title: Incidence of dentinal defects after preparation of severely curved root canals using the Reciproc single-file system with and without prior creation of a glide path.
abstract: OBJECTIVE
  To investigate the incidence of dentinal defects after preparation of severely curved root canals using the Reciproc single-file system with and without prior creation of a glide path.
  
  
  METHODS
  Mesial roots from extracted mandibular first molars were collected and scanned with CBCT to assess the morphology of the root canal systems. Three groups of 20 anatomically comparable specimens were generated. The control group was left unprepared, whilst the experimental groups were prepared with Reciproc R25 with and without a glide path (groups RG and R, respectively). Roots were then sectioned perpendicular to the long axis at 2, 4, 6, 8 and 10 mm from the apex, and coloured photographs of the sections at 40× were obtained. Two blinded examiners registered the presence of dentinal defects twice at 2-week interval. Data were statistically analysed using the Fisher exact and Cochran's Q tests.
  
  
  RESULTS
  No defects were observed in the control group. The overall incidence of dentinal defects was 26% in group R and 24% in group RG, with no significant differences between them (P > 0.05). Dentinal defects occurred significantly more often in the middle and coronal thirds compared to the apical third of the canals (P < 0.05).
  
  
  CONCLUSIONS
  Prior preparation of a glide path had no impact on the incidence of dentinal defects when using Reciproc files.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt. shehab007@yahoo.com.
authors.forename: S E D M
authors.initials: SE
authors.lastname: Saber
authors.affiliation: Central Interdisciplinary Ambulance in the School of Dentistry, University of Münster, Münster, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Schäfer
mesh_terms: D003762:Dental Instruments; D003804:Dentin / Q000293:injuries*; D004867:Equipment Design; D006801:Humans; D008334:Mandible; D008875:Middle Aged; D008963:Molar / Q000033:anatomy & histology; D009532:Nickel; D018915:Root Canal Preparation / Q000009:adverse effects* / Q000295:instrumentation* / Q000379:methods; D014025:Titanium; D014092:Tooth Root / Q000033:anatomy & histology*
chemical_list: D009532:Nickel; D014025:Titanium
keywords: M-wire; dentinal defects; reciprocating; single-file systems