• temporomandibular joint;
  • temporomandibular disorder;
  • estrogen;
  • BMP-4;
  • Runx2;
  • BSP

Objective:  Temporomandibular disorder (TMD) includes a number of clinical conditions involving the masticatory musculature or the temporomandibular joint (TMJ) and associated structures. Previous studies have shown the presence of high-affinity estrogen receptors in the TMJ articular cartilage. The aim of this study was to evaluate the developmental changes in mouse TMJ under estrogen deficiency.

Materials and methods:  Four-month-old ovariectomized mice were killed after certain weeks. We examined the significant alterations of the expression patterns of bone morphogenetic protein (BMP)-4, Runx2, and bone sialoprotein (BSP) after ovariectomy.

Results:  In the control group, BMP-4, Runx2, and BSP expressions showed no definite difference at any stage. In the ovariectomy group, the intensity of BMP-4 and Runx2 expression increased after ovariectomy. BSP immunoreactivity, however, increased slightly at 2 weeks but then decreased gradually.

Conclusions:  Estrogen plays important roles in the metabolism and maintenance of TMJ via regulations of signaling molecules such as BMP-4, Runx2, and BSP. Our results suggest that estrogen deficiency is a candidate cause of TMD. This study revealed further osteogenetic properties of estrogen that may be useful in the clinical treatment and prevention of TMD.