The dental assistant, Jason, was unable to find anything definitive, which to me is good news in itself. He did find that my bite was a little uneven, that I was biting down on one high spot on the bridge, so he ground down a bit of the opposing tooth. Evened it out. That may have caused some of the pain, the uneven bite, or not. In any case, no sign of decay or anything meaningful. If the pain continues I can go the next step: to the endodontist, who can do tests through bridges. I don't really want to go to that step because I anticipate a fair amount of money for it, but will wait and see.
My dentist recently expanded his office and has now brought in high-tech equipment. There are flat-screen monitors suspended above the patients' chairs, keyboards on the counter (I think wireless). The dental tech writes in symptoms and results in a fancy new program, and X-rays are now digital, show up immediately on the screen. Way cool stuff. Like it.