Indiana University-Purdue University Indianapolis (IUPUI)The pulps of 112 permanent teeth of monkeys were surgically exposed and left open to the oral environment for 25 to 27 hours. Then one-third of the exposed, infected pulps were capped with a paste of calcium hydroxide and tap water; one-third were treated with an antibiotic paste compased of erythromycin estolate 10 per cent, streptomycin sulfate 10 per cent, and starch q.s. as the vehicle; and one-third were treated with a paste of zinc oxide powder, one drop of eugenol and one drop of formocresol. The teeth were extracted after one and two years post-operative intervals and were microscopically evaluated. The calcium hydroxide treated teeth had the highest percentage of sati...