title: Quantitative molecular and culture analyses of bacterial elimination in oval-shaped root canals by a single-file instrumentation technique.
abstract: OBJECTIVE
  Bacterial reduction in oval-shaped root canals by a single-instrument technique was compared ex vivo with a conventional nickel-titanium rotary technique. Data obtained from two quantification methods, quantitative real-time polymerase chain reaction (qPCR) and culture, were also compared.
  
  
  METHODS
  Oval-shaped canals of extracted teeth contaminated with Enterococcus faecalis were instrumented using either a single Reciproc instrument or the BioRaCe instrument series. Bacteriological samples were taken before (S1) and after instrumentation (S2). Bacterial quantification was performed using qPCR and culture.
  
  
  RESULTS
  Intragroup analysis showed that both protocols promoted a highly significant bacterial reduction (P < 0.001). Intergroup analysis (S2 samples) showed no significant differences between the two instrumentation systems (P > 0.05). As for the quantification methods, qPCR revealed significantly higher counts of E. faecalis in S1 than culture (P < 0.05), but no significant differences occurred for S2 (P > 0.05).
  
  
  CONCLUSIONS
  The single-file technique was comparable with the conventional technique in oval-shaped canals provided the width of apical preparation, volume of irrigants and duration of irrigation are kept similar. No significant difference was observed for qPCR and culture in post-instrumentation samples, indicating that both methods can be reliably used for studies of antibacterial effectiveness.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, RJ, Brazil.
authors.forename: F R F
authors.initials: FR
authors.lastname: Alves
authors.forename: I N
authors.initials: IN
authors.lastname: Rôças
authors.forename: B M
authors.initials: BM
authors.lastname: Almeida
authors.forename: M A S
authors.initials: MA
authors.lastname: Neves
authors.forename: J
authors.initials: J
authors.lastname: Zoffoli
authors.forename: J F
authors.initials: JF
authors.lastname: Siqueira
mesh_terms: D058491:Bacterial Load; D001431:Bacteriological Techniques; D001641:Bicuspid / Q000382:microbiology; D018441:Biofilms; D003722:Dental Alloys / Q000737:chemistry; D003786:Dental Pulp Cavity / Q000382:microbiology*; D004492:Edetic Acid / Q000627:therapeutic use; D013293:Enterococcus faecalis / Q000302:isolation & purification*; D004867:Equipment Design; D006801:Humans; D007180:Incisor / Q000382:microbiology; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D009532:Nickel / Q000737:chemistry; D060888:Real-Time Polymerase Chain Reaction; D012388:Root Canal Irrigants / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D012399:Rotation; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D014025:Titanium / Q000737:chemistry
chemical_list: D003722:Dental Alloys; D012388:Root Canal Irrigants; C040654:titanium nickelide; D009532:Nickel; D004492:Edetic Acid; D014025:Titanium; D012973:Sodium Hypochlorite