Variables That Influence Changes in Temporomandibular Joint Structure

Abstract

ABSTRACT Background There are no objective measures which forecast longitudinal changes in the temporomandibular joint (TMJ). Objective To identify variables that predicted longitudinal changes in TMJ structure. Methods Over an average of 8 years, baseline and follow‐up computed tomography and magnetic resonance imaging data were reviewed by calibrated radiologists. Baseline to follow‐up changes in TMJ structure were grouped according to A = no changes, B = got better and C = got worse. For the current investigation, Groups A and B were combined (AB). Baseline measures included ramus length; occlusal plane angle and anteroposterior position; and condyle rectilinear area (major axis × minor axis lengths), aspect ratio (major axis length/minor axis length) and axial angle. These variables were combined with DC/TMD Axis II physical symptoms scores (PHQ‐15) and an abbreviated 7‐question oral behaviour checklist score (7QBC) to determine an Anatomic‐Psychophysiologic Score (APS). Mixed‐effects logistic modelling was used to estimate the contribution of baseline variables in APS that were significantly different between groups. Results From 401 adult subjects who provided longitudinal data, TMJs from females (426) and males (90) had baseline images with sufficient field‐of‐view for cephalometric measurements. TMJs were assigned to groups AB ( n = 303) and C ( n = 213). Significant group differences ( p < 0.001) in APS were found for the combination of sex, ramus length, condyle rectilinear area and axial angle, occlusal plane anteroposterior position and 7QBC. Model accuracy was good (sensitivity, 0.85; specificity, 0.80; aROC = 0.91). Conclusions The combination of sex and cephalometric and behaviour measures was found to be predictive of longitudinal changes in the TMJ.