title: Ex vivo evaluation of four final irrigation protocols on the removal of hard-tissue debris from the mesial root canal system of mandibular first molars.
abstract: OBJECTIVE
  To evaluate the efficacy of four final irrigation protocols on the reduction of hard-tissue debris accumulated within the mesial root canal system of mandibular first molars using micro-CT analysis.
  
  
  METHODS
  Forty mesial roots of mandibular molars with a single and continuous isthmus connecting the mesiobuccal and mesiolingual canals (Vertucci's Type I configuration) were selected and scanned at a resolution of 8.6 μm. Canals were enlarged sequentially using WaveOne Small and Primary instruments activated in reciprocating motion without intracanal irrigation to allow debris to accumulate within the mesial root canal system. Then, specimens were anatomically matched and distributed into four groups (n = 10), according to the final irrigation protocol: apical positive pressure (APP), passive ultrasonic irrigation (PUI), Self-adjusting File (SAF) and XP-endo Finisher (XPF). The final irrigation procedures were performed over 2 min using a total of 5.5 mL of 2.5% NaOCl per canal. Reconstructed data sets were coregistered, and the mean percentage reduction of accumulated hard-tissue debris after the final irrigation procedures was compared statistically between groups using the anovapost hoc Tukey test with a significance level set at 5%.
  
  
  RESULTS
  Reduction of accumulated hard-tissue debris was observed in all groups after the final irrigation protocol. Overall, PUI and XPF groups had higher mean percentage reductions of accumulated hard-tissue debris (94.1% and 89.7%, respectively) than APP and SAF groups (45.7% and 41.3%, respectively) (P < 0.05). No significant differences were found when comparing the results of PUI and XPF groups (P > 0.05) or APP and SAF groups (P > 0.05).
  
  
  CONCLUSIONS
  The PUI technique and XP-endo Finisher instrument were associated with significantly lower levels of AHTD compared with conventional irrigation and the modified SAF system protocol in mesial root canals of mandibular molars.
authors.affiliation: Department of Restorative Dentistry, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: G B
authors.initials: GB
authors.lastname: Leoni
authors.affiliation: Department of Restorative Dentistry, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: M A
authors.initials: MA
authors.lastname: Versiani
authors.affiliation: Department of Endodontics, Faculty of Dentistry, University of Ribeirão Preto, Ribeirão Preto, SP, Brazil.
authors.forename: Y T
authors.initials: YT
authors.lastname: Silva-Sousa
authors.affiliation: Department of Endodontics, Faculty of Dentistry, University of Ribeirão Preto, Ribeirão Preto, SP, Brazil.
authors.forename: J F B
authors.initials: JF
authors.lastname: Bruniera
authors.affiliation: Department of Restorative Dentistry, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: J D
authors.initials: JD
authors.lastname: Pécora
authors.affiliation: Department of Restorative Dentistry, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: M D
authors.initials: MD
authors.lastname: Sousa-Neto
mesh_terms: D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D008334:Mandible; D008963:Molar / Q000000981:diagnostic imaging / Q000601:surgery*; D018915:Root Canal Preparation / Q000379:methods*; D007507:Therapeutic Irrigation / Q000379:methods*; D055114:X-Ray Microtomography
keywords: apical positive pressure; hard-tissue debris; isthmus; mandibular molar; microcomputed tomography; root canal irrigation