title: Comparative evaluation of the antimicrobial efficacy of a 5% sodium hypochlorite subsonic-activated solution.
abstract: BACKGROUND
  The study evaluated the efficacy of subsonic agitation of sodium hypochlorite (NaOCl) in reducing bacterial load in the root canal.
  
  
  METHODS
  Root canals of 112 extracted human single-root teeth were preflared using K-Flexofiles (Dentsply Maillefer, Ballaigues, Switzerland) up to #20 and then shaped using ProTaper S1-S2-F1-F2-F3 (Dentsply Maillefer) at the working length. Irrigation was performed with 33 mL of 5% NaOCl, alternating with 10 mL of 10% EDTA. After ethylene oxide sterilization, the root canals were infected with 30 microL of Enterococcus faecalis culture and randomly assigned to four groups (n = 25) of different irrigation regimens plus positive and negative controls. Irrigation was performed with 2 mL of 5% NaOCl. In the NaOCl 15 group, the irrigant was left in place for 15 seconds, and in the NaOCl 30 group it was left in place for 30 seconds. In the EndoActivator (EA; Dentsply Tulsa Dental Specialties, Tulsa, OK) 15 and EA 30 groups, NaOCl was subsonically agitated with EA for 15 and 30 seconds, respectively. The residual bacterial count was then evaluated. Differences among groups were analyzed with one-way analysis of variance and the post hoc Bonferroni test (p < 0.05).
  
  
  RESULTS
  A statistically significant difference was evidenced among groups (F(3) = 9.01, p < 0.001). The standard irrigation groups (NaOCl 15 and 30) showed higher microbial counts than the EA 30 group (p < 0.05).
  
  
  CONCLUSIONS
  Thirty seconds of NaOCl subsonic agitation with EndoActivator appears to be slightly more effective in reducing bacterial load in the root canal compared with NaOCl irrigation alone.
authors.affiliation: Department of Endodontics, University of Turin, Turin, Italy. dampasq@libero.it
authors.forename: Damiano
authors.initials: D
authors.lastname: Pasqualini
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Cuffini
authors.forename: Nicola
authors.initials: N
authors.lastname: Scotti
authors.forename: Narcisa
authors.initials: N
authors.lastname: Mandras
authors.forename: Daniela
authors.initials: D
authors.lastname: Scalas
authors.forename: Francesco
authors.initials: F
authors.lastname: Pera
authors.forename: Elio
authors.initials: E
authors.lastname: Berutti
mesh_terms: D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D015169:Colony Count, Microbial; D003786:Dental Pulp Cavity / Q000382:microbiology*; D013293:Enterococcus faecalis / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D009339:Needles; D012388:Root Canal Irrigants / Q000008:administration & dosage / Q000627:therapeutic use*; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods; D012973:Sodium Hypochlorite / Q000008:administration & dosage / Q000627:therapeutic use*; D013010:Sonication; D013594:Syringes; D013997:Time Factors
chemical_list: D000890:Anti-Infective Agents; D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite