In vitro endotoxin penetration of coronally unsealed endodontically treated teeth

Abstract The purpose of the study was to evaluate the penetration of bacterial endotoxin (L.P.S.) through obturated root canals. Twenty-four single-rooted teeth were instrumented in a uniform manner. The root canals of 16 teeth were obturated with gutta-percha and Roth's sealer and 8 teeth were similarly obturated but without sealer. The teeth were then divided into three groups. Group 1 – Positive control (4 teeth). Teeth obturated without sealer were used. Sticky wax was softened in an open flame and painted over the external root surface except the apical 2 mm and coronal canal orifice which were left free of the sticky wax. Group 2 – Negative control (4 teeth). Again teeth without sealer comprised the teeth in this group. However, in this group the sticky wax covered the apical area of the root and the canal orifice coronally, in addition to the rest of the root. Group 3 – Experimental (16 teeth). The teeth obturated in conjunction with sealer were used. Otherwise the teeth were treated as in group 1. The coronal root half was then hermetically sealed from the apical root half so that LPS placed coronally could move only through the obturated canal space to the apical segment. One ml of water containing 100 μg/ml endotoxin was placed in the upper chambers and pyrogen-free water in the lower chambers. The upper and lower chambers were then tested for endotoxin at different time periods up to 21 days. The upper chambers tested positive for endotoxin at all test times for all teeth. All 4 positive control teeth showed endotoxin in the lower chambers by 24 hrs. None of the 4 negative control teeth showed endotoxin in the lower chambers for the duration of the study. Five of the 16 (31.5%) experimental teeth had demonstrable L.P.S. in the lower chambers by the end of the 21 day test period. According to the results of this study, endotoxin may move through obturated root canals.