Condyle and Mandible Shape in Patients With Different Growth Patterns

Objectives: The purpose of this study was to determine condylar head and neck angulations in patients presenting different growth patterns, using cone-beam computed tomography (CBCT) images.
Methods: Seventy-four CBCT images were processed and analyzed using the third-party software system Dolphin 3D Imaging. These patients were grouped depending on their growth pattern (37 – vertical growth; 37 – non-vertical growth). 3D volume segmentation was performed on the mandible of each of these patient images to include distal to the seventh molar, inclusive of the angle and ramus of the mandible, coronoid process, and condylar head, bilaterally. The segmentations were saved as STL files and analyzed using MATLAB, a software system for developing algorithms, analyzing and visualizing data, and performing numerical computation. Ten images were volume segmented three times each to determine the reliability of the method, leaving a week between trials.
Results: Overall, all landmarks showed excellent reliability (>0.98) and permitted the use of all landmarks located. It was found with segmentation that there was a 90% similar shape patterns, making the method reliable. Shape wise, there were no major differences between vertical and non-vertical growers in the posterior aspect of the mandible, but there was a slight tendency in the gonial angle and antegonial notch to be more pronounced in vertical growers.
Conclusions: Overall, no significant differences were found in the shape of the posterior aspect of the mandible. A different diagnostic method to use in 3D images is needed to determine growth pattern, as shown by the present results.