Bacterial penetration through temporary restorative materials in root-canal-treated teeth in vitro.

Seventy extracted single-rooted mandibular premolars were used in this study to determine the length of time needed for bacteria present in natural human saliva to penetrate through three commonly used temporary restorative materials and through the entire root canal system obturated with the lateral condensation technique. Five intact teeth with no decay were used in the negative control group and five teeth with extensive decay in communication with the canal, in the positive control group. The 60 teeth used in the experimental group were divided into three groups. In Group 1, the access cavities of 20 teeth were temporarily restored with gutta percha, in Group 2 with IRM and in Group 3 with Cavit-G. All 70 teeth were mounted individually where the crown was placed in contact with human saliva. All five teeth in the positive control group caused broth turbidity within 24 h. In contrast, broth in the negative control group remained clear throughout the entire experimental period. In the experimental group, the average time for broth contamination of access cavities closed with gutta percha, IRM and Cavit-G was 7.85, 12.95 and 9.80 days, respectively. The Kruskal-Wallis nonparametric test showed significant differences among the groups, while the multiple comparison test showed that the IRM group was statistically better than the gutta percha group when the average lengths of time for contamination were compared (P < 0.05).