All dental cements used to glue crowns break down in the mouth, and direct electrical contact can occur between the filling and the crown.

In the case of this tooth, there was open contact between the crown and the filling through the oral environment since the filling went below the gum line, and the crown stopped at the gums.

The corrosion materials on the edge of the crown are silver-tin corrosion by-products lacking mercury. I remind you the filling started out 50% mercury. The missing mercury all escaped into my biological ecosystem whether blood stream, tissue or GI track. My resulting ill health from mercury exposure is now well documented.

The only amalgam section demonstrating true uncorroded alloy is the silver chunk marked by the dentists drill. All the rest have changed phases to varying degrees, all releasing mercury. These images are magnified 6 to 24X, depending on the image. All the images are of objects mounted on a chunk of yellow printer ink, which conveys a yellowish-reddish tint to the image.

Each of the gif's below is "clickable" for a full size jpeg view. What you are looking at is the inside of a gold crown, and chunks of amalgam retrieved from the underlying buildup.

These images are all views of what was left inside the crown of tooth #14.

These images are of amalgam chunks retrieved from within tooth #14.