Discrepancy of coronal morphology between mandibular condyle and fossa is related to pathogenesis of anterior disk displacement of the temporomandibular joint

Objective. To evaluate whether morphological discrepancy between the mandibular condyle and fossa of the temporomandibular joint (TMJ) is related to disk displacement on magnetic resonance imaging (MRI). Study design. This study included 61 patients with unilateral internal derangement based on both MRI and clinical examination. Coronal morphologies of the condyle and fossa were divided into four groups based on Oberg's classification. According to the coronal morphology of the condyle and fossa, all joints were dichotomized into either harmonized group or a discrepancy group (e.g., angled condyle and concave fossa). The incidence of discrepancy and the relationship of the discrepancy to other findings on MRI were statistically evaluated. Results. The discrepancy had a significantly higher incidence on the affected side. The discrepancy correlated with incidence of disk deformity on the affected side. Conclusion. Morphological discrepancy between the condyle and fossa is related to development of anterior disk displacement in the TMJ.