Eronat N, van Mullem PJ, Wijnbergen M. An enzyme histochemical study of the infiuence of formocresol and calcium hydroxide on the dental pulp. Endod Dent Traumatol 1988; 4: 37-43.Abstract -Sections of goat incisor pulps were studied after a 5min application of formocresol (FC) or after calcium hydroxide or saline/ZnOE treatment followed by freeze-sectioning. After 3-7 days the incisal part of the pulp was necrotic, as shown by absence of lactate dehydrogenase (LDH) activity. The necrotic zone was much larger after FC than after saline/ZnOE or calcium hydroxide. The LDH negative area after application of FC appeared to consist of a layer showing nuclei that were wellpreserved by the formaldehyde from the FC, and an area of tissue breakdown, which showed no or a reduced structure according to hematoxylin atid eosin. Well-preserved nuclei were not found in the 2 other groups. After 14 days all necrotic tissue, except that subjacent to calcium hydroxide, had been replaced by vital (LDH-positive) tissue. After saline/ZnOE or calcium hydroxide treatment, hard-tissue formation was found in all teeth, and after FC treatment in the majority of teeth.