TISSUE REACTION TO GUTTA-PERCHA PARTICLES OF VARIOUS SIZES WHEN IMPLANTED SUBCUTANEOUSLY IN GUINEA-PIGS

Tissue reaction to gutta-percha was studied using subcutaneously impla nted Teflon cages in guinea pigs. Gutta-percha was tested in three for ms: (i) as large particles prepared by dividing gutta-percha cones int o pieces, (ii) as fine particles prepared by ball-milling of gutta-per cha, and (iii) as particles produced by dissolving gutta-percha in ros in-chloroform. Gutta-percha evoked two distinct types of tissue respon se. The large pieces were well encapsulated and the surrounding tissue was free of inflammation. The fine particles evoked an intense, local ized tissue response, characterized by the presence of macrophages and multinucleated giant cells. The rosin-chloroform treated gutta-percha induced a similar tissue reaction to that observed with the fine part icles of gutta-percha. In addition, cell remnants were present in asso ciation with the material, which indicates an initial toxicity to rosi n-chloroform treated gutta-percha. These results show that the size an d surface character of gutta-percha can determine the type of tissue r eaction to the material. The accumulation of macrophages around gutta- percha may be an important factor in the impairment of healing of peri apical lesions when teeth are root filled with excess material.