A cephalometric evaluation of hard- and soft-tissue changes during the third stage of Begg treatment.

This study examined the effect of lingual root torque during the third stage of Begg treatment upon the maxillary central incisor, hard-tissue Point A, and soft-tissue Point A. Lateral cephalograms were taken, at the beginning and end of Stage III, of eighteen patients undergoing Begg treatment. Linear and angular measurements were made in an attempt to find the anteroposterior changes which occurred in the above structures as well as the superior-inferior changes which occurred in the maxillary first molar and the maxillary central incisor. It was found that the apex of the maxillary incisor, Point A, and soft-tissue Point A moved posteriorly a significant amount following Stage III mechanics. Also, the incisal edge of the maxillary central incisor moved anteriorly and extruded significantly. Weak correlations between hard- and soft-tissue changes may be due to changes in thickness of the upper lip related to growth and to growth of the nose.