In vitro study assessing apical leakage of sealer-only backfills in root canals of primary teeth

To assess the sealing ability of zinc oxide-eugenol (ZOE), Apexit, and Sealapex used as sealer-only backfills in root canals of primary teeth using the high-pressure replica technique.

Two hundred and seventy root canals of deciduous molars as well as primary anterior teeth were randomly assigned to three groups (n=90). Root canals were prepared to size 35 and filled with either zinc oxide-eugenol (ZOE), Apexit, or Sealapex using a lentulo filler. Twenty-four hours after setting of the materials the roots were nail-varnished (except for the apical tip), and half of the specimens (n=45) were penetrated by a coloured (rhodamine B) epoxy resin. The resin was infiltated into the pores and cavities of the teeth in a high-pressure vessel. The remaining groups (n=45) were stored in 100% humidity, and infiltration of the resin followed after 40d. Apical leakage was assessed by means of a grinding technique using eight steps of 0.5mm each.

ZOE and Apexit failed to seal the root canals in both subgroups. This was significantly different from the root canals filled with Sealapex where in both subgroups some 30% of the specimens revealed a tight seal up to a distance of 2.9mm of the apex.

Under the conditions of this study it can be concluded that Sealapex shows less leakage than ZOE and Apexit. With regard to the three materials tested, Sealapex should be a viable alternative for sealer-only obturation of pulpectomized primary teeth. The high-pressure replica technique seems to be suitable for assessing leakage of root canal filling materials.