title: Efficacy of chemical sterilization and storage conditions of gutta-percha cones.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
authors.affiliation: Dental School, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, Brazil.
authors.forename: P G
authors.initials: PG
authors.lastname: da Motta
authors.forename: C B
authors.initials: CB
authors.lastname: de Figueiredo
authors.forename: S M
authors.initials: SM
authors.lastname: Maltos
authors.forename: J R
authors.initials: JR
authors.lastname: Nicoli
authors.forename: A P
authors.initials: AP
authors.lastname: Ribeiro Sobrinho
authors.forename: K L
authors.initials: KL
authors.lastname: Maltos
authors.forename: H P
authors.initials: HP
authors.lastname: Carvalhais
mesh_terms: D000891:Anti-Infective Agents, Local; D019551:Dental Disinfectants / Q000494:pharmacology*; D004356:Drug Storage; D005557:Formaldehyde; D001411:Geobacillus stearothermophilus / Q000187:drug effects; D005976:Glutaral / Q000494:pharmacology; D006171:Gutta-Percha; D011108:Polymers; D012973:Sodium Hypochlorite / Q000494:pharmacology; D013242:Sterilization / Q000379:methods*
chemical_list: D000891:Anti-Infective Agents, Local; D019551:Dental Disinfectants; D011108:Polymers; D005557:Formaldehyde; D006171:Gutta-Percha; D012973:Sodium Hypochlorite; D005976:Glutaral; C003043:paraform