Temporary top filling

The top filling must be a minimum of 4 mm thick and tolerate the biting forces the desired time period. Zinc oxide eugenol (ZOE) is the temporary filling material with the best seal. IRM and Cavit are also regarded as tight materials. However, zinc phosphate cement, glass-ionomer, amalgam and composite materials are not suitable for temporary top fillings in endodontics, unless they are placed on top of ZOE or Cavit, e.g. Cotton pellets should not be used under the top filling because of proven risk for leakage.
Sealing of the access cavity with a temporary top filling between appointments as well after the final root filling is of central importance for the prognosis of the treatment. Even a minor coronal leakage will result in a loss of the antimicrobial activity of various root canal medicaments and establishment of a new, more resistant flora in the canal. In addition, numerous studies have indicated that an unprotected root filling with gutta-percha and sealer may become contaminated through its whole length in a matter of one to few weeks.