CN117017532A

CN117017532A - Combined personalized target dental arch curve modeling method and model

Info

Publication number: CN117017532A
Application number: CN202311062429.9A
Authority: CN
Inventors: 郑旭; 张佳超
Original assignee: Romo Technology Beijing Co ltd
Current assignee: Romo Technology Beijing Co ltd
Priority date: 2023-08-22
Filing date: 2023-08-22
Publication date: 2023-11-10

Abstract

The application provides a combined personalized target dental arch curve modeling method and model, wherein the modeling method comprises the following steps: respectively determining the relation between a first characteristic parameter and a second characteristic parameter of a specific dental jaw and an ideal arch according to the measurement data of a plurality of reference dental jaws, wherein the arch curves of all the reference dental jaws meet the ideal arch standard, and the first characteristic parameter and the second characteristic parameter are kept unchanged in one arch adjustment period of the specific dental jaw; generating a first curve and a second curve according to the relation between the first characteristic parameter, the second characteristic parameter and the ideal bow; and splicing the part of the first curve in the first dentition interval and the part of the second curve in the second dentition interval to obtain a personalized target dental arch curve of the specific dental jaw corresponding to at least one dental arch adjustment period. The technical scheme provided by the application can establish the target dental arch curve which better accords with the functions and development stages of the dental arch curve aiming at different positions of the dental jaw.

Description

Combined personalized target dental arch curve modeling method and model

Technical Field

The application belongs to the technical field of orthodontic treatment, relates to a target dental arch curve generation technology, and particularly provides a combined personalized target dental arch curve model and a modeling method.

Background

Bow correction refers to the operation of expanding, contracting and arching the dental arch by using various orthodontic appliances, provides a necessary basis for ideal arrangement of dental columns by adjusting the arching to ideal arching, and particularly for children/teenagers with oral deformity problems, if the arching has problems of too wide, too narrow or asymmetrical arches, the arching will cause and aggravate sparse, crowding, uneven arches, and have comprehensive effects on the morphology of upper and lower jawbones and facial muscles, and since the arching of the dental arch of children and teenagers is in a continuously changing stage along with the age, if the problem cannot be timely intervened, the effect of the pure dental columns will be poor or even ineffective, so how to determine an ideal arch or target arch (generally described by a target arch curve) that the dental jaw to be corrected should have is an important step in the orthodontic operation.

There are various methods for generating or determining ideal arches, for example, curves in the form of polynomial functions, beta functions, spline functions, etc. can be used to fit a real arch curve before treatment (corresponding to tooth arrangement state before treatment), then a curve which is more suitable for the real arch curve is selected from a plurality of established ideal arch curves (corresponding to a plurality of typical normal arch states), and then a doctor or technician performs personalized adjustment on the width, length, etc. of the curve based on the selected ideal arch curve according to treatment requirements, and finally a target arch curve (i.e. the arch desired to be achieved through treatment) is generated.

Although the above method can generate a personalized target dental arch curve according to the tooth arrangement situation of each patient, the process of adjusting the dental arch curve from the dental arch curve before correction to the target dental arch curve can only be manually carried out by virtue of the experience of doctors or technicians, and the above adjusting process does not consider the anchoring effect of the inherent characteristics irrelevant to the dental arch state in constructing an ideal dental arch curve, so that the generated personalized target dental arch curve is always more comfortable only in visual sense, and the curve shape of the personalized target dental arch curve cannot be ensured to meet the functional requirements of dental arch development and dentition arrangement, in addition, through analysis of a large number of normal dental arch shapes, different dental arch shapes are shown at different positions of the dental arch, and for children/teenagers, obvious differences exist between the development degree and development speed of the dental arch in different areas, so that the target dental arch curve more conforming to the functions and development stages of the dental arch is required to be established at different positions of the dental arch.

Disclosure of Invention

The application aims to solve the problems in the prior art and provide a combined personalized target dental arch curve modeling method and a dental arch curve model built by the combined personalized target dental arch curve modeling method.

A first aspect of the present application provides a combined personalized target dental arch model modeling method comprising the steps of:

respectively determining the relation between a first characteristic parameter and a second characteristic parameter of a specific dental jaw and an ideal arch according to the measurement data of a plurality of reference dental jaws, wherein the arch curves of all the reference dental jaws meet the ideal arch standard, and the first characteristic parameter and the second characteristic parameter are kept unchanged in one arch adjustment period of the specific dental jaw;

generating a first curve and a second curve according to the relation between the first characteristic parameter, the second characteristic parameter and the ideal bow;

and splicing the part of the first curve in the first dentition interval and the part of the second curve in the second dentition interval to obtain a personalized target dental arch curve of the specific dental jaw corresponding to at least one dental arch adjustment period.

Preferably, the first characteristic parameter is determined by a geometric feature of a first set of teeth, wherein the first set of teeth comprises a plurality of specific teeth of the upper or lower jaw of a specific dental jaw.

Preferably, the second characteristic parameter is determined by a geometric feature of a second set of teeth, wherein the second set of teeth is a proper subset of the first set of teeth.

Preferably, the first characteristic parameter, the second characteristic parameter are determined from different sets of teeth at different stages of development of a particular dental jaw.

Preferably, the first characteristic parameter is the sum of 5-5 crown widths of the mandible; and, the second characteristic parameter is a 2-2 crown width sum, a 3-3 crown width sum, or a 4-4 crown width sum of the mandible.

Preferably, the first characteristic parameter is the sum of 4-4 crown widths of the mandible; and, the second characteristic parameter is a 2-2 crown width sum or a 3-3 crown width sum of the mandible.

Preferably, the first dentition interval is left and right posterior dentition; and, the second dentition interval is an anterior dentition interval.

Preferably, the junction point of the first dentition interval and the second dentition interval is positioned in the projection area of the cuspids on the jaw plane.

Further, a first curve for a particular dental jaw is generated by:

determining a relation between a first characteristic parameter of a specific dental jaw and an ideal dental arch characteristic parameter of the specific dental jaw according to the measurement data;

determining the relation between the first curve of the specific dental jaw and the ideal dental arch characteristic parameter according to the measurement data;

the first curve represented by the first characteristic parameter of the particular dental jaw is determined from the relationship between the first characteristic parameter of the particular dental jaw and its ideal dental arch characteristic parameter and the relationship between the first curve of the particular dental jaw and its ideal dental arch characteristic parameter.

Preferably, the ideal arch characteristic of a particular dental jaw is related only to the ideal arch it has; and, the ideal arch characteristic of a particular dental jaw is statistically strongly correlated with its first characteristic.

Preferably, the ideal arch characteristic of a particular dental jaw is determined by the geometry of the arch curve when it is in an ideal arch.

Preferably, the ideal dental arch characteristic is the 5/6 abutment dimension of the mandible of a particular dental arch in an ideal arch.

Preferably, the first curve is a polynomial function of degree 2N and comprises only up to M even terms, wherein N, M is an integer and N.gtoreq.M.gtoreq.2.

Preferably, the coefficients of the M even terms are each statistically strongly correlated with the ideal arch characteristic parameters.

Further, the relationship between the first curve of a particular dental jaw and its ideal dental arch characteristic is determined according to the following steps:

obtaining an optimal dental arch curve of each reference dental jaw, wherein the optimal dental arch curve and a first curve of a specific dental jaw have the same function form, and coefficients of M even terms of the optimal dental arch curve are determined based on measurement data fitting of the reference dental jaw;

obtaining an intermediate dental arch curve of each reference dental arch, wherein the intermediate dental arch curve and a first curve of a specific dental jaw have the same function form, M even-order coefficients of the intermediate dental arch curve comprise M-1 fixed coefficients and an intermediate coefficient, wherein the M-1 fixed coefficients are determined according to the statistical value of the corresponding even-order coefficients in each optimal dental arch curve, and the intermediate coefficient is determined based on the measurement data fitting of the reference dental jaw;

And determining the relation between the first curve of the specific dental arch and the ideal dental arch characteristic parameters according to the statistical relation between the ideal dental arch characteristic parameters and the intermediate coefficients of each reference dental arch and the statistical relation between the intermediate coefficients of each reference dental arch and M even terms of the optimal dental arch curve, wherein the M even terms of the first curve are represented by the ideal dental arch characteristic parameters of the specific dental arch.

Preferably, the M-1 fixed coefficients are determined from the mean of the coefficients of the corresponding even terms in each optimal arch curve.

Preferably, the even term corresponding to the intermediate coefficient is the even term with the smallest frequency.

Preferably, the form of the polynomial function of degree 2N is:

Y＝AX ⁴ +BX ² ，

wherein X, Y is the coordinates of each point on the function curve and X, Y is on the jaw plane, and A, B is the coefficients of the fourth and second terms of the function curve.

Preferably, the second curve is a perfect circle, and the diameter of the perfect circle is statistically strongly correlated with the second characteristic parameter.

Preferably, the second curve is a beta function, and an integral parameter of the beta function is statistically strongly correlated with the second characteristic parameter.

Preferably, the combined personalized target dental arch curve further comprises a transition curve, and the first curve and the second curve are spliced through the transition curve.

Further, a transition curve is generated by:

intercepting a part of the first curve in the first dentition interval to a posterior tooth area by a specific length;

a transition curve is generated based on a fit of the remaining portion of the first curve to the portion of the second curve that is in the second dentition interval.

A second aspect of the present application provides a combined personalized target dental arch model for characterizing an ideal dental arch that a particular dental jaw should have;

the curve model is obtained by splicing a part of a first curve in a first dentition interval of a specific jaw and a part of a second curve in a second dentition interval of the specific jaw;

the first curve has a polynomial function form of 2N times and only comprises at most M even terms, wherein N, M is an integer, N is more than or equal to M and is more than or equal to 2, and coefficients of the M even terms are characterized by first characteristic parameters of a specific dental jaw;

the second curve is a perfect circle, and the diameter of the second curve is characterized by a second characteristic parameter of a specific dental jaw;

the first characteristic parameter and the second characteristic parameter are both maintained unchanged during an arch adjustment period of a particular dental jaw.

Preferably, the particular dental jaw further has an ideal arcuate characteristic parameter, the ideal arcuate characteristic parameter being related to the shape of the first curve of the particular dental jaw; and, the ideal bow characteristic parameter is statistically strongly correlated with the first characteristic parameter.

Preferably, the curve model is generated by the aforementioned combined personalized target dental arch curve modeling method.

According to the combined personalized target dental arch curve modeling method and the combined personalized target dental arch curve model established by the method, the attractive appearance and the functional requirements of dental arch forms are comprehensively considered, the differences of different positions of the dental arch in the development process are combined, the ideal forms of the different positions are respectively represented through different functional forms, the influence of subjective factors is eliminated, and the physiological development characteristics of the dental arch are more met on the basis of considering the attractive appearance and the functionality.

Drawings

FIG. 1 is a flow chart of a prior art personalized target dental arch curve generation method;

FIG. 2 is a flow chart of a combined personalized target dental arch curve modeling method provided in accordance with an embodiment of the application;

FIG. 3 is a graph showing the result of fitting a real dental jaw that meets the ideal arching criterion using a 4-degree function;

FIG. 4 is a dental chart of a mandible;

FIG. 5 is a flow chart of generating a first curve in accordance with some preferred embodiments of the present application;

FIG. 6 is a flow chart of determining a relationship between a first curve of a particular dental jaw and its ideal dental arch characteristic parameters in some embodiments;

FIG. 7 is a summary of a first curve of a plurality of reference dental jaws having an ideal arch configuration;

FIG. 8 is a flow chart of an embodiment of the present application;

FIG. 9 is a schematic diagram of establishing a jaw plane in accordance with an embodiment of the application;

FIG. 10 is a graph showing the result of coordinate adjustment of feature points of each reference dental jaw according to an embodiment of the present application;

FIG. 11 is a schematic illustration of measuring crown width of a reference dental jaw in accordance with an embodiment of the present application;

FIG. 12 is a schematic illustration of a measurement of 5-6 abutment dimensions of a reference dental jaw in accordance with an embodiment of the present application;

FIG. 13 is a summary schematic illustration of 5-6 abutment dimensions of respective reference dental jaws according to an embodiment of the present application;

FIG. 14 is a diagram of a statistical B according to an embodiment of the present application _adjust And A is a _best Schematic representation of the correlation;

FIG. 15 is a graph of A statistics according to an embodiment of the present application _best And B is connected with _best Schematic representation of the correlation;

FIG. 16 is a graph of 5-6 adjacent spot size and B as counted according to an embodiment of the present application _adjust Schematic representation of the correlation;

FIG. 17 is a schematic illustration of a orthotopic fit of the anterior dental region of a reference dental jaw in accordance with an embodiment of the present application;

FIG. 18 is a schematic diagram of a first curve and a second curve according to an embodiment of the application;

fig. 19 is a schematic view of a combined personalized target arch curve generated in accordance with an embodiment of the application.

Detailed Description

The present application will be further described below based on preferred embodiments with reference to the accompanying drawings.

In the description of the embodiments of the present application, it should be noted that, if the terms "upper," "lower," "inner," "outer," and the like indicate an azimuth or a positional relationship based on that shown in the drawings, or an azimuth or a positional relationship that a product of the embodiments of the present application conventionally put in use, it is merely for convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element to be referred to must have a specific azimuth, be configured and operated in a specific azimuth, and thus should not be construed as limiting the present application. Furthermore, in the description of the present application, terms first, second, etc. are used herein for distinguishing between different elements, but not limited to the order of manufacture, and should not be construed as indicating or implying any relative importance, as such may be different in terms of its detailed description and claims. Furthermore, various structures on the drawings are exaggerated or reduced for ease of understanding, but such is not intended to limit the scope of the present application.

FIG. 1 is a flow chart showing a prior art method for generating a personalized target dental arch curve, as shown in FIG. 1, in the process of implementing the method, firstly, characteristic points of teeth (such as a mid-incisor and side-incisor edge midpoint, a cuspid point, a first premolars and a second premolars cuspid point, a first molar and a second molar near-mid-cheek cuspid point, a far-mid-cheek cuspid point, etc.) are selected from a dental jaw model to be corrected through step 110, and then curve fitting is performed through the characteristic points to obtain a real dental arch curve of upper jaw and lower jaw in the form of a polynomial function, etc., which represents a dental arch form before treatment (i.e., in a malformed state); further, in step 130, a standard dental arch curve which is relatively matched with the real dental arch curve is searched by using a pre-established standard dental arch curve library to serve as a basis for generating a target dental arch curve; finally, in step 140, the physician or technician adjusts the standard dental arch curve according to his own experience and the treatment requirements, and finally generates the target dental arch curve.

Although the method can generate the target dental arch curve individually aiming at different dental jaws to be corrected, on one hand, the method starts from the dental arch curve in a malformed state before treatment, and an experienced doctor or technician adjusts the dental arch curve manually and empirically to obtain a result, so that the effect is obviously dependent on the experience of an operator; on the other hand, although the generation of the true dental arch curve utilizes the mark points on the dental arch to be corrected, the idea of determining the target dental arch curve later is to draw the dental arch form to be corrected to one of a plurality of predetermined ideal dental arch forms, rather than generating a real personalized target dental arch from the inherent characteristics of the dental arch to be corrected, more manifestations are that an operator (or the operator and a patient can simultaneously make the operator and the patient feel the dental arch form with ideal subjective feeling, and the dental arch form cannot be guaranteed to meet the objective rule and the function requirements of dental development and dental row arrangement.

In particular, the applicant found by statistical analysis of a large population with normal oral conditions: although a common four-time function curve and the like can be used for fitting a dental arch with aesthetic degree and function conforming to the standard, the curve is realized through mathematical error minimization to a greater extent, however, different areas (such as an anterior dental area and a posterior dental area) of the actual dental jaw can show different development and change trends in different stages of growth and development, so that the dental arch curve overall presents a composite form, is difficult to characterize through a single type of curve function, and the dental arches of different areas are respectively described through different types of curves; meanwhile, the ideal dental arch shapes in different areas have strong correlation with certain inherent morphological characteristics of the dental jaw respectively, so that the personalized target dental arch curve which is truly in one-to-one correspondence with each specific dental jaw can be obtained from the inherent shapes.

Based on the above considerations, embodiments of the present application provide a combined personalized target arch curve modeling method for creating a target arch curve for any particular dental arch during at least one arch adjustment cycle, wherein the particular dental arch may be any dental arch that requires an arch adjustment operation, such as an expansion, contraction or arch asymmetry correction operation, due to an oral deformity problem.

In addition, there may be a plurality of adjustment cycles for the adjustment of the dental arch, for example, for children and teenagers whose dental arch is in a developmental stage, the dental arch itself is continuously growing during the adjustment of the dental arch thereof, and thus the dental arch adjustment process thereof may include a plurality of adjustment cycles in each of which the development condition of the dental arch itself is substantially maintained in conformity, and one target dental arch curve may be used as an adjustment target for the stage.

In some preferred embodiments, as shown in FIG. 2, the method includes the steps of:

step 210: respectively determining the relation between a first characteristic parameter and a second characteristic parameter of a specific dental jaw and an ideal arch according to the measurement data of a plurality of reference dental jaws, wherein the arch curves of all the reference dental jaws meet the ideal arch standard, and the first characteristic parameter and the second characteristic parameter are kept unchanged in one arch adjustment period of the specific dental jaw;

step 220: generating a first curve and a second curve according to the relation between the first characteristic parameter, the second characteristic parameter and the ideal bow;

step 230: and splicing the part of the first curve in the first dentition interval and the part of the second curve in the second dentition interval to obtain a personalized target dental arch curve of the specific dental jaw corresponding to at least one dental arch adjustment period.

The method is characterized in that a relation between a first characteristic parameter and a second characteristic parameter which are inherent to any specific dental arch and an ideal dental arch is established, and for the specific dental arch which needs to be subjected to dental arch adjustment, the first characteristic parameter and the second characteristic parameter characterize the morphological characteristics of the dental arch, and the first characteristic parameter and the second characteristic parameter do not change due to the change of the dental arch morphology in a dental arch adjustment period, so that the relation between the first characteristic parameter and the second characteristic parameter and the ideal dental arch can be determined as an anchoring standard, and a personalized target dental arch curve which corresponds to the specific dental arch one by one is established by utilizing the relation, so that subjective factor influence in the process of manually adjusting and generating the target dental arch curve can be obviously eliminated, and dental function and development rules are more met.

In the embodiment of the present application, the reference dental jaw refers to a dental jaw which is evaluated by a pre-specified ideal arch standard (for example, by taking the overall form of a dental arch curve, or the geometric parameters of characteristic mark points, etc. as the standard, and the establishment of the standard considers both aesthetic and functional aspects), and meets the standard, and represents a group of people with normal and ideal arrangement of dental arches and dental columns in the group of people. Various technical means known to those skilled in the art, such as CBCT, ultrasound, three-dimensional oral scanning, and the like, may be used to model, measure, and the like, the morphology of the plurality of reference dental jaws, and further obtain various measurement data thereof. Furthermore, the number of reference dental jaws should be sufficiently large to meet the criteria for performing correlation statistics. The above embodiments are known to those skilled in the art and will not be described in detail herein.

In the embodiment of the application, a first curve is generated according to the relation between a first characteristic parameter and an ideal arch, a second curve is generated according to the relation between a second characteristic parameter and the ideal arch, then the part of the first curve in a first dentition interval and the part of the second curve in a second dentition interval are respectively spliced, and the parts of different curves in different dentition intervals are spliced to obtain a combined dental arch curve, which is mainly based on the following considerations:

1) The arch state is described simply by using a curve of a functional form, such as a beta function curve, a fourth order term curve, etc., and although a fitting parameter which satisfies the minimum cost function as a whole can be found mathematically, the shape may be different from the optimal shape conforming to the functional and developmental characteristics in a part of dentition, such as an anterior dentition. Fig. 3 shows the result of fitting a real tooth jaw meeting the ideal tooth bow state standard by using a 4-degree function, and as shown in fig. 3, although the tooth bow curve obtained by fitting can meet the condition that the overall cost function of each mark point on the tooth row is minimum, the curve shape of the front tooth area is more similar to a rounded trapezoid, however, according to the analysis of the geometric characteristics of each front tooth of the tooth jaw (such as the crown width of the left 3 # tooth to the right 3 # tooth), the arrangement of the front teeth is found to be more similar to a circle, and obviously, by describing the curves of different function forms for different tooth row areas, although the curve of the tooth bow with non-minimized cost function can be obtained mathematically, the function requirement of the tooth bow shape is met.

2) For the crowd in the development stage of the dental arch, the dental arch not only presents different dental arch forms in each area, but also presents obvious differences in development speed and development state in the development process of the dental arch in each area, the relationship between ideal dental arch forms of each area is continuously changed, and the characteristics that the ideal dental arch curve is changed in stages and in different areas are formed on the whole, therefore, the combined personalized target dental arch curve of the specific dental arch is required to be established in stages and in different dental row areas, and the combined personalized target dental arch curve can be more attached to the development characteristics of the dental arch.

Specifically, the first characteristic parameter and the second characteristic parameter both characterize the inherent characteristic of any specific dental jaw in a dental arch adjusting period, and the characteristic is irrelevant to the dental arch state in the adjusting period, namely whether the dental arch is in an ideal arch state of the dental arch adjusting period or not at the moment, and the values of the first characteristic parameter and the second characteristic parameter remain unchanged in the dental arch adjusting period.

Accordingly, in different development stages of the jaw, the eruption time and the eruption speed of different teeth are different, for example, the tooth replacement period is generally from 5 to 6 years old until the end of about 12 years old, and during this period, the deciduous teeth are not shed and the eruption and the growth of the permanent teeth are performed simultaneously and synchronously, so that in some specific embodiments, the values of the first characteristic parameter and the second characteristic parameter need to be comprehensively considered in different dental arch adjustment periods, and are determined according to the characteristics of different dental sets.

In some preferred embodiments, the first characteristic parameter is determined by a geometric feature of a first set of teeth, wherein the first set of teeth comprises a plurality of specific teeth of the upper or lower jaw of a specific dental jaw. The second characteristic parameter is determined by the geometric features of a second set of teeth, wherein the second set of teeth is a proper subset of the first set of teeth, i.e. the first set of teeth comprises and more than all teeth of the second set of teeth. A specific embodiment for determining the first characteristic parameter and the second characteristic parameter is described below with reference to the drawings.

Fig. 4 shows a specific mandibular dental chart, the plane of which is the jaw plane, as shown in fig. 4, in some preferred embodiments, the first set of teeth may comprise a total of L5 to R5 teeth, accordingly, the first characteristic parameter is the sum of the 5-5 crown widths of the mandible, i.e., the sum of the crown widths of the L5 to R5 teeth in fig. 4 (it should be noted that in the present application, the sum of n1-n2 crown widths refers to the result of measuring the crown width of each tooth from the Ln1 tooth on the left side to the Rn2 tooth on the right side of the maxilla or mandible, and obtaining and superposing the crown widths of the teeth), the second set of teeth is a proper subset of the first set of teeth, which may comprise a total of 4 teeth from L2 to R2, and accordingly, the second characteristic parameter is the sum of the crown widths of the L2 to R2 teeth in fig. 4; in addition, the second set of teeth may also comprise a total of 6 teeth from L3 to R3, or a total of 8 teeth from L4 to R4, and accordingly the second characteristic parameter is the 3-3 crown width sum or the 4-4 crown width sum of the mandible.

In other embodiments, when the L5 and R5 teeth have not erupted or reached a stable state, they cannot be used as stable references, and thus are excluded when generating the target arch curve, thereby determining the first set of teeth as L4 to R4 total 8 teeth of the mandible, the second set of teeth as L3 to R3 total 6 teeth of the mandible, or L2 to R2 total 4 teeth, and accordingly, the first characteristic parameter is the sum of 4-4 crown widths of the mandible, and the second characteristic parameter is the sum of 3-3 crown widths or 2-2 crown widths of the mandible.

As described above, the first characteristic parameter and the second characteristic parameter are determined based on the fact that the first characteristic parameter and the second characteristic parameter reflect the inherent characteristic of a specific dental jaw in a certain dental development stage, that is, the inherent characteristic is not changed due to whether the dental arch state is in an ideal arch or not in the dental development stage; at the same time, the first and second characteristics are determined from different sets of teeth at different stages of development of the jaw.

Further, as shown in fig. 4, in a preferred embodiment of the present application, the first dentition interval is a left-side and right-side posterior dentition region, and the second dentition interval is an anterior dentition region, wherein, preferably, the boundary point between the first dentition interval and the second dentition interval is located in the projection area of the cuspids (i.e., the L3 teeth and the R3 teeth in fig. 4) on the jaw plane.

The steps for generating the first curve and the second curve are described in detail below with reference to the drawings.

(1) A first curve is generated.

FIG. 5 illustrates a flow chart for generating a first curve in some embodiments of the application, as shown in FIG. 5, by:

step 310, determining the relation between the first characteristic parameter of the specific dental jaw and the ideal dental arch characteristic parameter according to the measured data;

step 320, determining the relation between the first curve of the specific dental jaw and the ideal dental arch characteristic parameter according to the measured data;

step 330, determining a first curve represented by the first characteristic parameter of the specific dental jaw according to the relation between the first characteristic parameter of the specific dental jaw and the ideal dental arch characteristic parameter thereof and the relation between the first curve of the specific dental jaw and the ideal dental arch characteristic parameter thereof.

The ideal dental arch characteristic parameter characterizes a characteristic which can be found on a specific dental arch when the specific dental arch is in an ideal dental arch shape and is only related to an ideal dental arch curve, namely, if a specific value of the ideal dental arch characteristic parameter is determined, the dental arch curve used for describing the target dental arch state can be determined simultaneously, and meanwhile, the ideal dental arch characteristic parameter is an objective statistic which is independent of experience of doctors or technicians and excludes subjective factors because the ideal dental arch characteristic parameter comes from statistics of reference dental jaws of a crowd which simultaneously meets normal aesthetic and functional standards.

For a particular dental jaw, the ideal dental arch characteristic can be determined by the geometry of the arch curve when it is in the ideal arch, e.g., in some preferred embodiments, the ideal dental arch characteristic is the 5/6 abutment dimension when the mandible is in the ideal arch. In the present application, the m1/m2 abutment dimension refers to the distance between the abutment points of the m1 st tooth and the m2 nd tooth on both sides of the upper jaw or lower jaw, and the 5/6 abutment dimension refers to the distance between the abutment points of the L5 th and L6 th teeth on the left side and the abutment points of the R5 th and R6 th teeth on the right side, as exemplified in fig. 4.

In an embodiment of the application, for any particular dental arch, its ideal dental arch characteristic is statistically strongly correlated with its first characteristic, i.e. when a particular dental arch is arcuately adjusted, its first characteristic is always constant during one of the arch adjustment periods and can be measured before the start of the arch adjustment period, whereas its ideal dental arch characteristic corresponds to the target state at the end of the correction period, until the dental arch state of the particular dental arch reaches the ideal state of the arch adjustment period, its ideal dental arch characteristic is actually realized.

Because the first characteristic parameter has strong correlation with the ideal dental arch characteristic parameter, a relation between a real-time measurable quantity and an objective target quantity excluding subjective influence factors can be established, namely, when the first characteristic parameter is measured for any specific dental jaw, the objective correction target is determined by the ideal dental arch characteristic parameter, and therefore, the first curve is also determined.

In the embodiment of the application, the first curve represents the main form of the ideal dental arch and the dentition arrangement, and various curve functions can be used for describing the main form, so that the relation between the characteristic parameter of the ideal dental arch and the first curve is the relation between the characteristic parameter of the second curve and the coefficient of a proper curve function, and research finds that the smooth ideal dental arch curve can be better described by using a polynomial function curve compared with a Beta function curve, therefore, in the preferred embodiment of the application, the first curve is a polynomial function of 2N times and only comprises at most M even terms, wherein N, M is an integer and N is equal to or greater than M.

For example, in one particular embodiment, the first curve may be represented using the following fourth degree polynomial:

Y＝AX ⁴ +BX ² ，

Wherein X, Y is the coordinates of each point on the curve and X, Y is located on the jaw plane, the X axis and the Y axis are orthogonal, the Y axis corresponds to the projection of the median sagittal plane on the jaw plane, A, B is the coefficients of the fourth term and the second term of the curve, and only the even term is included to ensure symmetry of the curve relative to the Y axis. The first curve in the above form is a curve on a two-dimensional plane, which includes two coefficients A, B that can adjust the shape of the curve, so that by counting the dental arch curves of a plurality of reference dental jaws, a specific expression of the relationship between the ideal dental arch characteristic parameters and A, B can be obtained.

It should be appreciated that the polynomial expression of the fourth degree term is only one specific embodiment, and in some other embodiments, the first curve may also be a sixth degree polynomial and include at least two multiple degree terms, such as a sixth degree term and a quadratic term; in some other embodiments, the first curve may also be in the form of a three-dimensional curve.

By analysing the measured data of the plurality of reference dental arches it has been found that, since the first curve comprises at least two polynomial coefficients which together influence the shape of the curve and whose influence is coupled to each other such that no significant correlation between the polynomial coefficients and the ideal dental arch characteristic parameters occurs, an intermediate dental arch curve is required by which the relation between the ideal dental arch characteristic parameters and the respective polynomial coefficients is established, for which purpose, in some preferred embodiments, the relation between the first curve of any one particular dental arch and its ideal dental arch characteristic parameters can be determined by the following steps, as shown in fig. 6:

Step 321, obtaining an optimal dental arch curve of each reference dental jaw, wherein the optimal dental arch curve and the first curve have the same function form, and the coefficients of M even terms of the optimal dental arch curve are determined based on the measurement data fitting of the reference dental jaw.

Specifically, the corresponding optimal arch curve can be fitted from the measured data of each reference dental jaw by methods known to those skilled in the art.

And step 322, obtaining an intermediate dental arch curve of each reference dental arch, wherein the intermediate dental arch curve and the first curve have the same functional form, and M even-order coefficients comprise M-1 fixed coefficients and an intermediate coefficient, wherein the M-1 fixed coefficients are determined according to the statistical value of the corresponding even-order coefficients in each optimal dental arch curve, and the intermediate coefficient is determined based on the measurement data fitting of the reference dental arch.

Specifically, when m=2, statistics is firstly performed on one even term coefficient in multiple groups of optimal dental arch curves, a statistical value, such as a mean value, is obtained as a fixed coefficient of the even term, and then, under the condition that the fixed coefficient of the even term is unchanged, an intermediate dental arch curve of each reference dental jaw is obtained by fitting, and obviously, the other even term coefficient (i.e. the intermediate coefficient) of the intermediate dental arch curve is different for different reference dental jaws. In this way, an optimal dental arch error with each reference jaw can be obtained which is sufficiently small, but which contains only one intermediate dental arch of variable coefficients.

Through correlation statistics, the variable intermediate coefficient is found to be strongly correlated with the two polynomial coefficients of the optimal dental arch curve and the ideal dental arch characteristic parameters respectively, so that the variable intermediate coefficient can be used as a bridge to establish the relationship between the ideal dental arch characteristic parameters and the coefficients of the polynomials, and therefore in step 330, the M even term coefficients of the first curve of the specific dental arch represented by the ideal dental arch characteristic parameters can be determined according to the statistical relationship between the ideal dental arch characteristic parameters and the intermediate coefficient of each reference dental arch and the statistical relationship between the intermediate coefficient of each reference dental arch and the M even terms of the optimal dental arch curve.

Through correlation statistics, it is found that, in the dental arch curve represented by the polynomial function, the coefficient of the higher order term is generally smaller by two orders of magnitude, that is, the coefficient of the lower order term varies significantly more than the coefficient of the higher order term, and the coefficient of the higher order term determines the basic shape of the curve, and the coefficient of the lower order term causes the difference in curve details, so that, in the preferred embodiment, the intermediate coefficient should be selected from the lower order terms (such as the smallest even order term) to improve the statistical correlation as much as possible.

In the above description, a polynomial function comprising two polynomials is taken as an example, and when M is greater than 2, the same procedure may be used, for example, to fix the coefficients of M-1 polynomials, obtain an intermediate dental arch curve with a variable intermediate coefficient, and calculate the correlation between the intermediate coefficient and the polynomial coefficients of each set of optimal dental arch curves.

After finding the ideal dental arch characteristic parameter and the first characteristic parameter and the statistical relationship between the ideal dental arch characteristic parameter and each polynomial coefficient of the first curve through the steps 321 and 322, respectively, the relationship between the first characteristic parameter of the specific dental arch and each polynomial coefficient of the first curve can be established in step 323, and the first characteristic parameter is the constant quantity of the specific dental arch in one dental arch adjustment period, so the method can automatically generate the first curve through the measurable data of the dental arch before the dental arch adjustment period.

(2) A second curve is generated.

Fig. 7 shows the result of summing a plurality of first curves of reference dental jaw having an ideal arch shape, wherein each of the first curves is aligned with the anterior abutment as the origin.

In fig. 7, three black circles are intersections of each first curve, wherein the left and right intersections are respectively located in the projection area of the L3 teeth and the R3 teeth on the jaw plane, and the intersections represent a trend that each first curve develops to the left and right in the front tooth area, so that the front tooth area presents a trend of rounded trapezium, however, clinical studies on the function and development characteristics of the dental arch form show that the arrangement of each tooth in the front tooth area is closer to a perfect circle, and therefore, in the preferred embodiment of the present application, the target dental arch curve is described as a circular second curve in the front tooth area and is described as a first curve in the form of a polynomial function in the rear tooth area.

In particular, in the embodiment of the application, the diameter of the perfect circle of the second curve is statistically strongly correlated with the second characteristic parameter, so that after the measured value of the second characteristic parameter is obtained, the second curve characterized by the second characteristic parameter can be obtained.

Furthermore, in some alternative embodiments, a beta function may also be used as the second curve, and accordingly, the integral parameter of the beta function is statistically strongly correlated with the second characteristic parameter.

(3) And splicing the first curve and the second curve.

After the first curve and the second curve are obtained through the above steps, in step 230, the portion of the first curve located in the first dentition interval and the portion of the second curve located in the second dentition interval are spliced, so that the personalized target arch curve of the specific dental arch corresponding to at least one arch adjustment period can be obtained.

Since the first curve and the second curve may be offset at the interface between the first dentition interval and the second dentition interval, in some preferred embodiments, the truncated first curve and the second curve are connected by a transition curve, wherein the transition curve may be generated by:

It should be noted that the specific length of the cut-out should not be too small to avoid causing severe turning when the first curve is spliced with the second curve, nor too large to avoid excessively large deviation of the morphology of the fitted target curve caused by excessive cutting-out, and in some preferred embodiments, the specific length of the cut-out is equal to or greater than the crown length of the first premolars and equal to or less than 10mm.

A specific embodiment of the present application will be described below with reference to the accompanying drawings, and fig. 8 shows a specific flow of this embodiment, and as shown in fig. 8, this embodiment includes the following steps:

step A, a three-dimensional digital model of a reference dental jaw is obtained, and characteristic points are marked:

in the embodiment, firstly, 55 groups of dental three-dimensional digital models meeting ideal dental arch state standards are obtained as reference dental, data statistics analysis is carried out, and statistics shows that the target dental arch curve of the lower jaw is outwards shifted by 2.5mm to obtain an upper jaw target dental arch curve meeting aesthetic and functional requirements, so that the generation of the target dental arch curve of the lower jaw is only carried out in the embodiment;

After the three-dimensional digital model of the mandible is obtained, a plurality of characteristic points can be identified on the reference dental jaw in a manual or automatic labeling mode, the characteristic points can be dental cusp points on crowns of specific teeth, near middle buccal cusp points or far middle buccal cusp points and other specific position points on each dental jaw known to a person skilled in the art, for example, the incisor midpoints of the left and right teeth 1, the incisor midpoints of the left and right teeth 2, the dental cusp points of the left and right teeth 3, the buccal cusp points of the left and right teeth 4, the buccal cusp points of the left and right teeth 5, the near middle buccal cusp points and far middle buccal cusp points of the left and right teeth 6, and the near middle buccal cusp points and far middle buccal cusp points of the left and right teeth 7 can be labeled on the reference dental jaw respectively.

And B, correcting a coordinate system:

for each reference dental, coordinates are created with the midpoints of the left and right tooth feature points No. 1, and the left and right tooth feature points No. 6, as shown in fig. 9, the three-point composition plane is a jaw plane, and the jaw plane is an XY plane.

Step C, adjusting coordinates:

the midpoints of teeth 1-1 are set as the origin of coordinates (0, 0), 55 sets of feature points are adjusted, and the final adjustment result is shown in fig. 10.

Step D, counting crown width data:

For each reference jaw, as shown in fig. 11, crown widths of the respective reference jaws are measured according to crown width measurement criteria, and crown width sums of 5-5, 4-4,3-3,2-2 are statistically summarized, wherein the manner of obtaining crown width sums has been described above.

Step E, counting the size data of the adjacent points:

for each reference jaw, the 5-6 abutment dimensions were measured and counted separately as shown in fig. 12, wherein the manner of obtaining the abutment dimensions was described above, and the summary of the 5-6 abutment dimensions for each reference jaw is shown in fig. 13.

Step F, counting the correlation and corresponding relation between the crown width and the adjacent point size:

the 5-5 crown widths and (i.e., first characteristic parameters) and 5-6 abutment spot sizes (i.e., ideal arch characteristic parameters) of the 55 sets of reference jaws are counted, respectively, and the correlation between the 5-5 crown widths and the 5-6 abutment spot sizes of the portions 5-5 crown widths and 5-6 abutment spot sizes of the 55 sets of reference jaws is found to be more than 0.55 by statistics, as shown in table 1 below; the ratio of the two is further counted to obtain the average value of the ratio of the two.

Table 1 refers to the statistics of the dental jaw (part)

Step G, determining a functional form of the first curve:

Fitting different function types finds that the beta function has larger deviation in the use processThe method comprises the steps of carrying out a first treatment on the surface of the The fourth order polynomial function has better stability than the sixth order polynomial function, the sixth order function has larger fluctuation and the curve is not smooth, therefore, the fourth order polynomial function is selected as the dental arch curve function, the odd order terms are removed to ensure the symmetry of the curve relative to the Y axis, and finally, the function form of the first curve is determined as Y=AX ⁴ +BX ² 。

Step H, fitting an optimal dental arch curve:

performing curve fitting on each reference dental jaw through the characteristic points to obtain the distance from the characteristic points to the fitted curve and the optimal dental arch curve with the minimum value, wherein the optimal coefficients of 4 times of items and 2 times of items are A respectively _best And B _best 。

Table 2 below shows the A of the best arch curve obtained by partial fitting _best And B _best 。

TABLE 2 optimal coefficients (portions) of optimal dental arch curves

A _best	B _best
		-0.00003	-0.02012
-0.00007	-0.00894
		-0.0001	-0.00243
-0.00009	-0.00586
		-0.00006	-0.01768
-0.00005	-0.01134

Step I, determining an intermediate dental arch curve:

it was found by statistics that although the 5-6 abutment size is closely related to the shape of the optimal arch curve, the 5-6 abutment size is related to A _best And B _best Does not exhibit a strong correlation, i.e., A _best And B _best The effect on the shape of the arch curve is coupled and cannot be characterized solely by its relation to the ideal arch characteristic, for which purpose an intermediate arch curve needs to be established, which has a point size of abutment with 5-6, a, respectively _best And B _best Coefficients that all have a strong correlation.

Further, through statistical finding, the fourth term coefficient A _best General quadratic term coefficient B _best Two orders of magnitude smaller, which determines the basic shape of the curve, B _best The variation is large, which forms different detail features of different curves, for which purpose a is first of all given by a _best Is taken as the fixed coefficient A of each intermediate dental arch curve _ave The fixed coefficient is kept unchanged for the middle dental arch curve of each reference dental jaw, and then curve fitting is carried out through the distance from the characteristic point to the curve and the minimum, so that the middle dental arch curve of each reference dental jaw is obtained, and the quadratic term coefficient of each dental arch curve is the middle coefficient B _adjust 。

Step J, determining B _adjust With 5-6 adjacent spot size, A _best 、B _best Is the relation of:

by B for each reference jaw _adjust 5-6 Adjacent Point size, A _best 、B _best Statistics were performed, as shown in FIGS. 14 to 16, B _adjust And A is a _best Correlation is 0.765, A _best And B is connected with _best The relativity is-0.797,5-6 o-ringContact size and B _adjust The correlation is: 0.799, i.e. using intermediate coefficient B _adjust As a "bridge," the coupling correlation between the ideal dental arch feature parameter and the optimal dental arch curve coefficient can be broken down into multiple strong correlations that can be transferred through linear expressions.

Step K, establishing a relation between the width of the crown of 5-5 and a first curve;

finally, using the relation between the width of the 5-5 dental crown obtained in the step F and the size of the 5-6 abutment point, and the size of the 5-6 abutment point obtained in the step J and A _best 、B _best The relation between the two is that an optimal dental arch curve function represented by a 5-5 dental crown width sum (namely, a first characteristic parameter which is kept unchanged in a dental arch adjusting period) can be obtained, obviously, for any dental jaw needing to be subjected to dental arch-shaped correction, the corresponding first curve can be obtained by measuring the dental arch curve function with the 5-5 dental crown width sum and then utilizing the representation form, the process does not contain interference of artificial adjustment, and simultaneously accords with aesthetic standards and dental jaw development characteristics, and can ensure that the requirements of dental jaw functions are met.

Step L, fitting the bow of the anterior dental area of the reference dental jaw through a perfect circle:

the anterior dental regions of the 55 reference dental jaws were fitted using a perfect circle, respectively, and the fitting results are shown in fig. 17.

Step M, establishing a relation between the width of the 2-2 dental crowns and a second curve:

the correlation of the 2-2 crown width and the corresponding orthodontics in the anterior dental zone portion of each reference dental jaw was counted to be 0.95, resulting in a second curve characterized by the 2-2 crown width and.

Step N, curve splicing:

as shown in fig. 18, each first curve is shortened by 8.5mm in the intraoral direction at the edge of the first dentition interval, and then the rest of the first curve and the part of the second curve in the first dentition interval are bridged by the transition curve, so as to finally obtain the combined personalized target dental arch curve, and the result is shown in fig. 19.

It should be understood that the foregoing embodiments are merely illustrative of specific embodiments of the modeling method provided by the present application, and those skilled in the art may adjust parameters such as the selected reference jaw and various feature points thereof according to actual needs without departing from the scope of the present application, and may further perform several improvements and modifications to the present application, which also fall within the scope of the claims of the present application.

The application also provides a combined personalized target dental arch curve model, which is used for representing ideal dental arch which a specific dental jaw should have;

the curve model is obtained by splicing a part of a first curve in a first dentition interval of a specific dental jaw and a part of a second curve in a second dentition interval of the specific dental jaw.

The first curve has a polynomial function form of 2N times and only comprises at most M even terms, wherein N, M is an integer, N is more than or equal to M is more than or equal to 2, and coefficients of the M even terms are characterized by first characteristic parameters of a specific dental jaw; the second curve is a perfect circle, and the diameter of the second curve is characterized by a second characteristic parameter of a specific dental jaw; the first characteristic parameter and the second characteristic parameter are both maintained constant during an arch adjustment period of a particular dental jaw.

In some preferred embodiments, the particular dental jaw further has an ideal arch-shaped characteristic, the ideal arch-shaped characteristic being related to the shape of the first curve of the particular dental jaw; and, the ideal arcuate characteristic parameter is statistically strongly correlated with the first characteristic parameter.

In some preferred embodiments, the curve model is generated by the foregoing combined personalized target dental arch curve modeling method, and specific embodiments thereof are described in detail above and are not described herein.

Claims

1. A method of modeling a combined personalized target dental arch curve, comprising:

2. The combined personalized targeted dental arch curve modeling method according to claim 1, wherein:

the first characteristic parameter is determined by a geometric feature of a first set of teeth, wherein the first set of teeth comprises a plurality of specific teeth of an upper or lower jaw of a specific dental jaw.

3. The combined personalized targeted dental arch curve modeling method according to claim 2, wherein:

the second characteristic parameter is determined by a geometric feature of a second set of teeth, wherein the second set of teeth is a proper subset of the first set of teeth.

4. A combined personalized target dental arch modeling method according to claim 2 or 3, characterized in that:

the first characteristic parameter and the second characteristic parameter are determined by different tooth sets at different development stages of a specific dental jaw.

5. A combined personalized target dental arch curve modeling method according to claim 3, wherein:

the first characteristic parameter is the sum of the width of the 5-5 dental crowns of the mandible; the method comprises the steps of,

the second characteristic parameter is the sum of 2-2 crown widths, the sum of 3-3 crown widths, or the sum of 4-4 crown widths of the mandible.

6. A combined personalized target dental arch curve modeling method according to claim 3, wherein:

The first characteristic parameter is the sum of the width of the 4-4 dental crowns of the mandible; the method comprises the steps of,

the second characteristic parameter is the sum of the width of the 2-2 dental crowns or the sum of the width of the 3-3 dental crowns of the mandible.

7. The combined personalized targeted dental arch curve modeling method according to claim 5 or 6, wherein:

the first dentition interval is a left-side and right-side rear dentition interval; the method comprises the steps of,

the second dentition interval is an anterior dentition interval.

8. The combined personalized targeted dental arch curve modeling method according to claim 1, wherein:

the junction point of the first dentition interval and the second dentition interval is positioned in the projection area of the cuspids on the jaw plane.

9. The method of modeling a combined personalized target dental arch curve according to claim 1, wherein the first curve for a particular dental jaw is generated by:

10. The combined personalized targeted dental arch curve modeling method according to claim 9, wherein:

the ideal arch characteristic parameter of a specific dental jaw is related to the ideal arch that the specific dental jaw has; the method comprises the steps of,

the ideal arch characteristic of a particular dental jaw is statistically strongly correlated with its first characteristic.

11. The method of combined personalized targeted dental arch curve modeling according to claim 10, wherein:

the ideal arch characteristic of a particular dental jaw is determined by the geometry of the arch curve when it is in an ideal arch.

12. The method of combined personalized targeted dental arch curve modeling according to claim 11, wherein:

the ideal dental arch characteristic parameter is the 5/6 abutment dimension of the mandible of a particular dental arch in an ideal arch.

13. The method of modeling a combined personalized target dental arch curve according to claim 9,

the first curve is a polynomial function of degree 2N and only comprises up to M even terms, wherein N, M is an integer and N.gtoreq.M.gtoreq.2.

14. The method of combined personalized targeted dental arch curve modeling according to claim 13, wherein:

the coefficients of the M even terms are all statistically strongly correlated with the ideal dental arch characteristic parameters.

15. The method of modeling a combined personalized target dental arch curve according to claim 13, wherein the relationship between the first curve of a particular dental jaw and its ideal dental arch characteristic parameters is determined according to the steps of:

16. The method of combined personalized targeted dental arch curve modeling according to claim 15, wherein:

and the M-1 fixed coefficients are determined according to the average value of the coefficients of corresponding even terms in each optimal dental arch curve.

17. The method of combined personalized targeted dental arch curve modeling according to claim 15, wherein:

and the even number item corresponding to the intermediate coefficient is the even number item with the minimum times.

18. The method of claim 13, wherein the polynomial function of degree 2N is in the form of:

Y＝AX ⁴ +BX ² ，

19. The combined personalized targeted dental arch curve modeling method according to claim 1, wherein:

the second curve is a perfect circle, and the diameter of the perfect circle is statistically strongly correlated with the second characteristic parameter.

20. The combined personalized targeted dental arch curve modeling method according to claim 1, wherein:

the second curve is a beta function, and an integral parameter of the beta function is statistically strongly correlated with the second characteristic parameter.

21. The combined personalized targeted dental arch curve modeling method according to claim 1, wherein:

the combined personalized target dental arch curve further comprises a transition curve, and the first curve and the second curve are spliced through the transition curve.

22. The method of combined personalized targeted dental arch curve modeling according to claim 21, wherein the transition curve is generated by:

23. A combined personalized target dental arch curve model for characterizing an ideal dental arch that a particular dental jaw should have, characterized by:

the method comprises the steps that a part of a first curve in a first dentition interval of a specific jaw and a part of a second curve in a second dentition interval of the specific jaw are spliced;

24. The combined personalized target dental arch model of claim 23, wherein:

the particular dental jaw also has an ideal arcuate characteristic that relates to the shape of the first curve of the particular dental jaw; the method comprises the steps of,

the ideal bow characteristic parameter is statistically strongly correlated with the first characteristic parameter.

25. The combined personalized target dental arch model of claim 24, generated by the combined personalized target dental arch modeling method of claim 1.