OK, so one whopping risk factor of note, tobacco, which for several decades of use (your term light is relative) is a good one. Very knowledgeable, and capable of describing to your doctors what is actually going on (can tell from your description here). Also importantly aware that many of us, me included, have been through reams of misdiagnosis before the bad news finally came, delaying everything that follows and making the chances of beating things worse.
1. I like the endo idea. He is going to drill a hole right down through the center of that mobile tooth and into the pulp chamber, which you haven't described in detail. Teeth with an abscess OFTEN but not always are sensitive to percussion you don't say about those in the area. When he does that, if putrid pus emerges, he is going to have an immediate answer. Infection, to the point of screwing up the tooth which is now spilling over into the surrounding tissue, and if left untreated for long enough, causing bone loss/mobility, and finally a decent size, palpable (but usually tender) mass of significant size. Smooth and mobile as a rule so that fits. Infections often produce a warm feeling, and they, if left untreated, refer symptoms to surrounding area, such as your ear. Given all the dental work of varying quality you could have a TMJ issue, but that is likely remote. While you say that you have brushed and flossed for years, your many years of endo and restorative work indicate that all is not perfect in your oral world regardless of your description. This is assuming that your dental treatment professionals didn't just wish to use you for practice. If your dental heath is compromised, there are lots of good things besides cancer to pick from, and while a continuous pain in the rear, way better to deal with than having the big C.
2. There is no reason that you cannot pursue two courses of exploration at the same time. Dental x rays are crude by head and neck standards. I would not base my freedom from something bad based on them, and tube head angulation when they are taken can mask an abscess or worse. I would begin an additional line of inquiry. That mass can be punctured and the contents in it biopsied. Seems kinda like a simple thing to do, and not expensive. It would give you another data point. The Oral CDx brush test is a pathetic brush cytology system for superficial class two lesions, and yours is not a good indication for its use. So a consultation with someone that is not in your current group of practitioners that is in the world of oral cancer is in order. This I would do as soon as practical given all the opportunities for this to be many things.
By the by I have had a therapist or two, the first one after being someone who didn't deal with my actions and experiences in a country very far away, where horrible things happen to very good people, or just harmless bystanders daily- and the another instance on the couch being less adapted than most of the people here to dealing with my cancer diagnosis and treatment.... Let's see, that doesn't count the one that I went to after my first divorce, and another one when I found that I had a preclusion (and ability) to wish to terminate the existence of the doctors that misdiagnosed me for so long. If you go to one, don't get the soft restraints, I have found they are too easy to chew through....even though some days it really isn't worth the trouble. Besides, I find it particularly hard to believe that someone that hasn't killed anyone, or had his friends die in his arms as their warm blood drips on you, or really fought for his life (the 405 freeway in rush hour traffic in your Mercedes does not count), in a battle where the odds were against them, could have a clue as to what is screwed up in my head. Therapy does allow you to vent- (a good thing) - but didactic knowledge vs. life experiences is not sufficient in my mind, to give them the ability to straighten out someone as screwed up as I have been. Beneficial to some during some stages of life, be many times completely devoid of usable answers.... as in the typical " well what do you think is behind this feeling of yours Brian?"
By the by, Grant in Chicago had plenty of misdiagnosis, but for all the press he has gotten, the story has been told here many more, actually innumerable times, with far worse outcomes. Be thankful you are not black and poor because this would significantly reduce your chances of finding out what's what. So there is an upside. You're educated and on a path to discovery. Keep us posted as the results from your exploration reveal themselves. I hope that one of the real doctors here from dental will post his observations. Please also excuse my writing style tonight, I am not in my best form, and I do not wish it to come across as flippant (having now re-read it) or dismissive in ay way of the seriously anxious situation that you find yourself in.
