end of the connecting rod 3, a sleeve 4 on the bow expander body 1, and a screw (not shown). The fixing member 31 has a threaded hole, the inner hole of the sleeve 4 has an internal thread, and the screw passes through the threaded hole on the fixing member 31 and is threaded to the sleeve 4.

[0026] Understandably, by improving the traditional integral welded structure of the bony expander to a detachable threaded locking structure, the connecting rod 3 and the expander body 1 can be easily separated through a detachable assembly of "fixing element 31-sleeve 4-screw". This ensures that the threaded connection is stable and reliable during treatment, and the ring 2 can be removed simply by unscrewing the screw after the expansion treatment. This avoids the problems of cumbersome procedures, prolonged chairside time, patient discomfort, and soft tissue damage risk caused by traditional grinding operations. It achieves a balance between convenient clinical operation, comfortable patient experience, and reliable structural connection. At the same time, the expander body 1 continues to be retained in the mouth to maintain the therapeutic effect through micro-implants, which is in line with the design concept of MARPE technology, which is minimally invasive and highly safe.

[0027] In one embodiment, such as Figures 1 to 3 As shown, the number of connecting rods 3 is set to two, and the number of sleeves 4 is adapted to the number of connecting rods 3. Understandably, the number of connecting rods 33 is set to two, and the number of sleeves 44 is adapted to the number of connecting rods 33, that is, each expander unit is equipped with two connecting rods 3 and two sleeves 4, respectively connecting to the two side rings 2, forming a symmetrical and stable mechanical transmission structure. This design enhances the connection strength and stability of the detachable structure, ensuring that the expander is subjected to uniform force throughout the treatment process, effectively avoiding structural loosening or damage caused by single-point force, while maintaining ease and flexibility of operation.

[0028] In one embodiment, such as Figures 1 to 3 As shown, the screw head has a notch that matches a screwdriver, the outer diameter of the screw shank matches the specification of the internal thread of the sleeve 4, and the screw thread direction is opposite to the disassembly direction. Understandably, the screw head has a notch for screwdriver operation, the screw shank's outer diameter precisely matches the internal thread specification of the sleeve 4 to ensure a tight connection, and the screw thread direction is opposite to the disassembly direction. This design effectively resists loosening caused by external forces during treatment, prevents the screw from coming loose, and ensures the stability of the dilator in the patient's mouth and the treatment effect.

[0029] In one embodiment, such as Figures 1 to 3As shown, the inner diameter of the threaded hole on the fixing member 31 is larger than the outer diameter of the screw shank and smaller than the outer diameter of the screw head. Understandably, the threaded hole of the fixing member 31 adopts a stepped hole design with an inner diameter larger than the outer diameter of the screw shank and smaller than the outer diameter of the screw head. This allows the screw to pass smoothly through the threaded hole of the fixing member 31 and connect threadedly to the sleeve 4. Simultaneously, the screw head is confined to the outer end face of the fixing member 31, forming an axial clamping force that firmly locks the fixing member 31 (and the connecting rod 3 and the ring 2 fixed thereto) to the end face of the sleeve 4, achieving reliable locking of the detachable components. This design ensures the feasibility of screw assembly and ensures the axial stability of the connection structure through head confinement, preventing loosening and shaking of the ring assembly during treatment, while retaining the functional characteristic of easy disassembly by unscrewing the screw.

[0030] In one embodiment, such as Figures 1 to 3 As shown, the main body 1 of the expander is also provided with anchorage pin holes 11 for installing micro-implants. Understandably, the anchorage pin holes 11 on the main body 1 of the expander allow the micro-implants to be precisely and securely implanted into the double-layered cortical bone of the posterior maxilla, providing reliable bony anchorage for the expander. This ensures that the orthodontic force acts directly and effectively on the jawbone, thereby significantly improving the treatment effect of maxillary lateral hypoplasia while reducing side effects on teeth and periodontal tissues.

[0031] In one embodiment, such as Figures 1 to 3 As shown, the expander body 1 is also provided with a connecting block 12. Two mirror-arranged expander bodies 1 are connected by the connecting block 12. The connecting block 12 has an expander screw built in, and the lateral distance between the two expander bodies 1 can be adjusted by rotating the expander screw. Understandably, the connecting block 12 is located between the two mirror-arranged expander bodies 1, and the built-in expander screw forms a mechanical adjustment mechanism. By rotating the expander screw, the rotational motion is converted into a lateral relative displacement between the two expander bodies 1, thereby achieving progressive and controllable expander expansion. This design makes the expander units on both sides form an integrated linkage structure, ensuring synchronous and equal expander expansion on both sides, and avoiding jawbone deviation caused by asymmetrical expander expansion.

[0032] The method of using the detachable maxillary expander of the present invention includes two operation stages: assembly and fixation, and disassembly and separation.

[0033] Assembly and fixing stage: First, place the entire assembly of the ring 2 and the connecting rod 3 in the predetermined position, so that the threaded hole on the fixing part 31 at the end of the connecting rod 3 is aligned with the threaded interface of the sleeve 4 on the body of the expander; then, take the screw, pass it through the threaded hole of the fixing part 31, and screw it into the internal thread of the sleeve 4. Tighten the screw with a screwdriver to firmly lock the connecting rod 3 to the body of the expander. At this time, the entire expander forms a stable overall structure and can be used for normal expander treatment.

[0034] Disassembly and separation stage: When the treatment is completed and the band 2 needs to be removed, the doctor only needs to use a screwdriver to unscrew each screw in the opposite direction. After the screws are completely removed from the sleeve 4, the fixing part 31 is no longer axially constrained. At this time, the entire assembly of the band 2 and the connecting rod 3 can be easily separated from the expander body 1 and removed. The expander body 1 continues to be fixed to the palate through the micro implant in the anchorage pin hole 11, so that it can be retained in the patient's mouth to maintain the expansion effect.

[0035] Furthermore, the detachable maxillary expander of the present invention employs a digital design method, based on the patient's oral cavity scan model, and is customized using 3D design software, including the following steps:

[0036] S1. Determine the position of the expander; determine the placement position of the expander body 1 on the patient's digital intraoral scan model. Import the 3D model of the expander body 1 into the software and register it with the intraoral scan model; after positioning, perform a Boolean subtraction operation to subtract the intersecting intraoral scan model portion from the expander body 1 model to ensure that the expander body 1 can accurately fit the patient's palatal dome shape.

[0037] S2. Design band 2. Based on the crown morphology in the oral scan model, design band 2 to wrap the crown in the software. There are two bands on each side, which are fixed to the first molars and first premolars on both sides respectively.

[0038] S3 is a detachable device designed with four sleeves 4 for connection at the four corners of the bow expander body 1. The inner diameter and thread specification of the sleeve 4 are determined according to the selected screw diameter. The sleeve 4 has a complete internal thread, and the thread specification matches the matching screw.

[0039] S4. The cannula 4 is divided into upper and lower parts to prepare for subsequent connection. The originally one-piece cannula 4 is cut into a fixing component 31 and a cannula 4 body in the software; this division prepares for the detachable function: the fixing component 31 is fixed together with the belt loop 2 through the connecting rod 3, and the cannula 4 body is connected to the expander body 1; the cutting position and angle are optimized according to the comfort and ease of operation in clinical wear.

[0040] S5. Connect the fastener 31 to the belt ring 2 via the connecting rod 3. Assemble the cut fastener 31 with the belt ring 2 designed in step S2 via the connecting rod 3. The upper end of the connecting rod 3 is fixedly connected to the palatal side of the belt ring 2. The connection method is designed as an integral molding or a reserved welding interface. The lower end of the connecting rod 3 is connected to the fastener 31.

[0041] S6. Connect the sleeve 4 to the bow expander body 1. The bow expander body 1 and the sleeve 4 form a fixed connection assembly. The end is reserved with an interface for docking with the fixing part 31. Each interface has an internal thread.

[0042] S7. Complete the assembly design of the entire detachable bow expander. Virtually assemble the "ring 2-connecting rod 3-fixed part 31" assembly obtained in step S5 with the "bow expander body 1-sleeve 4" assembly obtained in step S6. Align the annular hole of the fixed part 31 with the interface of the sleeve 4 and connect the two together with screws. At this time, the entire bow expander presents a complete detachable structure: the ring 2 and the connecting rod 3 are integrated, the bow expander body 1 is integrated, and the two are detachably connected by screws and sleeve 4.

[0043] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A detachable maxillary expander, characterized in that, It includes a pair of mirror-arranged and connected arch expander units, each arch expander unit including an arch expander body (1), a band (2) for fixing to the patient's crown, and a connecting rod (3) detachably connected to the arch expander body (1) and the band (2). The arch expander body (1) of each arch expander unit is connected and used for fixing to the patient's palate with a micro implant. The first end of the connecting rod (3) is welded to the belt ring (2), and the second end of the connecting rod (3) is connected to the bow expander body (1) through a detachable component. The detachable component includes a fixing member (31) at the second end of the connecting rod (3), a sleeve (4) on the bow expander body (1), and a screw. The fixing member (31) has a threaded hole, the inner hole of the sleeve (4) has an internal thread, and the screw passes through the threaded hole on the fixing member (31) and is threaded to the sleeve (4).

2. The detachable maxillary expander according to claim 1, characterized in that, In each bow expansion unit, the number of connecting rods (3) is set to 2, and the number of sleeves (4) is adapted to the number of connecting rods (3).

3. The detachable maxillary expander according to claim 2, characterized in that, The head of the screw is provided with a notch that matches the screwdriver, the outer diameter of the screw shaft matches the specification of the internal thread of the sleeve (4), and the screw thread direction is opposite to the disassembly direction.

4. The detachable maxillary expander according to claim 2, characterized in that, The inner diameter of the threaded hole on the fastener (31) is greater than the outer diameter of the screw shank and less than the outer diameter of the screw head.

5. The detachable maxillary expander according to claim 4, characterized in that, The main body (1) of the bow expander is also provided with support nail holes (11) for installing micro implants.

6. The detachable maxillary expander according to claim 5, characterized in that, The bow expander body (1) is also provided with a connecting block (12). Two mirror-arranged bow expander bodies (1) are connected by the connecting block (12). The connecting block (12) has a built-in bow expander screw. The lateral distance between the two bow expander bodies (1) can be adjusted by rotating the bow expander screw.

7. A design method for a detachable maxillary expander, characterized in that, S1. Determine the placement position of the expander body (1) on the patient's digital oral scan model, import the three-dimensional model of the expander body (1) into the software, and register and position it with the oral scan model; after positioning, perform Boolean subtraction operation, subtract the part of the oral scan model that intersects with the expander body (1) model to ensure that the expander body (1) is adapted to the patient's palatal dome shape. S2. Design bands (2). Based on the crown morphology in the oral scan model, design bands (2) that wrap around the crown in the software. There are two bands on each side, which are fixed to the first molars and the first premolars on both sides respectively. S3. At the four corners of the bow expander body (1), four sleeves (4) are designed for connection. When designing, the inner diameter and thread specification of the sleeve (4) are determined according to the selected screw diameter. The sleeve (4) has a complete internal thread, and the thread specification matches the matching screw. S4. Divide the sleeve (4) into upper and lower parts. Cut the original one-piece sleeve (4) into a fixing part (31) and the body of the sleeve (4) in the software. The fixing part (31) is fixed together with the belt ring (2) through the connecting rod (3), and the body of the sleeve (4) is connected to the bow expander body (1). S5. Connect the fastener (31) to the belt ring (2) through the connecting rod (3), and assemble the cut fastener (31) to the belt ring 2 through the connecting rod (3); the upper end of the connecting rod (3) is fixedly connected to the palatal side of the belt ring (2), and the connection method is designed as an integral molding or a reserved welding interface, and the lower end of the connecting rod (3) is connected to the fastener (31); S6. Connect the sleeve (4) to the bow expander body (1). The bow expander body (1) and the sleeve (4) form a fixed connection assembly. The end is reserved with an interface for docking with the fixing piece (31). Each interface has an internal thread. S7. Virtually assemble the belt ring (2), connecting rod (3), fixing piece (31) with the bow expander body (1) and sleeve (4). Align the annular hole of the fixing piece (31) with the interface of the sleeve (4) and connect the two together with screws. The belt ring (2) and connecting rod (3) are integrated, and the bow expander body (2) is integrated. The two are detachably connected by screws and sleeve (4).

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