A detailed analysis of four long-term silver cone root canal fillings

Because many failures in root canal therapy have been attributed to the use of silver cones as a filling material, it was decided to examine four roots of three teeth, each of which had been successfully treated endodontically with silver cones ranging from 24 to 34 years previously. These roots, which were resected for periodontal reasons, were examined both under the scanning electron microscope and histologically. Examination with the scanning electron microscope revealed that all four cones were moderately to severely corroded. Histologic examination of two teeth disclosed corrosion products along the entire wall and, in one instance, within the dentinal tubules and apical tissue. The corrosion products, however, were most extensive in the cone that appeared to be loose fitting within the canal. The results indicated that corrosion products occurred in all of the teeth examined. Therefore, corrosion may not be the primary factor accounting for failure in teeth endodontically treated with silver cones.