ABILITY OF BACTERIAL-ENDOTOXIN TO DIFFUSE THROUGH HUMAN DENTIN

An in vitro system was developed to determine whether bacterial endoto xin is capable of diffusing through dentin without the use of filtrati on pressure. Cavities were prepared in five third molar teeth in order to produce a split chamber device consisting of occlusal and pulpal c hambers with 0.5 mm of intervening dentin. Endotoxin was introduced in to the occlusal chamber and the effluent in the pulpal chamber was sam pled every 30 min for 5 h and at 24 h using the limulus lysate assay. In four specimens the initial appearance of endotoxin in the effluent ranged from 15 min to 4 1/2 h. In two specimens the concentration of e ndotoxin in the effluent leveled off in 4 1/2 and 5 h, respectively, w hereas in another two the concentration continued to increase througho ut the experiment. In one specimen no endotoxin was detected. The resu lts indicate that endotoxin is capable of passing through 0.5 mm of de ntin.