During endodontic therapy a temporary filling material may be placed between appointments to prevent the root canal from being contaminated. However, many temporary materials do not provide an adequate long-term seal, allowing contaminants to enter the root canal space and even move into periapical tissues. An adequate coronal seal is essential to ensure successful treatment. A study by Madarati, et al compared the sealing properties of 4 restorative materials used to seal the coronal access. The study involved 135 previously extracted mandibular premolars; each tooth was endodontically prepared using a step-back technique with 5.25% sodium irrigation. Canal apices were sealed with gutta-percha and coronally sealed with one of the 4 sealing materials in a thickness of 3.5 to 4 mm. The 4 materials were coltosol, a zinc oxide calcium sulfate; carefil, a chemically cured glass ionomer cement; intermediate restorative material (IRM), a reinforced zinc oxide eugenol cement; and zinc phosphate cement. The teeth were then incubated, thermocycled, immersed in dye, and analyzed for dye penetration. It was found that the glass ionomer and zinc oxide calcium sulfate cements had the lowest microleakage, but these materials leaked more with time. The IRM material had the highest microleakage. The manufacturer of the zinc oxide calcium sulfate recommends waiting no longer than 2 weeks between appointments to ensure that the coronal access maintains a proper seal.
(Source: Aust Endod J. December 2008;34:89-93)
