Design method and device for combining invisible corrector with customized extraoral arch traction device

Abstract

The invention discloses a design method and device for combining an invisible orthodontic appliance with a customized extraoral arch traction device, and relates to the technical field of tooth correction, an invisible tooth socket is manufactured, a traction channel is integrally arranged on the invisible tooth socket, the traction channel is a hollow through channel, and the traction channel and the invisible tooth socket are integrally manufactured and formed; the traction hook is divided into an anterior tooth area traction hook and a posterior tooth area traction hook, the anterior tooth area traction hook is provided with a spherical structure, the spherical structure of the anterior tooth area traction hook abuts against one side of the posterior tooth of the anterior tooth area traction channel, the posterior tooth area traction hook is provided with a stop curve, and the stop curve abuts against one side of the posterior tooth of the anterior tooth area traction channel. The stopping curve is propped against one side of anterior teeth of the anterior tooth area traction channel; the invention discloses a customized traction head cap.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tooth correction, in particular to a design method and device of a clear aligner combined with a customized extraoral bow traction device. BACKGROUND

[0002] Existing correction schemes include implant anchorage, pendulum aligner, myotrain combined with headgear and extraoral bow, and simple clear aligner, but all have problems:

[0003] I. Implant anchorage: conflict between growth and invasiveness

[0004] Limitations: not suitable for patients in the growth and development period, invasive treatment, limited patient acceptance.

[0005] Core reasons:

[0006] Conflict between bone integration dependence and growth instability:

[0007] Implant anchorage provides absolute anchorage through the bone integration of anchorage pins with the jawbone, which requires a stable bone environment. However, patients in the growth and development period (10-14 years old) have rapidly growing jawbones (especially the maxilla and the mandibular ramus), which continuously change in bone density, alveolar bone height, and tooth position, potentially leading to anchorage pin loosening, displacement, and even affecting the normal development trajectory of the jawbone.

[0008] Physiological and psychological threshold of invasive operation:

[0009] Local anesthesia is required for the rotation of anchorage pins into the jawbone, which carries risks such as bleeding, infection, and mucosal ulceration. Teenage patients have psychological fears of "surgery," and adult patients may refuse invasive treatment due to work and social needs (such as postoperative swelling), leading to reduced acceptance.

[0010] II. Pendulum aligner: defects in anchorage design and force control

[0011] Limitations: weak anchorage control, prone to anterior teeth labial inclination.

[0012] Core reasons:

[0013] Single and unstable anchorage source:

[0014] Pendulum aligner relies on posterior teeth (usually second molars) as anchorage teeth, pushing the first molars distally through a spiral spring. However, the root area of a single anchorage tooth is limited, making it difficult to resist the counterforce of pushing the molar, leading to anchorage tooth mesial inclination or forward movement, thereby weakening the anchorage effect.

[0015] "Lever effect" of force transmission:

[0016] When the thrust of the coil spring is transmitted to the molar through the archwire, the force line is easy to deviate from the long axis of the tooth, forming a "moment" - while the molar moves distally, the reaction force is transmitted to the anterior teeth through the dental arch, causing the anterior teeth to be labially inclined (especially the lower anterior teeth), and this phenomenon is more obvious in cases of crowded dentition (because the anterior teeth themselves have a compensatory trend towards the lips).

[0017] Three, muscle activator combined with headgear and facebow: limitations of functional positioning and structural design

[0018] Limitations: lack of tooth movement control, limited angle adjustment of traction direction, low comfort.

[0019] Core reasons:

[0020] Functional positioning focuses on "jaw growth" rather than "tooth movement":

[0021] Muscle activator guides jaw growth by changing the tension of the perioral muscles (such as mandibular protrusion), and headgear and facebow suppress maxillary growth through external force, but neither of them has designed a fine structure (such as brackets and attachments) for three-dimensional tooth movement, so they cannot achieve torque, rotation or root control of teeth, and can only complete simple overall movement.

[0022] Traction direction depends on "mechanical hard connection", with low adjustment precision:

[0023] The external bow of the traditional headgear and facebow is a standardized wire that needs to be bent manually to adjust the angle (such as high and low traction), with an error of 3-5°, making it difficult to precisely control the force ratio in the sagittal direction (forward and backward) and the vertical direction (up and down); and the connection between the external bow and the headgear is a fixed point, which cannot be dynamically adjusted according to the patient's head shape, causing the direction of force to easily deviate with head movement.

[0024] Lack of rigid structure and personalized adaptation:

[0025] The base of the muscle activator is a heat-cured plastic, and the headgear is a hard plastic or metal frame, which has "large-area rigid compression" contact with the oral mucosa and the skin of the head, lacking elasticity and cushioning; and the standardized size cannot adapt to the height of the palatine vault and the head shape of different patients, resulting in a strong foreign body sensation, mucosal ulcer or headache when worn.

[0026] Four, simple invisible aligners (such as Invisalign): insufficient force strength and anchorage stability

[0027] Limitations: limited effectiveness for cases with high demand for anchorage.

[0028] Core reasons:

[0029] "Force ceiling" of elastic film:

[0030] Invisible aligners apply force through the elastic deformation of a thermoplastic diaphragm (such as TPU material), typically with a force of 50-150g per tooth, which gradually decreases over time (approximately 30% decrease within 2 weeks). For high anchorage requirements (such as requiring a continuous force of 200-300g per side to push molars distally, or resisting the anterior movement of posterior teeth to retract anterior teeth), the diaphragm cannot provide a sufficiently strong and stable force, resulting in inefficient movement of anchorage teeth or target teeth.

[0031] Anchorage relies on "crown retention," resulting in insufficient stability.

[0032] The retention of clear aligners depends on the crown shape and attachments (such as rectangular attachments). However, anchorage teeth (such as molars) may rotate or tilt mesially under stress due to insufficient friction between the attachments and the aligner, leading to loss of anchorage. This is especially true in adult cases, where crown wear and periodontal tissue recession further reduce retention and exacerbate the difficulty of anchorage control. Summary of the Invention

[0033] Purpose of the invention: The technical problem to be solved by the present invention is to provide a design method and device for an invisible orthodontic device combined with a customized external bow traction device, which solves the problems of unstable traction direction, poor fixation, low comfort, and difficulty in monitoring force value.

[0034] Technical solution

[0035] To solve the above problems, the technical solution provided by the present invention is as follows:

[0036] A design method for an invisible orthodontic appliance combined with a customized extraoral arch traction device, including...

[0037] We manufacture invisible braces and integrate traction channels into them.

[0038] The traction channel is a hollow, through-channel, and the traction channel and the invisible braces are integrally formed.

[0039] Customized traction hooks, which are divided into anterior tooth traction hooks and posterior tooth traction hooks.

[0040] The anterior tooth traction hook is provided with a spherical structure, which abuts against the posterior tooth side of the anterior tooth traction channel. The posterior tooth traction hook is provided with a stop bend, which abuts against the anterior tooth side of the anterior tooth traction channel.

[0041] Customized traction headgear.

[0042] Furthermore, the traction channel can be freely placed in any tooth position in the anterior, posterior, or entire dentition according to the orthodontic needs. The traction channel in the anterior region is at an angle of 20-40 degrees to the occlusal plane, and the traction channel in the posterior region is at an angle of 30-40 degrees to the occlusal plane. The angle of the traction channel must ensure that the traction force line is consistent with the long axis of the tooth.

[0043] Furthermore, the outer diameter of the traction channel in the anterior tooth region is 3-4 mm, and the inner diameter is 1.0-1.5 mm; the outer diameter of the traction channel in the posterior tooth region is 3-4 mm, and the inner diameter is 1.5-2 mm.

[0044] Furthermore, the anterior traction hook extends from the anterior side through the entire anterior traction channel to the posterior side. The spherical end of the anterior traction hook passes through the anterior traction channel and is located on the posterior side of the anterior traction channel. The anterior traction hook abuts against the anterior traction channel through the bent part.

[0045] Furthermore, the posterior traction hook is a unidirectional J-shaped hook. The posterior traction hook is an integral structure composed of a support structure and a connecting structure. The support structure is a support bar that extends in an arc shape towards the posterior teeth at both ends. The support bar has a stop curve on the side facing the posterior teeth. The stop curve is a curved protrusion integrally set on the support bar. The stop curve is used to abut against the posterior traction channel. The posterior traction hook has a retention end on the rear side of the stop curve. The retention end extends backward and is inserted into the posterior traction channel.

[0046] Furthermore, the connecting structure is set on the supporting structure. The connecting structure is fixed on both sides of the supporting structure and is inclined outward. The connecting structure is used to connect with the head cap. The J-shaped hook of the posterior tooth traction hook is located at the end of the connecting structure. After the connecting structure is connected with the head cap, it plays a supporting role for the supporting structure. The connecting structure is an arc-shaped bracket. The supporting structure is fixed on the connecting structure. The retaining end of the supporting structure is inserted into the posterior tooth traction channel.

[0047] Furthermore, when multiple traction channels are set on the posterior teeth, the multiple support structures can be combined into one and share a single connection structure.

[0048] Furthermore, both the anterior and posterior traction hooks have barbed designs at the points where they are inserted into the traction channel.

[0049] Furthermore, the traction hook in the posterior tooth region has a cylindrical structure.

[0050] An invisible brace combined with a customized external oral traction device is manufactured using the aforementioned design method for an invisible brace combined with a customized external oral traction device.

[0051] Beneficial effects

[0052] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0053] The technical solution provided by this invention utilizes a synergistic approach of integrated, hollowed-out channels in invisible aligners, dual-morphology customized traction hooks, and personalized headgear. This digital and customized approach permeates the entire process, achieving integrated orthodontic treatment encompassing "tooth movement, anchorage stabilization, and growth regulation," offering a novel solution for the combined application of invisible orthodontics and extraoral traction. It effectively addresses the core pain points of traditional orthodontic anchorage techniques, demonstrating significant technological innovation and clinical value. Its unique advantages in complex case treatment and the technological trend towards precision orthodontics give it broad market prospects. Future development requires further unlocking its technological potential through clinical data accumulation, cost optimization, and collaborative promotion. The integrated molding technology creates invisible aligners with traction channels that perfectly complement customized traction hooks and personalized headgear, ensuring precise and efficient transmission of traction force to the target position. This not only improves the stability and retention of the orthodontic force but also fully considers the patient's wearing experience, significantly enhancing comfort and making the entire orthodontic process more efficient and humane. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0055] Figure 2 This is a top view of the anterior tooth traction hook of Embodiment 1 of the present invention;

[0056] Figure 3 This is a side view of the anterior tooth traction hook of Embodiment 1 of the present invention;

[0057] Figure 4 This is a top view of the anterior tooth traction hook of Embodiment 1 of the present invention;

[0058] Figure 5 This is a schematic diagram illustrating the use of Embodiment 1 of the present invention. Detailed Implementation

[0059] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0060] Example 1

[0061] A design method for an invisible aligner combined with a customized extraoral traction device includes an invisible aligner with a traction channel, a traction hook, and a head cap. The traction hook is installed between the head cap and the invisible aligner. After the patient wears the head cap, the external force is transmitted to the invisible aligner through head anchorage, thereby achieving the orthodontic effect on the patient.

[0062] Make invisible braces and integrate traction channels into the invisible braces.

[0063] Based on the patient's dental condition, a custom-made invisible braces is created. During the fabrication process, a traction channel is integrally formed into the invisible braces. This traction channel is a hollow, through-hole structure, integrated with the invisible braces as a single unit, rather than being fixed to the braces as an external attachment. This integrated design allows for efficient force transmission, reduces the errors associated with external attachments, and eliminates gaps between the traction channel and the braces, minimizing bacterial growth during patient use.

[0064] A dental model of the patient is obtained through oral scanning or traditional impression method. Based on the patient's dental model and the stage of the patient's orthodontic treatment, a plan for invisible braces that meets the patient's orthodontic needs is designed.

[0065] Based on the structure of the invisible braces, the type of orthodontic treatment for the patient's teeth, and the force application angle of the invisible braces, a traction channel is set on the invisible braces. The traction channel is used to connect with the traction hook and is directly integrated with the invisible braces. The traction channel is located on the labial outer surface of the invisible braces and is used to continuously apply force to the invisible braces, thereby ensuring the orthodontic effect of the invisible braces.

[0066] The direction, size, and position of the traction channel are individually designed according to the treatment plan, and can be freely placed in the anterior, posterior, or any position of the entire dentition as needed. The angle and position of the traction channel should fully consider its directional adjustability and dimensional adaptability.

[0067] The traction channel is adjustable in direction. Based on the patient's dental arch morphology and treatment goals, the angle of the traction channel can be preset to 25-40°. Specifically, the traction channel in the anterior teeth region has an angle of 20-40 degrees with the occlusal plane, preferably 30 degrees, while the traction channel in the posterior teeth region has an angle of 30-40 degrees with the occlusal plane, preferably 35 degrees. The angle of the traction channel must ensure that the traction force line is consistent with the long axis of the tooth.

[0068] The traction channel is designed to be adaptable to the size of the patient's teeth, avoiding excessive size which could cause the traction hook to wobble or insufficient size which could compress the tooth structure. Since the crown width of anterior teeth is typically 5-8mm and that of posterior teeth is typically 10-12mm, the preset inner diameter of the traction channel is adjusted accordingly. For anterior teeth, the outer diameter of the traction channel is 3-4mm, and the inner diameter is 1.0-1.5mm; for posterior teeth, the outer diameter is 3-4mm, and the inner diameter is 1.5-2mm.

[0069] The traction channel is integrated into the invisible braces. The invisible braces with the traction channel are used in conjunction with the traction hook. The traction channel and the invisible braces are molded as one piece, avoiding the directional deviation caused by poor adhesion of traditional additional devices. The traction direction error is ≤1°, which is 3-5° compared with the error of traditional technology. It can directly solve the problem of "unstable traction direction".

[0070] Customized towing hook:

[0071] The system employs dual-shape traction hooks, with different shapes used to connect the traction channels in the anterior and posterior regions of the invisible braces.

[0072] The anterior traction hook, used to connect to the anterior traction channel, employs an "arc-shaped bending structure with a spherical end." The anterior traction hook matches the anterior traction channel (e.g., tooth position 3-3). The anterior traction hook is a bidirectional J-shaped hook, with its traction end bending towards the gum line, suitable for high-level traction to depress the anterior teeth. In use, the bent end is inserted through the anterior traction channel, and the hook extends from the anterior side through the entire channel to the posterior side. The spherical end of the hook passes through the channel and is located on the posterior side. The hook abuts against the channel through the bent portion. Because the force applied by the hook is a backward pulling force, the hook provides continuous tension to the traction channel through the bent portion, thus achieving continuous force on the invisible braces and further applying force to the patient's teeth. The spherical structure at the end of the anterior traction hook prevents it from dislodging during head or mouth movements. Simultaneously, the spherical structure reduces friction on the oral mucosa when the hook contacts it. The anterior traction hook has a flattened structure, ensuring effective traction while minimizing occlusal interference.

[0073] The posterior traction hook adopts an "extended support with stop curve" structure. The posterior traction hook is a unidirectional J-shaped hook, an integral structure composed of a support structure and a connecting structure. The support structure consists of a support bar extending towards the posterior teeth at both ends in an arc shape. A stop curve is located on the side of the support bar facing the posterior teeth. The stop curve is a curved protrusion integrally formed on the support bar, used to abut against the posterior traction channel. The posterior traction hook has a retention end behind the stop curve, extending posteriorly and inserting into the posterior traction channel (e.g., tooth position 6-6), using the stop curve to hold the posterior traction channel in place. The connecting structure is set on the supporting structure. The connecting structure is fixed on both sides of the supporting structure and is inclined outward. The connecting structure is used to connect with the headgear. The J-shaped hook of the posterior tooth traction hook is located at the end of the connecting structure. After the connecting structure is connected with the headgear, it plays a supporting role for the supporting structure. The connecting structure is an arc-shaped bracket. The supporting structure is fixed on the connecting structure. The retention end of the supporting structure is inserted into the posterior tooth traction channel. At this time, the stop bend plays a role in resisting the posterior tooth traction channel. By continuously applying force to the posterior tooth traction channel through the stop bend, a continuous force is applied to the invisible braces, and further force is applied to the patient's teeth.

[0074] Both the anterior and posterior traction hooks feature barbed designs at the insertion points into the traction channels. Specifically, the bent structure of the anterior traction hook and the retention end of the posterior traction hook are barbed, enhancing anti-rotation capabilities. The traction ends of both hooks are tilted distally, suitable for pushing molars distally; that is, the end of the anterior traction hook used to connect to the head cap and the end of the posterior traction hook used to connect to the head cap are both tilted distally. The flat design of the anterior hook avoids occlusal interference, while the cylindrical structure of the posterior traction hook conforms to biomechanical principles, enhancing its synergistic effect with tooth long axis control.

[0075] Material selection: Titanium alloy is 3D printed and has an elastic modulus of 20-25 GPa. Compared with the elastic modulus of 190 GPa of traditional stainless steel traction hooks, it can reduce the instantaneous impact force on tooth tissue through the elastic deformation of the traction hook.

[0076] By redesigning the structure of the traction hook, the clinical challenge of "weak anchorage control" was effectively solved. The posterior traction hook adopts a unique stop-bend structure, forming a stable mechanical locking mechanism with the traction channel, significantly enhancing anchorage stability. Experimental data show that this design reduced the anchorage loss rate from approximately 30% with traditional traction hooks to 12%, a reduction of 60%, greatly improving the predictability and effectiveness of orthodontic treatment.

[0077] Meanwhile, this traction system fully considers the anatomical characteristics and functional needs of different tooth positions: the anterior tooth region adopts a flattened design that conforms to the dental arch morphology, minimizing occlusal interference while ensuring traction effectiveness; the posterior tooth region utilizes a cylindrical structure that conforms to biomechanical principles, enhancing synergy with tooth long axis control. This zoned, differentiated design enables precise control of three-dimensional tooth movement, including complex tooth movement needs such as torque adjustment and rotational correction, providing reliable technical support for personalized orthodontic treatment.

[0078] By cooperating with the traction channel and the traction hooks in the anterior and posterior tooth areas, the fixing structure of the traction hook and the traction channel is precisely matched, thereby significantly improving the friction between the traction hook and the traction channel. This can increase the friction coefficient by 40%, prevent the traction hook from rotating or falling off, and improve the stability of the fixation.

[0079] Furthermore, the traction channel is designed to be integrated with the invisible braces according to the orthodontic needs. Therefore, when using it, the doctor only needs to install the traction hook into the traction channel. There is no need for the doctor to manually adjust the J-hook angle of the traction hook. The channel direction is preset by digital design, which simplifies clinical operation and reduces chair time by more than 50%.

[0080] Customized traction headgear:

[0081] The headgear is used in conjunction with the traction hooks to provide traction force for the invisible braces. Based on the patient's skull CT data, a 3D scan is used to generate a model of the head circumference, head height, and skull surface contour. The traction direction is determined in conjunction with the treatment plan, and a personalized headgear is made by anatomically locating the headgear to avoid the frontal artery, occipital artery, and cervical lymph node areas. The pressure generated when using the headgear is distributed to the temporal and occipital muscle-rich areas, while avoiding other directional forces caused by traction.

[0082] The headgear has adjustable bases on both sides, and an adjustment strap connected to the adjustable base is provided on the headgear. The adjustment strap has an adjustment buckle, which is installed on the headgear. The headgear has several adjustment buckles in different directions on the adjustable base. The adjustment buckles allow the adjustable base to slide back and forth on the headgear through the adjustment strap. By extending one side of the adjustment strap and shortening the other side of the adjustable base in opposite directions, the adjustable base can be moved to any side.

[0083] An electronic force gauge is rotatably mounted on the adjustable base. This force gauge can rotate slightly on the base, allowing for ±15° angle adjustments to compensate for the traction force direction during patient head movements. Preferably, the electronic force gauge is rotatably positioned on the outside of the adjustable base and can be limited by a locking block or damping mechanism, or the headgear and traction hook can be connected via a universal joint. The bottom of the electronic force gauge features a pull-down rigid band with a certain degree of elasticity. This elasticity requires a self-locking structure, which can be made of a telescopic tube with elastic protrusions and multiple limiting holes. Self-locking is achieved by inserting the elastic protrusions into the multiple limiting holes.

[0084] The pull-down rigid band has a matching buckle at the end, which is used to engage with the J-shaped hook at the end of the connection structure of the anterior traction hook and the posterior traction hook, thereby fixing the traction hook on the matching buckle and connecting the head cap and the invisible braces through the traction hook.

[0085] The electronic force gauge can display the traction force at the end of the pull-down rigid band in real time, thus providing the traction force provided by the traction hooks to the invisible braces. The headgear provides a traction force of 150-400g to the invisible braces via the traction hooks, and the electronic force gauge has a display accuracy of ±5g. The electronic force gauge can connect to the doctor's terminal via Bluetooth or network and automatically alarms in case of abnormalities.

[0086] The headgear is made of silicone material inside, or a silicone pad is placed at the base of the headgear and the skin to reduce pressure, thereby solving the problem of "low comfort". The silicone material matches the individual contour, and the contact pressure is ≤2kPa, while the traditional headgear is 5-8kPa. The patient's comfortable wearing time has increased from an average of 8 hours / day to 12 hours / day.

[0087] The headgear achieves "precise force control." The electronic force gauge avoids the force fluctuations caused by the traction force decay of traditional rubber bands. Furthermore, the error of the electronic force gauge is much smaller than that of traditional rubber bands, with an error of ≤5g. In contrast, the traction force error provided by traditional rubber bands varies over time, ranging from 20-30g, which can reduce the risk of periodontal tissue damage.

[0088] In other implementations, a neck strap can be used instead of a headgear. The neck strap is equipped with an adjustable base, which can be self-locked and unlocked via a buckle structure. When the adjustable base is unlocked, it can move freely on the neck strap. At the same time, an electronic force gauge is also rotatably mounted on the adjustable base. The electronic force gauge can also be self-locked and unlocked to fix and deflect its angle, so as to meet the traction force direction compensation when the patient's head moves. The electronic force gauge is equipped with an upwardly extending and retractable rigid band. The upwardly extending rigid band has a certain degree of elasticity and also needs to have a self-locking structure. The top of the upwardly extending rigid band is equipped with a matching buckle, which is used to engage with the J-shaped hook at the end of the connection structure of the anterior tooth traction hook for connecting the headgear and the posterior tooth traction hook.

[0089] The pull-down rigid strap has a matching buckle at the end.

[0090] The preferred process for the coordinated operation of the invisible braces with traction channels, traction hooks, and headgear is as follows:

[0091] Digital design phase: Dental data is obtained through intraoral scanning and combined with cephalometric radiographs to determine the treatment goals, namely the direction and distance of movement of each tooth position, such as pushing the molars 3mm distally and indenting the anterior teeth 2mm. Based on this, the position and angle of the traction channel are planned. For example, the conventional traction channel positions are: tooth 6-6 position for posterior traction channel, tooth 2-2 position for anterior traction channel, 35° distal traction, and 30° high traction.

[0092] Manufacturing stage: The invisible braces and traction channels are 3D printed as a whole. The traction hooks are printed according to the shape of the channels and then embedded into the channels. The headgear is customized according to the skull model and equipped with electronic force measuring devices.

[0093] Clinical application stage: After the patient wears invisible braces, the traction hook is inserted into the channel and connected to the head cap through a universal joint. The electronic force measuring device sets the initial force value (such as 250g in the posterior region and 200g in the anterior region). The doctor monitors the force value changes through the terminal and adjusts the channel direction or force value parameters every 2 weeks.

[0094] An extraoral arch, consisting of a headgear or neck strap, traction hooks, and invisible braces, utilizes the head or neck as support to transmit external forces to the dentition and jawbone via the traction hooks, achieving the following key functions:

[0095] Limiting excessive maxillary growth: By applying a posterior and superior traction force, maxillary protrusion is inhibited, improving facial proportions.

[0096] Strengthening molar anchorage: Prevents molars from moving forward and provides stable support for anterior tooth retraction, especially suitable for adolescents during their growth and development period.

[0097] Distal movement of molars: By adjusting the magnitude of the traction force, the molars are moved distally, improving the occlusal relationship.

[0098] It is suitable for Angle Class II malocclusion, high-angle cases, and patients who need anchorage control. Angle Class II malocclusion: especially for patients with maxillary protrusion and mandibular retrusion, it improves overjet relationship by inhibiting maxillary growth and promoting molar distalization.

[0099] High-angled cases: Vertical development is controlled by high-level traction, reducing clockwise rotation of the mandible and improving facial shape.

[0100] Anchorage control needs: In borderline cases between extraction and non-extraction, as an alternative to implant anchorage (especially in adolescents with active jaw remodeling, where implants are prone to loosening).

[0101] Example 1: High traction in the anterior region for deep overbite correction

[0102] Case: A 12-year-old patient with skeletal Class II malocclusion, deep overbite of the anterior teeth (overbite up to 8mm), requiring intrusion of the upper anterior teeth by 2.5mm.

[0103] Technical solution:

[0104] Invisible braces: A 30° high-level traction channel is designed on the lingual side of the crown of the upper anterior teeth (1-1, 2-2), with an inner diameter of 3.5mm, which matches the "flat arc-shaped + spherical end" anterior tooth traction hook.

[0105] Towing hook: The retaining end is a "spherical end" (1.8mm in diameter), and the towing end is bent towards the center and hooked onto the head cap towing ring.

[0106] Headgear: Headband + top strap design, pull down the traction ring until the electronic force gauge shows 250g / side, wear for 12 hours daily.

[0107] Results: After 3 months, the upper anterior teeth were depressed by 2mm, the overbite was reduced to 4mm, and there was no labial inclination of the anterior teeth (the incidence of labial inclination of the anterior teeth is about 25% with traditional techniques).

[0108] Example 2: Distal traction of molars in the posterior region

[0109] Case: A 14-year-old patient with severe crowding of teeth (space requirement of 10mm) needs to have the maxillary first molar pushed 4mm distal to each side.

[0110] Technical solution:

[0111] Invisible braces: A distal traction channel with an inner diameter of 2mm is designed on the buccal side of the crown of the maxillary first molar (6-6) and at a 5° angle to the occlusal plane, matching the "flat arc + stop curve" posterior tooth traction hook.

[0112] Towing hook: The retaining end has a spherical protrusion and a stop curve (8mm apart), and the towing end is tilted 5° to the distal center to connect to the headgear and neck strap.

[0113] Headgear: A composite design of neck strap and forehead strap. Pull down the traction ring until the electronic force gauge shows 250g / side. Wear for 14 hours daily.

[0114] Results: After 6 months, the molar was moved distally by 3.8 mm, resulting in a gap of 9.5 mm. The mesial inclination of the anchorage tooth (second molar) was <2° (compared to 3-5° with traditional techniques).

[0115] The traction channels on invisible braces are set in multiple sets. It is not that only one set of cooperating anterior traction channels and anterior traction hooks can be set in the anterior teeth area, and only one set of cooperating posterior traction channels and posterior traction hooks can be set in the posterior teeth area.

[0116] If two or more traction channels are needed in the anterior region of invisible braces according to the orthodontic requirements, multiple anterior traction channels can be set in the anterior region according to the orthodontic requirements. The anterior traction hook can be set with multiple "arc-shaped bending structure with ball-shaped end" structure at the end that needs to connect to the anterior traction channel in a bifurcated manner, so as to connect with different anterior traction channels. Alternatively, multiple independent anterior traction hooks can be set to connect to different anterior traction channels. The connection of multiple independent traction hooks with different traction channels can more precisely control the force angle of the traction hook.

[0117] When multiple traction channels are set on the posterior teeth, they can also be set at any position in the posterior region of the invisible braces. Multiple support structures can be combined into one and share a common connecting structure. Multiple support structures share the middle structural part, while the parts extending towards the posterior teeth are designed independently to connect with multiple traction channels. Multiple support structures can be set on the same connecting structure by merging and combining them, i.e., a double-bar parallel traction hook. The angle and tilt of multiple support structures can be set individually, so that each connecting structure can provide appropriate traction force for the corresponding posterior traction channel, and also prevent excessive inconvenience and discomfort to the wearer caused by too many connecting structures.

[0118] Example 3:

[0119] Case background:

[0120] A 16-year-old adolescent patient has bilateral first molar elongation (2.5 mm), resulting in anterior open bite (4 mm). It is necessary to indent the posterior teeth while maintaining the vertical height of the anterior teeth.

[0121] Combination of technical means:

[0122] Invisible braces and traction channels:

[0123] Location: Palatal side of the crowns of the first and second molars (6-6, 7-7) on both sides, with a 45° vertical traction channel designed (the channel direction is at a 45° angle to the occlusal plane) and an inner diameter of 2.5 mm.

[0124] Multi-channel collaborative design: The 6-6 channel and the 7-7 channel are integrally formed by buccal connecting ribs to form a "rigid support frame" to avoid deformation of the braces when a single channel is subjected to force.

[0125] Towing hook device:

[0126] Form: "Double rod parallel type" traction hook, two titanium alloy rods (1.2mm in diameter) are inserted into channels 6-6 and 7-7 respectively, and the top ends meet into a single traction ring (8mm in diameter), distributing the traction force to multiple back teeth.

[0127] Fixing design: The traction hook is inserted into the channel to a depth of 8mm, with a ball buckle at the end and a stop curve at the front to lock with the groove at the bottom of the channel to prevent it from coming out during traction.

[0128] Headgear and force control:

[0129] Headgear type: High forehead band + top band headgear (three-point fixation), traction force is transmitted vertically downward through the top traction band to avoid lateral force causing buccal and lingual tilting of the posterior teeth.

[0130] Electronic force gauge: Set the initial force value to 220g / side (a higher force value is required for vertical compression), wear for 14 hours a day, and the force value fluctuation range is controlled within ±10g (the fluctuation range of traditional technology is ±30g).

[0131] Correction effect:

[0132] Eight months later, the first molar was depressed by 2mm, the second molar by 1.8mm, and the anterior open bite decreased to 1mm.

[0133] There was no bone resorption in the posterior alveolar region (CBCT showed that bone density remained at baseline level), and the occlusal relationship returned to normal.

[0134] Therefore, it is evident that the combination of invisible braces with a customized extraoral traction device has the following advantages:

[0135] I. Addressing the compatibility deficiencies of traditional devices

[0136] Improve facial fit

[0137] Traditional extraoral devices are mostly pre-processed standardized products, which have poor fit with the patient's facial shape and can easily lead to complications such as redness, swelling, allergies or blisters caused by pressure on the occipital bone, skull, face and lips. Personalized design can reduce local pressure by matching the patient's jaw and facial contour.

[0138] Overcoming the limitations of fixed headband size

[0139] Existing headbands are mostly fixed sizes of large, medium, and small, which cannot accurately fit different head sizes, resulting in poor wearing comfort and affecting the stability of traction. Personalized adjustment structures can achieve dynamic adaptation.

[0140] II. Optimize the accuracy of traction direction and force value

[0141] Achieving personalized matching between traction direction and jaw plane.

[0142] By designing a traction structure at a predetermined angle to the patient's occlusal plane (such as the anteroinferior traction direction), the traction force is ensured to be parallel to the midsagittal plane, avoiding maxillary rotation and maximizing the promotion of maxillary anterior development.

[0143] Solving the problem of limited adjustment range of traditional devices

[0144] Existing devices cannot simultaneously meet clinical needs in terms of both traction force magnitude and direction. Personalized designs achieve precise control of traction force direction through adjustable connection structures (such as angle locking components).

[0145] III. Improving Clinical Treatment Efficacy and Safety

[0146] Promotes directional growth of the maxilla during growth and development

[0147] For skeletal Class II malocclusion (maxillary protrusion or mandibular hypoplasia, or mandibular posterior-inferior rotation), anterior force is applied through personalized traction direction to directly promote maxillary bone growth, improve skeletal discrepancies, and coordinate the posterior occlusal plane, making it especially suitable for children and adolescents.

[0148] Reduce unintended tooth movement and compensation.

[0149] IV. Improve patient compliance with wearing the device

[0150] Optimize wearing comfort and convenience

[0151] Personalized devices reduce restrictions on head movement through lightweight materials (such as titanium alloys) and flexible external bow design, while avoiding the extended operation time and infection risk caused by the complex adjustment of traditional devices.

[0152] Meets the needs of long-term wear

[0153] To address the requirement that anterior traction requires wearing the device for more than 12 hours a day, the forehead and chin supports are designed to fit the shape of the face, reducing discomfort and improving patient compliance.

[0154] V. Integrating Multi-Dimensional Corrective Goals

[0155] To achieve the synergistic effect of "growth improvement - anchorage control - occlusal adjustment", for example, vertical control can be performed to indent the molars while moving them distally, and the alignment and vertical control of the anterior teeth can be performed at the same time.

[0156] Example 2

[0157] Combined with appendix Figures 1-5 A type of invisible aligner combined with a customized extraoral traction device includes a head cap, traction hooks, and invisible aligners. The traction hooks are connected between the head cap and the invisible aligners. The head cap is worn on the user's head to provide initial traction force to the invisible aligners. The traction hooks then further transmit the traction force to the invisible aligners. Thus, by using the head cap, traction hooks, and invisible aligners in combination, and with the head as a support, external force is transmitted to the dentition and jawbone through the traction hooks, thereby achieving the orthodontic purpose.

[0158] The headgear is made by scanning the user's head shape. The headgear fits the user's head shape perfectly. Through the design of the headgear's shape corresponding to the user's head, the headgear can fit the user's head perfectly after the user wears it. Therefore, the headgear will not easily move after the user wears it, thus keeping the headgear stable and achieving traction stability.

[0159] The headgear is equipped with an adjustable base that can slide on the headgear. The adjustable base also has a self-locking function. When the adjustable base is self-locked, it is fixed on the headgear. When the adjustable base is unlocked, it can slide on the headgear to adjust its position.

[0160] The self-locking structure of the adjustable base can be selected in various styles, preferably a combination of an adjusting strap and a snap-on adjusting buckle. By installing the snap-on adjusting buckle on the headband, each adjustable base has at least two adjusting buckles installed in opposite directions (front and back). An adjusting strap connects the adjusting buckle to the adjustable base. Unlocking the adjusting buckle moves the adjusting strap to further adjust the adjustable base. When locking the adjustable base is required, simply snap the unlocking mechanism in place. Each adjustable base has an adjustable strap with slack for movement. In other embodiments, the adjusting buckle and adjusting strap can also use an adjustable structure similar to the shoulder strap of a backpack.

[0161] Alternatively, the self-locking structure of the adjustable base can be configured with equidistant limiting holes arranged sequentially in the direction of the adjustable base's movement on the headgear. Buttons or plugs that fit into the limiting holes can be installed on the adjustable base. Thus, when the adjustable base moves to the appropriate position, the self-locking of the adjustable base can be achieved by inserting the button or plug into the corresponding limiting hole.

[0162] An electronic force gauge is rotatably mounted on the adjustable base. The force gauge can rotate slightly on the adjustable base, preferably allowing for ±15° angle adjustments to compensate for the traction force direction during patient head movements. Preferably, the electronic force gauge is rotatably positioned on the outside of the adjustable base and can be limited by a locking block or damping mechanism, or the headgear and traction hook can be connected via a universal joint.

[0163] The electronic force gauge has a pull-down rigid band at the bottom, which has a certain telescopic function. This telescopic function requires a self-locking structure, which can be made of a telescopic tube with elastic protrusions and multiple limiting holes. Self-locking is achieved by inserting the elastic protrusions into the multiple limiting holes.

[0164] The pull-down rigid strap has a matching buckle at the end, and the traction hook is connected to the matching buckle and fixed to the matching buckle, so as to provide traction force to the user by using the user's head.

[0165] The invisible braces have several traction channels, which are hollow through channels. The traction channels are an integral part of the invisible braces, rather than being fixed to the invisible braces as an external attachment. The integral design of the traction channels and the invisible braces can effectively transmit force. The integral structure can also reduce the error of external attachments. At the same time, there are no gaps between the traction channels and the invisible braces, so bacteria are less likely to grow when patients use them.

[0166] The traction channel is used to connect with the traction hook. The traction channel is directly integrated with the invisible braces and is located on the labial outer surface of the invisible braces. It is used to apply continuous force to the invisible braces, thereby ensuring the orthodontic effect of the invisible braces.

[0167] The direction, size, and position of the traction channel are designed individually based on the treatment plan, and can be freely placed in the anterior, posterior, or any position across the entire dentition as needed. The angle and position of the traction channel should fully consider its directional adjustability and dimensional adaptability.

[0168] The traction channel is adjustable in direction. Based on the patient's dental arch morphology and treatment goals, the angle of the traction channel can be preset to 25-40°. Specifically, the traction channel in the anterior teeth region has an angle of 20-40 degrees with the occlusal plane, preferably 30 degrees, while the traction channel in the posterior teeth region has an angle of 30-40 degrees with the occlusal plane, preferably 35 degrees. The angle of the traction channel must ensure that the traction force line is consistent with the long axis of the tooth.

[0169] The traction channel is designed to be adaptable to the size of the patient's teeth, avoiding excessive size which could cause the traction hook to wobble or insufficient size which could compress the tooth structure. Since the crown width of anterior teeth is typically 5-8mm and that of posterior teeth is typically 10-12mm, the preset inner diameter of the traction channel is adjusted accordingly. For anterior teeth, the outer diameter of the traction channel is 3-4mm, and the inner diameter is 1.0-1.5mm; for posterior teeth, the outer diameter is 3-4mm, and the inner diameter is 1.5-2mm.

[0170] The traction hooks are dual-form traction hooks, with different shapes used to connect the traction channels of the anterior and posterior teeth areas on the invisible braces.

[0171] Both ends of the anterior traction hook are equipped with bent J-shaped hooks. The J-shaped end of the anterior traction hook located inside the user's mouth faces the lingual side. The end of the anterior traction hook located inside the mouth has a spherical structure. The structure of "arc-shaped bending structure combined with spherical end" is suitable for high-level traction to depress the anterior teeth. In use, the bent end is inserted through the anterior traction channel. The anterior traction hook passes through the entire anterior traction channel from the anterior side to the posterior side. The spherical end of the anterior traction hook passes through the anterior traction channel and is located on the posterior side of the anterior traction channel. The anterior traction hook abuts against the anterior traction channel through the bent part. Since the force direction of the anterior traction hook is backward pulling force, the anterior traction hook can continuously provide pulling force to the traction channel through the bent part, thereby achieving continuous force on the invisible braces and further applying force to the patient's teeth. The spherical structure at the end of the anterior traction hook prevents it from dislodging during head or mouth movements. Simultaneously, the spherical structure reduces friction on the oral mucosa when the hook contacts it. The anterior traction hook has a flattened structure, ensuring effective traction while minimizing occlusal interference.

[0172] The posterior traction hook consists of a connecting structure for connection and a supporting structure for supporting the posterior traction channel. The end of the supporting structure that connects to the traction channel adopts an "extended support with stop curve" structure, and the end of the connecting structure has a J-shaped hook for connection with the head cap. The supporting structure and the connecting structure are combined into a single unit.

[0173] The support structure consists of a support strip extending towards the posterior teeth in an arc shape at both ends. A stop curve is located on the side of the support strip facing the posterior teeth. The stop curve is an integrally formed curved protrusion on the support strip, used to hold the posterior traction channel. The posterior traction hook has a retention end behind the stop curve, extending posteriorly and inserting into the posterior traction channel (e.g., tooth position 6-6). The stop curve holds the posterior traction channel in place. The connecting structure is located on the support structure, fixed to both sides of the support structure and sloping outwards. The connecting structure connects to the headgear. The J-shaped hook of the posterior traction hook is located at the end of the connecting structure. After connecting to the headgear, the connecting structure supports the support structure. The connecting structure is an arc-shaped bracket. The support structure is fixed to the connecting structure, and the retention end of the support structure is inserted into the posterior traction channel. At this point, the stop curve acts as a stop for the posterior traction channel, continuously applying force to the posterior traction channel through the stop curve, thereby achieving continuous force on the invisible braces and further applying force to the patient's teeth.

[0174] Both the anterior and posterior traction hooks feature barbed designs at the insertion points into the traction channels. Specifically, the bent structure of the anterior traction hook and the retention end of the posterior traction hook are barbed, enhancing anti-rotation capabilities. The traction ends of both hooks are tilted distally, suitable for pushing molars distally; that is, the end of the anterior traction hook used to connect to the head cap and the end of the posterior traction hook used to connect to the head cap are both tilted distally. The flat design of the anterior hook avoids occlusal interference, while the cylindrical structure of the posterior traction hook conforms to biomechanical principles, enhancing its synergistic effect with tooth long axis control.

[0175] Material selection: Titanium alloy is 3D printed and has an elastic modulus of 20-25 GPa. Compared with the elastic modulus of 190 GPa of traditional stainless steel traction hooks, it can reduce the instantaneous impact force on tooth tissue through the elastic deformation of the traction hook.

[0176] If two or more traction channels are needed in the anterior region of invisible braces according to the orthodontic requirements, multiple anterior traction channels can be set in the anterior region according to the orthodontic requirements. The anterior traction hook can be set with multiple "arc-shaped bending structure with ball-shaped end" structure at the end that needs to connect to the anterior traction channel in a bifurcated manner, so as to connect with different anterior traction channels. Alternatively, multiple independent anterior traction hooks can be set to connect to different anterior traction channels. The connection of multiple independent traction hooks with different traction channels can more precisely control the force angle of the traction hook.

[0177] When multiple traction channels are set on the posterior teeth, they can also be set at any position in the posterior region of the invisible braces. Multiple support structures can be combined into one and share a common connecting structure. Multiple support structures share the middle structural part, while the parts extending towards the posterior teeth are designed independently to connect with multiple traction channels. Multiple support structures can be set on the same connecting structure by merging and combining them, i.e., a double-bar parallel traction hook. The angle and tilt of multiple support structures can be set individually, so that each connecting structure can provide appropriate traction force for the corresponding posterior traction channel, and also prevent excessive inconvenience and discomfort to the wearer caused by too many connecting structures.

[0178] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A design method for an invisible orthodontic appliance combined with a customized extraoral bow traction device, characterized in that, include We manufacture invisible braces and integrate traction channels into them. The traction channel is a hollow through-channel, and the traction channel and the invisible braces are integrally formed. Customized traction hooks, which are divided into anterior tooth traction hooks and posterior tooth traction hooks. The anterior tooth traction hook is provided with a spherical structure, which abuts against the posterior tooth side of the anterior tooth traction channel. The posterior tooth traction hook is provided with a stop bend, which abuts against the anterior tooth side of the anterior tooth traction channel. Customized traction headgear.

2. The design method of an invisible orthodontic device combined with a customized extraoral bow traction device according to claim 1, characterized in that, The traction channel can be freely placed in any position of the anterior, posterior, or entire dentition according to the orthodontic needs. The traction channel in the anterior region is at an angle of 20-40 degrees to the occlusal plane, and the traction channel in the posterior region is at an angle of 30-40 degrees to the occlusal plane. The angle of the traction channel must ensure that the traction force line is consistent with the long axis of the tooth.

3. The design method of an invisible orthodontic appliance combined with a customized extraoral bow traction device according to claim 1, characterized in that, The outer diameter of the traction channel in the anterior tooth region is 3-4 mm, and the inner diameter is 1.0-1.5 mm. The outer diameter of the traction channel in the posterior tooth region is 3-4 mm, and the inner diameter is 1.5-2 mm.

4. The design method of an invisible orthodontic appliance combined with a customized extraoral bow traction device according to claim 1, characterized in that, The anterior traction hook extends from the anterior side through the entire anterior traction channel to the posterior side. The ball-shaped end of the anterior traction hook passes through the anterior traction channel and is located on the posterior side of the anterior traction channel. The anterior traction hook abuts against the anterior traction channel through the bend.

5. The design method of an invisible orthodontic appliance combined with a customized extraoral bow traction device according to claim 1, characterized in that, The posterior traction hook is a unidirectional J-shaped hook. The posterior traction hook is an integral structure composed of a support structure and a connecting structure. The support structure is a support bar that extends in an arc shape towards the posterior teeth at both ends. The support bar has a stop curve on the side facing the posterior teeth. The stop curve is a curved protrusion integrally set on the support bar. The stop curve is used to abut against the posterior traction channel. The posterior traction hook has a retention end on the rear side of the stop curve. The retention end extends backward and is inserted into the posterior traction channel.

6. The design method of an invisible orthodontic appliance combined with a customized extraoral arch traction device according to claim 5, characterized in that, The connecting structure is set on the supporting structure. The connecting structure is fixed on both sides of the supporting structure and is inclined outward. The connecting structure is used to connect with the head cap. The J-shaped hook of the posterior tooth traction hook is located at the end of the connecting structure. After the connecting structure is connected with the head cap, it plays a supporting role for the supporting structure. The connecting structure is an arc-shaped bracket. The supporting structure is fixed on the connecting structure. The retaining end of the supporting structure is inserted into the posterior tooth traction channel.

7. The design method of an invisible orthodontic appliance combined with a customized extraoral bow traction device according to claim 6, characterized in that, When multiple traction channels are set on the posterior teeth, the multiple support structures can be combined into one and share a single connection structure.

8. The design method of an invisible orthodontic device combined with a customized extraoral bow traction device according to claim 1, characterized in that, Both the anterior and posterior traction hooks have barbed designs at the points where they are inserted into the traction channel.

9. The design method of an invisible orthodontic appliance combined with a customized extraoral bow traction device according to claim 1, characterized in that, The traction hook in the posterior tooth region has a cylindrical structure.

10. A type of invisible brace combined with a customized extraoral arch traction device, characterized in that, It is manufactured by combining the invisible orthodontic device of any one of claims 1-9 with a customized external oral traction device design method.

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