A cross-sectional study of the relationship between serum sexual hormone levels and internal derangement of temporomandibular joint

Temporomandibular disorders (TMD) are defined as clinical conditions that involve the masticatory muscles, temporomandibular joint (TMJ) or both. The aim of this study was to evaluate serum 17 beta-oestradiol and progesterone levels in menstruating women affected by internal derangement of the TMJ. A total of 142 women (mean age 30.2 +/- 6.7) who referred to medical diagnostic laboratory of Iranian Academic Centre for Education, Culture and Research (ACECR), Mashhad Branch, were enrolled during 2007 and 2008. Forty-seven individuals had disc displacement with reduction (Group IIa) according to Research Diagnostic Criteria (RDC)/TMD Axis I diagnosis. Radioimmunoassay was used for the detection of serum 17 beta-oestradiol and progesterone levels in all 142 subjects. The mean progesterone level was significantly higher in control group (11.6 +/- 10.4 ng mL(-1)) compared to women with TMD (8.4 +/- 6.8 ng mL(-1), P = 0.03). No significant difference was found in two groups regarding 17 beta-oestradiol level. Lower progesterone level in women with TMD can suggest the more important role of this hormone in the development of the disorder.