This is the infamous expose on the dangers on Mercury Amalgam fillings that first aired in 1990. Unlike most 60 Minutes segments, it was never aired again, followed up on, or publicly referred to even once.
Because of the damning indictments present in this segment, whenever this clip appears online it has the habit of mysteriously disappearing soon after.
Several countries have banned mercury fillings since this show aired. In January 2008, Norway and Sweden totally banned mercury fillings. In April 2008, Denmark banned mercury fillings. Norwegian Minister of the Environment Erik Solheim said, "Mercury is among the most dangerous environmental toxins." (See reference). Yet, in most countries dentists do not explain to patients that there is even a controversy about what is being put in their mouths.
There are three parts to the video. They may link automatically. If they don't, here are parts 2 and 3: