Soft tissue profile changes following mandibular advancement surgery: Predictability and longterm outcome

The objectives of this cephalometric study were to assess long-term changes in the soft tissue profile following mandibular advancement surgery and to investigate the relationship between soft tissue and hard tissue movements . The sample consisted of 61 patients treated consecutively for mandibular retrognathism with orthodontic therapy combined with bilateral sagittal spl it osteotomy and rigid fixation. Lateral cephalograms were taken on 6 occas ions: immediately before surgery, immediately after surgery, 2 and 6 months after surgery, and 1 and 3 years after surgery. Postsurgical changes in th e upper and the lower lips and the mentolabial fold were more pronounced am ong low-angle cases compared with high-angle cases, In accordance with othe r studies, the soft tissue chin and the mentolabial fold were generally fou nd to follow their underlying skeletal structures in a 1:1 ratio. Because o f the strong influence skeletal relapse has on soft tissue profile changes, alternative ratios of soft tissue-to-hard tissue movement that accounted f or mean relapse were also generated, It is suggested that if a more realist ic long-term prediction of the postsurgical soft tissue profile is desirabl e, then ratios incorporating mean relapse should be used rather than estima tes based on a 1.1 relationship.