RU2841643C1 - Method for assessing position of upper jaw by lateral teleroentgenogram - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely to orthodontics, dentistry. Lateral teleroentgenogram shows a junction point of the frontal and nasal bones, the centre of the sella turcica fossa, and the point of the anterior nasal spine. Position of the upper jaw is determined by the value of the angle with the apex at the junction of the frontal and nasal bones and the sides passing through the centre of the fossa of the sella turcica and the point of the anterior nasal spine. Values from 71° up to 95° in males and from 76° up to 92° in women are considered normal.

EFFECT: method enables diagnosing the position of the upper jaw in the absence of an anatomical landmark – the deepest point of the anterior contour of the alveolar process of the upper jaw, allows to improve and detail diagnostics for further planning of treatment and evaluation of results of treatment of orthodontic patients due to use of an anterior nasal spine point as an anatomical reference point.

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Description

The invention relates to orthodontics and can be used to assess the position of the upper jaw using a lateral teleradiogram (TRG).

The sources available for research describe a method for analyzing the position of the upper jaw in the sagittal plane by determining the value of the angle with the apex at point N and the sides passing through point S and point A (angle SNA), where: point S is the center of the sella turcica fossa, N is the junction of the frontal and nasal bones, A is the deepest point of the anterior contour of the alveolar process of the upper jaw (Digital teleradiography in dentistry. A manual for doctors / V.N. Trezubov, N.V. Zubkova, I.R. Cheminava, R.A. Rozov; edited by V.N. Trezubov, St. Petersburg, Publishing House "AVRORA", 2022-200 p., diagrams and ill. p. 88).

The disadvantage of this method is the impossibility of determining the position of the upper jaw to establish a diagnosis for the purpose of planning orthodontic treatment in the absence of an anatomical landmark of point A due to injury, after surgery, or due to a developmental defect - cleft palate (Fig. 1).

The technical result of the invention consists in the possibility of diagnosing the position of the upper jaw in case of its anatomical defect, improving and detailing the diagnostics for further treatment planning and evaluating the results of treatment of orthodontic patients.

The specified technical result is achieved in a method for assessing the position of the upper jaw using a lateral teleroentgenogram, including determining an angular parameter in which the junction point of the frontal and nasal bones, the center of the sella turcica fossa, and the anterior nasal spine point are determined on the lateral teleroentgenogram, and the position of the upper jaw is determined by the size of the angle with the apex at the junction point of the frontal and nasal bones and the sides passing through the center of the sella turcica fossa and the anterior nasal spine point, considering the norm to be values from 71° to 95° for men and from 76° to 92° for women.

In the claimed method, the point of the anterior nasal spine - Ans is used as an anatomical landmark. This point is usually used when determining the linear parameter - the length of the upper jaw. The use of the SNAns angle to assess the position of the upper jaw is unknown.

The method is illustrated in Fig. 1-7, where:

Fig. 1 - teleroentgenogram of the patient without point A;

Fig. 2 shows the known angular parameter SNA;

In Fig. 3 - the studied angular parameter SNAns;

In Fig. 4, 5 - teleroentgenograms of the patient without point A before and after treatment;

In Fig. 6, 7 - correlation of the position of points A and Ans in men and women.

In the study, we analyzed 222 TRGs of patients over 18 years of age of both sexes with a normal value of the interapical angle, showing the relationship of the upper and lower jaws in the sagittal plane, and analyzed the SNAns angles and the dependence of the position of points A and Ans. The value of the SNAns angle in men ranged from 71° to 95°, in women - from 76° to 92°. The average values of the SNAns angle are presented in Table 1.

Based on the results of X-ray cephalometric analysis of lateral TRGs, strong positive correlations were found between the parameters SNA-SNAns M (r = 0.89) W (r = 0.82) - Fig. 6, 7.

Thus, the possibility of determining the initial position of the upper jaw in the sagittal plane and planning a change in this position during combined treatment with osteotomy is confirmed, even in the absence of an anatomical landmark - the deepest point of the anterior contour of the alveolar process of the upper jaw.

The method is confirmed by the following clinical example.

Example 1. Patient A., 18 years old, complains of unsatisfactory facial aesthetics. Point A is absent due to a defect in the anterior portion of the upper jaw after an injury, and it is impossible to determine the position of the upper jaw using known methods. TRG analysis by the SNAns angle showed upper retrognathia - 73°.

Osteotomy planning was performed based on the results of the TRG analysis and the planned value of the SNAs angle after surgery was 85°.

The method allows for diagnostics of the position of the upper jaw in the absence of an anatomical landmark - the deepest point of the anterior contour of the alveolar process of the upper jaw, and allows for improvement and detailing of diagnostics for further treatment planning and evaluation of treatment results for orthodontic patients.

Claims (1)

A method for assessing the position of the upper jaw using a lateral teleroentgenogram, including determining an angular parameter, characterized in that the lateral teleroentgenogram determines the junction point of the frontal and nasal bones, the center of the sella turcica, and the point of the anterior nasal spine, the position of the upper jaw is assessed based on the size of the angle with the apex at the junction point of the frontal and nasal bones and the sides passing through the center of the sella turcica and the point of the anterior nasal spine, considering the norm to be values from 71° to 95° for men and from 76° to 92° for women.