Aseptics: Root filling & Top filling

During the whole endodontic treatment the pulp chamber and the canal(s) must be tightly sealed with a temporary top filling. The quality of the seal is of central importance; oral bacteria can be cultured from the calcium hydroxide paste under a leaking top filling. Zinc oxide eugenol (ZOE) gives the best seal, but is not hard enough alone for larger cavities and long-term treatment. Cavit-G and IRM also give a good seal, for large and long lasting fillings IRM should be used on the top to ensure permanence. No cotton pellets should be used under the temporary fillings as they considerably increase the risk for leakage.

After the canal has been permanently filled with gutta-percha and sealer, the quality of the top filling remains equally important as before root filling. Leakage studies have indicated that the root filling without a top filling becomes contaminated through its whole length by oral bacteria, which eventually may lead to unnecessary retreatment.

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