Postoperative stability of 2-jaw surgery with clockwise rotation of the occlusal plane.

Objective: The objective of this study was to investigate the skeletal stability after Le Fort I osteotomy with clockwise rotation and bilateral sagittal split osteotomy.

Materials And Methods: The sample consisted of 31 young Korean patients who were treated with Le Fort I osteotomy with clockwise rotation and setback bilateral sagittal split osteotomy. The lateral cephalographs were obtained before surgery (T1), right after surgery (T2), and on an average of 6.23 months after the operation (T3). The horizontal and vertical relations of landmarks to the reference line and soft tissue changes were evaluated.

Result: During the T2 - T1 period, there was superior and anterior movement of the posterior part (PNS, UMD) and advancement and impaction of the anterior part (ANS, A point, UIE) of the maxilla. The mandible was moved superiorly and posteriorly. During the T3 - T2 period, maxillary segment showed counterclockwise rotational relapse. The posterior part was relatively stable especially in the vertical position and the anterior part moved in the posterior and superior directions. Mandibular landmarks showed forward relapse in the horizontal aspect and superior relapse in the vertical aspect. The posterior part (PNS and UMD) showed a significantly higher stability rate (>70%) in the vertical aspect and the anterior part of the maxilla (ANS, A point) demonstrated a significantly lower value (<30%) in the vertical aspect. According to the skeletal changes, the soft tissue of the lower facial profile is rotated clockwise.

Conclusions: Two-jaw surgeries involving clockwise rotation of the occlusal plane showed stable results especially in the maxillary posterior landmarks. The clockwise rotational movement can be beneficial to increase skeletal stability and facial aesthetics in Asians.