The effect of the removal of the
smear layer on coronal leakage of root fillings was studied using two sealer cements. Sixty single-rooted teeth with mature apices were prepared chemomechanically using a modified double-flared technique with non-cutting tipped files and copious irrigation with 2%
sodium hypochlorite. The teeth were randomly allocated to four groups of 15 teeth each. Two groups were treated with 40%
citric acid to remove the
smear layer. Two groups of teeth, one with and one without
smear layer, were filled by lateral condensation of
gutta-percha with either
Tubliseal or a resin-based
glass ionomer,
Vitrebond. The teeth were stored for 1 week, thermocycled, and the extent of coronal leakage determined for each group after immersion in Indian ink for 90 h. The teeth were demineralized, dehydrated and immersed in
methyl salicylate which rendered them transparent. Linear measurement of
dye penetration was recorded. The mean depth (+/- SD) of leakage for the groups in which the
smear layer was left intact was 4.26 +/- 1.53 mm and 6.83 +/- 1.65 mm for the
Vitrebond and
Tubliseal, respectively. When the
smear layer had been removed, the mean depth of leakage for the
Vitrebond group was 1.13 +/- 0.29 mm, and 3.72 +/- 1.23 mm for the
Tubliseal group. There was a statistically significant difference in leakage between the groups (P < 0.001). With both sealers, those teeth in which the
smear layer had been removed showed less leakage than the specimens in which the
smear layer was left intact (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)