title: Apical Transportation, Centering Ability, and Cleaning Effectiveness of Reciprocating Single-file System Associated with Different Glide Path Techniques.
abstract: BACKGROUND
  The aim of this study was to evaluate the apical transportation, the centering ability, and the cleaning effectiveness of a reciprocating single-file system associated to different glide path techniques.
  
  
  METHODS
  The mesial root canals of 52 mandibular molars were randomly distributed into 4 groups (n = 13) according to the different glide path techniques used before biomechanical preparation with Reciproc System (RS): KF/RS (sizes 10 and 15 K-files), NGP/RS (no glide path, only reciprocating system), PF/RS (sizes 13, 16, and 19 PathFile instruments), and NP (no preparation). Cone-beam computed tomography analysis was performed before and after instrumentation for apical third images acquisition. Apical transportation and its direction were evaluated by using the formula D = (X1 - X2) - (Y1 - Y2), and the centering ability was analyzed by the formula CC = (X1 - X2/Y1 - Y2 or Y1 - Y2/X1 - X2). The samples were submitted to histologic processing and analyzed under a digital microscope for debris quantification. The values were statistically analyzed (Kruskal-Wallis, the Dunn multiple comparisons test, P < .05).
  
  
  RESULTS
  All groups had similar apical transportation values, with no significant difference among them (P > .05). Groups had a tendency toward transportation in the mesial direction. No technique had perfect centering ability (=1.0), with no significant difference among them. KF/RS had larger amount of debris, with statistically significant difference in comparison with NGP/RS (P > .05).
  
  
  CONCLUSIONS
  The different glide path techniques promoted minimal apical transportation, and the reciprocating single-file system tested remained relatively centralized within the root canal. Also, the different techniques interfered in the cleaning effectiveness of the reciprocating system.
authors.affiliation: Department of Endodontics, School of Dentistry, Federal University of Amazonas, Manaus, Amazonas, Brazil.
authors.forename: Guilherme Moreira
authors.initials: GM
authors.lastname: de Carvalho
authors.affiliation: Department of Endodontics, School of Dentistry, Federal University of Amazonas, Manaus, Amazonas, Brazil.
authors.forename: Emílio Carlos
authors.initials: EC
authors.lastname: Sponchiado Junior
authors.affiliation: Department of Endodontics, School of Dentistry, Federal University of Amazonas, Manaus, Amazonas, Brazil.
authors.forename: Angela Delfina Bittencourt
authors.initials: AD
authors.lastname: Garrido
authors.affiliation: Department of Physiology and Pathology, Araraquara School of Dentistry, São Paulo State University, Araraquara, São Paulo, Brazil.
authors.forename: Raphael Carlos Comelli
authors.initials: RC
authors.lastname: Lia
authors.affiliation: Department of Restorative Dentistry, Araçatuba School of Dentistry, São Paulo State University, Araçatuba, São Paulo, Brazil. Electronic address: drlucas.garcia@gmail.com.
authors.forename: Lucas da Fonseca Roberti
authors.initials: Lda F
authors.lastname: Garcia
authors.affiliation: Department of Endodontics, School of Dentistry, State University of Amazonas, Manaus, Amazonas, Brazil.
authors.forename: André Augusto Franco
authors.initials: AA
authors.lastname: Marques
mesh_terms: D001696:Biomechanical Phenomena; D006801:Humans; D008334:Mandible; D008963:Molar; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D019227:Tooth Apex / Q000033:anatomy & histology*
keywords: Apical transportation; centering ability; cleaning effectiveness; glide path; reciprocating motion