title: Computed micro-tomographic evaluation of glide path with nickel-titanium rotary PathFile in maxillary first molars curved canals.
abstract: BACKGROUND
  X-ray computed micro-tomography scanning allows high-resolution 3-dimensional imaging of small objects. In this study, micro-CT scanning was used to compare the ability of manual and mechanical glide path to maintain the original root canal anatomy.
  
  
  METHODS
  Eight extracted upper first permanent molars were scanned at the TOMOLAB station at ELETTRA Synchrotron Light Laboratory in Trieste, Italy, with a microfocus cone-beam geometry system. A total of 2,400 projections on 360° have been acquired at 100 kV and 80 μA, with a focal spot size of 8 μm. Buccal root canals of each specimen (n = 16) were randomly assigned to PathFile (P) or stainless-steel K-file (K) to perform glide path at the full working length. Specimens were then microscanned at the apical level (A) and at the point of the maximum curvature level (C) for post-treatment analyses. Curvatures of root canals were classified as moderate (≤35°) or severe (≥40°). The ratio of diameter ratios (RDRs) and the ratio of cross-sectional areas (RAs) were assessed. For each level of analysis (A and C), 2 balanced 2-way factorial analyses of variance (P < .05) were performed to evaluate the significance of the instrument factor and of canal curvature factor as well as the interactions of the factors both with RDRs and RAs.
  
  
  RESULTS
  Specimens in the K group had a mean curvature of 35.4° ± 11.5°; those in the P group had a curvature of 38° ± 9.9°. The instrument factor (P and K) was extremely significant (P < .001) for both the RDR and RA parameters, regardless of the point of analysis.
  
  
  CONCLUSIONS
  Micro-CT scanning confirmed that NiTi rotary PathFile instruments preserve the original canal anatomy and cause less canal aberrations.
authors.affiliation: Department of Endodontics, University of Turin Dental School, Turin, Italy. damianox@mac.com
authors.forename: Damiano
authors.initials: D
authors.lastname: Pasqualini
authors.forename: Caterina Chiara
authors.initials: CC
authors.lastname: Bianchi
authors.forename: Davide Salvatore
authors.initials: DS
authors.lastname: Paolino
authors.forename: Lucia
authors.initials: L
authors.lastname: Mancini
authors.forename: Andrea
authors.initials: A
authors.lastname: Cemenasco
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Cantatore
authors.forename: Arnaldo
authors.initials: A
authors.lastname: Castellucci
authors.forename: Elio
authors.initials: E
authors.lastname: Berutti
mesh_terms: D019412:Anatomy, Cross-Sectional / Q000379:methods; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003722:Dental Alloys / Q000737:chemistry*; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D054327:Lubricants / Q000737:chemistry; D008437:Maxilla / Q000000981:diagnostic imaging; D008866:Microsurgery / Q000379:methods; D008963:Molar / Q000000981:diagnostic imaging*; D009532:Nickel / Q000737:chemistry*; D012388:Root Canal Irrigants / Q000008:administration & dosage; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D012973:Sodium Hypochlorite / Q000008:administration & dosage; D013193:Stainless Steel / Q000737:chemistry; D014025:Titanium / Q000737:chemistry*; D019227:Tooth Apex / Q000000981:diagnostic imaging; D055114:X-Ray Microtomography / Q000379:methods*
chemical_list: D003722:Dental Alloys; D054327:Lubricants; D012388:Root Canal Irrigants; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium; D012973:Sodium Hypochlorite