Changes in the integumental profile of the chin and lower lip after genioplasty.

The results of a cephalometric study of changes in the soft tissue profiles after horizontal osteotomy for genioplasty were analyzed in 14 subjects. Scatter diagrams relating changes at the soft tissue landmarks of the mandible (point C, LI) to changes at the hard tissue landmark of the pogonion were plotted to illustrate the relationship between the movement of these pairs of landmarks of the lower third of the face. Finally, graphic representation of the regression equations computed from this study gave the clinician a means of predicting skeletal and integumental changes resulting from the surgical procedure under consideration. The following results were obtained. -For all subjects in this study, an anterior change at the hard tissue landmark, Pog, was accompanied by an anterior movement in the soft tissue landmarks of the lower third of the face. The greatest amount of change in the soft tissue occurred at point C, with less anterior change at ILS, and the least at LI. -The response of the soft tissues of the chin had a high correlation with changes at Pog, the corresponding underlying hard tissue landmark. Comparison of changes between them indicated that 1.0-mm change at Pog resulted in approximately 0.8-mm anterior change at point C, the overlying soft tissue landmark. -The response of the soft tissue of the lower lip showed a correlation to changes at Pog. Comparison of changes between them indicated that 1.0 mm-change at Pog resulted in approximately 0.4-mm anterior displacement at LI, the overlying soft tissue landmark. However, the correlation was not sufficiently great to be used in any individual prediction. -The relationship of the response of hard tissues and soft tissues was similar for large and small amounts of surgical movement.