OR 65 Apexification in immature dog teeth using osteogenic protein-1, mineral trioxide aggregate, and calcium hydroxide

When normal root formation is interrupted following pulpal pathosis, complete endodontic therapy cannot be performed without root-end induction. Calcium hydroxide has been the material of choice for apexification. The purpose of this study was to compare the efficacy of osteogenic protein-! (OP-l), calcium hydroxide, and mineral trioxide aggregate (MTA) in the formation of a hard tissue barrier in immature roots of dogs. Root canals of sixty-four mandibular and maxillary premolars of four six-month-old beagle dogs were contaminated with their own oral flora. Following development of periradicular lesions, the canals were cleaned and shaped using 5.25% sodium hypochlorite as the root canal irrigant. To sterilize the canals, calcium hydroxide was placed in the root canals for one week. After the removal of calcium hydroxide, each canal was filled with one of the four test materials in a balanced design with Pulpdent paste, MTA, OP-1 delivered in a collagen carrier, and the carrier alone (negative control). The pulp chambers of the teeth were sealed with MTA. The animals were euthanized after twelve weeks. The amount of hard tissue formation and the degree of inflammation were evaluated radiographically and histomorphometrically. The data was analyzed statistically using ANOVA, Chi square, and Cochran.MantelHenszel. No apical hard tissue formation was observed in roots filled with the collagen carrier alone, while varying amounts of osteodentin were seen in the other experimental groups depending on the test material. MTA induced apical hard tissue formation more often than the other test materials (P=0.001). The degree of inflammation, in ascending order, was MTA, calcium hydroxide, OP- 1, and collagen carrier alone. No significant statistical differences in the degree of inflammation were found. Based on the results, it appears that MTA can be used as an apical barrier for apexification in immature roots