Re: Thank you for explanation and here is what the dentist office has to say

Hi, you're welcome. I am not sure what to make of what that dentist said. It could be a stain or something, but again if he isn't even sure, then you'd be advised to seek out another biologic dentist as you're thinking of doing. The fact the other dentist pointed that out, it may well be a bit of Amalgam and this biologic dentist is probably irritated by the fact it had been discovered. Hard to say.

A second opinion may well be a good move. HEre is a link you may find helpful in trying to track a dentist down
http://www.holisticdentalnetwork.com/directory.php#USA
. I am not living in the US, I live in New Zealand, so when you say Toronto, I haven't a clue exactly where that is.

If nothing looks close enough on that list of dentists, you may wish to "ask the doctor" on there. You'll see that option near the top in the middle.

I hope this is helpful.