COMPARISON BETWEEN SULPHORHODAMINE-B DYE STAINING AND CR-51-RELEASE METHOD IN CYTOTOXICITY ASSAY OF ENDODONTIC SEALERS

The aim of this study was to evaluate Sulphorhodamine-B (SRB) staining against Cr-51-release in cytotoxicity tests of six endodontic sealers , namely, MU sealer (Mahidol University) ROCANAL 2, ROCANAL 3, Apexit, Endomethasone, and AH-26. Monolayers (5 x 10(5) cells/ml) of the mous e cell line Mu-mu-1 were used as test cells. Following incubation at 3 7 degrees C in 5% CO2 for 24 h in the presence of each sealer, cells w ere stained with 0.4% SRB and the absorbance at 540 nm determined as m easure of cell viability. For Cr-51-release assay, cells were labelled with Cr-51 before testing with sealers, and radioactivity in the supe rnatant was measured in a liquid scintillation counter. Both technique s indicated that Apexit was the least toxic sealer. In view of the eas e of conducting SRB staining for tests of cell viability, this may be the method of choice over Cr-51-release assay in the evaluation of end odontic sealer cytotoxicity.