OR 50 Effect of root canal obturation and/or coronal seal on the success of root canal therapy

Numerous in vitro studies have shown the importance of preventing coronal leakage following root canal therapy. The purpose of this study was to evaluate the effect of coronal seal on the formation of periradicular lesions in dogs. Ninety-six root canals of mandibular and maxillary premolars of six beagle dogs were cleaned and shaped. They were then divided into four equal groups of 16 root canals each. The canals in group I were obturated with gutta percha and sealer and were covered with 2mm of MTA. The roots in group II were also obturated with gutta percha and sealer but received no coronal seal. The roots in group II1 and IV were not obturated but had a coronal seal of either IRM or MTA respectively. At 6, 12, or 24 weeks, two dogs were euthanized. After histologic prepm-ations of the samples, the size of periapical lesions (if present) and the degree of inflammation were measured morphomctrically and analyzed statistically using ANOVA. There were significant statistical difference between groups I and IV versus groups II and IIl. The results of this in vivo study show the importance of coronal seal in the development of periradicular lesions following root canal therapy. Supported in part by the AAE Foundation.