The assessment of the short‐ and long‐term changes in the condylar position following sagittal split ramus osteotomy (SSRO) with rigid fixation

Abstract

The purpose of this study was to compare the short- and long-term changes in condylar position related to the glenoid fossa, and skeletal and occlusal stability after orthognathic surgery. All of the study patients were assessed by cone-beam computed tomography images for condylar rotational changes and anteroposterior position in the pre-surgery, post-surgery and post-retention period. The condylar positions were evaluated on three planes: axial, coronal and sagittal. In the skeletal and occlusal measurements, there was no significant difference between the post-surgery group and the post-retention group. After sagittal split ramus osteotomy (SSRO), the condyle on the axial plane rotated inward (P < 0.05) and maintained during the post-retention period. In the anteroposterior condylar position related to the glenoid fossa, the condyles had changed from the anterior position in the pre-surgery group to a concentric position in the post-surgery group and then returned to the anterior position in the post-retention groups. These results suggested that the changed anteroposterior condylar position in the glenoid fossa after SSRO with rigid fixation had moved from a concentric to anterior position for post-retention period.

Effect of post–orthognathic surgery condylar axis changes on condylar morphology as determined by 3-dimensional surface reconstruction

“…1 During surgery, the condylar axis rotates to maintain the intersegmental contact after the distal segment moves anteriorly or posteriorly. Kim et al 4 reported that in patients who had undergone SSRO with rigid fixation, the condyle showed an inward rotation on the axial plane and was positioned posteriorly, on the a Postgraduate student, Department of Orthodontics, School of Dentistry, Pusan National University Dental Hospital, Yangsan, South Korea.…”

Cone-beam computed tomography evaluation on the changes in condylar long axis according to asymmetric setback in sagittal split ramus osteotomy patients

“…13 The rotation might be determined by many factors, including surgeon's experience, patient type, and time point of postoperative data. Some studies 8,14 evaluated the changes at 3 months after surgery; other studies [10][11][12][13] used the data 6 months after surgery. However, few studies evaluated condylar rotation changes immediately after surgery.…”

“…Literature review of recent CBCT studies [12][13][14][15] regarding the positional changes in condyle after orthognathic surgery showed a significant change in condylar rotation by the surgery. However, few studies dealt with its contributing factors.…”

“…Kim et al 12,13 assessed the changes in condylar position after SSRO using CBCT scan data. While condylar positions were evaluated on three planes, the condyle on the axial plane showed significant inward rotation in their study.…”

3D Assessment of Orthognathic Surgical Outcomes

“…One is based on linear and angular measurements (Jung et al, 2009;Kim et al, 2010Kim et al, , 2011Park et al, 2012a) that apply the concepts used routinely in 2D cephalometry to 3D images. The second method is based on the use of iterative closest point algorithms (Cevidanes et al, 2007;Carvalho Fde et al, 2010;Almeida et al, 2011;Motta et al, 2011) that analyze the smallest displacements between two structures but do not take into account the shape being measured.…”