Maxillary incisor proclination effect on the position of point A in Class II division 2 malocclusion

To test the hypothesis that the magnitude of alteration in the position of point A is not associated with proclination of the upper incisors in Class II division 2 malocclusion.

Cephalometric films were taken for 30 Class II division 2 patients (8 males and 22 females; average age, 18.3 years) before and after upper incisor proclination. The total change in the position of point A was measured by superimposing the pretreatment and postproclination lateral cephalograms on the sella-nasion line at the sella. To determine the local effect of alveolar bone remodeling associated with upper incisor proclination on the position of point A, postproclination tracing of the maxilla was superimposed on the pretreatment tracing according to the Bolton template of maxillary superimposition.

The total vertical displacement in Point A position was downward by 0.84 mm (P = .002), and the total horizontal displacement was forward by 0.45 mm (P = .054). Assessment of local changes in point A revealed that the position of point A had moved backward by 0.60 mm (P = .001). No significant change was observed in the value of the sella-nasion-point A angle (SNA).

The hypothesis is rejected. The position of point A is affected by local bone remodeling associated with proclination of the upper incisor in Class II division 2 malocclusion, but this minor change does not significantly affect the SNA angle.