Soft Tissue Movement in Orthognathic Surgery: Does Pre-Operative Soft Tissue Thickness Affect Movement Change?

Background: The aim of this study was to examine whether the thickness of the preoperative soft tissue affects the degree of soft tissue movement relative to the hard tissue movement after orthognathic surgery. Methods: This is a retrospective examination of lateral cephalometric X-rays of patients who underwent orthognathic surgery in single medical center, during a 5-year period. Demographic and operative data were collected. Soft tissue thickness was measured in preoperative cephalometric X-ray, followed by superimposition of postoperative (>6 months) cephalometric X-rays by overlapping fixed bony points. Results: In the upper jaw, there was a decrease in the relative movement of soft tissue with an increase in the initial thickness in surgeries performing advancements up to 5 mm (r = −0.288). In mandibular advancements, there was a clear decrease in soft tissue movement ratio with an increase in the initial soft tissue thickness (r = −0.418), while there was no correlation in mandibular setback cases (r = 0.062). The same correlation between the decrease in relative soft tissue movement and the increase in initial soft tissue thickness was found in advancement genioplasty (r = −0.411). Conclusion: This research shows a general pattern of decrease in relative movement of soft tissue in orthognathic surgery correlated to an increase in its initial thickness.