CBCT-Based Comparative Evaluation of Temporomandibular Joint Morphology and Joint Spaces

Objectives: To investigate the changes in anteroposterior and mediolateral positions of the mandibular condyle by measuring joint spaces after orthodontic treatment in adults using CBCT. Material and Methods: A sample of 180 individuals was searched in the patient database at the UCSF Orthodontic Clinic, from which 30 were selected based on the following search criteria: subjects older than 18 years of age who had final CBCT taken between two time points from January of 2015 to June of 2016. Exclusion criteria were orthognathic surgery cases, individuals with craniofacial anomalies, poor scan resolution, skeletal asymmetry, and patients with significant CO=CR discrepancy. Tomograms of right and left TMJs of 30 patients were analyzed by a radiologist, and descriptions of each joint were obtained and divided into four groups (normal, active erosive, active repair and active stable) according the size, shape and quality of the condyle at two time points. Anatomage Invivo5 software was used to obtain sagittal and coronal oblique views of the condyle. The oblique views were corrected to parallel and perpendicular to the mediolateral long axis of the condyles. Through defined landmarks as described by Ikeda el al. the linear measurements were made from superior, anterior, and posterior joint spaces between the condyle and fossa in sagittal and coronal view at two time points. Results: Five patients with degenerative joint disease (DJD) had stable repair of the condyles and changed at the end of treatment. Only one joint with DJD progressed from active repair to stable repair group during the treatment time. In both sagittal and coronal joint spaces measurements, there were no significant changes for all six measurement variables. (P value >0.1). Also, there was no significant difference in joint spaces when compared between two different treatment groups: extraction and non-extraction (P value > 0.1) Conclusion: Orthodontic treatment did not cause significant changes in the condylar positions of adults with normal osseous anatomy or with DJD that was stable or in the repair phase. There was no statistically significant correlation between changes in joint spaces based on non-extraction vs. extraction treatment