Objective To introduce a modified model for quantitative testing of glucose microleakage by constant air pressure and evaluate the sealing ability of four root canal sealers including AH Plus, Roeko Seal, Cortisomol and RC Sealer. Methods Fifty-six straight maxillary anterior teeth were randomly divided into four experimental groups with 12 samples in each group, group A: AH Plus, group B: Roeko Seal, group C: Cortisomol, group D: RC Sealer, and positive and negative control group with 4 samples in each. After regular root preparation, samples in experimental groups were obturated by cold gutta-percha lateral compaction technique with sealers according to group description. Control groups were obturated with cold gutta-percha only. Through the model above, the value of glucose microleakage
from crown to root was measured at 1, 3, 5, 7, 10, 15, 20, 25, 30 days with the glucose oxidase-peroxidase method （GOD-POD）. Results At day 1, 3, 5, no significant difference of microleakage was found between group A and B （P>0.05）. The same result was also seen between group C and D. From 7 days, microleakage value in each experimental group gradually increased, and statistical difference was found between groups（Pmodel using constant air pressure is easy to establish, sensitive and practical. Among all the sealers evaluated, polydimethylsiloxane based root canal sealer, Roeko Seal has the greatest sealing ability, while epoxy-amine resin based AH Plus is second and Zinc Oxide based Cortisomol and RC Sealer have the least sealing ability.
