Unilateral condylar hyperplasia: a 3-dimensional quantification of asymmetry

Purpose
Objective quantifications of facial asymmetry in patients with Unilateral Condylar Hyperplasia (UCH) have not yet been described in literature. The aim of this study was to objectively quantify soft-tissue asymmetry in patients with UCH and to compare the findings with a control group using a new method.

Material and Methods
Thirty 3D photographs of patients diagnosed with UCH were compared with 30 3D photographs of healthy controls. As UCH presents particularly in the mandible, a new method was used to isolate the lower part of the face to evaluate asymmetry of this part separately. The new method was validated by two observers using 3D photographs of five patients and five controls.

Results
A significant difference (0.79 mm) between patients and controls whole face asymmetry was found. Intra- and inter-observer differences of 0.011 mm (−0.034-0.011) and 0.017 mm (−0.007-0.042) respectively were found. These differences are irrelevant in clinical practice.

Conclusion
After objective quantification, a significant difference was identified in soft-tissue asymmetry between patients with UCH and controls. The method used to isolate mandibular asymmetry was found to be valid and a suitable tool to evaluate facial asymmetry.