Modification of the angle of the lower third of the face

Determination of vertical dimension of occlusion by roentgencephalometric method, with the help of the angle of the lower third of the face, has been described in literature. The aim of this study was to modify the angle of the lower third of the face and correlate its determination with reference planes for orientation of casts in the articulators space, to determine mean value and measures of variability of the modified angle in a random sample, and the possibility to use this angle as a control value for establishing the height of the lower third of the face. On a sample of 131 roentgenograms in L-L projection, with teeth in maximal intercuspation, points: N, IS47, THA, SNA, SNP, Xi and Pg were traced down. By the use of this points the angle of the lower third of the face (angle K) was constructed. The values of the angle were measured and statistically analyzed. Mean value of the angle was 48.5 degrees, with standard deviation of 4.41 and coefficient of variation 9.09%. The investigated angle can serve as a control value for determination of intermaxillary relationships and should not be accepted as an strict norm.