Soft Tissue Changes of the Lower Lip Following Isolated Mandibular Advancement Osteotomies

The purpose of this study was to evaluate the soft tissue changes that occur following isolated mandibular advancement surgery. A sample of 70 non-growing patients were examined by tracing pre and post-operative radiographs. Then various landmarks were chosen and hand measured to determine hard and soft tissue changes. Significant correlations were found for many of the horizontal and vertical tissue landmarks and weaker correlations for all other landmarks. The decrease in the interlabial gap and the angular changes in the lower lip reflect the direction of surgical movement. The data from this study supports previous studies of smaller sample sizes and suggests a 1:1 soft to hard tissue ratio for rough clinical prediction in the chin and sublabial area. Reliability tests demonstrate the measurement technique to be accurate