The only non-precious stone that I know is the pulp stone. One of the factors contributing to root canal failure is remaining infected pulp tissue and the pulp stones, if left behind unnoticed, are the main reason for trapping tissue and retaining infection. Pulp stone removal is therefore a crucial factor in achieving a successful result in endodontic treatment. The following case shows how a large pulp stone can result in failure of a reasonably well done root canal treatment by trapping infected tissue, hiding the MB2 canal and retaining infection.
Proper access cavity (i.e. adequately large and at the level of the CEJ) in order to visualize the outline of the pulp stone/chamber floor is the key in removing it completely. In the above example the pulp stone is easily dislodged by troughing around it using a large diamond-coated ultrasonic tip and applying the energy directly to the calcified tissue. For demonstration and documentation purposes, no water was used in this case; however, it is highly recommended to use water for its cooling effect and in order to facilitate the debris removal.