Biologic evaluation of SPAD. I. A comparison between the tissue reactions to SPAD, Gelfoam, and silver amalgam

The biologic properties of Traitement SPAD, a material suggested for filling root canals and the periapical region in cases of periapical involvement, were tested and compared with those of Gelfoam and silver amalgam. Empty polyethylene tubes were used as a negative control. The reactions of the subcutaneous tissues of rats to the test and to the control materials are reported. The initial tissue reaction to SPAD was very mild. However, this reaction increased with time to become moderate and persisted throughout the period of the study with no signs of absorption of the material. The inflammatory response to Gelfoam was initially greater. However, it decreased with time and the material was removed by the macrophages with subsequent reduction in the size of the surgical gap. The greatest inflammatory reaction was recorded after the use of silver amalgam, with the formation of capsules around the specimens, indicating that the material was extremely irritant before it had set. The longer the silver amalgam remained in situ, the milder the tissue reaction became.