Factors related to the prevalence of anterior disc displacement without reduction and bony changes of the temporomandibular joint in patients with facial asymmetry

Abstract

PurposeThe aim of the study was to determine the factors related to the prevalence of anterior disc displacement without reduction (ADDwoR) and bony changes of the mandibular condyle (bony changes) in temporomandibular joints (TMJs) of patients with dentofacial deformity exhibiting facial asymmetry. Patients and methodsA total of 75 female patients (150 joints) with facial asymmetry, who had undergone orthognathic surgery, were examined with magnetic resonance imaging (MRI) of the TMJ and cephalometric analysis. Logistic regression analysis was performed to determine whether there was a statistically significant association between age, cephalometric measurements, and prevalence of ADDwoR and bony changes. ResultsFacial asymmetry, the prevalence of ADDwoR, and bony changes were more frequently found on the left side than that of the right side. Unilateral ADDwoR (n=28) and unilateral bony changes (n=14) were only found on the deviated side. The difference between the distance of upper incisal midpoints and lower incisal midpoints from the facial midline (U1–L1 distance) was significantly larger in 36 patients with ADDwoR and 52 patients with bony changes. According to logistic regression analysis, U1–L1 distance might be related to the prevalence of ADDwoR and bony changes in the TMJs with facial asymmetry. ConclusionU1–L1 distance related to the prevalence of ADDwoR and bony changes in TMJs of patients with dentofacial deformity exhibiting facial asymmetry.