Morphometric Characterization of Asymmetric Mandibles Due to Condylar Hyperactivity

J Oral Maxillofac Surg. 2019 May;77(5):1056-1067. doi: 10.1016/j.joms.2018.12.020. Epub 2018 Dec 31.

Abstract

Purpose: Mandibular asymmetry related to condylar hyperactivity (CH) presents a complex set of morphologic features that pose challenges for its correction. Using state-of-the-art morphometric techniques, this report provides a detailed and hierarchical description of the features present in CH-related asymmetric mandibles and offers new knowledge for the surgical treatment of CH.

Materials and methods: Sixty patients were included in the sample. Thirty had CH-related asymmetric mandibles and the other 30 had clinically symmetric mandibles. Twenty-eight 3-dimensional landmarks were placed on computed tomographically based reconstructions of each participant's mandible and analyzed using geometric morphometric analysis for the quantitative and qualitative comparison of their morphologic features.

Results: All 60 participants exhibited asymmetry. However, those with CH exhibited a broad range of shapes and even shared several morphologic features with the controls. Mainly the ramus and then the body were the main contributors of the differences between groups.

Conclusions: There is considerable overlap of anatomic features characterizing symmetric and asymmetric mandibles; based on shape alone, the 2 groups can be easily misclassified. The ramus and body of the affected side in CH-related asymmetric mandibles were the main contributors to asymmetry of the structure. The chin, a usual diagnostic structure, did not greatly contribute to the structural asymmetry of the mandible.

MeSH terms

  • Chin
  • Facial Asymmetry*
  • Humans
  • Imaging, Three-Dimensional
  • Mandibular Condyle*