Relationship between menton deviation and temporomandibular disc displacement in adult patients

Purpose: This study investigated the relationships among characteristics of maxillomandibular asymmetry in patients with menton deviation and temporomandibular joint (TMJ) disc conditions, including normal disc position (NDP), anterior disc displacement with reduction (ADDwR), rotational disc displacement with reduction (RDDwR), and anterior and/or rotational disc displacement without reduction (DDwoR). Materials and methods: Eighty-six patients with menton deviation (62 female patients and 24 male patients) were included. The TMJ magnetic resonance images were categorized into four groups: bilateral-NDP (n = 15), ADDwR (n = 13), RDDwR (n = 19) and DDwoR (n = 39). The characteristics of menton deviation and maxillomandibular asymmetry were determined using posteroanterior and lateral cephalograms. Differences in cephalometric variables among the groups were statistically analysed. Results: Patients with menton deviation under Skeletal Class I, and Skeletal Class II relationship showed a higher rate of DDwoR on lateral cephalograms. Significant differences were detected among groups on posteroanterior cephalograms with respect to the cant of the frontal mandibular plane and menton deviation. These two variables were significantly greater in the DDwoR group than in the bilateral-NDP group. Conclusion: The anteroposterior jaw relatioship and mandibular deviation may be associated with the severity of TMJ disc displacement.