Is Angell Animal Medical Center an option? You mentioned Tufts which is in the same sort of general area. At the least, your vet can consult with an Angell vet about your cat. Here's the info: http://mspca.pub30.convio.net/vet-services/angell-boston/boston-referral-services.html
Not nearby, I could take him to Tufts or Cornell, but I probably wouldn't reading some of the reviews. I wonder if I could ask her if she could consult with a specialist after the dental xrays are taken. They actually do that for the regular xrays which I like even though it is an extra fee. My fear is them not being vigilant enough in figuring out what's wrong and missing something. It puzzles me that dentists have to spend 3 years in speciality training and now your average vet is doing dental diagnosis.