SEALING PROPERTIES OF KETAC-ENDO GLASS-IONOMER CEMENT AND AH26 ROOT-CANAL SEALERS

Sealing capacity, setting shrinkage and setting time of a recently int roduced glass ionomer cement Ketac-Endo were compared with that of a c onventional sealer AH26. Sixty half-cylinders, 8 mm long, 4 mm in diam eter, made from fresh bovine root dentine, had their smear layer remov ed before being cemented together while separated by 1-mm spacers. Thi s resulted in a group of 15 cylinders cemented with Ketac-Endo and a s imilar group with AH26. After coating the lateral surface with nail va rnish, one end of each cylinder was connected with a tube filled with water under 120 kPa (1.2 atm) pressure. At the other end the fluid lea king through the cemented interface of the cylinders was measured by d isplacement of an air bubble in an attached standard glass capillary. In this particular setup where the sealers were used in bulk between t wo opposing dentine surfaces, Ketac-Endo leaked significantly more tha n AH26. After shear loading the cemented specimens, it was found that the area of adhesive failure was 88% for Ketac-Endo, and 15% for AH26. The leakage pathways were most probably at the dentine-sealer interfa ce for Ketac-Endo and through cohesive fractures in the sealer for AH2 6.