The Role of Reproductive Hormones in Orofacial Pain

It has long been recognized that more women than men present for treatment of certain orofacial pain conditions. Evidence is accumulating that at least some of this discrepancy is due to the influence of female reproductive hormones on orofacial pain. The use of hormone replacement therapy in women is associated with a moderately increased risk of developing temporomandibular pain. However, temporomandibular pain is perceived to be of the highest intensity at times of low or fluctuating endogenous estrogen. Most research concerning hormonal effects on burning mouth and atypical odontalgia/persistent idiopathic facial pain has examined the effect of exogenous hormones. Although there are certainly indications that hormonal factors play a role in these pain conditions, more research is needed to clarify these associations. A range of peripheral and central pain mechanisms have been investigated in an attempt to explain the observed gender patterns in clinical pain conditions and the assumed relationship between hormonal factors and orofacial pain. At this point, some studies indicate that the presence of female reproductive hormones enhances pain response, while other studies suggest that these hormones decrease pain response. These seemingly contradictory findings could be explained if hormones act differently in peripheral tissues and at different levels of the nervous system.