Low Bone Mineral Density and Temporomandibular Joint Derangement in Young Females

Aim: To analyze the bone mineral density (BMD) in a group of young female patients with a disc displacement in at least 1 temporomandibular joint (TMJ) as well as in a group of age-matched young females with a normal condyle-disc relationship. Methods: Fifty-six young female patients with anterior disc displacement based on magnetic resonance imaging (MRI) and 40 age- and gender-matched controls with asymptomatic TMJs were recruited for this study. Subjects between 18 and 30 years were recruited. Based on the MRI findings, 10 of the 40 subjects in the control group also had anterior disc displacement. In all, 16 subjects had an anterior disc displacement with reduction (DDwR), 50 had an anterior disc displacement without reduction (DDw/oR), and 30 had a normal condyle-disc relationship. BMD was measured in the lumbar area by means of dual-energy x-ray absorptiometry. The relationship between the 3 types of condyle-disc relationship and BMD was then analyzed. Results: Patients with a DDw/oR had a significantly lower mean BMD value in the lumbar area than the subjects with a normal condyle-disc relationship (P .05, analysis of variance, post-hoc with Bonferroni test). Twenty-two (44%) of 50 patients with DDw/oR had osteopenia. Conclusion: Low BMD is often associated with DDw/oR in young Taiwanese female patients. Keywords: anterior disc displacement, bone mineral density, internal derangement, temporomandibular joint