I think it’s great you’ve written a book about jaw pain. I’ve suffered from TMJ, took a class on it to learn how to deal with it, what makes it worse, steps I can take to alleviate the symptoms. It’s no fun!
I think the market is probably fine for your book. It was perception from your posting that you were dead set on getting an agent with TMJ, though. 🙂 I’m glad you have had some bites. Good luck, and please keep us informed.