title: Efficacy of 3D conforming nickel titanium rotary instruments in eliminating canal wall bacteria from oval-shaped root canals.
abstract: OBJECTIVE
  To evaluate the effectiveness of TRUShape® 3D Conforming Files, compared with Twisted Files, in reducing bacteria load from root canal walls, in the presence or absence of irrigant agitation.
  
  
  METHODS
  Extracted human premolars with single oval-shaped canals were infected with Enterococcus faecalis. Teeth in Group I (N=10; NaOCl and QMix® 2in1 as respective initial and final irrigants) were subdivided into 4 subgroups: (A) TRUShape® instrumentation without irrigant activation; (B) TRUShape® instrumentation with sonic irrigant agitation; (C) Twisted Files without irrigant agitation; (D) Twisted Files with sonic irrigant agitation. To remove confounding factor (antimicrobial irrigants), teeth in Group II (N=10) were irrigated with sterile saline, using the same subgroup designations. Specimens before and after chemomechanical débridement were cultured for quantification of colony-forming units (CFUs). Data from each group were analyzed separately using two-factor ANOVA and Holm-Sidak multiple comparison (α=0.05). Canal wall bacteria were qualitatively examined using scanning electron microscopy (SEM) and light microscopy of Taylor-modified Brown and Brenn-stained demineralised sections.
  
  
  RESULTS
  CFUs from subgroups in Group I were not significantly different (P=0.935). For Group II, both file type (P<0.001) and irrigant agitation (P<0.001) significantly affected log-reduction in CFU concentrations. The interaction of these two factors was not significant (P=0.601). Although SEM showed reduced canal wall bacteria, bacteria were present within dentinal tubules after rotary instrumentation, as revealed by light microscopy of longitudinal root sections.
  
  
  CONCLUSIONS
  TRUShape® files removed significantly more canal wall bacteria than Twisted Files when used without an antibacterial irrigant; the latter is required to decontaminate dentinal tubules.
  
  
  CONCLUSIONS
  Root canal disinfection should not be focused only on a mechanistic approach. Rather, the rational choice of a rotary instrumentation system should be combined with the use of well-tested antimicrobial irrigants and delivery/agitation techniques to establish a clinically realistic chemomechanical débridement protocol.
authors.affiliation: Discipline of Endodontics, Department of Dentistry, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil.
authors.forename: Eduardo A
authors.initials: EA
authors.lastname: Bortoluzzi
authors.affiliation: College of Dental Medicine, Georgia Regents University, Augusta, GA, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Carlon
authors.affiliation: College of Dental Medicine, Georgia Regents University, Augusta, GA, USA.
authors.forename: Mohamed M
authors.initials: MM
authors.lastname: Meghil
authors.affiliation: College of Dental Medicine, Georgia Regents University, Augusta, GA, USA.
authors.forename: Ahmed R
authors.initials: AR
authors.lastname: El-Awady
authors.affiliation: State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Niu
authors.affiliation: College of Dental Medicine, Georgia Regents University, Augusta, GA, USA.
authors.forename: Brian E
authors.initials: BE
authors.lastname: Bergeron
authors.affiliation: College of Dental Medicine, Georgia Regents University, Augusta, GA, USA.
authors.forename: Lisiane
authors.initials: L
authors.lastname: Susin
authors.affiliation: College of Dental Medicine, Georgia Regents University, Augusta, GA, USA.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Cutler
authors.affiliation: College of Dental Medicine, Georgia Regents University, Augusta, GA, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Pashley
authors.affiliation: College of Dental Medicine, Georgia Regents University, Augusta, GA, USA. Electronic address: ftay@gru.edu.
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Tay
mesh_terms: D000497:Alloys; D000890:Anti-Infective Agents / Q000494:pharmacology; D058491:Bacterial Load; D001641:Bicuspid / Q000382:microbiology; D001645:Biguanides / Q000494:pharmacology; D003762:Dental Instruments / Q000382:microbiology*; D003786:Dental Pulp Cavity / Q000187:drug effects / Q000382:microbiology*; D003804:Dentin / Q000187:drug effects / Q000382:microbiology; D004203:Disinfection / Q000295:instrumentation / Q000379:methods; D013293:Enterococcus faecalis / Q000187:drug effects / Q000472:pathogenicity; D006801:Humans; D011108:Polymers / Q000494:pharmacology; D012388:Root Canal Irrigants / Q000494:pharmacology; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D012390:Root Canal Therapy / Q000295:instrumentation* / Q000379:methods; D012399:Rotation; D012973:Sodium Hypochlorite / Q000494:pharmacology
chemical_list: D000497:Alloys; D000890:Anti-Infective Agents; D001645:Biguanides; D011108:Polymers; C557698:QMix root canal irrigant; D012388:Root Canal Irrigants; C013616:nitinol; D012973:Sodium Hypochlorite
keywords: Canal conforming; Dentine conservation; E. faecalis; Nickel titanium; Rotary instrumentation; Sonic agitation