CN114652468A

CN114652468A - Design method, manufacturing method and system of pre-activated bow expander and pre-activated bow expander

Info

Publication number: CN114652468A
Application number: CN202210242424.3A
Authority: CN
Inventors: 郑旭; 孙靖超
Original assignee: Shanghai Alemu Health Technology Co ltd
Current assignee: Shanghai Alemu Health Technology Co ltd
Priority date: 2022-03-11
Filing date: 2022-03-11
Publication date: 2022-06-24
Anticipated expiration: 2042-03-11
Also published as: CN114652468B

Abstract

The application provides a design method, a manufacturing method and a system of a pre-activated arch expander and the pre-activated arch expander, wherein the design method comprises the following steps: determining target arch expansion parameters according to the initial dental digital model in the initial dental arch form, wherein the target arch expansion parameters comprise target arch expansion amount and target arch expansion force; determining a target dental digital model in the form of a target dental arch according to the initial dental digital model and the target dental arch expansion parameters; and designing a pre-activated arch expander digital model based on the target arch expanding parameters and the target dental digital model. According to the technical scheme, the pre-activated arch expander can be optimally designed and manufactured according to a design target, and the arch expanding effect of the dental jaw can be more accurately realized.

Description

Design method, manufacturing method and system of pre-activated bow expander and pre-activated bow expander

Technical Field

The application relates to the technical field of orthodontic, in particular to a design method, a manufacturing method and a system of a pre-activated arch expander and the pre-activated arch expander.

Background

The arch expander is a common appliance in the field of orthodontic treatment and can be used for correcting narrow dental arches, crowded dentition, coordinating the widths of upper and lower dental arches and the like.

The arch expander generally comprises a fixing part for fixing the appliance on teeth and an arch expanding part for expanding the arch, wherein elastic restoring force generated after the arch expanding part applies force and deforms acts on the teeth and is transmitted to alveolar bones, so that the widths of upper and lower jaw arches and alveolar bone arches can be increased, and the arch expanding effect is realized.

When the existing bow expander is manufactured, a technician generally manufactures a pre-treatment initial model according to the requirements of a doctor design list, arch wires with different diameters and different performances can be selected as bow expanding components and bent into bow expanding springs with different shapes, a spiral bow expander can also be used, and fixing components can be manufactured into fixed or movable bow expanders by using belt rings, clamping rings and the like. When a doctor uses the arch expander clinically, the expansion part needs to be adjusted and activated by self, the operation mode greatly depends on the experience and clinical operation technique of the doctor, the actual generated correcting force and the realized expansion amount of the arch expander after activation cannot be estimated accurately, and the difference with the expected correcting scheme is probably larger, so that the curative effect needs to be monitored continuously in the whole arch expanding process, the adjustment is repeated, the operation predictability is poor, and the operation is difficult to master for beginners. Furthermore, for children who need to expand their arches, repeated attachment and detachment of the appliances in the oral cavity is likely to cause them to feel pain and discomfort, resulting in poor fitting.

Because of the above problems with the conventional pantograph expanders, there is a need for a manufacturing method and a manufacturing system that can manufacture a pantograph in a pre-activated state according to predetermined target pantograph parameters (such as pantograph amount, pantograph force, etc.).

Disclosure of Invention

In order to solve the problems in the prior art, an aspect of the present application provides a design method of a pre-activated arch expander, the pre-activated arch expander including a retention band and an expansion part, including the following steps:

s100: determining target arch expansion parameters according to the initial dental digital model in the initial dental arch form, wherein the target arch expansion parameters comprise target arch expansion amount and target arch expansion force;

s200: determining a target dental digital model in the form of a target dental arch according to the initial dental digital model and the target dental arch expansion parameters;

s300: and designing a pre-activated arch expander digital model based on the target arch expanding parameters and the target dental digital model.

Preferably, the target amount of arch expansion comprises one or more of the following parameters corresponding to adjusting the dental jaw from the initial arch configuration to the target arch configuration: the upper jaw overall arch expansion amount, the upper jaw unilateral arch expansion amount, the upper jaw anterior tooth area arch expansion amount, the upper jaw posterior tooth area arch expansion amount, the lower jaw overall arch expansion amount, the lower jaw unilateral arch expansion amount, the lower jaw anterior tooth area arch expansion amount and the lower jaw posterior tooth area arch expansion amount.

Further, the target arch expansion amount is determined by the difference of the widths of the corresponding positions of the initial dental arch form and the target dental arch form.

Further, a difference in width of the corresponding positions of the initial dental arch form and the target dental arch form is determined based on the measurement of the initial dental digital model and the arch analysis.

Preferably, the target arch expansion force includes the amount and direction of the arch expansion force to which each tooth corresponding to the adjustment of the jaw from the initial arch form to the target arch form is subjected.

Preferably, the pre-activated expander design method further comprises the step of adjusting the target expansion amount and/or target expansion force according to expansion force loss.

Preferably, the pre-activated expander manufacturing method further comprises the step of adjusting the target digital dental model according to expansion force loss.

Further, the step S300 includes the steps of:

s310: determining target geometric parameters of a pre-activated arch expander according to the target dental digital model;

s320: searching whether a preset pantograph expander digital model meeting the matching requirement exists in a database according to the target pantograph expansion parameters and the target geometric parameters, if the search result is true, deriving the search result as a pre-activated pantograph expander digital model, simultaneously deriving material parameters of the pre-activated pantograph expander digital model, and then finishing the design, and if the search result is false, executing a step S330;

s330: and designing by using a finite element method according to the target geometric parameters and the target bow expansion parameters to obtain a pre-activated bow expander digital model meeting the bow expansion constraint conditions and material parameters thereof.

Preferably, the target geometric parameters include one or more of the following parameters: the number, shape and fixing position of the retaining strap loops, the number of the spring coils contained in the arch expansion component, the position, diameter and angle of each spring coil, the radian of the arch wire between adjacent spring coils, and the bending angle, length and radian of the lingual arm contained in the arch expansion component.

Preferably, the material parameters include one or more of the following parameters: the composition and properties of the material from which the arch-expanding component is made, and the cross-sectional form and size of the arch wire from which the arch-expanding component is made.

Preferably, the material parameter comprises a parameter of a material property that varies with temperature.

Further, the matching requirement in step S320 is: the deviation between the geometric parameter of the preset pantograph expander digital model and the target geometric parameter is smaller than a preset first threshold value, and the deviation between the actual pantograph expansion parameter of the preset pantograph expander digital model and the target pantograph expansion parameter is smaller than a preset second threshold value.

Further, step S330 specifically includes the following steps:

s331: generating an initial dental finite element model according to the initial dental digital model;

s332: generating an initial intermediate arch expander finite element model according to the target geometric parameters and the target arch expander parameters and setting initial values of material parameters of the intermediate arch expander finite element model;

s333: performing finite element calculation on the effect of the finite element model of the middle arch expander on the initial dental finite element model, wherein the calculation result comprises the actual arch expansion parameters of the middle arch expander and the morphological change condition of the initial dental finite element model;

s334: and optimizing the geometric parameters and the material parameters of the finite element model of the intermediate expander according to the result of the finite element calculation, repeating the finite element calculation until the calculation result meets the preset judgment condition and the calculation result meets the expansion constraint condition, and exporting the finite element model of the intermediate expander at the moment as a pre-activated expander digital model and exporting the material parameters of the intermediate expander digital model.

Preferably, the arch expansion constraint condition comprises one or more of the following conditions:

the constraint condition of the contact part of the middle dental arch expander finite element model and the initial dental finite element model, the biomechanical constraint condition of the initial dental finite element model for displacement under the action of arch expanding force and the limitation condition of the tooth root movement of the initial dental finite element model.

Preferably, the step S334 is followed by the steps of:

s335: and adding the optimized pre-activated pantograph expander digital model serving as a new preset pantograph expander digital model into a database, and storing corresponding actual pantograph expansion parameters, geometric parameters and material parameters in the database.

Another aspect of the present application provides a method of manufacturing a pre-activated expander, comprising the steps of:

the first step is as follows: designing a digital model of the pre-activated pantograph expander by using the design method of the pre-activated pantograph expander;

the second step is that: manufacturing a retention band ring and a bow-expanding component by utilizing a digital model of a pre-activated bow expander and corresponding material parameters;

the third step: assembling the retention belt ring and the arch expanding component on a target dental solid model to obtain a pre-activated arch expander matched with the target dental arch shape, wherein the target dental model is a solid model manufactured according to the target dental digital model.

Preferably, the third step is followed by the following steps:

the fourth step: the pre-activated expander is maintained in a configuration matching the initial arch configuration.

Optionally, the pre-activated arch expander is maintained in a configuration matching the initial arch configuration using the following steps:

applying a deforming force to a pre-activated arch expander to install it onto an initial dental mockup, the initial dental mockup being generated based on the initial dental digital model;

the pre-activated arch expander is maintained in a configuration matching the initial dental arch using a removable transfer template.

Optionally, the manufacturing material of the pre-activated arch expander is a material with shape memory effect and the human mouth temperature is within the transformation temperature range of the manufacturing material; the ambient temperature conditions for manufacturing and assembling the pre-activated expander are within the transformation temperature range of the manufacturing material;

the pre-activated arch expander is maintained in a configuration matching the initial arch configuration using the following steps:

mounting a pre-activated arch expander to an initial dental solid model, generated based on the initial dental digital model, at an ambient temperature condition outside of a transformation temperature range of the manufacturing material such that it remains in a configuration matching an initial dental arch configuration.

Another aspect of the present application provides a pre-activated arch expander comprising a retention band and an arch expanding member, the pre-activated arch expander being manufactured using the aforementioned pre-activated arch expander manufacturing method.

Yet another aspect of the present application provides a pre-activation expander manufacturing system comprising:

the design unit is used for designing a digital model of the pre-activated pantograph expander by using the design method of the pre-activated pantograph expander;

the production unit is used for manufacturing the retention belt ring and the bow expanding component by utilizing the digital model of the pre-activated bow expander and the corresponding material parameters;

and the assembling unit is used for assembling the retention belt ring and the arch expanding component on the target dental solid model to obtain the pre-activated arch expander matched with the target dental arch shape, and the target dental model is the solid model manufactured according to the target dental digital model.

The design method, the manufacturing method and the system of the pre-activated arch expander and the pre-activated arch expander provided by the embodiment of the application have the following beneficial effects:

(1) according to the technical scheme, the method comprises the steps of determining arch expansion amount parameters based on the difference of widths of corresponding parts of a target dental arch form and an initial dental arch form, generating a target dental digital model, using the target dental digital model as a design basis of pre-activating the overall geometric form of the arch expander, further determining target arch expansion force applied to a jaw to be corrected and material parameters of manufacturing materials required to be selected according to the target arch expansion amount, enabling the geometric form of the arch expander to be in a pre-activated state matched with the target dental arch form through the steps, and enabling the actual arch expansion force applied to the dental arch to meet a preset arch expansion force range, so that the defect that the existing arch expander needs to be continuously taken out of an oral cavity to adjust the shape during use is effectively overcome, and the use experience is greatly improved;

(2) the problem of expansion force loss caused by expansion of the dental arch in the expansion process is considered, and the actual expansion effect of the pre-activated expansion appliance and the expected expansion effect are more consistent by compensating the target expansion amount or the target expansion force and adjusting the target dental model.

(3) For patients with similar ages and/or similar dental arch characteristics, key parameters in the orthodontic schemes, such as arch expansion amount, arch expansion force and the like, are often relatively large in similarity, and geometric characteristics and mechanical characteristics of arch expanders designed and manufactured for the patients are also relatively similar, so that the orthodontic schemes of previous patients and corresponding arch expanders can often provide beneficial references for the current orthodontic schemes and the designs of the arch expanders, and the existing technology generally directly manufactures the arch expanders, but cannot improve the design and manufacturing efficiency by using the existing arch expanders. By retrieving the digital model of the preset expander stored in the historical case in the database, the model matched with the correction target can be rapidly retrieved, so that the design and manufacturing time of the pre-activated expander is greatly shortened;

(4) simulating the actual bow expansion effect of the bow expander by using a finite element method, and optimizing a finite element model of the bow expander according to the deviation from a design target, so that the error of design according to manual experience in the prior art is improved, and the bow expansion effect of the pre-activated bow expander is effectively improved;

(5) in the preferred embodiment of the present application, the method further comprises adjusting the shape of the pre-activated arch expander to an inactivated state matching the initial arch form and locking it by transferring the template; or using a material with a memory effect to manufacture the expansion bow part and keeping the expansion bow part in the unactivated state by controlling the temperature. The bow expander in the inactivated state manufactured by adopting the mode is more convenient and faster in clinical installation and use process, and can greatly improve the treatment efficiency and the comfort degree of product use.

Drawings

FIG. 1 is a schematic view of an expander according to the prior art;

FIG. 2 is a flow chart of a method of manufacturing a pre-activated expander according to an embodiment of the present application;

FIG. 3 is a schematic view of an initial dental digital model according to an embodiment of the present application;

FIG. 4 is a schematic diagram of determining a target arch curve, an initial arch curve, and a comparison of the two, according to an embodiment of the present application;

FIG. 5 is a schematic diagram of generating a digital model of a target dental jaw according to an embodiment of the present application;

fig. 6 is an implementation flow of step S300 according to an embodiment of the present application;

FIG. 7 is a schematic view of a pre-activated arch expander that matches a target arch configuration according to an embodiment of the present application;

FIG. 8 is a flowchart illustrating an implementation of step S320 according to an embodiment of the present disclosure;

FIG. 9 is a flowchart illustrating an implementation of step S330 according to an embodiment of the present disclosure;

FIGS. 10A-10C illustrate the morphology change (strain) of the initial dental finite element model under the effect of bowing during the finite element calculation process according to an embodiment of the present application;

FIG. 11 is a flow chart of a method of manufacturing a pre-activated expander according to an embodiment of the present application;

FIG. 12 is a schematic view of a pre-activated arch expander locked in an inactive state by a transferred template according to an embodiment of the present application;

fig. 13 is a system configuration block diagram of a pre-activation pantograph manufacturing system according to an embodiment of the present application.

Detailed Description

Hereinafter, the present application will be further described based on preferred embodiments with reference to the accompanying drawings. The exemplary embodiments mentioned in the description and the drawings are only for illustrative purposes and are not intended to limit the scope of the present application. It will be understood by those skilled in the art that many other embodiments may be employed and that various changes may be made to the described embodiments without departing from the spirit and scope of the present application. It will be readily understood that the aspects of the present application, as generally described and illustrated herein, could be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are encompassed within the present application.

In addition, various components on the drawings are enlarged or reduced for convenience of understanding, but this is not intended to limit the scope of the present application. In the description of the embodiments of the present application, if there is an orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", etc. based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship which is conventionally put when products of the embodiments of the present application are used, it is only for convenience of description and simplification of the present application, and it is not intended to indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present application.

In addition, to the extent that flow diagrams, functional descriptions, and method claims do not follow, the order in which the blocks are presented should not be limited to the various embodiments which perform the recited functions in the same order, unless the context clearly dictates otherwise.

In order to better explain the embodiments of the present application, we first briefly explain the design and manufacturing process of the existing expander. Fig. 1 shows an example of an arch expander installed on a dental model 100 in the prior art, and as shown in fig. 1, the arch expander generally comprises a retention band 210 and an expansion part 220, wherein the retention band is used for firmly fixing the arch expander on teeth, and the expansion part 220 comprises a plurality of spring coils 221, lingual arms 223 and a plurality of segments of arch wires 222 for connecting the spring coils and the lingual arms, and after the arch expander is installed on an upper jaw or a lower jaw, due to the deformation of the expansion part 220, an expansion force is generated on the teeth and alveolar bones under the action of a rebound force, thereby realizing the arch expansion effect.

The design and manufacture of the existing arch expander depend on the experience of doctors and technicians, and the doctors need to estimate parameters such as arch expansion amount, arch expansion force and the like according to the arch condition of the upper jaw and/or the lower jaw of a patient clinically and then activate arch expansion parts by themselves or teach the patient and parents to apply force by themselves. The design and manufacturing method of the existing bow expander at least has the following problems:

(1) under the condition that a target dental arch form is not available or a dental model in the target dental arch form is used as a reference basis, the arch expander is manufactured on an initial dental model only by the experience of doctors and technicians, the arch expander is activated only by the experience of the doctors during clinical application, and the size and direction of the actually generated correcting force and the parameters such as the arch expanding effect which can be realized after activation are difficult to determine whether to accord with the expected correcting scheme or not, so that the effect and safety of the arch expander in clinical use are difficult to predict, the effect and safety are difficult to monitor by doctors, and patients are also required to be well matched.

(2) For patients with similar ages and/or similar dental arch characteristics, the arch expansion parameters, such as arch expansion amount, arch expansion force and the like, in the correction scheme of the patients often have greater similarity, the geometric characteristics of the arch expanders designed and manufactured for the patients and the characteristics of the selected arch expander manufacturing materials are also similar, so that the correction scheme of the previous patients and the corresponding arch expanders can often provide beneficial references for the current correction scheme and the design of the arch expanders, and the existing technology generally directly manufactures the arch expanders, but cannot improve the design and manufacturing efficiency by using the existing arch expanders.

(3) Because the expander needs to be activated to apply force during the installation process and then installed in the mouth of a patient, the expander is easy to deform during the activation process, so that the matching degree with the jaw of the patient is poor, even force which is not beneficial to treatment is generated, and the unpredictability and the risk of curative effect are increased. Because of poor predictability and difficult risk estimation, force application is generally cautious when the current clinical arch expander is used, multiple times of repeated force application and disassembly of the orthopedic appliance are needed, or a patient needs to learn to apply force by himself, so that the use is not very convenient. Therefore, many doctors are willing to select the movable type arch expander, the time beside the chair of the doctors is reduced, the risk is reduced, but the movable type arch expander is large in size, poor in effect and capable of requiring more cooperation of patients, discomfort and treatment course of the patients are increased, and inconvenience is brought to the clinical treatment effect and patient management of children needing arch expansion correction.

To solve the above problems in the prior art, an aspect of the present application provides a design method of a pre-activated arch expander, the pre-activated arch expander includes a retention band and an expansion part, fig. 2 shows a flow chart of the design method of the pre-activated arch expander provided by the present application, and as shown in fig. 2, the design method includes the following steps:

The following describes steps S100 to S300 in detail with reference to the drawings and embodiments.

Step S100 is a process of determining target arch expansion parameters required for arch expansion of the dental jaw according to the initial dental digital model, specifically, the target arch expansion parameters include a target arch expansion amount and a target arch expansion force.

Fig. 3 is a schematic view of an initial digital model of a jaw according to an embodiment of the present application, wherein the initial digital model of a jaw can be obtained by various methods, for example, in some embodiments of the present application, a digitized three-dimensional model of a tooth, a periodontal tissue, an alveolar bone, etc. can be obtained by optical scanning, X-ray/ultrasonic imaging, CT scanning, or nuclear magnetic resonance, and the digitized three-dimensional model of each tissue site is further processed by denoising, filling holes, registering, etc. to obtain the initial digital model of a jaw, and the step of establishing the initial digital model of a jaw is known to those skilled in the art.

It should be noted that the initial dental digital model may only contain the geometric feature information of the initial dental, for example, in some embodiments of the present application, the initial dental digital model may be composed of triangular patches that do not contain thickness information; in addition, the initial digital dental model may also be a finite element model including information of physiological tissues and biomechanical characteristics of each part, for example, in other embodiments of the present application, the digitized three-dimensional model of each part may be filled to be integrated, and the finite element mesh may be divided according to a preset rule to form finite element units of different tissue parts such as teeth, periodontal tissues, alveolar bone, and the like, and finally, material parameters of the finite element units of each part are set respectively, where the material parameters may include parameters such as elastic modulus, poisson ratio, and the like, which reflect biomechanical characteristics of the tissue, and the initial finite element dental model is finally obtained. The above steps of establishing the initial dental finite element model are known to those skilled in the art.

The initial digital model of the jaw generated through the above steps represents the state of the jaw before the correction, and for a patient with a narrow dental arch, the initial dental arch form is usually in a shape of an acute circle, and in addition, some abnormal dental arch forms can exist. The process of performing arch expansion correction on the jaw is a process of gradually adjusting the jaw from an abnormal initial dental arch form to a target dental arch form by wearing an arch expander.

In some embodiments of the present application, by measuring the initial dental digital model, information representing the initial dental arch form can be obtained, and information representing the target dental arch form can be further obtained through arch analysis, and after the information is obtained, the target arch expansion amount can be determined according to the difference between the widths of the corresponding positions of the initial dental arch form and the target dental arch form.

In the field of orthodontic technology, dental arch curves are often used to qualitatively and quantitatively describe the form of dental arches, the dental arch curves reflect the curves similar to the arches formed by fitting characteristic points of each tooth on the dentition, obviously, the upper jaw and the lower jaw respectively have respective dental arch curves, and according to the form of the dental arches, the dental arch curves can be correspondingly divided into an initial dental arch curve (or called as an existing dental arch curve) and a target dental arch curve (or called as an ideal dental arch curve), and according to the difference of the widths of corresponding parts of the initial dental arch curve and the target dental arch curve, the target dental arch expansion amount can be conveniently and accurately determined. The following describes in detail an embodiment of determining the initial dental arch curve, the target dental arch curve by measuring the initial dental digital model and determining the target arch expansion amount by the difference of the widths of the corresponding portions of the initial dental arch curve and the target dental arch curve with reference to fig. 4.

Based on the size of the teeth, each patient had an ideal oval-shaped Bonwill arch curve for the upper and lower jaws. Comparing the existing Bonwill dental arch curve of the patient with the ideal Bonwill dental arch curve, wherein the difference value of the widths of the corresponding parts is the arch expansion amount required to expand the arch.

The most buccal contact points of the adjacent surfaces of No. 5 and No. 6 teeth on the left and right sides of the lower tooth are selected, the most buccal contact points are used as diameters to make a circle, and when the dental arch shape is an ideal oval shape, according to the Bonwill dental arch curve principle, the tooth cusps and incisal edges of the lower jaw from the No. 4 tooth on the left side to the No. 4 tooth on the right side are required to fall on the circular arc. Correspondingly, the occlusal contact points of No. 4 teeth from the left side to the right side of the lower jaw to No. 4 teeth on the upper dental arch are also distributed on an arc with equal size, namely, the connecting line of the central fossa of No. 5 teeth occlusal surface (the central fossa point of the upper jaw No. 5 teeth occlusal surface corresponds to the most buccal point of the contact points of the adjacent surfaces of No. 5 and No. 6 teeth) on the left side and the right side of the upper jaw is a circle with diameter, and the circle completely overlaps with the circle of the lower dental arch with ideal shape.

When the width of the dental arch is narrowed, a circle is drawn according to the rule, the diameter ratio of the circle is reduced when the dental arch is in an ideal dental arch form, the dental arch curve formed from the left side No. 4 tooth to the right side No. 4 tooth deviates from a circular arc, so that the dental arch presents an acute circular shape, or the dental arch curve is still basically kept on the circular arc, but the dentition is crowded. It is now necessary to widen the arch to the desired width to obtain clearance, restore arch morphology to the anterior of the adducted cusp-rounded arch curve, or expand the arch curve to align the dentition.

Specifically, in some embodiments of the present application, as shown in fig. 4, the target amount of arch expansion may be determined by:

(1) determining a target arch curve: the distances from the crown of 10 teeth from the left side No. 5 tooth to the right side No. 5 tooth of the lower jaw of the initial dental model to the proximal-distal-to-widest position are respectively measured, the distances are added to obtain the semi-circular arc length which an ideal Bonwill dental arch curve (namely a target dental arch curve) of the initial dental model should have, and then the radius of the semi-circular arc length is obtained, then the midpoint of a connecting line of the most buccal side contact points of the adjacent surfaces of the No. 5 and No. 6 teeth on the left side and the right side of the lower jaw is taken as the center of a circle, and a circle is drawn according to the radius of the ideal Bonwell dental arch curve obtained by calculation, so that a dental arch curve (namely the target dental arch curve which is represented by a dotted circle in figure 4) corresponding to the ideal dental arch form can be obtained.

(2) Determining initial dental arch curves corresponding to the lower jaw and the upper jaw respectively: connecting contact points of the most buccal sides of the adjacent surfaces of No. 5 and No. 6 teeth on the left side and the right side of the lower jaw of the initial dental digital model by using a straight line, drawing a circle by taking the midpoint of the connection of the two points as the center of a circle and the connecting line of the two points as the diameter, wherein the circle is the initial dental arch curve of the lower jaw; the center points of the left and right occlusal surfaces of No. 5 teeth of the upper jaw are connected by straight lines, and a circle is drawn by taking the center point of the connection of the two points as the center of the circle and the line connecting the two points as the diameter, and the circle is the initial arch curve of the upper jaw (the initial arch curves of the upper jaw and the lower jaw are shown by solid lines in fig. 4). In performing the arch analysis, the target arch curve may also be transferred to the corresponding position of the upper jaw as shown in fig. 4 to facilitate further comparative measurements.

(3) Respectively determining the target arch expansion amount of the upper jaw and the lower jaw: and calculating the width difference value of the target dental arch curve and the maxillary (or mandibular) initial dental arch curve at the corresponding position to obtain the target maxillary (or mandibular) arch expansion amount.

In some embodiments of the present application, the width of the target arch curve-the width of the upper jaw (or lower jaw) initial arch curve can be directly used as the overall arch expansion amount of the upper jaw (or lower jaw); in other embodiments of the present application, the width of the target arch curve-the width of the initial arch curve of the upper jaw (or lower jaw) can be used as the arch expansion amount of the rear part of the upper jaw (or lower jaw), and the arch expansion amount of the front part of the upper jaw (or lower jaw) or the arch expansion amount of the single side of the upper jaw (or lower jaw) can be adjusted according to the actual condition of the patient.

By using the multiple modes to express the target arch expansion amount, a more accurate arch expansion target can be formulated according to the specific arch form of the patient, and more accurate reference is provided for subsequent determination of arch expansion force and manufacture of the arch expander.

After the target expansion amount is determined through the above steps, it is necessary to further determine a target expansion force. The target arch expansion force characterizes a parameter of the orthodontic force that needs to be applied to the teeth to adjust the jaw from an initial arch configuration to a target arch configuration, and specifically, in some embodiments of the present application, includes a range and direction of values of the arch expansion force that are applied to each tooth by a one-time arch expansion.

In some embodiments of the present application, the amount and direction of the targeted arch expansion force applied to each tooth may have certain values; in other embodiments of the present application, the target arch expansion force applied to each tooth may also be expressed as a range of values for the magnitude and direction of a set of forces, i.e., arch expansion forces between the upper and lower limits of the range may all achieve the desired target arch expansion amount.

In the technical solution of the present application, the target expansion force may be determined in various ways, and specifically, in some embodiments of the present application, the target expansion force may be determined according to the principles of orthodontic mechanics based on the initial dental arch form and the target expansion amount;

in other embodiments of the present application, historical cases having similarities with patient age, dental condition, dental arch form, etc. may be retrieved from a database based on the initial dental arch form and the target arch expansion amount, and the realized arch expansion amount and the corresponding applied arch expansion force information may be obtained from the treatment plan recorded in the historical cases and used as a reference to determine the target arch expansion force;

in some further embodiments of the present application, the relationship between the amount of expansion and the force of expansion may be determined based on experimental measurement and/or clinical treatment result statistics, specifically, by counting the expansion force applied by the expander to the jaw of the patient and the expansion effect actually achieved after the expansion operation in a large number of clinical treatment cases, or by making a solid model that can simulate the whole jaw of alveolar bone, periodontal tissue and teeth, and using a film pressure sensor to experimentally measure the expansion force applied by the expander and the morphological change of the solid model of the jaw, the relationship between the amount of expansion and the force of expansion can be obtained, and the expression form of the relationship may be various, for example: a curve of the relationship between the amount of expansion and the force of expansion expressed in the form of a curve on a two-dimensional plane, or a relationship between the amount of expansion and the force of expansion expressed in the form of a function generated by polynomial fitting or the like. After the relationship between the expansion amount and the expansion force is obtained, the target expansion force required to be applied to realize the target expansion amount can be conveniently determined.

In some preferred embodiments of the present application, the step of adjusting the target expansion amount and/or the target expansion force according to one or more of the age, the development condition, and the type of malocclusion of the patient is further included in the process of determining the target expansion amount and/or the target expansion force, and specifically, due to the difference in age, the development condition, the type of malocclusion, and the like of different patients, the expansion amount and/or the expansion force need to be adjusted according to the specific conditions thereof in the process of determining the expansion amount and the expansion force so as to meet the actual expansion requirement.

In some preferred embodiments of the present application, in the process of determining the target amount of expansion and/or the target expansion force, the method further comprises the step of adjusting the target amount of expansion and/or the target expansion force according to expansion force loss.

The main reason for the loss of the expansion force is that after the expansion device is fixed to the jaw in the initial form to start expansion, the expansion force applied to the jaw by the expansion device is not constant, and gradually decreases as the dental arch is gradually expanded, and when the expansion force is insufficient to counteract the supporting force generated inside the dental tissue, the expansion effect cannot be continued on the jaw, and the actual expansion amount may be smaller than the target expansion amount. In addition, the expression rate of the expansion amount is related to various factors such as the length and shape of the tooth root of a patient, the biological response of the alveolar tissues to the expansion force, and the like, in addition to the attenuation of the expansion force, and thus, a clinician needs to comprehensively consider the expression rate according to the age, anatomical features, developmental conditions, and the nature and characteristics of the narrow arch of the patient. In some preferred embodiments of the present application, the above medical information and the factor of the reduction of the expansion force can be considered in a superimposed manner to obtain a more reasonable compensation of the expansion amount and the expansion force (it should be noted that the compensation of the expansion force should be performed by taking care that the compensated expansion force does not exceed a certain upper limit to avoid possible damage to the dental tissues), for example, in some specific embodiments of the present application, the compensation of the expansion amount at different parts of the jaw can be increased by 30% -50% according to the specific situation of the reduction of the expansion force, so as to obtain the compensated target expansion amount.

After the target arch expansion amount and the target arch expansion force are obtained through the steps, a target dental digital model is further obtained through the step S200, and the target dental digital model represents the condition of the dental jaw in the form of the target dental arch. An embodiment of generating a digital model of a target jaw is described below in conjunction with FIG. 5.

As shown in fig. 5, in some embodiments of the present application, an appropriate dental arch splitting line L (e.g., a straight line extending along the midsagittal direction in the figure) may be selected to split the initial dental digital model 110 (the initial dental digital model 110 in fig. 5 is specifically a digital model of the upper jaw) on the dental arch cross section, and the initial dental digital model is divided into a left part and a right part, and the left side and the right side are translated and opened according to the arch expansion amount obtained in the above step, so as to achieve the rear arch expansion amount; rotating the half-side dental arch by taking the central socket point of the occlusal surface of the No. 5 upper jaw tooth as the circle center until 1/3 points outside the mesial marginal crest of the maxillary canine (which are occlusion contact points corresponding to the upper and lower maxillary canine) fall on the curve of the target dental arch, thereby respectively realizing the arch expansion amount of the front part of the lower jaw and the front part of the upper jaw; and for the digital model of the lower jaw, rotating the half dental arch by taking the most buccal contact point of the adjacent surfaces of No. 5 and No. 6 teeth of the lower jaw as a circle center until the cusp of the cuspid tooth of the side falls on the curve of the target dental arch, and finally, performing operations such as filling, shape trimming and the like on the gap between the models generated after the translation and rotation operations to finally obtain the digital model 120 of the target dental arch in the form of the target dental arch.

Obviously, according to the specific situation of the initial dental arch form, a plurality of dental arch splitting lines in different directions can be arranged at different positions, so that the generated target dental jaw digital model can be more accurately fitted with the target dental arch form.

Furthermore, in some preferred embodiments of the present application, the pre-activated expander manufacturing method further comprises the step of adjusting the target dental digital model according to the expansion force attenuation (loss), the reason for adjusting the target dental digital model according to the expansion force attenuation is described in detail in the foregoing description, and is not repeated herein.

After the target arch expansion amount, the target arch expansion force and the target jaw digital model are determined through steps S100 to S200, respectively, the pre-activation arch expander digital model can be designed through step S300. Fig. 6 shows a specific implementation flow of step S300 according to an embodiment of the present application, and as shown in fig. 6, in some specific implementations of this embodiment, step S300 specifically includes the following steps:

The following describes steps S310 to S330 in detail.

Specifically, after the target dental digital model is generated, in step S310, the target geometric parameters of the pre-activated arch expander can be determined according to the overall shape of the target dental digital model and the characteristics of the shape, size, position, etc. of each tooth, and the material parameters of the manufacturing material can be determined according to the requirements on the target arch expanding force.

The target geometric parameter characterizes a geometric form to which the pre-activated arch expander corresponds when the pre-activated arch expander is used to adjust the jaw from an initial arch form to a target arch form, and in some embodiments of the present application may specifically include one or more of the following parameters: the number, shape and fixing position of the fixing belt rings (the fixing position of the fixing belt rings can be represented by tooth positions, the shape of the fixing belt rings can be represented by parameters such as the height of the belt rings, whether the belt rings cover the joint surface, whether the joint pads are added, whether the belt rings are connected with adjacent belt rings and the like), the number of the spring coils contained in the arch expansion component, the position, diameter and angle of each spring coil, the radian of an arch wire between the adjacent spring coils, and the bending angle, length and radian of a tongue side arm contained in the arch expansion component. With the above-mentioned geometric parameters determined, the key features of the geometry of the pre-activated expander are also determined, and fig. 7 shows a pre-activated expander that matches the target dental arch form (and is worn on the target dental digital model), wherein the positions of the retention band loops and the positions of the spring coils are determined by the calibrated key points N1-N6, respectively, after which the other geometric parameters can be further determined in combination with the morphological features of the target dental digital model.

In step S320, an expander digital model meeting the matching requirement is retrieved from a plurality of preset expander digital models stored in a database according to the target expander parameters and the target geometric parameters, and is used as a pre-activated expander digital model, and simultaneously, material parameters of the expander digital model are extracted for manufacturing of a subsequent pre-activated expander.

Wherein the material parameter characterizes a property of a manufacturing material used for the pre-activated pantograph, in particular a property related to the magnitude of the pantograph force, and may in particular comprise one or more of the following parameters: the composition and properties of the material from which the arch-expanding component is made, and the cross-sectional form and size of the arch wire from which the arch-expanding component is made. The arch expansion component can be made of metal, alloy and/or polymer materials which can be used for orthodontic treatment, obviously, the manufacturing materials with different components have different performances such as density, hardness, elastic modulus and the like, and meanwhile, the basic structure of the arch expansion component has different section shapes (such as the section of an arch wire can be rectangular, circular or elliptical) and sizes (such as the side length of the rectangle and the diameter of the circle) corresponding to different arch expansion forces.

In the field of orthodontic technology, as treatment cases are accumulated, a database for storing case information often stores a large amount of case data for arch expansion treatment using an arch expander, wherein each case data may include one or more of the following information: initial arch form of the jaw, target arch form, digital model of the expander used for treatment and its corresponding geometric parameters, material parameters and actual expansion parameters (i.e. information of expansion amount and expansion force actually achieved clinically using the expander or obtained by finite element calculation). In the design and manufacturing process of the pre-activated arch expander for the existing patient, if the digital model of the arch expander which can realize the same or similar arch expanding target and the corresponding material parameters can be directly retrieved from the database, the digital model can be directly used for manufacturing the pre-activated arch expander, thereby greatly shortening the design and manufacturing time.

Fig. 8 is a flowchart of step S320 according to a specific embodiment of this embodiment, and as shown in fig. 8, in some embodiments of the present application, a database is searched for whether there is a preset pantograph digital model meeting matching requirements based on the target geometric parameters and the target pantograph parameters, if the search result is true, the search result is saved as a pre-activated pantograph digital model, and if the search result is false, step S330 is executed.

By traversing the database, it can be retrieved whether there is a pre-activated pantograph which meets the matching requirement, in some preferred embodiments of this example, as shown in fig. 8, the matching requirement is that the deviation of the geometric parameter of the pre-set pantograph digital model from the target geometric parameter is smaller than a pre-set first threshold value and the deviation of the actual pantograph parameter of the pre-set pantograph digital model from the target pantograph parameter is smaller than a pre-set second threshold value.

Optionally, in order to retrieve a matched preset digital model of the expander, one or more parameters selected from the number, shape and fixed positions of the retention strap loops, the number of the spring coils, the position, diameter and angle of each spring coil, the radian of the arch wire between the adjacent spring coils, the angle, length and radian of the lingual arm included in the expander are selected and given corresponding weights according to the degree of influence on the overall shape of the expander, a weighted deviation function of the target geometric parameter and the geometric parameter of the preset digital model of the expander is further established, and whether the preset expander with the weighted deviation function smaller than a preset first threshold exists is retrieved from a database; meanwhile, whether a preset pantograph expander digital model with the deviation between the actual pantograph expansion parameter and the target pantograph expansion parameter smaller than a preset second threshold value exists or not can be searched in the same mode, if the preset pantograph expander digital model simultaneously meeting the two matching requirements exists, the preset pantograph expander digital model is directly used as a preset activated pantograph expander digital model, and corresponding geometric parameters and material parameters are saved for a subsequent manufacturing process.

In some embodiments of this embodiment, after obtaining the pre-activated digital model of the arch expander through the above-mentioned search, the pre-activated digital model of the arch expander can be further fine-tuned based on the target digital model of the jaw, for example, adjusting the shape of the retention band to make it more fit to the teeth for retention, or analyzing the contact condition of the arch expanding component and the oral tissue, and adjusting the shape of the arch expanding component according to the analysis result to avoid excessive contact with the upper jaw or the lower jaw of the oral cavity.

The above is merely an exemplary illustration of retrieving the pre-activated pantograph digital model from the database by using the matching requirement according to a preferred embodiment, in a specific implementation process, the matching requirement may be adjusted according to different expression forms of the target pantograph parameter and the target geometric parameter, for example, in some alternative embodiments, the target pantograph force in the target pantograph parameter is a set of value ranges determined by an upper limit value and a lower limit value, and the second threshold value should be set correspondingly according to the value range that the actual pantograph parameter of the pre-activated pantograph falls into.

The reason for searching in the database by jointly using the target geometric parameters and the target bow-expanding parameters is as follows: the target geometric parameters represent the overall morphological characteristics of the pre-activated arch expander, and the target arch expanding parameters represent the degree of change and force application conditions for the expansion of the dental jaw, for example, the overall sizes of the dental jaw of an adult patient and a child patient are obviously different, so that the target geometric parameters are greatly different, and the target arch expanding parameters can be similar; similarly, even if the target geometry to be achieved for both patients is the same, if the initial arch morphology of the two jaws is significantly different, the amount of arch expansion that needs to be achieved and the corresponding arch expansion force that needs to be applied will also vary, i.e., the target arch expansion parameters will differ significantly. Therefore, the matched digital model of the pantograph expander cannot be retrieved well only by the target geometric parameters or the target pantograph expansion parameters, and the parameters need to be used jointly to realize the accurate retrieval of the digital model of the preactivated pantograph expander.

If the matching digital model of the pre-activated pantograph expander cannot be retrieved from the database in step S320, the design and optimization of the digital model of the pre-activated pantograph expander needs to be performed by using the finite element method in step S330.

Further, in this embodiment, as shown in a specific implementation flow shown in fig. 9, step S330 further includes the following steps:

s334: and optimizing the geometric parameters and the material parameters of the finite element model of the middle arch expander according to the calculation result of the finite element calculation, repeating the finite element calculation until the calculation result meets the preset judgment condition and the calculation result meets the arch expansion constraint condition, and deriving the finite element model of the middle arch expander at the moment as a pre-activated arch expander digital model and deriving the material parameters of the finite element model.

The following describes steps S331 to S334 in detail.

Step S331 is used for generating an initial dental finite element model, and the specific implementation manner is already described in step S100 with respect to the initial dental digital model generating step, and will not be described herein again.

Step S332 of generating a finite element model of the intermediate arch expander for optimization and setting initial values, specifically, the initial values of the number, shape and fixing position of the retaining ring bands of the intermediate arch expander, the number of the spring coils included in the arch expander, the position, diameter and angle of each spring coil, the radian of the arch wire between the adjacent spring coils, the angle, length and radian of the tongue side arm included in the arch expander, and other parameters (i.e. the initial values of the geometric parameters of the finite element model of the intermediate arch expander) are determined) may be first set with reference to the target geometric parameters, so as to generate the initial three-dimensional model of the intermediate arch expander, and then the three-dimensional model of the intermediate arch expander is subjected to finite element mesh division, and then estimated material parameters are given to the three-dimensional model of the divided mesh as the initial values according to the target arch expander parameters, and the material parameters may include material components and material properties for manufacturing the arch expander, for example, the type of the material selected by the arch expander, the density, hardness, elastic modulus, poisson's ratio and other parameters of the material, and the material parameters also comprise the section form and size of the arch wire, namely the section form and size of the arch wire can be adjusted according to the target arch expansion parameters, and finally the intermediate arch expander finite element model for further optimization is obtained through the steps.

Step S333 performs finite element calculation using the intermediate arch expander finite element model and the initial dental finite element model to obtain the interaction result of the two. Techniques for obtaining stresses and strains caused by finite element model interactions using finite element calculation methods are known to those skilled in the art, and the above calculations can be performed using well-established finite element simulation software. Specifically, the intermediate expander finite element model may be assembled to the initial dental finite element model and set corresponding boundary conditions to constrain the motion pattern between the two, and then the interaction result of the two is obtained by finite element method calculation, for example, the calculation result may include the actual expansion parameters (including actual expansion force and actual expansion amount) generated by the intermediate expander finite element model acting on the initial dental finite element model, and the morphological change condition generated by the initial dental finite element model under the expansion action of the intermediate expander finite element model.

Specifically, in some embodiments of the present application, the degrees of freedom of some specific nodes on the intermediate arch expander finite element model may be limited, then the load is applied to the rest portion to strain the intermediate arch expander finite element model, the load application manner is adjusted, for example, the magnitude and direction of the load applied to different portions are adjusted, the intermediate arch expander finite element model is deformed to match the initial dental finite element model, the deformed intermediate arch expander finite element model is assembled to the initial dental finite element model, the degree of freedom limitation on the nodes and the load applied to the nodes are released, and at this time, the actual arch expanding force applied by the intermediate arch expander finite element model to the initial dental finite element model may be calculated by a finite element method.

FIGS. 10A to 10C respectively show the morphology change (strain) of the initial dental finite element model under the action of the arch expansion in the finite element calculation process. Because the initial dental finite element model is continuously deformed under the action of the arch expansion force applied by the intermediate arch expander finite element model, the stress and strain distribution condition is continuously changed in the whole calculation process, the stress and strain distribution condition can be updated at a certain time interval (for example, every other day), the finite element calculation can be stopped until the arch expansion force provided by the intermediate arch expander finite element model and the impedance force generated by the deformation of the periodontal tissue represented by the continuously changed initial dental finite element model reach a new mechanical equilibrium state, and at the moment, the difference between the dental arch form of the dental finite element model and the initial dental arch form reflects the actual arch expansion amount which can be realized by the intermediate arch expander finite element model. And (4) counting the actual bow expansion force distribution condition obtained by the calculation and the actual bow expansion amount condition to obtain the actual bow expansion parameters of the finite element model of the middle bow expander.

In some preferred embodiments of this embodiment, the material parameters of the intermediate expander finite element model include temperature-dependent parameters. Specifically, by setting the material parameters of the finite element model of the intermediate expander (e.g., the elastic modulus as a function of temperature), it can be used to calculate and verify the expansion effect of the expander made of a shape memory material (e.g., nitinol). The temperature memory material has the characteristic of recovering the initial shape of the temperature memory material within the transformation temperature range, and by utilizing the characteristic, the temperature of the middle arch expander finite element model can be adjusted, so that the middle arch expander finite element model is softer in the assembling stage and is easy to be attached to the initial dental finite element model, and the trend of recovering the initial shape of the middle arch expander finite element model is generated after the assembling is finished, so that the arch expanding force is generated on the initial dental model.

Step S334 is a step of optimizing the finite element model of the middle arch expander according to the finite element calculation result to obtain a digital model of the pre-activated arch expander meeting the design requirements.

Specifically, in some optional embodiments of this embodiment, the preset decision condition may be a limit on a deviation range between an actual bow expanding parameter and a target bow expanding parameter, which is implemented by the finite element model of the intermediate bow expander, that is: comparing the actual bow expanding parameters of the calculated finite element model of the intermediate bow expander with the expected target bow expanding parameters, if the deviation is larger than the defined range, adjusting the geometric parameters and/or the material parameters of the finite element model of the intermediate bow expander to obtain a new finite element model of the intermediate bow expander and carrying out the finite element calculation again, for example: if the actual arch expansion force or the actual arch expansion amount of the intermediate arch expander finite element model is smaller than the target value, the diameter of an arch wire of the arch expander can be increased, the position and the number of turns of a spring coil can be adjusted, and the elastic modulus of the arch expander material can also be increased, the step S333 is repeatedly calculated by using the adjusted new intermediate arch expander finite element model to obtain new actual arch expansion parameters and perform new comparison, the steps can be performed for multiple times until the deviation between the actual arch expansion parameters and the target arch expansion parameters is smaller than a limited range, the intermediate arch expander finite element model at the moment is determined as a pre-activated arch expander digital model, and corresponding material parameters are extracted for manufacturing of a subsequent pre-activated arch expander.

In addition, in the step of optimizing the finite element model of the intermediate pantograph expander, the influence of pantograph constraint conditions on the design of the pantograph expander needs to be considered, and in some embodiments of the present application, the pantograph constraint conditions include one or more of the following conditions: the constraint condition of the contact part of the middle dental arch expander finite element model and the initial dental finite element model, the biomechanical constraint condition of the initial dental finite element model for displacement under the action of arch expanding force and the limitation condition of the tooth root movement of the initial dental finite element model.

Specifically, in the process of expanding the dental jaw by the expander, if the parts of the expander, such as the spring coil, the arch wire and the like, are contacted with oral mucosa, gingival tissues and the like or even pressed, discomfort can be caused to a patient, and in a serious case, pain and inflammation can be caused; in addition, if the arch expander is not designed properly, the speed of displacement of the jaw under the action of the arch expanding force is too high, and the situations of discomfort, pain, even bone fracture and the like can also occur; in addition, if the position and direction of the action of the arch expanding force are not properly arranged, excessive inclination of the teeth to the labial and buccal sides and poor inclination of the tooth roots can be caused, and even the risk of breaking the bone is caused, so that in the process of calculating the interaction between the middle arch expander finite element model and the initial dental finite element model, if the calculation result violates the arch expanding constraint condition, the middle arch expander finite element model is correspondingly adjusted to meet the arch expanding constraint condition.

In some preferred embodiments of this embodiment, as shown in fig. 9, the step S334 further includes the following steps:

Compared with the existing bow expander manufacturing method, the steps S320 and S330 are respectively used for searching the digital model of the pre-activated bow expander and optimizing finite element calculation, and the method has the following remarkable advantages:

by retrieving the digital model of the preset expander stored in the historical case in the database, the model matched with the correction target can be rapidly retrieved, so that the design and manufacturing time of the pre-activated expander is greatly shortened; and the actual bow expansion effect of the bow expander is simulated by using a finite element method, and the finite element model of the bow expander is optimized according to the deviation from the design target, so that the error of design according to manual experience in the prior art is improved, and the bow expansion effect of the pre-activated bow expander is effectively improved.

Another aspect of the embodiments of the present application provides a method for manufacturing a pre-activated expander, and fig. 11 shows a flowchart of a method for manufacturing a pre-activated expander according to an embodiment of the present application, as shown in fig. 11, including the following steps:

Specifically, after a pre-activated arch expander digital model is obtained through the pre-activated arch expander design method, manufacturing materials are selected according to corresponding material parameters, the retention belt ring and the arch expanding component are manufactured through digital manufacturing technologies such as 3D printing and numerical control machine manufacturing, finally, the retention belt ring and the arch expanding component are assembled on the target dental jaw solid model through welding, bonding or other fixed connection modes, and finally the pre-activated arch expander matched with the target dental arch form is obtained. The target dental solid model is a solid model corresponding to the target dental digital model and can be manufactured through technologies such as 3D printing and numerical control machine tool manufacturing.

Compared with the prior art that a technician manufactures an arch expander on an initial model before treatment according to the requirements of a doctor design list, and then the doctor adjusts and activates the arch expander component in clinic, the manufacture of the arch expander on the target dental solid model can ensure that the arch expander is in a pre-activation state matched with the target dental arch form after the manufacture is finished, thereby effectively solving the problem that the existing technology cannot perform disposable arch expansion and needs to continuously adjust the form of the arch expander; meanwhile, the target dental jaw solid model is used as a reference, so that the manufactured arch expander, particularly the geometric form of an arch expanding component, can better meet the geometric parameters determined by the design requirements, and the actual arch expanding effect of the pre-activated arch expander is ensured to meet the expected arch expanding requirement; in addition, the arch expanding component is manufactured on the target dental solid model, so that the contact condition of the arch expanding component and soft tissues of the upper jaw, the lower jaw and the like can be observed in time and adjusted correspondingly, and the phenomena of pain, discomfort and the like caused by excessive contact with the parts in the using process of the arch expanding device are avoided.

The manufacturing of the pre-activated expander can be completed through the steps, and because the shape of the pre-activated expander is matched with the target expansion shape, in the actual use process, a doctor needs to apply force to the pre-activated expander to deform the pre-activated expander until the pre-activated expander is basically matched with the current dental arch shape of the patient so as to ensure that the pre-activated expander is installed on the dental jaw of the patient.

In order to improve the convenience and comfort of the installation process, in some preferred embodiments of the present application, after the steps are completed, the method further includes a fourth step of: the pre-activated expander is maintained in a configuration matching the initial arch configuration.

The form of the pre-activated arch expander is kept in a non-activated state matched with the original dental arch form through the fourth step, so that a doctor can conveniently and quickly wear the arch expander on the dental jaw of a patient, and then the arch expander is activated to start arch expanding operation, so that the assembly efficiency and the wearing comfort degree can be greatly improved.

Specifically, in some embodiments of the present application, as shown in fig. 12, a deforming force is applied to the pre-activated arch expander to mount it to the initial dental solid model (the initial dental solid model is a solid model corresponding to the initial digital dental model and can be manufactured by 3D printing, numerical control machine manufacturing, etc.), and then the pre-activated arch expander is maintained in a form matching the initial arch using a removable transfer template 300, and during actual use, after the doctor wears the above-mentioned expander in a non-activated state on the patient's jaw and ensures that both are firmly fixed, the transfer template 300 is removed to restore the expander to a pre-activated state.

The form of the transfer template may be various, for example, the transfer template 300 shown in fig. 12 may be coated on the side of the pantograph members away from the jaw with a photosensitive material, and cured by illumination after being coated to a certain thickness, that is, the pantograph is locked in the non-activated state; furthermore, one skilled in the art may also use mechanical snaps, latches, or cooperating hooks, wires, or any other structure that can lock and unlock.

In other embodiments of the present application, the material of construction of the pre-activated expander is a material having a shape memory effect and the human mouth temperature is within the transformation temperature range of said material of construction; the ambient temperature conditions under which the third step is carried out are within the transformation temperature range of the manufacturing material; the pre-activated arch expander is maintained in a configuration matching the initial arch configuration using the following steps: mounting a pre-activated arch expander to an initial dental solid model, generated based on the initial dental digital model, at an ambient temperature condition outside of a transformation temperature range of the manufacturing material such that it remains in a configuration matching an initial dental arch configuration.

Specifically, an alloy material having a shape memory effect, such as nitinol, may be selected as the material from which the preactivated expander is made, the material having a transformation temperature range close to the temperature of the human mouth and having the property of re-recovering to its original shape when the material changes shape outside its transformation temperature range and is re-recovered to within the transformation temperature range.

In making a pre-activated arch expander from the nickel-titanium alloy material, the pre-activated expander can be made when the ambient temperature is within the transformation temperature range of the nickel-titanium alloy material, and then the ambient temperature or the temperature of the pre-activated expander is adjusted to any temperature outside the transformation temperature range (e.g., room temperature) and the pre-activated expander is deformed to fit onto the initial dental solid model, at which temperature the pre-activated expander will maintain a shape that matches the initial dental arch form and not exert an expansion force on the initial dental jaw.

After the manufacturing of the pre-activated appliance is completed, the pre-activated appliance can be stored by using the temperature until the pre-activated appliance is clinically required to be installed on the jaw of a patient, because the pre-activated appliance also keeps a shape matched with the initial jaw, the pre-activated appliance can be easily installed on the jaw of the patient without applying force to deform the pre-activated appliance, after the installation is completed, the temperature of the pre-activated appliance gradually approaches to reach the oral cavity temperature of the patient, and because the oral cavity temperature is within the range of the metamorphosis temperature of the alloy material, the arch expanding component of the appliance changes to the shape corresponding to the target jaw due to the memory effect, so that the arch expanding force is generated, and the arch expanding effect on the jaw is realized.

It is specifically noted that the technology of making orthodontic appliances using shape memory materials (e.g., making shell appliances for aligning teeth using polymeric materials with shape memory effect) has been disclosed in a number of patents, however the procedure for making a pre-activated arch expander using shape memory materials in this application is significantly different from the prior art described above. The shell-shaped appliance made of the shape memory material is generally placed in hot water to be softened when being worn (no special requirement is made on the softened shape) so as to be conveniently worn on teeth, and the appliance gradually generates the appliance force after being cooled; the pre-activated expander of the present application deforms the alloy material having a shape memory effect outside its transformation temperature range to a form that matches the original dental jaw and maintains the form until the time of wear. The specific steps described above are taken in the manufacture and wear of the pre-activated expander of the present application because:

(1) different from the wearing mode that the shell-shaped appliance for aligning teeth can be integrally sleeved on the teeth in a softer state, the arch expander needs to accurately position the retention bands positioned at two sides when being worn so as to ensure the accuracy of the action positions and the action directions of the arch expander, therefore, the ideal wearing mode is to ensure that the arch expander is in a state matched with the initial arch form at the moment of wearing, thereby ensuring that the retention bands can be accurately and smoothly positioned at the correct positions.

(2) The shell-shaped appliance for aligning teeth has only a slight difference (generally about 0.25 mm) between the target shape and the initial shape of each correction stage in the correction process, so that the shell-shaped appliance does not generate obvious deviation by softening and then wearing the shell-shaped appliance on the teeth. The arch expansion amount of the arch expander to be realized is far larger than the offset of the shell-shaped appliance to teeth, if the same mode of softening the arch expansion part without limiting the softened form is adopted, the change process of the form of the arch expansion part, such as the position of a spring coil, the radian of an arch wire, the bending angle of a tongue side arm and the like, is uncontrollable in the process of gradually recovering the arch expansion force, the direction of the arch expansion force transmitted to a jaw is inevitably greatly deviated, and further the arch expansion amount of different parts is inconsistent with the designed value. Therefore, in manufacturing the pre-activated expander of the present application using a material with shape memory effect, it is necessary to maintain the correct application of the expansion force while the expander is easy to wear through the specific steps described above.

Another aspect of the present application provides a pre-activated arch expander comprising a retention band and an arch expanding member, the pre-activated arch expander being manufactured using the aforementioned pre-activated arch expander manufacturing method. The specific structure of the above-mentioned preactivated arch expander has been described in detail in the description of the design and manufacturing method of the preactivated arch expander, and is not described herein again.

Another aspect of the present application provides a pre-activation expander manufacturing system, as shown in fig. 13, comprising:

The above-mentioned specific embodiments of the units have been described in detail in the description of the method for manufacturing the pre-activated arch expander, and are not described herein again.

While the present invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof as defined in the appended claims.

Claims

1. A design method of a pre-activated arch expander, wherein the pre-activated arch expander comprises a retention band ring and an arch expanding component, and is characterized by comprising the following steps:

2. The pre-activated expander design method of claim 1, wherein:

the target arch expansion amount comprises one or more of the following parameters corresponding to adjusting the dental jaw from an initial arch form to a target arch form:

the upper jaw overall arch expansion amount, the upper jaw unilateral arch expansion amount, the upper jaw anterior tooth area arch expansion amount, the upper jaw posterior tooth area arch expansion amount, the lower jaw overall arch expansion amount, the lower jaw unilateral arch expansion amount, the lower jaw anterior tooth area arch expansion amount and the lower jaw posterior tooth area arch expansion amount.

3. The pre-activated expander design method of claim 1, wherein:

the target arch expansion amount is determined by the difference value of the widths of the corresponding positions of the initial dental arch form and the target dental arch form.

4. The pre-activated expander design method of claim 3, wherein:

and determining the difference value of the widths of the corresponding positions of the initial dental arch form and the target dental arch form based on the measurement of the initial dental digital model and the arch analysis.

5. The pre-activated expander design method of claim 1, wherein:

the target arch expansion force comprises the numerical value and the direction of the arch expansion force applied to each tooth corresponding to the adjustment of the jaw from the initial arch form to the target arch form.

6. The pre-activated expander design method of claim 1, wherein:

the method also comprises the step of adjusting the target expansion amount and/or the target expansion force according to the expansion force loss.

7. The pre-activated expander design method of claim 1, wherein the step S300 further comprises the steps of:

8. The pre-activation expander design method of claim 7, wherein the target geometric parameters include one or more of the following parameters:

the number, shape and fixing position of the retaining strap loops, the number of the spring coils contained in the arch expansion component, the position, diameter and angle of each spring coil, the radian of the arch wire between adjacent spring coils, and the bending angle, length and radian of the lingual arm contained in the arch expansion component.

9. The pre-activation expander design method of claim 7, wherein the material parameters comprise one or more of the following parameters:

the composition and properties of the material from which the arch-expanding component is made, and the cross-sectional form and size of the arch wire from which the arch-expanding component is made.

10. The pre-activated expander design method of claim 7, wherein:

the material parameters include a parameter of a material property that varies with temperature.

11. The pre-activated expander design method of claim 7, wherein the matching requirement in step S320 is:

the deviation between the geometric parameter of the preset pantograph expander digital model and the target geometric parameter is smaller than a preset first threshold value, and the deviation between the actual pantograph expansion parameter of the preset pantograph expander digital model and the target pantograph expansion parameter is smaller than a preset second threshold value.

12. The design method of the pre-activated expander according to claim 7, wherein the step S330 specifically comprises the steps of:

s334: and optimizing the geometric parameters and the material parameters of the finite element model of the intermediate arch expander according to the results of the finite element calculation, repeating the finite element calculation until the calculation results meet preset judgment conditions and the calculation results meet arch expansion constraint conditions, and exporting the finite element model of the intermediate arch expander at the moment as a pre-activated digital model of the arch expander and exporting the material parameters of the digital model.

13. The pre-activated expander design method of claim 12, wherein: the arch expansion constraint condition comprises one or more of the following conditions:

14. The pre-activated expander design method of claim 12, further comprising the following steps after said step S334:

15. A method of manufacturing a pre-activated expander, comprising the steps of:

the first step is as follows: designing a pre-activated pantograph digital model according to the pre-activated pantograph design method of any one of claims 1 to 14;

16. The method of manufacturing a pre-activated expander according to claim 15, further comprising the following steps after the third step:

the fourth step: the pre-activated arch expander is maintained in a configuration that matches the initial arch configuration.

17. The method of claim 16, wherein the pre-activated expander is maintained in a configuration matching the initial dental arch configuration using the steps of:

18. The method of manufacturing a pre-activated expander as recited in claim 17, wherein:

the manufacturing material of the pre-activated arch expander is a material with a shape memory effect, and the temperature of the oral cavity of a human body is within the transformation temperature range of the manufacturing material;

the ambient temperature conditions for manufacturing and assembling the pre-activated expander are within the transformation temperature range of the manufacturing material;

19. A pre-activated arch expander comprising a retention strap loop and an arch expanding member, characterized in that:

the pre-activated expander is manufactured using the pre-activated expander manufacturing method of any one of claims 15-18.

20. A pre-activation expander manufacturing system, comprising:

a design unit for designing a digital model of a pre-activated pantograph expander using the pre-activated pantograph expander design method according to any one of claims 1 to 14;