Not only are composite fillings mercury-free, but they have several other advantages. They use bonding technology that bonds them to the tooth, which reinforces the tooth, making it more resistant to fracture. Amalgam fillings also corrode over time and can develop cracks and gaps between the filling and the tooth, as shown in this photograph. When people have old amalgam fillings that are starting to crack and leak, they should be replaced. Not only are they more comfortable, but they look much nicer. Even back teeth show when you smile broadly or laugh, and it’s nice to have everything in your mouth white, the way it was meant to be. See how much nicer the “after” photograph looks on the right with the amalgams removed. Amalgams turn black when they corrode, and they tinge the entire tooth a bluish gray. Composites look beautiful and natural.