The facial deformity caused by mandibular prognathism has long been of great interest to the orthodontist. The deformity of the lower jaw is readily expressed as a profile disfigurement, since the soft tissues of the face depend on the lower jaw for much of their contour. The dental literature is replete with various surgical techniques for the correction of mandibular prognathism. The consequences of surgery on facial appearance are of great importance, Therefore an accurate prediction of the post-operative facial profile comprises an essential and integral part of the diagnostic and treatment planning procedures of the combined surgical & orthodontic therapy. This book therefore aims to describe the inter- relationships of the soft tissue and dentoskeletal profiles after total mandibular setback osteotomies and to detect whether there were any cephalometric variables that could contribute to an accurate prediction of the surgical effect on the soft tissue profile. BSSO, mandibular set back was done. Results showed that the facial concavity, to the relationship of the hard and soft tissue chin to the upper face, was decreased, facial esthetics was improved.