Advancement genioplasty--cephalometric analysis of osseous and soft tissue changes.

Background: Genioplasty is often performed to esthetically improve patient's profiles in the lower facial third. Many factors account for the variability in soft tissue response like dissection technique, magnitude and direction of movement and stability of the genial segment. Optimum treatment planning thus requires an understanding of the soft tissue response to various genial procedures.

Aims And Objective: To determine the stability, ratio of hard and soft tissues and changes in the lower facial profile after advancement genioplasty.

Materials And Methods: Ten patients were evaluated cephalometrically for the soft tissue changes in relation to hard tissues after advancement genioplasty. Pre operative, immediate post operative and 6 months post operative lateral cephalogram were taken. Pre operative tracings were superimposed with post operative cephalograms to produce a composite tracing. Changes in the osseous tissues are assessed and related to the net changes in the soft tissues.

Results: The ratio of horizontal changes of osseous to soft tissues was found to be 1:0.89. The mean resorption was 0.85 mm (10.7%). The vertical changes are minimal and non significant. There are significant changes in the soft tissue profile such as decrease in the soft tissue thickness, facial convexity angle, lower facial submental angle and increase in mentolabial sulcus depth.

Conclusion: The standard advancement genioplasty procedure by inferior osteotomy of the chin with broadest musculo-periosteal pedicle with rigid internal fixation was followed. The soft tissue response is almost equal to the bony movement. The stability of the hard tissues is good with minimum amount of resorption so as to achieve more predictable results.