In our April 2012 TMJ News Bites, we reported on a study by Chinese scientists suggesting that estrogen increases pain sensitivity in the jaw by stimulating a brain center (the hippocampus) to express receptors for acid, heat and other noxious stimuli. The experiment used female rats with inflamed jaws whose ovaries had been removed. When rates were given replacement estrogen hormones, they displayed behaviors indicating pain in response to normally mild pressure in comparison to females without ovaries t