Unilateral temporomandibular joint disorders diagnosed as both disc displacement without reduction and osteoarthritis show vertical craniofacial asymmetry in women

Abstract

This study investigated the effects of unilateral temporomandibular joint disorders (TMJDs), specifically disc displacement without reduction and osteoarthritis on one side of the temporomandibular joint (TMJ), on facial asymmetry in women, while the contralateral TMJ exhibits normal findings. Participants were retrospectively enrolled and divided into an affected group (n = 42 with unilateral TMJD) and a control group (n = 49 with bilateral healthy TMJs). The affected group was dagnosed with osteoarthritis on cone-bema computed tomograph and anterior disk displacement without reduction on magnetic resonance imaging. The control group showed normal findings bilaterally on both tests. Facial asymmetry was quantified using an asymmetry index derived from posteroanterior cephalograms, comparing both groups. The relationship between TMJD sub-findings and facial asymmetry was also investigated. Significant increases in the asymmetry indexes of the vertical distances from the antegonial notch and gonion to a horizontal reference plane were observed in the affected group (p < 0.05). Additionally, there was a noticeable upward canting of the maxillary, occlusal, and mandibular planes towards the affected side (p < 0.05). Horizontal asymmetry did not differ significantly between groups (p > 0.05). Parafunctional habits in the affected group were correlated with higher asymmetry indexes of the antegonial notch distance (p < 0.05). Women with unilateral TMJD exhibit significantly greater vertical facial asymmetry compared to those without TMJD. These findings may assist clinicians in diagnosing vertical asymmetry in patients with unilateral TMJD using cephalograms and in predicting facial asymmetry progression.