The front left central incisor is broken to the gum line. The previous crown was in for over 20 years and has not been root canaled. The patient presented with pain, a root canal was performed and a few days later his crown came off.
The image below-left shows the tooth after a cord is packed. A cord is like a small rope that is wedged in between the tooth and gum to push the gum tissue away from the tooth. After this step the cast post/core is cemented on (below-right).
The image below is the final crown after cementation. The cord is still in place. Once it is removed the gums will return to their original position and colour.