Pulp response to ferric sulfate, diluted formocresol and IRM in pulpotomized primary baboon teeth

This study investigated the pulp response to a 15.5 percent ferric sulfate solution (FS) and a 20 percent dilution of formocresol (DFC) in pulpotomized primary teeth of baboons, after four and eight weeks. Pulpotomies were performed in seventy-nine primary teeth of 4 baboons. After coronal pulp resection, the pulp stumps were painted with ferric sulfate for fifteen seconds, in thirty-two teeth (group 1); in another thirty-two teeth, a cotton pellet moistened with dilution of formocresol was placed over the pulp stumps for five minutes, and removed (group 2). In fifteen teeth, IRM was placed directly over the pulp stumps after hemostasis (group 3--control). The teeth of all groups were sealed with IRM, and examined for inflammatory changes under a microscope by two blinded examiners. Seventy-seven teeth were assessed. Mild or no inflammation was found in 58 percent (18/31) of the teeth of group 1, in 48 percent (15/31) of those of group 2, and in 73 percent (11/15) of those of group 3. Severe inflammation was found in 35 percent (11/31) of group 1, 29 percent (9/31) of group 2, and in 7 percent (1/15) of group 3. No statistically significant difference between the three groups was observed for degree of inflammation, periradicular or interradicular abscess or inflammatory root resorption (chi-square p > 0.05). Dentin bridges were observed in 52 percent (16/31) of the teeth in group 1, 52 percent (16/31) of those of group 2, and in 73 percent (11/15) of those of group 3. No difference was found between the experimental and control groups for the presence of dentin bridge, (p > 0.05). Ferric sulfate produced pulp responses that compared favorably to those of diluted formocresol.