Comparative neurotoxic effects of root canal filling materials on rat sciatic nerve

The neurotoxic effects of the root canal filling materials--Endomethasone, N2 Universal, Traitement SPAD, Sealapex, and Calciobiotic Root Canal Sealer (CRCS)--were investigated on isolated rat sciatic nerves after local application. All of the canal filling materials reversibly inhibited the compound action potential (cAP) amplitudes. N2 Universal produced a 50% inhibition in 4.2 +/- 0.2 min. Traitement SPAD, Endomethasone, and CRCS produced the same inhibition in 6.4 +/- 0.3, 6.5 +/- 0.2, and 6.6 +/- 1.1 min, and Sealapex in 9.2 +/- 2.0 min. The inhibitory effect of Sealapex decreased fastest, and 43% recovery of cAP amplitude was observed in 60 to 70 min. The inhibitory effects of Endomethasone, CRCS, and N2 Universal were more pronounced, and 10 to 20% recovery in cAP amplitudes were observed in 2 h. The inhibitory effect of Traitement SPAD was more persistent with 4% recovery in 2.5 h.