Ultrastructural observations of human pulp healing following exposure

ABSTRACT

Traumatic exposures were done under local anesthesia in eight human maxillary premolars from patients [12-20 years]. The exposure was capped with calcium hydroxide, then filled with zinc oxide. Three teeth were extracted after two days and five teeth after one week. After two days the pulp showed numerous defensive pulp cells which migrated to the area with accumulation of inflammatory cells, fragments of cell organels and some aggregation of calcium hydroxide. The pulp cells showed increase in size with extensive development and proliferation of rough endoplasmic reticulum. Macrophages appeared in close contact with the fibroblasts. Irregularly arranged collagen fibrils were seen between the cells. One week following the operative procedure, the pulp showed an increase in the rough endoplasmic reticulum with marked distention of the cisternea. The mitochondria and the Golgi aparatus were well developed. Newly formed collagen fibres could be identified by the presence of active differentiated cells. Some minute foci of calcification were seen along the collagen fibres. It seems that collagen is capable to induce precipitation of calcium