Endotoxin penetration into root cementum of periodontally healthy and diseased human teeth

This study was undertaken to determine the extent of in vitro penetration of E. coli endotoxin into the root cementum of periodontally healthy and diseased teeth. Freshly extracted teeth were washed in distilled water, scaled and divided into two groups of 16 teeth each. Nine diseased and five healthy teeth in the first group were immersed in various concentrations of E. coli endotoxin for 2 to 12 weeks. They were then prepared for indirect immunofluorescence examination after treatment with anti-endotoxin antibody and rhodamine conjugated secondary antibody. Teeth in the second group were prepared for autoradiographic examination by immersing nine diseased and five healthy teeth in tritium labelled E. coli endotoxin for 2 to 12 weeks. The latter technique also allowed for semi-quantitative study of the depth of endotoxin penetration by creating facets on the root at various depths after endotoxin exposure. This technique was also used to investigate the strength of endotoxin binding to the tooth surface by brushing for 1 minute and re-examining the tooth for the presence of endotoxin. Controls included periodontally diseased and healthy teeth. Results of the study showed that (1) endotoxin adheres to the tooth surface without penetration into the root cementum of either periodontally healthy or diseased teeth, and (2) the binding of the endotoxin to the root surface appears to be weak.