The crown of an RC treated tooth is fractured near the gingival margin. The coronal end of the silver cone used in filling that canal is visible at that level. Treatment is:
To prepare post space alongside the silver cone using burs and Peso reamers
To grind away the coronal part of silver cone using round burs or end cutting burs
To remove the silver cone and re-treat the canal using a gutta-percha; and then to create the needed post space
To remove the silver cone, notch it, coat it with a freshly mixed sealer replace it in the canal and twist off the coronal segment