In surgical orthodontic treatment, it is necessary to evaluate the relationship between changes of hard tissue and those of soft tissue in order to predict the post-treatment soft tissue profiles of jaw deformity patients. Individual differences of patients influence the relationship between changes of hard and soft tissue. This review compares the influence of sagittal split ramus osteotomy (SSRO) with combined maxillary and mandibular ramus surgery in changes of post-treatment soft tissue profiles of skeletal mandibular prognathism. The review also compares the influence of different profile patterns in changes of post-treatment soft tissue profiles of mandibular prognathism.
Skeletal changes of SSRO influence soft tissue changes more than those of combined maxillary and mandibular ramus surgery because of differences in the postoperative tension generated in muscles and soft tissue attached to the mandible.
The post-treatment soft tissue B point was located more backwardly than the predicted point in the facial patterns with a high mandibular plane angle and a long lower anterior facial height. In the facial patterns with a low mandibular plane angle, the post-treatment line of the lower lip was positioned more inferiorly and backwardly than the predicted lower lip line.
The influence on the predictability of post-treatment soft tissue profiles might differ depending on the surgical methods and profile patterns in mandibular prognathism.

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The purpose of this study was to evaluate hard and soft tissue changes in mandibular prognathic patients with open bite following different orthognathic surgery.
Twenty adult patients who underwent orthognathic surgery to correct mandibular protrusion and open bite were selected for this study. The subjects were divided into the following two groups based on surgical method: 12 subjects who underwent mandibular setback osteotomy with the sagittal split technique (one jaw group) and 8 subjects who underwent mandibular setback osteotomy with the sagittal split technique and combination (Le fort I and horseshoe) osteotomy in bimaxillary surgery (two jaw group). A pair of pre- and post-operative lateral cephalograms was used for hard and soft tissue analysis. Statistical analysis using a paired t test was performed for comparative study.
No significant differences were observed in the pre-operative anterior occlusion, dento-skeletal pattern and facial profile between the two groups. Anterior occlusion was improved in both groups following surgery and no significant differences were observed in the post-operative overjet and overbite between the two groups. However, significant differences were observed both in the dento-skeletal and facial profile changes between the two groups. The amount of mandibular up-backward movement, especially the chin portion in the two jaw group was significantly larger than that in the one jaw group due to the clockwise rotation of the maxillary occlusal plane following superior repositioning of the maxillary posterior portion. In accordance with this larger mandibular up-backward movement coupled with maxillary advancement in the two jaw group, more harmonized bimaxillary skeletal relationship as well as better facial profile were achieved in the two jaw group in comparison with that in the one jaw group. It is suggested that a combination of Le fort I and horseshoe osteotomy in bimaxillary surgery is a useful technique to treat mandibular prognathic patients with open bite.

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