CN115054395B

CN115054395B - Method for synchronously measuring crowding degree of teeth and gap required for leveling Spee curve

Info

Publication number: CN115054395B
Application number: CN202210686778.7A
Authority: CN
Inventors: 聂志华
Original assignee: Shanghai Yinqi Dental Technology Co ltd
Current assignee: Shanghai Yinqi Dental Technology Co ltd
Priority date: 2022-06-17
Filing date: 2022-06-17
Publication date: 2024-03-19
Anticipated expiration: 2042-06-17
Also published as: CN115054395A

Abstract

A method for simultaneously measuring crowding of teeth and the gap required to flatten the Spee curve is disclosed. By simulating the teeth to move along the dental archwire, aligning the teeth and leveling the Spee curve, measuring the displacement of the farthest midpoint of the last molar, the gap required for alignment and leveling is obtained at one time, the error generated by the separation measurement of crowding degree and Spee curve curvature by the traditional method is avoided, and a doctor can be helped to better formulate a scheme.

Description

Method for synchronously measuring crowding degree of teeth and gap required for leveling Spee curve

Technical field:

the present application relates to the field of model analysis in orthodontic modeling, and more particularly to a method for measuring a three-dimensional model analysis that can simultaneously measure the degree of crowding of teeth and the gap required to flatten the Spee curve.

The background technology is as follows:

currently, in orthodontic treatment, model analysis is an essential step, wherein crowding and Spee curve curvature are the items that must be measured, and from these two items, the doctor calculates the gap required for leveling of tooth alignment. Patent CN112022383a discloses a method for determining a gap required for orthodontic treatment, which is divided into a first gap value, namely, a dentition crowding degree, a second gap value, namely, a gap required for leveling a Spee curve, a third gap is a difference between an arch prominence degree and a standard arch, and a fourth gap is a molar distal movement amount when an occlusion state is adjusted to a standard occlusion. The four gap values are distinguished because they are difficult to measure simultaneously and therefore can only be subdivided when measured on a plaster model. The method sometimes makes it difficult to distinguish between the first and fourth terms, for example, when the molars must be moved mesially or distaliy during tooth alignment, then the amount of distal movement of the molars is calculated as the amount of movement required for bite adjustment or as the amount of gap required for the first term, alignment. Many patients have some degree of misalignment of their molars themselves, and when the molars align, they twist and the molars tend to move far apart, then the gaps created by the alignment of the molars themselves are not apparent in this method, resulting in large calculation errors.

The existing three-dimensional model measurement and analysis is to manually measure on a three-dimensional model, part of software is automatically calculated, and the three-dimensional model measurement and analysis is still based on a traditional method, and is divided into crowding degree and Spee curvature measurement, and then the numerical values of the required gaps are obtained by adding. Essentially, such three-dimensional model analysis methods are not different from the measurements on the plaster model, and still result in errors.

Meanwhile, because the existing model analysis only considers the individual dental jaw, namely the upper jaw or the lower jaw to independently carry out measurement analysis. The gap required by the matching of the upper bow and the lower bow is not included, the influence of the adjustment of the width of the bow on the crowding degree is not considered, and the influence of the matching of the upper bow and the lower bow on the crowding degree is not considered.

Definition of crowding, textbook, seventh edition of orthodontics, describes: most crowding measures, typically the sum of the widths of the individual crowns in the dental arch prior to the first molar of the mandible. Measured in this way, the presence of irregularities in the first molar and the second molar is ignored, but the molar will produce a greater resistance force when aligned, resulting in forward movement of the anterior tooth, while the molar will produce a small amount of distal movement. Therefore, even if the molar is slightly irregular, the crowding degree should be calculated, and the reliability of the plan formulation should be improved. Because the traditional gypsum model is not accurate enough, tedious, and poor in repeatability and precision, and the deviation is brought to diagnosis, a more accurate and rapid measurement method is needed.

The invention comprises the following steps:

the embodiment of the disclosure provides a method for synchronously measuring the crowding degree of teeth and leveling the gap required by a Spee curve, which relates to three-dimensional model measurement and analysis, and aims to solve the problem of large error in model analysis in the prior art, and simultaneously can be rapidly carried out, simply, rapidly and accurately.

Traditional crowding degree analysis is carried out, the existing length of the dental arch is measured, brass wires are usually used for comparison one by one along the adjacent points of teeth on a model, the total length is measured after straightening, and then all crown widths are added to be used as the existing length of the dental arch. However, due to the existence of the tooth tip, the brass wire is required to enter the adjacent point accurately, so that the brass wire is bent, and the measurement error is large. Spee curve curvature is defined as: the lower incisor ends are straight from the last lower molar buccal tip and the lowest buccal tip of the side tooth is the greatest distance from the straight line. However, since the dental arch is U-shaped, the method thus measures two-dimensional data. Meanwhile, only one lowest buccal tip is measured, the heights of other teeth are ignored, and the error is increased. The method described in textbooks of orthodontics: approximately estimate the gap required to flatten the Spee curve as the sum of the Spee curves on the left and right sides/2+0.5 mm, which is simply the average statistically obtained by the learner, and the error is large for the analysis of a single patient.

Setting the adjacent points of two middle incisors as the midpoints of dental archwires, manually setting the dental archwires or automatically calculating the dental archwires according to Beta functions or other functions, executing an automatic tooth arrangement step, arranging all teeth along the dental archwires in order without torsion, simultaneously automatically adjusting the heights of all teeth in a state of maintaining standard inclination and torque, enabling all teeth to translate, enabling the highest cusp to contact with an occlusal plane, automatically recording the furthest middle point of the last tooth (the highest point of the distal cheek cusp of the last molar or other characteristic points) at the moment, and after aligning and leveling from an initial position to alignment, moving the point to the distal middle (rear) by the amount of a gap required by single-side alignment +leveling, wherein the left side is Y1, the right side is Y2, and the gap required by single-jaw alignment leveling Y=Y1+Y2.

If the central incisors are in a state that the labial side is severely inclined, the contact points of the central incisors are X beyond the boundary of the alveolar bone, and then the entire dental arch is required to be moved distally (posteriorly) along the occlusal plane by a distance of X to arrange all teeth within the boundary of the alveolar bone, so that the last tooth on both sides is simultaneously moved distally (posteriorly) by a distance of X, and then the single jaw aligns a gap y=y1+y2+xj2 required for leveling.

Because of the usual orthodontics of patients, teeth are often not clean, i.e. the teeth themselves are twisted, and the Spee curve curvature is very deep for patients with deep occlusions, it is difficult to distinguish between crowding and the gap required to flatten the Spee curve curvature. Therefore, the invention can synchronously calculate the gap required by alignment and leveling by setting the final arch shape, all teeth are released from torsion alignment, the tooth cusps are contacted with the occlusal plane to achieve the state of leveling Spee curve and then calculating the backward movement amount of the farthest midpoint of the last tooth of the arch. Meanwhile, the present invention also considers the case that if the contact point protrusion of the central incisor is located outside the alveolar bone, the amount of gap needs to be increased.

Description of the drawings:

FIG. 1 is a view showing the teeth moving in the distal direction after untwisting, correcting the inclination and torque along the archwire, the most original point movement amounts of the last tooth being Y1, Y2, respectively;

FIG. 2 shows a leveling Spee curve for a tooth that has been aligned, i.e., translating the highest point of the tooth to the occlusal plane, with the amount of movement Y of the origin of the last tooth, Y1 on the right and Y2 on the left;

FIG. 3 shows the incisors tilted beyond the alveolar bone boundary X by a distance X required to move distally;

Detailed Description

In order to better understand the technical solutions of the present disclosure, the following description will clearly and completely describe the technical solutions of the embodiments of the present disclosure with reference to the drawings in the embodiments of the present disclosure. It will be apparent that the described embodiments are merely embodiments of a portion, but not all, of the present disclosure. All other embodiments, which can be made by one of ordinary skill in the art without inventive effort, based on the embodiments in this disclosure, shall fall within the scope of the present disclosure.

It should be noted that the terms "first," "second," and the like in the description and claims of the present disclosure and in the foregoing figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the disclosure described herein may be capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

First, partial terms or terminology appearing in describing embodiments of the present disclosure with reference to "orthodontics" are applicable to the following explanation:

degree of congestion: i.e. the length of the dental arch minus the existing length of the dental arch.

Spee curve curvature is defined as: the lower incisor ends are straight from the last lower molar buccal tip and the lowest buccal tip of the side tooth is the greatest distance from the straight line.

Gap required for synchronous alignment leveling = crowding degree + gap required for leveling Spee curve curvature

Claims

1. A method for simultaneously measuring crowding of teeth and leveling of a gap required for a Spee curve for analysis of a three-dimensional model in dental correction, comprising the steps of:

step one, setting the adjacent points of two middle incisors as dental arch curve midpoints, automatically calculating dental arch curves according to Beta functions or other functions, or manually setting the dental arch curves;

step two, under the condition of no torsion, correction of inclination and torque, all teeth are translated in a far-middle direction along a dental arch curve to automatically arrange teeth;

step three, automatically adjusting the heights of all teeth in a state of maintaining standard inclination and torque, and vertically translating all teeth to enable the highest tooth tip to be contacted with an occlusal plane;

calculating the farthest midpoint of the last tooth, namely the distance required by one-side alignment leveling after aligning and leveling from an initial position, wherein the value is the distance required by one-side alignment leveling, the left side is recorded as Y1, the right side is recorded as Y2, and the distance required by one-jaw alignment leveling is Y=Y1+Y2;

and step four, if the labial side of the central incisor is in a severely inclined state, and the distance that the contact point of the central incisor exceeds the boundary of the alveolar bone is X, the whole dental arch needs to be moved far and medium along the occlusal plane by X distance to arrange all teeth into the boundary of the alveolar bone, at the moment, the last tooth on two sides needs to be moved far and medium simultaneously, and then the single jaw aligns and levels a required gap Y=Y1+Y2+X X2.