Effect of proclination of the upper incisors on Point A in adult Class II division 2 individuals: A cephalometric study

Abstract

The study aimed to identify and evaluate changes in the cephalometric position of Point A due to an incisal inclination change caused by orthodontic treatment in non-growing Class II division 2 patients. A total of 24 pairs of consecutive pre-treatment and post-treatment lateral cephalograms were systematically collected from the departmental database and hand traced. The total change in the position of Point A was investigated by superimposing pre-treatment and post-treatment lateral cephalograms at a stable basicranial line. The treatment changes in maxillary incisor inclination, the sagittal position of Point A, SNA angle, movement of incisor root apex, and incisal edge were calculated. The mean SNA angle was reduced significantly suggesting that the A point had moved backward solely due to orthodontic remodeling. Point A distance to true vertical was reduced significantly (mean 1.2 mm), suggesting that local remodeling has occurred due to orthodontic treatment. The incisal edge also moved forward significantly (mean 2.6 mm). The apex of the upper incisor moved significantly backward as a result of its counterclockwise rotation (mean 3.2 mm). The upper incisor to palatal plane values also showed a highly significant change in inclination of the upper incisors (mean 12.30). Counter-clockwise rotation of the upper incisor causing its root apex to move more palatally makes remodeling changes in Point A in the form of its retraction roughly by one-third the amount of the backward movement of the upper incisors’ root apex. Moreover, it can be inferred that the retraction of Point A in millimeters will roughly be equal to the reduction in SNA angle in degrees.