Condyle bone destruction: the association between temporomandibular joint vibration and finite element analysis

Objective The objective of the study is to investigate the stress distributions of condyle and articular disc at different mandibular plane angles and the association between the temporomandibular joint (TMJ) vibration and anatomical relationship. Setting and sample population Data from 195 untreated patients were analyzed. Patients were, respectively, divided into 3 groups, based on cone-beam computed tomography (CBCT): Group 0 presenting normal condyles, Group 1 presenting mild bone change, and Group 2 presenting severe bone change; based on magnetic resonance imaging (MRI): normal disc position (N), disc displacement with reduction (DDR) and disc displacement without reduction (DDNR); based on the mandibular plane angle: low, normal and high. Methods (1) According to peak frequency, average amplitude, and occurrence phase, association was assessed between TMJ condition and TMJ vibration; (2) A three-dimensional finite element model of masticatory system was established and the relationship between mandibular plane angle and condyle bone destruction was described. Results The average amplitude of TMJ vibration negatively correlated with pathological condition of the articular disc ( p < 0.01). The angle of SN-MP was strongly relevant to bone destruction of condyle ( p < 0.01), and the biomechanical analysis showed that with the increase of SN-MP angle, the area of stress concentration in the posterior slope of condyle rose. Conclusions The average amplitude of TMJ vibration decreased with the pathological position state of articular disc, and condyle bone destruction was positively associated with SN-MP angle.