Endotoxic activity in teeth with necrotic pulps.

From root canals of 13 teeth with necrotic pulps, samples were taken for analysis of endotoxin content by means of the Limulus by lysate technique. The results were related to the viable bacteria count of root canal samples, phenol/water-extracted lipopolysaccharides (LPS) from different gram-negative anaerobic bacteria, and to different fractions of inflammation exudate. It was found that the endotoxic activity of the root canal samples was correlated with the presence and the number of gram-negative bacteria in the root canal.