OR 12 Modulation of replacement root resorption

Replacement resorption (RR) occurs following severe injury to the periodontal ligament (PDL). It has been suggested that inflammatory reactions precede RR. The purpose of this study was to examine and compare histologically the effect of topical application of two anti-inflammatory medications and stannous fluoride (SF) on the development of RR Thirty-four root canals of beagle dog mandibular 2 "a, 3 rd, and 44 premolars received root canal therapy. They were then extracted and left to bench dry for one hour. Following removal of their PDLs, they were soaked for five minutes in either 10gg/ml Toradol (n=10), 16~g/ml of Decadron (n=ll), or 1% stannous fluoride (n=10) which has been shown to inhibit RR. The remaining three roots were rinsed in saline and served as controls. After treating the surfaces of the roots, they were replanted and rigidly splinted for two months. The dogs were sacrificed and their jaws were decalcified. Transverse sections (5bzm) were stained and root surfaces were classified according to Andreasen's criteria of: 1) unchanged, 2) resorbed, or 3) ankylosed. Contingency Table Analysis showed significant differences (p<0.002) between the experimental and the control groups, and in many of the pairwise comparisons (p<0.015). Our results show that local application of SF prevents RR and is more effective than Toradol and Decadron. Supported in part by the AAE Foundation.