Journal of Dental Medicine

Background and Aims: The seal provided by a root canal filling may be compromised by post space preparation. The aim of this study was to compare coronal microleakage around cast posts and prefabricated pins.

Materials and Methods: Thirty-eight extracted single-rooted, maxillary human teeth were prepared with step back method and filled with gutta-percha and sealer. After removing 8 mm of coronal gutta-percha with peeso-reamer drills #2 in twenty canals, the teeth were divided into three groups: cast post & core, prefabricated pin,  and gutta-percha (without any post or pin). After thermocycling, the samples were immersed in India ink for seven days. Finally, the specimens were cleared and the coronal microleakage of dye was then measured by the stereomicroscope. The data were analyzed by One-way ANOVA and Tukey HSD tests.

Results: According to the results, the mean dye penetration in cast posts, pins, and group without post or pin was 3.3 (0.39), 5.2 (0.47), and 7.2 (0.15) mm, respectively. There was no statistically significant difference between the groups (P>0.05).

Conclusion: Considering the importance of adequate filling of crown for prevention of microleakage, the method for coronal filling must be selected with caution. According to the results of this study, no significant difference between microleakage of cast posts and prefabricated pins was observed.

Background and Aims: Since impression materials usually contact with saliva, blood, and oral soft tissues, their microbial contamination are harmful in immunocompromised patients. The aim of the present study was to determine the bacterial and fungal contamination in common impression materials.

Materials and Methods: In current lab trial study, 5 different samples from each 4 impression materials were homogenized in 1 ml Tween 80 and then 100µl of each sample were cultured onto blood agar, EMB, or sabouraud dextrose agar. Bacterial and fungal cultures were incubated at 37º C and 30º C, respectively. The isolated bacterial and fungal colonies were enumerated and identified using specific diagnostic media and tests. Data were analyzed using Kruskal-Wallis test.

Results: Totally 75% of samples had one or several bacterial contaminations. Iranian alginate and Speedex (putty) were the most contaminated samples. On the other hand, Speedex (light body) and foreign alginate showed lower contamination. Species of Micrococcus, Staphylococcus, Bacilluses, Corynebacteria, gram negative Citrobacter, Actinomycetes and Neisseria were isolated from the analyzed impression materials. Aspergillus, Penicillium, Alternaria, Cladosporium and Sepdonium were the fungi isolated from impression materials. Statistical significant difference was shown between bacterial contamination of Iranian and foreign alginates (P=0.001). There was no statistical significant differences between the bacterial and fungal isolated colonies (CFU/gr) of 4 tested impression materials (P=0.21).

Conclusion: Several opportunistic bacteria and fungi were isolated from impression materials especially from Iranian alginate and Speedex putty which indicated their contamination.