TMJ in facial class III deformity. Condyle/fossa relations.

The aim of this study was to ascertain the joint space present in the TMJ of subjects diagnosed with Class III dentofacial deformity with an indication for orthognathic surgery. Fourteen subjects were recruited from the Division of Oral and Maxillofacial Surgery at the Universidad de La Frontera, Chile. All subjects were admitted to the study after signing an informed consent and undergoing cephalometric analyses to define the severity of the deformity. Then, the joint space was analyzed, studying a cone beam CT image of the TMJ, which was evaluated in the coronal and sagittal views, defining the most anterior, median and posterior joint space (sagittal view), as well as the lateral, median and medial joint space (coronal view). The data were recorded in millimeters by an observer and data were analyzed after measuring the same parameter at three different times. A student's t-test was used for the analyses. Differences observed in both joints were not greater than 0.2 mm with spaces between 2 mm and 1.5 mm, thereby establishing the homogeneity of the sample, which presented no significant differences between the two joint spaces (right and left). It can be concluded that the joint space is symmetrical in both condyles and that no important changes are present compared to the results indicated in the international literature.