A new method of estimating the teeth, dentition position relative to the coordinate point, which is the same for both dentitions, has been proposed. Such coordinate point is suggested as LP (Fig. 3.1).
The N-Po line was taken as a reference line on the grounds that many anthropologists consider it to be the most stable and little changing with age (Fig. 3.2).
In addition, the N-Po line allows comparing the data of photometric studies of the face with angular and linear parameters of head teleroentgenogram. The N-Po reference line is convenient for three-dimensional studies (3D diagnostics).
The occlusal line is drawn on two points: in the area of the molars, it is the point of closure of the mesial buccal cusp of the first molar of the upper jaw and the intercuspal fissure of the first molar of the lower jaw. In the incisors, the starting point is the point where the incisal edge of the man-dibular central incisor closes and the notch in the area of the palatine surface of the upper mandibular central incisor
(Fig. 3.3).
To perform the necessary measurements relative to the LP point, the upper and lower dentition models are placed along a line drawn along the median palatine suture in the mutually opposite direction.
The position of the upper dentition is determined by the distance from LP point to Mu point, which is the point of intersection of the median palatine suture with the transversal
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Fig. 3.1. LP point at the intersection of the N-Po and OcP lines
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Fig. 3.2. N-Po reference line
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Fig. 3.3. The occlusal plane line in patients with physiological occlusion
line drawn through the mesial buccal cusps of the right and left first molars of the upper dentition.
The position of the lower dentition is determined by the distance from LP point to Ml point, which is the point of intersection of the median palatine suture with the transversal line drawn through the fissures of the right and left first molars of the upper dentition (Fig. 3.4).