This person had a visible crack in the enamel on the outside cusp of this pre-molar which was sensitive to bite on. When the old silver filling was removed, the crack was visible under the old restoration. The amalgam acts as a wedge through the center of the tooth.
Biting pressure over the years eventually cause small fractures which sometimes lead to larger fractures. These cracks and fissures make crowning the tooth necessary and sometimes result in the loss of the tooth altogether. If you know someone who still has silver fillings, encourage them to see their dentist (or call us if they don’t have one) and have them checked out before they encounter the same problems as this unfortunate individual.