It's been awhile, since I had read some of your previous messages over at OBT (old/original BrainTalk), so forgive me if I've forgotten some things you wrote.
Did you check on possible gluten sensitivity, Vitamin B-12 deficiency, adverse reactions to toxic mold? (including how mold can release toxins &/or heavy metals, into the air, etc., from surfaces that mold is growing on)
I did a quick google check on burning mouth syndrome (BMS), and saw an interesting article, at this link:
Here's a copy & paste of one section from this article, as food for thought:
"What causes BMS [burning mouth syndrome]?
The exact cause of BMS is difficult to determine. In 30 percent of cases it is caused by a variety of existing conditions that affect the oral and systemic health. Some conditions include the onset of menopause, diabetes, and deficiencies in such nutrients as iron, zinc, folate, thiamin, riboflavin, pyridoxine and cobalamin [Vitamin B-12], and complications to cancer therapy (radiation and chemotherapy) .
In 70 percent of cases, no specific diagnosis for the symptoms can be made. BMS symptoms may occur from xerostomia (dry mouth), tongue thrusting, bruxism (teeth grinding), irritating or ill-fitting dentures, and thrush (a common fungal infection characterized by a white discharge). Some research points to nerve disorders and damage; psychological factors, particularly depression and anxiety; allergies; acid reflux; and medications that cause dry mouth. Its not unusual for a patient suffering from BMS to have more than one cause attributed to the ailment or to have health care providers fail to find any cause at all.
According to research from the American Academy of Family Physicians, about one-third of patients say BMS symptoms appeared shortly after a dental procedure, recent illness or medication course.
If you haven't ruled out all the causes mentioned above, it might be helpful to check on these. What do you think of the above info?