Efficacy of chemical sterilization and storage conditions of gutta-percha cones.

AIM

The objective of the present study was to assess the efficacy of 2.5% sodium hypochlorite and 2.2% glutaraldehyde ('Cidex') as sterilizing agents for gutta-percha cones. The efficacy of storage of gutta-percha cones in the presence or absence of paraformaldehyde was also evaluated.

METHODOLOGY

Gutta-percha cones artificially contaminated with a suspension of Bacillus stearothermophilus (ATCC/7953) were treated with either 2.2% glutaraldehyde for 10, 15, 30 and 60 min and 10 and 12 h, or 2.5% sodium hypochlorite for 5, 10 and 15 min. The cones were then incubated in thioglycollate medium for the determination of microbial growth. In parallel, additional sterile gutta-percha cones were stored in sealed containers with or without paraformaldehyde tablets for 30 days. The containers were opened 30 min a day and exposed to the environment of a functioning dental clinic. Twelve cones were removed weekly from the containers to determine whether contamination had occurred.

RESULTS

The results showed that 2.5% sodium hypochlorite was effective after 5, 10 and 15 min, whereas 10 and 12 h contact with 2.2% glutaraldehyde was necessary to obtain sterilization. There was no contamination of the gutta-percha cones when stored with or without paraformaldehyde.

CONCLUSIONS

Sodium hypochlorite (2.5%) and 2.2% glutaraldehyde ('Cidex') proved to be effective as sterilizing agents for gutta-percha cones, with sodium hypochlorite requiring shorter periods of use. No difference was observed between the two methods of cone storage.