2010 Volume 38 Issue 1 Pages 10-16
To estimate the skeletal antero-postero jaw relation from soft tissue profiles on laypersons or artistic products, a regression equation between the soft tissue profile and the skeletal antero-postero jaw relation was established from data for malocclusion patients with cephalograms. Eighty pretreatment lateral cephalograms of malocclusion patients who had visited our orthodontic clinic of Hokkaido University Hospital from 2002 to 2008 were used. The ANB angle on the hard tissue and the Sn-Ns-Pogs angle on the soft tissue, which was constructed from the subnasale point (Sn), the soft tissue nasion (Ns), and the soft tissue pogonion (Pogs), was measured from the cephalograms, and a regression equation between the Sn-Ns-Pogs angle and the ANB angle was calculated. Then the ANB angle of the laypersons were estimated from the Sn-Ns-Pogs angle of the lateral facial photographs we had as data. The results were as follows: (1) Mean values of the Sn-Ns-Pogs angle and the ANB angle were 7.8 degrees and 3.6 degrees, respectively. (2) The correlation coefficient between the Sn-Ns-Pogs angle and the ANB angle was r=0.84. The regression equation was y=0.73x-2.00, with the determination coefficient r^2=0.70. (3) The estimated ANB angle of the laypersons from the Sn-Ns-Pogs angle of the lateral facial photographs was 5.0 degrees as the mean value.
