There is an option that is sometimes possible that is between a composite and a crown. It is called an inlay or onlay. It is good in some circumstances when a composite wouldn't be good. It is less destructive to the tooth than a crown and strengthens the tooth, unlike a composite or amalgam which weakens the tooth. I have a combination of inlays and onlays, crowns, and composites. Most of my restorations are porcelain inlays or onlays.

I don't know how you verify that there is no amalgam under the crown. I guess you need to trust your dentist, although some here say they can spot it on the xray if there is mercury under the crown.