The aim of the present study is to improve the outcome of orthognathic surgery in the mandibular prognathism by evaluation of hard tissue and soft tissue profile changes following surgical mandibular steback procedure in Korean mandibular
prognathism.
Mandibular steback procedures were performed by means of sagittal split ramus osteotomy with rigid fixation in 50 patients(female 37, Male 13). Lateral cephalograms of each patient were taken presurgery, immediate postsurgery, and after a
folow-up
period 3 to 6 months. The mandibular prognathic patients have also a tendency of maxillary retrognathism. The mandibles were more protruded in Closed-bite group than in Open-bite group. By the mandibular setback, the mandibles of Closed-bite
group
rotated clockwise and mandibles of Open-bite group rotate counterclockwise. There was relapse in 58% of total patients. no relapse in 32%, and further posterior movement in 10%. Although a 9-10% relapse of the original surgical correction
occurred
and
this was larger in Open-bite group. there was not a close interrelation between amount of relapse and that of surgical mandibular setback. Soft issue profile changes fllowing mandibular setback occurred according to hard tissue changes, 0.12 : 1
at
the
upper lip, 0.89 : 1 at the lower lip, and 1: 1 at the chin.
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