Evaluation of condylar anatomy through Cone Beam CT scans

Objective: The use of Cone-Beam computed tomography (CBCT) provides an opportunity to look at the anatomy of the maxillary complex in three dimensions in a way that was not possible with lateral cephalograms or dental models. The description of the morphological aspect of a solid has recently became possible thanks to 3D images, showing at the same time the shape and the size of the object. By means of a 3D segmental reconstruction, we are also able to define the volumetric value of a facial structure, while taking in account its structural cavities, including the nasal cavity, the oral cavity, and the maxillary sinus. The aim of this comparative study was to evaluate the asymmetry of condylar anatomy between the right and the left condyles, with an higher accuracy than traditional radiographic relevations. Material and Methods: The mandibular condylar morphology was retrospectively assessed by using CBCT imagings of 12 patients without any Temporomandibular joint pathology, 6 males (average 35.5) and 6 females (average 35.66). The CBCT data of these patients were retrospectively recorded in a private radiological study, among patients that were undergoing an orthodontic treatment for problems of malocclusions (generally crowding). In order to be included, patients had to be free of symptoms relative to Temporomandibular disorders, at the time of their first clinical evaluation. In addition, they had not to be submitted to ortognathic surgery, and were not extreme brachycephalics and dolichocephalic subjects. All patients have been examined with a Cone Beam (Iluma) for the planning of the orthodontic treatment. The morphological analysis of the mandibular condyles was performed using Dicom files acquired through CBCT. The calculation of the condylar volume and the condylar surface was done with Mimics software. The voxel dimension of every performed scan was about 0.09 mm3, in order to measure minor dimensional differences between condyles. Results: The results showed a higher dimensional asymmetry between the right and the left mandibular condyles in the male group, rather than in the female group. However, in both the two groups, we observed a high inter-individual variation. Discussion: The observed differences were probably correlated to the different muscular tone, according to theory of functional matrix. In support of this observation there are some studies that showed a great asymmetry in the body structures, both in females and males, at a rate of about 5-10%, at mean. With this study, we have been able to identify the existence of a “normal” asymmetry in the condylar morphology and condylar volume, between the right and the left sides. In both the two groups, the measurements of the morphological variables presented a high inter-individual variability; this may be due to the existence of microscopical abnormalities (small cavities and sulci) in the condylar surface, that are able to influence the condylar morphology.