title: Adjunctive Steps for Disinfection of the Mandibular Molar Root Canal System: A Correlative Bacteriologic, Micro-Computed Tomography, and Cryopulverization Approach.
abstract: BACKGROUND
  This study evaluated the disinfecting ability of chemomechanical preparation with rotary nickel-titanium instruments, followed by 2 distinct adjunctive procedures in the root canals of extracted mandibular molars by means of a correlative analytical approach.
  
  
  METHODS
  Twenty-two extracted mandibular molars were selected and anatomically matched between groups on the basis of micro-computed tomographic analysis. In the first phase of the experiment, root canals were contaminated with Enterococcus faecalis and subjected to chemomechanical preparation with BT RaCe instruments and 2.5% NaOCl irrigation. Then either XP-Endo Finisher instrument or passive ultrasonic irrigation was used to supplement disinfection. Micro-computed tomography was used to show whether the percentage of unprepared areas correlated to bacterial counts. In the second phase, the same teeth were contaminated once again, and the adjunctive procedures were used. Samples from the isthmus area of mesial roots and the apical 5-mm fragment of distal roots were obtained by cryopulverization. Samples taken before and after treatment steps in both phases were evaluated by quantitative polymerase chain reaction and statistically analyzed.
  
  
  RESULTS
  In phase 1, preparation in both groups resulted in substantial decrease of bacterial counts (P < .001). The adjunctive approaches led to a further small bacterial reduction, which was significant for XP-Endo Finisher (P < .05). No significant differences were observed between groups for persisting bacterial counts. Correlative analysis revealed no statistically significant relationship between bacterial reduction and the percentage of unprepared areas (P > .05). In phase 2, both methods had significant antibacterial effects in the main canal, but none of them could predictably disinfect the isthmus/recess areas.
  
  
  CONCLUSIONS
  Both XP-Endo Finisher and passive ultrasonic irrigation exhibited antibacterial effectiveness, but only the former caused a significant reduction in the bacterial counts after chemomechanical preparation. None of them were effective in predictably disinfecting the isthmus/recess areas.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, RJ, Brazil. Electronic address: flavioferreiraalves@gmail.com.
authors.forename: Flávio R F
authors.initials: FR
authors.lastname: Alves
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, RJ, Brazil; Department of Health, Dentistry Division, Southwest State University of Bahia, Jequié, BA, Brazil.
authors.forename: Carlos V
authors.initials: CV
authors.lastname: Andrade-Junior
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, RJ, Brazil.
authors.forename: Marília F
authors.initials: MF
authors.lastname: Marceliano-Alves
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, RJ, Brazil.
authors.forename: Alejandro R
authors.initials: AR
authors.lastname: Pérez
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, RJ, Brazil.
authors.forename: Isabela N
authors.initials: IN
authors.lastname: Rôças
authors.affiliation: Department of Restorative Dentistry, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Marco A
authors.initials: MA
authors.lastname: Versiani
authors.affiliation: Department of Restorative Dentistry, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Manoel D
authors.initials: MD
authors.lastname: Sousa-Neto
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, RJ, Brazil.
authors.forename: José C
authors.initials: JC
authors.lastname: Provenzano
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, RJ, Brazil.
authors.forename: José F
authors.initials: JF
authors.lastname: Siqueira
mesh_terms: D000891:Anti-Infective Agents, Local / Q000627:therapeutic use; D003722:Dental Alloys / Q000627:therapeutic use*; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging / Q000382:microbiology; D004203:Disinfection / Q000379:methods*; D013293:Enterococcus faecalis / Q000187:drug effects / Q000302:isolation & purification; D006801:Humans; D008963:Molar / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000382:microbiology*; D009532:Nickel / Q000627:therapeutic use; D012388:Root Canal Irrigants / Q000627:therapeutic use*; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D012390:Root Canal Therapy / Q000379:methods; D014025:Titanium / Q000627:therapeutic use; D019227:Tooth Apex / Q000382:microbiology; D014092:Tooth Root / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000382:microbiology*; D014464:Ultrasonic Therapy / Q000379:methods; D055114:X-Ray Microtomography / Q000379:methods*
chemical_list: D000891:Anti-Infective Agents, Local; D003722:Dental Alloys; D012388:Root Canal Irrigants; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium
keywords: Adjunctive approaches; bacterial reduction; cryopulverization; endodontic treatment; micro-computed tomography; passive ultrasonic irrigation