The pulpal response to Protemp (ESPE Gmbh) was compared to zinc oxide-eugenol, Super Syntrex (de Trey) and Protemp plus zinc oxide-eugenol liner in 144 vervet monkey (Cercopithecus pygerythus) incisor teeth, according to ADA Specification No. 41. Cellular displacement into dentinal tubules, superficial and deep inflammation were present only in the 3-day specimens in all materials. Mean scores for the test material were lower than both negative and positive controls. In the 30-day specimens the prevalence of reparative dentine under the test material was similar to the negative control, while at 90 days it was less than the negative control, although the severity in affected specimens was more than the positive control. Use of a zinc oxide-eugenol liner reduced the severity of reparative dentine formation.