This study examined, histologically, the healing of intentionally produced inflammatory root resorption of replanted teeth in beagle dogs, treated with short- or long-term placement of calcium hydroxide. Thirty beagle dog incisors were randomly divided into four groups. In group 1 (negative control), uninfected incisors were extracted, the roots were longitudinally grooved and the teeth were replanted within 2 min. In group 2 the root canals were artificially infected followed by extraction, longitudinal grooving, and replantation as in group 1. Radiographs were taken biweekly and at the first signs of inflammatory root resorption or at 4 weeks, the root canals were fully instrumented and medicated with calcium hydroxide. In group 2, the root canals were permanently obturated with gutta-percha and sealer after 1 week of calcium hydroxide. The teeth in group 3 were treated as described in group 2 but after 1 wk the calcium hydroxide dressing was repacked for the duration of the study. In group 4 (positive control) the teeth were treated as described in groups 2 and 3 but no endodontic treatment was performed. Twelve weeks after the initiation of the endodontic treatment, sacrifice and histological preparation were carried out. In group 1, complete cemental repair was seen in all teeth. In group 2, five of ten teeth showed complete cemental repair whereas in group 3 complete cemental repair was seen in nine of ten teeth. None of the teeth in group 4 showed cemental repair. It was concluded that long-term may be more effective than short-term calcium hydroxide treatment of established inflammatory root resorption.

No 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 guttapercha 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 micrograms/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 upto 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.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison was made of the ability of hydroxyapatite cement, mineral trioxide aggregate, and super ethoxybenzoic acid to prevent the leakage of bacteria from root canals, when used as root-end filling materials. The materials were tested in a double-chamber device in which a root segment connects the upper (delivery) chamber and the lower (receiving) chamber. The root segment was prepared by having the root canal instrumented to a #45 file, and a 3-mm-deep, root-end preparation placed at the apical foramen. The canal of each root segment was filled with gutta-percha, and the root-end preparation was filled with one of three test materials, mixed according to the manufacturer's directions. Negative controls were constructed with sticky wax sealing the apical foramen. A titered suspension of radioactively (3H-thymidine)-labeled bacteria (Enterococcus fecalis) was placed into the delivery chamber, and sterile saline was placed into the receiving chamber such that the apical third of each root section was immersed. At various time points, samples were taken from the receiving chamber, and measured for 3H activity. The results indicated that (a) all the test materials leaked significantly compared with the negative controls; and (b) there was no significant difference found between the leakage rates of the three materials tested.