You got your amalgams when you were 11? I doubt that is the casr for most of them.

If the gold inlays and onlays are 60% gold, what else is in them?

If many are at least 15 years old, then perhaps they should be replaced. Did you ask you dentist about the cost for gold? I have a feeling dental insurance will not cover gold. Sometimes they don't even cover porcelain inlays and onlays.