Soft tissue compensation evaluation in patients with facial asymmetry using cone-beam computed tomography combined with 3D facial photographs

Abstract

ObjectivesThis study aimed to evaluate bilateral soft tissue, hard and soft-tissue thickness at various anatomical levels in patients with facial asymmetries. Moreover, we attempted to find out correlation between soft-tissue compensation and severity of asymmetry by using cone-beam computed tomography (CBCT) combined with 3D facial photographs. Study designBased on menton deviation (MD), twenty-four subjects were divided into: mild-asymmetry group (n=12) and moderate-to-severe-asymmetry group (n = 12). CBCT images were superimposed with 3D facial photographs. Distance from the midsagittal plane to the outermost point of soft-tissue and hard-tissue were measured and calculated soft-tissue thickness. Comparison of soft-tissue thickness between deviated and contralateral side at any anatomical levels were performed within group, and correlation between bilateral soft-tissue thickness subtractions (soft-tissue compensation) and MD values was evaluated. ResultsWithin group, Soft- and hard-tissue distances were greater in deviated side than contralateral side at any levels. In moderate-to-severe group, significant differences were found at gonion and body of mandible level, whereas soft-tissue thickness was only found to be higher on deviated side at the level of mandibular ramus. Soft tissue compensation was negatively correlated with MD value at level of mandibular ramus (R = −0.5, P < 0.05). ConclusionsAsymmetry was found to be larger in the lower third of the face and was notably remarkable in the moderate-to-severe group. Soft-tissue thickness was thicker on the deviated side of the mandibular ramus. Thus, the soft-tissue compensation seems to be minimized in patients with more severe asymmetry.