A plane-based landmark-free method to examine and diagnose facial bone asymmetry

Purpose: To illustrate the use of a method that has been developed to assess the facial bone symmetry in 3D using no landmark.

Patients and methods: The program is based on the optimal symmetry planes (OSPs), which are the median planes fitted to show the highest ratio of voxel pairing on the 2 sides of the computerized tomography images of the facial skeleton. The deviation angles (angles between the OSP of the midface and the mandible) and the deviation distances (distances between the 2 planes at the lower borders of the mandibles) were determined. Methods are illustrated with 9 normal subjects and 31 subjects with facial asymmetries and differences in measurements between the two groups of subjects were tested for statistical significance.

Results: Measurements based on the OSP were significantly different between the two groups of subjects ( p < 0.001). Low ratio of voxel pairing of the midface or mandible was associated with greater deflection of the OSP of the mandible ( p < 0.05).

Conclusions: Measurements based on the method were different in subjects with and without facial–skeletal asymmetries. This method has several special features: (1) automatic computing for planes of midface and mandible; (2) assesses all hard tissue using no landmark; (3) quantitative assessment in an understandable way; (4) results illustrated in 3D figures. The quantitative results and the illustrations obtained by the program can be useful in the diagnosis and management of the asymmetrical facial skeleton.

Only gold members can continue reading. Log In or Register to continue

Jan 21, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on A plane-based landmark-free method to examine and diagnose facial bone asymmetry
Premium Wordpress Themes by UFO Themes