Soft tissue response after Class III bimaxillary surgery : Impact of surgical change in face height and long-term skeletal relapse

Abstract

Objective: To analyze the impact of surgical change in anterior face height and skeletal relapse on the long-term soft tissue profile. Materials and Methods: Cephalometric radiographs of 81 patients taken before surgery and at five time points during a 3-year follow-up period were analyzed. All patients had Le Fort I and bilateral sagittal split osteotomies. The patients were divided into three subgroups according to the change in anterior face height during surgery. Calculations of soft to hard tissue ratios were based on the long-term soft tissue response relative to the surgical repositioning. Results: The horizontal surgical repositioning varied considerably, depending on whether anterior face height was increased or decreased. For upper lip prominence, the pattern of long-term change was the same irrespective of change in face height. In all groups, upper lip thickness decreased in both the short term and the long term, particularly in patients with surgical increase in face height. Lower lip thickness increased in the short term but decreased during the follow-up period. There were significant associations between horizontal soft tissue and corresponding hard tissue changes, except for soft tissue A-point and upper lip, when face height was increased. The ratios were higher for mandibular variables than for maxillary variables, particularly for B-point and pogonion when anterior face height had decreased. Conclusion: A change in facial height influences the soft tissue response. The mandibular soft tissues closely follow skeletal relapse beyond 2 months postsurgery. The findings have clinical implications for the relative maxillary and mandibular repositioning when planning surgery.