Posterior-anterior cephalometric analysis in patients with dentofacial deformities.

Abstract

Dentofacial deformities are generally classified with the lateral cephalogram. Such classification, however, is incomplete because facial asymmetry could not be diagnosed if the evaluation of the posterior-anterior cephalometric radiogram (P-A) is not considered. Sixty adults (30 male and 30 female) who had normal occlusion were randomly selected and their P-A cephalometric radiograms were traced on acetate tracing paper. We selected 18 landmarks as follows; MHW, CG, Lo, Rof, Po, Zyg, Ms, Nf, Zm, Mx, CMo, Mo, Co, ARE, Go, U1, L1, Me. According to Sassouni's report, a line connecting left and right lateroorbitale (Lo-Lo') was used as a horizontal reference line. The median sagital plane passes through the point Cista Galli (CG) and runs perpendicularly to the (Lo-Lo') line. We measured the difference between right and left points on the coordinate and calculated the standard deviation. Then we established the statistical chart of the P-A view based on the standard diviation (SD). We chose 3 points, Mx, Go and Me as the representation. If each point shifted beyond 2 SD, we difined it as deviation.According to the chart, the dentofacial deformities were classified into following 3 groups.Group 1; The deviation only on the mandible.Group 2; The deviation not only on the mandible but on the maxilla.Group 3; The deviation only on the maxilla.Totally 239 patients were operated in our hospital for past 10 years. 67 patients among 239 (approdmately 28%) had some degree of facial asymmetry. 43 patients belonged to group 1, 24 were group 2, and there were none in the group 3.