RU2248751C2 - Method for diagnosing dentition anomaly in sagittal direction on jaw models in permanent occlusion - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: method involves taking imprints from upper and lower jaw for manufacturing plaster jaw models. The lower jaw plaster model is used for measuring mesiodistal dimensions of twelve teeth: 46-41 and 31-36. Particular tooth lacking, its dimensions are calculated using percent proportions from mean dental parameter values table. Individual general projection length norm is calculated for upper and lower jaw using formulas; Lp_o=0.39*Σ₁₂ and Lp_u=0.35*Σ₁₂, where Lp_o and Lp_u are the individual general projection length norms of lower and upper jaw, respectively; 0,39 and 0,35 are indices describing relationship binding mean general projection length of lower and upper jaw to mean sum of mesiodistal dimensions of twelve teeth(46-41 and 31-36) of lower dental row in persons having physiological occlusion and permanent teeth dimensions within the limits of mean values, respectively; Σ₁₂ is the sum of mesiodistal dimensions of twelve teeth(46-41 and 31-36) measured on plaster model. Individual norm values of general upper and lower jaw projection length are compared to corresponding actual values measured on models. The values coinciding, conclusion is drawn concerning normal sagittal dimensions of denture. Difference being positive, increase in sagittal denture dimensions is considered to be the case. The difference being negative, reduction of sagittal denture dimensions is considered to be the case. Actual projection length values of the anterior segment are additionally determined by taking measurements from upper and lower jaw models, with distance between mesial point on labial approximal surface of incisor in vestibular position and point of intersection of line joining contact points of canine tooth and the first molar on the left and right side to median line of the upper jaw. Distance between contact point of lower central incisors cutting surfaces and point of intersection of line joining contact points of the first and the second premolars on the left and right side to median line of the lower jaw. Individual general projection length norms are calculated for upper and lower jaw anterior segment using formulas: lp_o=0.16*Σ₁₂ and lp_u=0.17*Σ₁₂, where lp_o and lp_u are the individual general projection length norms of lower and upper jaw anterior segment, respectively; 0,16 and 0,17 are indices describing relationship binding mean general projection length of lower and upper jaw anterior segment to mean sum of mesiodistal dimensions of twelve teeth(46-41 and 31-36) of lower dental row in persons having physiological occlusion and permanent teeth dimensions within the limits of mean values, respectively; Σ₁₂ is the sum of mesiodistal dimensions of twelve teeth(46-41 and 31-36) measured on plaster model. Individual norm values of general upper and lower jaw anterior segment projection length are compared to corresponding actual values measured on models. The values coinciding, conclusion is drawn concerning normal sagittal dimensions of denture. Difference being positive, increase in sagittal dimensions of anterior denture segment is considered to be the case. The difference being negative, reduction of dimensions of anterior denture segment is considered to be the case.

EFFECT: enhanced effectiveness in detecting denture anomalies in sagittal direction.

2 cl, 4 tbl

Description

The invention relates to medicine, namely to orthodontic dentistry.

The projection length in orthodontic practice is used to diagnose anomalies in the position of the teeth and anomalies of the dentition of the upper and lower jaws in the sagittal direction, as well as to monitor the effectiveness of the treatment.

It is known to use the total projection length of dentitions on jaw models for determining anomalies of dentition in the sagittal direction by determining with the help of a caliper and a ruler the distance between the point formed when the line drawn along the distal surfaces of the first molars and the perpendicular dropped onto it along the midline the corresponding jaw from the mesial point on the labial proximal surface of the vestibularly located upper incisor during measurements on the upper jaw or cont point of the lower central incisors during measurements on the lower jaw (Methodological recommendations for the diagnosis of dentoalveolar anomalies in jaw models: Method, rivers .; Edited by A.A. Kolesov, L.S. Persia, L.I. Kamyshova, A.A. .Anikienko. - Moscow, 1986 - 19 p.)

Thus, the projection length in orthodontic practice was not previously used to diagnose abnormalities of the dentition of the upper and lower jaws in the sagittal direction, but only to control the dynamics of the treatment: with an increase in the indicator, it was concluded that the length of the dentition in the sagittal direction was increased, and with decrease - about reducing the length of the dentition in the sagittal direction, that is, they noted the fact of an increase or decrease, not being able to assess this change, since the data there were no norms, there was also no possibility of dividing the dentition into segments, which greatly complicated the diagnosis of disorders of the dentition.

A similar technique for determining the dentition is present in cephalometry, where there are other measuring points and not an individual norm of the parameter, but the average one, and on the cephalogram it is not possible to distinguish segments of the dentition and determine the most appropriate means and place of orthodontic exposure.

The objective of the invention is the ability to determine the presence of anomalies of the dentition in the sagittal direction by determining the individual norms of the total projection length of the dentition of the upper and lower jaws and the projection length of the anterior segment of the upper and lower jaws.

This is achieved due to the fact that on the plaster model of the lower jaw, the mesiodist sizes of 12 teeth are measured: 46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36 teeth, and in the absence of any the tooth size is calculated through the percentage according to the table of average values of the parameters of the teeth, calculate the individual norm of the total projection length for the upper and lower jaws according to the formulas: Lp _o = 0.39 · Σ ₁₂ and Lp _U = 0.35 · Σ ₁₂ , where Lp ₀ and Lp _u are individual norms of the total projection length of the upper and lower jaws, respectively, 0.39 and 0.35 are the indices of the ratio of the average the total projection length of the upper and lower dentition, respectively, to the average sum of the mesiodist sizes of 12 teeth (46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36) of the lower dentition in individuals with physiological occlusion and the size of the permanent teeth within the average, Σ ₁₂ is the sum of the mesiodist sizes of 12 teeth: 46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36, measured on a plaster model; then compare the values of the individual norm of the total projection length of the upper and lower jaws with the corresponding actual values obtained on the models; if these values coincide, a conclusion is drawn about the normal sagittal size of the dentition, and if there is a difference between them, in the case of a positive value, it is concluded that the sagittal size of the dentition is increased, and if it is negative, a decrease in the sagittal size of the dentition; after which the actual projection lengths of the anterior segment are determined, which are measured on the models of the upper and lower jaws, for the upper jaw, the distance between the mesial point on the labial proximal surface of the vestibularly located upper incisor and the point of intersection of the line connecting the contact points of the canine and the first premolar to the right and on the left, with the median line of the upper jaw, and for the lower jaw, determine the distance between the contact point of the cutting surfaces of the lower central incisors intersection point line connecting contact points of the first and the second premolar on the left and right, with the median line of the lower jaw; then calculate the individual norms of the projection length of the anterior segment of the upper and lower jaws according to the formulas: lр _о = 0.16 · Σ ₁₂ and lp _u = 0.17 · Σ 12, where lp _o and lp _u are the individual norms of the projection length of the anterior segment of the upper and lower jaw, respectively, 0.16 and 0.17 are the indices of the ratio of the average projection length of the anterior segment of the upper and lower dentition, respectively, to the average sum of the mesiodist sizes of 12 teeth (46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36) of the lower dentition in individuals with physiological occlusion and sizes of constant CWA within the average values, Σ ₁₂ - the sum mesiodistal size 12 of the teeth 46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36, measured on the gypsum model; then compare the values of the individual norm of the projection length of the anterior segment of the upper and lower jaws with the corresponding actual values obtained on the models; if these values coincide, a conclusion is drawn about the normal sagittal size of the dentition, and if there is a difference between them, in the case of a positive value, it is concluded that the sagittal size of the anterior segment of the dentition is increased, and if it is negative, a decrease in the sagittal size of the anterior dentition row.

The theory of obtaining indices for calculating the individual norm of the total projection length and projection length of the dentition segments on the models of the jaws in a constant bite.

(сумма мезиодистальных размеров 11, 12 и 13), Σ | ₁₂₃₄ (сумма мезиодистальных размеров 31, 32, 33 и 34), Σ _{21| 12} (сумма мезиодистальных размеров 11, 12, 21 и 22),

(сумма мезиодистальных размеров 31, 32, 41 и 42), I_b (индекс Болтона), затем были определены фактические показатели общей проекционной длины верхней (Lp_o) и нижней (Lp_u) челюстей, проекционной длины переднего сегмента верхней (1р_о) и нижней челюстей (1p_u), и между полученными параметрами определены коэффициенты корелляции:On 20 pairs of models of jaws of individuals with physiological occlusion, the mesiodist sizes of 12 permanent teeth of the upper jaw and 12 permanent teeth of the lower jaw were measured, Σ _{12 was} calculated (the sum of the mesiodist sizes 46, 45, 44, 43, 42, 41, 31, 32, 33 , 34, 35, 36),

(the sum of the mesiodistal sizes 11, 12 and 13), Σ | ₁₂₃₄ (the sum of the mesiodistal sizes 31, 32, 33 and 34), Σ _{21 | 12} (the sum of the mesiodistal sizes 11, 12, 21 and 22),

(the sum of the mesiodistal sizes 31, 32, 41 and 42), I _b (Bolton index), then the actual indicators of the total projection length of the upper (Lp _o ) and lower (Lp _u ) jaws, the projection length of the anterior segment of the upper (1р _о ) were determined and the lower jaw (1p _u ), and between the obtained parameters the correlation coefficients are determined:

Tab. 1 Σ _{21 | 12} Σ _{21 | 12} Σ ₁₂ Σ _l2 I _b Σ | ₁₂₃ Σ | ₁₂₃₄ I r _about 0.45 0.55 0.45 0.47 0.49 0.41 Lp _o 0.71 0.69 0.82 0.79 0.76 0.75 Ip _u 0.43 -0.31 0.3 0.31 Lp _a 0.3 0.3 0.37 0.64 -0.43 0.35 0.41

A high and medium correlation strength of the projection length measurements was found at Σ ₁₂ , which made it possible to use the Σ ₁₂ parameter in calculating the individual indices of the ratio of the projection lengths of the dentition to the sum of the mesiodist sizes 46, 45, 44, 43, 42, 41, 31, 32, 33 , 34, 35, 36 in individuals with physiological occlusion and the size of permanent teeth in the range of average values according to the formulas:

n ₁ = l p _o / Σ ₁₂ ; n ₂ = l p _u / Σ ₁₂ ; n ₃ = Lp _o / Σ ₁₂ ; n ₄ = Lp _u / Σ ₁₂ ,

where n ₁ is the index of the ratio of the projection length of the anterior segment of the upper dentition to the sum of the mesiodist sizes of 12 teeth of the lower jaw in individuals with physiological occlusion and the size of the permanent teeth within average values;

n ₂ is the index of the ratio of the projection length of the anterior segment of the lower dentition to the sum of the mesiodist sizes of 12 teeth of the lower jaw in individuals with physiological occlusion and the size of permanent teeth within average values;

n ₃ is the index of the ratio of the total projection length of the upper dentition to the sum of the mesiodist sizes of 12 teeth of the lower jaw in individuals with physiological occlusion and the size of permanent teeth within average values;

n ₄ is an index of the ratio of the total projection length of the lower dentition to the sum of the mesiodist sizes of the 12 teeth of the lower jaw in individuals with physiological occlusion and the size of the permanent teeth in the range of average values;

Σ ₁₂ is the sum of the mesiodistal sizes 46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36;

lp _o is the projection length of the anterior segment of the upper dentition;

lp _u is the projection length of the anterior segment of the lower dentition;

Lp _o - total projection length of the upper dentition;

Lp _u is the total projection length of the lower dentition;

Tab. 2 No. n ₁ n ₂ n ₃ n ₄ 1 0.15 0.37 0.16 0.34 2 0.15 0.37 0.17 0.35 3 0.16 0.39 0.17 0.37 4 0.15 0.38 0.18 0.35 5 0.16 0.39 0.17 0.34 6 0.15 0.38 0.16 0.33 7 0.15 0.39 0.16 0.34 8 0.17 0.41 0.18 0.36 nine 0.16 0.38 0.18 0.36 10 0.16 0.40 0.17 0.36 eleven 0.16 0.39 0.17 0.34 12 0.16 0.40 0.19 0.37

thirteen 0.15 0.37 0.16 0.33 14 0.17 0.40 0.17 0.34 fifteen 0.14 0.39 0.17 0.34 16 0.15 0.39 0.19 0.37 17 0.14 0.39 0.16 0.33 eighteen 0.15 0.37 0.18 0.36 19 0.16 0.39 0.18 0.37 twenty 0.17 0.40 0.18 0.36

The arithmetic mean value M _cf was calculated for the indices of the ratio of the projection lengths of the dentition to the sum of the mesiodist sizes 46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36 in individuals with physiological occlusion and the size of the permanent teeth in limits of average values:

Tab. 3 n _{1 av} n _{3 av} n _{2 Wed} n _4av M _cf 0.16 0.39 0.17 0.35

The individual norms of the total projection length of the upper and lower jaws, the projection length of the anterior segment of the upper and lower jaws were determined by the formulas:

lp _o = 0.16 · Σ ₁₂

lp _u = 0.17 · Σ ₁₂

Lp _o = 0.39 · Σ ₁₂

Lp _u = 0.35 · Σ ₁₂ ,

where Σ ₁₂ is the sum of the mesiodistal sizes 46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36,

lp _o is the projection length of the anterior segment of the upper dentition,

lp _u is the projection length of the anterior segment of the lower dentition,

Lp _o - the total projection length of the upper dentition,

Lp _u is the total projection length of the lower dentition,

0.39 is the index of the ratio of the projection length of the upper dentition to the sum of the mesiodist sizes of 12 teeth of the lower jaw,

0.35 is the index of the ratio of the projection length of the lower dentition to the sum of the mesiodist sizes of 12 teeth of the lower jaw,

0,16 - the index of the ratio of the projection length of the anterior segment of the upper dentition to the sum of the mesiodist sizes of 12 teeth of the lower jaw,

0.17 is the index of the ratio of the projection length of the anterior segment of the lower dentition to the sum of the mesiodist sizes of 12 teeth of the lower jaw in individuals with physiological occlusion and the size of the permanent teeth in the range of average values.

The obtained values are presented in the table of individual norms of the total projection length of the upper and lower dentition and the projection length of the anterior segment of the upper and lower dentition.

Table 4 Σ ₁₂ Lp _o Lp _u I _o Ip _u 75 29.3 26.3 12.0 12.8 76 29.6 26.6 12,2 12.9 77 30,0 27.0 12.3 13.1 78 30,4 27.3 12.5 13.3 79 30.8 27.7 12.6 13,4 80 31,2 28.0 12.8 13.6 81 31.6 28,4 13.0 13.8 82 32,0 28.7 13.1 13.9 83 32,4 29.1 13.3 14.1 84 32.8 29.4 13,4 14.3 85 33,2 29.8 13.6 14.5 86 33.5 30.1 13.8 14.6 87 33.9 30.5 13.9 14.8 88 34.3 30.8 14.1 15.0 89 34.7 31,2 14.2 15.1 90 35.1 31.5 14,4 15.3 91 35.5 31.9 14.6 15,5 92 35.9 32,2 14.7 15.6 93 36.3 32.6 14.9 15.8 94 36.7 32.9 15.0 16,0 95 37.1 33.3 15,2 16,2 96 37,4 33.6 15.4 16.3 97 37.8 34.0 15,5 16.5 98 38,2 34.3 15.7 16.7 99 38.6 34.7 15.8 16.8 100 39.0 35.0 16,0 17.0 101 39,4 35,4 16,2 17,2 102 39.8 35.7 16.3 17.3 103 40,2 36.1 16.5 17.5 104 40.6 36,4 16.6 17.7 105 41.0 36.8 16.8 17.9 106 41.3 37.1 17.0 18.0 107 41.7 37.5 17.1 18.2

A method for the diagnosis of anomalies of the dentition in the sagittal direction on the models of the jaws in a constant bite.

The patient is taken casts from the upper and lower jaws, gypsum models of the jaws are made; determine the distance between the point formed at the intersection of the line drawn along the distal surfaces of the first molars and the perpendicular dropped onto it along the midline of the corresponding jaw from the mesial point on the labial proximal surface of the vestibularly located upper incisor when measured on the upper jaw or the contact point of the central lower incisors during measurements on the lower jaw; on the plaster model of the lower jaw, the mesiodist sizes of 12 teeth are measured: 46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36 teeth, and in the absence of any tooth, its size is calculated through the percentage according to the table of average values of the parameters of the teeth, then calculate the individual norm of the total projection length for the upper and lower jaws according to the formulas: Lp _o = 0.39 · Σ ₁₂ and Lp _u = 0.35 · Σ ₁₂ , where Lp _o and Lp _u - individual norms of the total projection length, respectively, of the upper and lower jaws, 0.39 and 0.35 - the indices of the ratio of the average total projection length respectively, of the upper and lower dentition to the average total mesiodistal size of 12 teeth (46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36) of the lower dentition in individuals with physiological occlusion and the size of the constants teeth within average values, Σ ₁₂ - the sum of the mesiodist sizes of 12 teeth: 46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36, measured on a plaster model; then compare the values of the individual norm of the total projection length of the upper and lower jaws with the corresponding actual values obtained on the models; if these values coincide, a conclusion is drawn about the normal sagittal size of the dentition, and if there is a difference between them, in the case of a positive value, it is concluded that the sagittal size of the dentition is increased, and if it is negative, a decrease in the sagittal size of the dentition; then determine the actual indicators of the projection length of the anterior segment, which is measured on models of the upper and lower jaws.

For the upper jaw, determine the distance between the mesial point on the labial proximal surface of the vestibularly located upper incisor and the point of intersection of the line connecting the contact points of the canine and the first premolar to the right and left, with the median line of the upper jaw, and for the lower jaw, determine the distance between the contact point of the cutting surfaces lower central incisors and the point of intersection of the line connecting the contact points of the first and second premolar left and right, with the median line of the lower jaw; then calculate the individual norms of the projection length of the anterior segment of the upper and lower jaws according to the formulas: lр _о = 0.16 · Σ ₁₂ and lр _u = 0.17 · Σ ₁₂ , where lр _о and lp _u are the individual norms of the projection length of the anterior segment of the upper and lower jaw, respectively, 0.16 and 0.17 are the indices of the ratio of the average projection length of the anterior segment of the upper and lower dentition, respectively, to the average sum of the mesiodist sizes of 12 teeth (46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36) of the lower dentition in individuals with physiological occlusion and constant sizes teeth within average values, Σ ₁₂ - the sum of the mesiodist sizes of 12 teeth: 46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36, measured on a plaster model; then compare the values of the individual norm of the projection length of the anterior segment of the upper and lower jaws with the corresponding actual values obtained on the models; if these values coincide, a conclusion is drawn about the normal sagittal size of the dentition, and if there is a difference between them, in the case of a positive value, it is concluded that the sagittal size of the anterior segment of the dentition is increased, and if it is negative, a decrease in the sagittal size of the anterior dentition row.

Clinical example.

Patient K., 15 years old, and / b No. 2435.

Patient K. took casts from the upper and lower jaws, and on the plaster model of the lower jaw, the mesiodist sizes of each of the 12 permanent teeth were measured (46 = 11, 45 = 7.5, 44 = 7.5, 43 = 8, 42 = 6, 41 = 5.5, 31 = 5.5, 32 = 6, 33 = 8, 34 = 7.5, 35 = 7.5, 36 = 11), Σ ₁₂ = 81 mm, then the individual norm of the total projection length was determined the upper jaw according to the formula 0.39 · Σ ₁₂ = 0.39 · 81 = 31.6 and the lower jaw according to the formula 0.35 · Σ ₁₂ = 0.35 · 81 = 28.4; then using a caliper and a ruler, we measured the distance between the mesial point on the labial proximal surface of the vestibularly located upper incisor and the point located on the line drawn along the distal surfaces of the first molars, on which the perpendicular is lowered, we obtained a value of 30 mm, compared the value of the individual norm of the total projection the length of the upper jaw with an actual value of 30-31.6 = -1.6 - a negative value of the difference indicates a decrease in the sagittal size of the upper dentition; then we measured the distance between the contact point of the lower central incisors and the point located on the line drawn along the distal surfaces of the first molars, on which the perpendicular is lowered, we obtained 26 mm, compared the value of the individual norm with the actual value of 26-28.4 = -2.4 - a negative value of the difference indicates a decrease in the sagittal size of the lower dentition; then, for the upper jaw, the distance between the mesial point on the labial proximal surface of the vestibularly located upper incisor and the point of intersection of the line connecting the contact points of the canine and the first premolar to the right and left and the midline of the upper jaw is determined, 11.4 mm are obtained, then the individual projection rate is determined the length of the anterior segment of the upper jaw by the formula 0,16 · Σ · 0.16 = ₁₂ 81 = 13 and the individual norm value compared with the actual value obtained for model 13-13 = 0 - no difference with idetelstvuet the normal sagittal size of the anterior segment of the upper dentition.

Then, for the lower jaw, we determined the distance between the contact point of the cutting surfaces of the lower central incisors and the intersection of the line connecting the contact points of the first and second premolar left and right in the midline of the lower jaw, obtained 16.2, determined the individual norm of the projection length of the anterior segment of the lower jaw 0,17 · Σ formula ₁₂ = 0.17 · 81 = 13.8, and then compared the individual norm value of the projection length of the anterior segment of the mandible with the actual value obtained for the model 16,2-13,8 = 2,4 - by ozhitelnoe difference value indicates an increase in sagittal size of the anterior segment of the lower dentition.

Claims (2)

1. A method for diagnosing dentition anomalies in jaw models in the sagittal direction in a constant bite, which consists in taking casts from the upper and lower jaws, making gypsum models of the jaws, determining the distance between the point formed when the line drawn along the distal surfaces of the first molars intersects, and perpendicular, lowered onto it along the midline of the corresponding jaw from the mesial point on the labial proximal surface of the vestibularly located upper incisor when measured on the upper jaw or the contact point of the central lower incisors when measuring the lower jaw, characterized in that on the plaster model of the lower jaw the mesiodist sizes of 12 teeth are measured: 46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35 , 36 teeth, and in the absence of any tooth, its size is calculated through the percentage according to the table of average values of the tooth parameters and the individual norm of the total projection length for the upper and lower jaws is calculated using the formulas Lp _o = 0.39 · ∑ ₁₂ and Lp _u = 0.35 · ∑ ₁₂ , where Lp _o and Lp _u are individual norms of the total projection of the corresponding length of the upper and lower jaws, respectively, 0.39 and 0.35 are the indices of the ratio of the average total projection length of the upper and lower dentitions, respectively, to the average sum of mesiodistal sizes of 12 teeth (46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36) of the lower dentition in individuals with physiological occlusion and the size of permanent teeth in the range of average values, ∑ ₁₂ is the sum of the mesiodist sizes of 12 teeth: 46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36, measured on a gypsum model; then compare the values of the individual norm of the total projection length of the upper and lower jaws with the corresponding actual values obtained on the models; if these values coincide, a conclusion is drawn about the normal sagittal size of the dentition, and if there is a difference between them, in the case of a positive value, it is concluded that the sagittal dimension of the dentition is increased, and if it is negative, a decrease in the sagittal size of the dentition. 2. A method for diagnosing dentition anomalies in the jaw models in the sagittal direction in a constant bite, which consists in taking casts from the upper and lower jaws, making gypsum models of the jaws, determining the distance between the point formed by crossing the line drawn along the distal surfaces of the first molars, and perpendicular, lowered onto it along the midline of the corresponding jaw from the mesial point on the labial proximal surface of the vestibularly located upper incisor when measured on the upper jaw or the contact point of the central lower incisors during measurements on the lower jaw, characterized in that they determine the actual projection lengths of the anterior segment, which are measured on the models of the upper and lower jaws, for the upper jaw, determine the distance between the mesial point on the labial proximal surface of the vestibularly located upper the cutter and the intersection point of the line connecting the contact points of the canine and the first premolar to the right and left, with the median line of the upper jaw, and for the lower jaw determine the distance between the contact point of the cutting surfaces of the lower Central incisors and the point of intersection of the line connecting the contact points of the first and second premolar left and right, with the median line of the lower jaw; then calculate the individual norms of the projection length of the anterior segment of the upper and lower jaws according to the formulas lp _o = 0.16 · ∑ ₁₂ and lp _u = 0.17 · ∑ ₁₂ , where lр _о and lр _u are the individual norms of the projection length of the anterior segment of the upper and of the lower jaw, respectively, 0.16 and 0.17 are the indices of the ratio of the average projection length of the anterior segment of the upper and lower dentitions, respectively, to the average sum of the mesiodist sizes of 12 teeth (46, 45, 44, 43, 42, 41, 31, 32, 33 , 34, 35, 36) of the lower dentition in individuals with physiological occlusion and sizes of constant slabs within average values, ∑ ₁₂ - the sum of mesiodistal sizes of 12 teeth: 46, 45, 44, 43, 42, 41, 31, 32, 33, 34, 35, 36, measured on a plaster model; then compare the values of the individual norm of the projection length of the anterior segment of the upper and lower jaws with the corresponding actual values obtained on the models; if these values coincide, a conclusion is drawn about the normal sagittal size of the dentition, and if there is a difference between them, in the case of a positive value, it is concluded that the sagittal size of the anterior segment of the dentition is increased, and if it is negative, a decrease in the sagittal size of the anterior dentition .