Authors: Senia ES, Marraro RV, Mitchell JL, Lewis AG, Thomas L.
Title: Rapid sterilization of gutta-percha cones with 5.25% sodium hypochlorite.
Journal: J Endod
Date: Apr 1975
Citation: 1(4):136-40
Category: Irrigants and Medicaments
Evidence-based Ranking: 5
Purpose/Objective: To evaluate the bactericidal action of undiluted Clorox (5.25% sodium hypochlorite) for the sterilization of gutta percha cones and to determine the optimum immersion time required to achieve this effect.

Materials and methods: Fresh isolates of the following organisms were subjected to the experimental conditions: Staphylococcus epidermidis, Corynebacterium xerosis, Bacillus subtilis, Escherichia coli, Streptococcus faecalis and a viable spore suspension of B subtilis. 100 gutta percha cones were used and the tests were done in duplicate. Gutta percha cones were fully immersed and soaked for one minute each of the previously prepared suspensions. The cones were allowed to air-dry for 30 minutes at 37C. They were then immersed in approximately 10ml of undiluted Clorox and permitted to soak for 30,45, or 60 seconds. The cones that were exposed separately to the vegetative and spore suspension of B subtilis were soaked additionally for 1.5, 2, 3, 4, 5, and 10 minutes. Growth was observed for 72 hours. Control procedures were performed by using saline instead of Clorox.

Results: All organisms except B subtilis were killed after a 30-second exposure to Clorox. The vegetative form of B subtilis was killed after a 45-second immersion time whereas the spore form of this microorganism required a one-minute sterilization period.

Conclusion: The data indicate that gutta percha cones may be sterilized, in all cases, by a one-minute immersion time in undiluted Clorox.

ReviewerÂ’s comments: This article proves that a 1-minute immersion in Clorox is effective in sterilizing gutta percha cones.