A study of the distribution of endotoxin in the dentinal wall of infected root canals.

Samples of dentinal walls from the pulpal surface of the root canal to the cementum side were prepared by an abrasive microsampling method from teeth extracted from patients diagnosed as having apical periodontitis. Endotoxin was extracted with citric acid, and endotoxin content was quantified using a colorimetric method. Endotoxin content was significantly higher in samples from the pulpal surface of root canals to 300 microns in depth than in those taken from farther toward the cementum side. Endotoxin was detected from all of a series of samples obtained from infected root canals.