Soft-tissue profile changes in Class II treatment

Abstract

By means of an x-ray cephalometric method, the soft-tissue and skeletal profiles were evaluated in postnormal Class II, Division 1 cases before and after orthodontic treatment. A comparison of the Class II cases before and after treatment showed that the main change that resulted from treatment involved the position of the upper incisors, which were more posteriorly located; also, the subspinale, lower incisors, the upper lip, and, to a lesser degree, the lower lip were more posteriorly located after treatment. A comparison of the thickness of the soft tissues after treatment with that before treatment in the postnormal cases showed that the thickness of the upper lip had increased and that of the lower lip had decreased after treatment. The degree of correlation between changes in the soft-tissue profile and changes in the skeletal profile during orthodontic treatment varied. Among the skeletal structures that were most affected during treatment, there was fairly good correlation between the displacement of the subspinale, incision inferior, and supramentale and the immediately overlying soft-tissue points (sulcus superior, labrale inferior, and sulcus inferior, respectively). By contrast, the correlation between the displacement of the incision superior and the labrale superior was rather poor. On the average, the retraction of the subspinale, incision inferior, and supramentale was accompanied by a practically equally large retraction of the respective soft-tissue points, whereas the ratio between the retraction of the incision superior and the labrale superior is about 2.5:1. There were large individual variations in the response of the soft tissues to changes in the underlying skeletal structures.