Maxillofacial Features Related to Mandibular Asymmetries in Skeletal Class III Patients.

PURPOSE: To analyze components related to different degrees of mandibular asymmetry in adults with skeletal Class III using cone-beam computed tomographic (CBCT) images.

MATERIALS AND METHODS: CBCT images from 138 patients were analyzed. Asymmetry was determined by the deviation of the gnathion point in relation to the midsagittal plane and classified as relative symmetry, moderate mandibular asymmetry, or severe mandibular asymmetry. Several maxillary and mandibular measurements were used to compare different degrees of mandibular asymmetry and the difference between measurements of the contralateral and deviated sides.

RESULTS: For patients with moderate and severe mandibular asymmetry, there were statistically relevant differences between bilateral measurements of the sagittal position of the condylar heads, the transverse and sagittal positioning of the gonion, ramus height, and mandibular body length, the transverse and vertical positioning of the jugale point, including a vertical positioning of the gonion only for severe asymmetry. In patients with severe mandibular asymmetry, there was a highly relevant correlation of gnathion lateral displacement with lower dental midline displacement and with the difference in height of the mandibular rami between the deviated and contralateral sides.

CONCLUSION: In patients with skeletal Class III, not only lateral displacement of the menton but also a series of morphologic changes differed markedly for each degree of mandibular asymmetry.