title: Comparison of apical transportation between two rotary file systems and two hybrid rotary instrumentation sequences.
abstract: BACKGROUND
  The aim of this study was to evaluate apical transportation of 2 rotary file systems and 2 hybrid rotary instrumentation sequences.
  
  
  METHODS
  One hundred twenty-four mesiobuccal canals of extracted molars were instrumented by 4 nickel-titanium rotary sequences. Group PF (n = 32) was instrumented with ProFile Series 29 to size #6 (#36/.06) at working length (WL). Group ES (n = 28) used EndoSequence to #35/.06. Group PFLS (n = 32) used ProFile Series 29 followed by LightSpeed in a hybrid technique to a final size #50. Group PTLS (n = 32) was instrumented with ProTaper and additional enlargement with LightSpeed to #50 in a hybrid technique. A double-digital radiographic technique was used to measure canal transportation at 0.5-5.0 mm from WL. Statistical analysis was carried out with one-way analysis of variance.
  
  
  RESULTS
  There was no statistically significant difference for apical transportation between the groups at any level from the WL (0.5 mm, P = .74; 1.0 mm, P = .09; 2.0 mm, P = .29; 3.0 mm, P = .65; 4.0 mm, P = .21; 5.0 mm, P = .12).
  
  
  CONCLUSIONS
  indicated that combining different file systems does not lead to increased levels of apical transportation. Hybrid instrumentation might be a valid alternative to achieve larger apical diameters without higher risk of procedural errors.
authors.affiliation: Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA. fsetzer@mac.com
authors.forename: Frank C
authors.initials: FC
authors.lastname: Setzer
authors.forename: Tae-Kyung
authors.initials: TK
authors.lastname: Kwon
authors.forename: Bekir
authors.initials: B
authors.lastname: Karabucak
mesh_terms: D003722:Dental Alloys / Q000737:chemistry; D003786:Dental Pulp Cavity / Q000473:pathology*; D004867:Equipment Design; D006801:Humans; D008422:Materials Testing; D009532:Nickel / Q000737:chemistry; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods / Q000592:standards; D012399:Rotation; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D019227:Tooth Apex / Q000473:pathology
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium