Mercury toxcicity can cause symptoms of MS.
The idea that Hg in the teeth provide a metal for biofilms to form in the head -- sinuses in particular -- is very plausible. And of course once those biofilms are established the biofilm has emergent properties that are more than the sum of its parts!
For each person the microorganism that triggers the MS syndrome will be different.
For a lady in John's article it appeared to be Acinetobacter calcoaceticus
In the case of the lady in this YouTube video it was Chlamydia pneumoniae https://www.youtube.com/watch?v=EpMvDe8-qsM
And a given microorganism probably can cause different diseases in different people.
I was talking to a third year medical student in the hallway a week ago and she was familiar with these ideas and says that they are taught in her classes. So, times are changing -- even here in China. There is hope!
But the trick may be to not to see your old doctor that is only a few years from retirement and has no energy or motivation to be up-to-date, but see a young, energetic and (still) conscientious doctor that hasn't been out of school for more than five years.