下顎枝矢状分割術を施行した下顎前突症患者の正貌軟組織変化

Abstract

The purpose of this study was to clarify soft tissue changes of a frontal face in prognathic patients following surgical mandibular retrusion.Twenty-two adult prognathic patients without facial asymmetry, who underwent sagittal splitting ramus osteotomy using screw fixation, formed the basis of this study. A pair of pre- and postoperative standardized frontal facial photos and lateral cephalograms were used for soft and hard tissue analysis. For quantitative evaluation of the facial photos, the amount of sagittal rotation of the head based on FH head position (0°) was computed using lateral cephalograms and the facial photos presenting less than ±2°of pitching angle of the head were used for the sample as proper frontal facial photos. A paired t test was used to indentify significant hard and soft tissue changes of a frontal face following surgery. A Pearson correlation analysis was used to distinguish soft tissue changes from hard tissue changes.The results were as follows:1.Skeletal deformity of the subjects was characterized by remarkable protrusion of the mandible, coupled with lingual tipping of the lower central incisors. Distinguishing mandibular backward movement with a small amount of rotation was found following surgery.2.Significant changes in the soft tissue were found in the shape and position of the lip. The thickness of the upper red lip significantly increased and the width of mouth aperture significantly decreased. The lip position demonstrated significant downward movement together with significantly increased height from subnasale to stomion and significantly decreased height from stomion to soft tissue menton.3.The facial width increased significantly at all areas and in particular, the ratio of facial width to lower facial height increased remarkably around the chin and lip areas.4.A significant correlation was found between the vertical positional change of lip and the sagittal change of the mandible, while no significant correlation was found between the change of lip shape and the sagittal change of the mandible.These results suggested significant effects of sagittal splitting ramus osteotomy on the change of lip shape and position as well as facial outline, which could remarkably improve the frontal facial appearance following surgery.