Association between 3-dimensional mandibular morphology and condylar movement in subjects with mandibular asymmetry

The purpose of this study was to evaluate the hypothesis that 3-dimensional mandibular morphology is correlated with condylar movement in patients with mandibular asymmetry.

Subjects were classified into 2 groups (n = 25 each): mandibular asymmetry with a menton deviation greater than 4 mm and no mandibular asymmetry with a menton deviation less than 4 mm. Linear and volumetric measurements of 3-dimensional mandibular morphology were recorded using computed tomography. Mandibular functional movement was recorded by computerized axiography (CADIAX; Gamma Dental, Klosterneuburg, Austria), and condylar path length, sagittal condylar inclination, and transverse condylar inclination on protrusion were measured. We calculated side-to-side asymmetry (shifted side vs nonshifted side) in mandibular morphology and assessed condylar movement by using an asymmetry ratio (nonshifted side/shifted side).

Significant differences in mandibular morphology and condylar movement were found between the 2 groups. In the group with menton deviation greater than 4 mm, significant correlations were found between the asymmetry ratio of mandibular morphology and condylar movement: ie, condylar path length and transverse condylar inclination. No significant correlations were found between any of these measurements in the group with menton deviation less than 4 mm.

In support of our hypothesis, the results suggested that 3-dimensional mandibular morphologic asymmetry is associated with condylar movement in subjects with mandibular asymmetry.