Long-term evaluation of progressive condylar resorption after orthognathic surgery in mandibular retrognathism with high mandibular plane angle: An analysis of three-dimensional computed tomography.

INTRODUCTION

The purposes of this study were to analyze the volumetric change of condyle in postoperative progressive condylar resorption (PCR) using three-dimensional computed tomography (3D CT) over a long-term follow-up period of at least 2 years after mandibular advancement surgery, and the correlation between changes in the condylar volume in 3D CT and the condylar size in orthopantomogram (OPG).

MATERIAL AND

METHODS

In 14 female patients with mandibular retrognathism and a high mandibular plane angle who underwent orthognathic surgery, OPGs, lateral cephalograms, and 3D CT scans were acquired before the surgery, immediately after the surgery, and at a follow-up of at least 2 years. Surgical movements and postoperative skeletal changes in lateral cephalogram, change of condylar size in OPG, and changes of condylar position and volume in CT were measured and statistically analyzed.

RESULTS

The average reduction in condylar volume was 154.3 mm3 (19.1 %). Postoperative PCR was observed in a total of 12 condyles in eight patients. The change in condylar volume positively correlated with changes in condylar width (p < 0.01) but not with changes in the condylar height on OPG.

DISCUSSION: The condylar width should be evaluated, instead of the height, when diagnosing PCR using OPG.