I would verify all the crowns had plastic, if not get them removed and replaced or extracted. The Amalgam or composite acts as a glue to hold the crown in place and can be completely fill the void of the crown, depending on the individual dentist practice. The contact between the dis-similar metals causes galvanic corrosion, and thus leachs mercury. After seeing the results in my mouth over long term exposure don't mess with this.

As the old saying goes "Don't let a tooth put you in the box!" As my dentist said, Your body can fight off this continous infection but it extracts a fee!

My sinus infections have cleared since mine were extracted as the roots went into my sinus cavity.

good luck