title: Incidence of Apical Crack Initiation during Canal Preparation using Hand Stainless Steel (K-File) and Hand NiTi (Protaper) Files.
abstract: OBJECTIVE
  To evaluate the incidence of apical crack initiation during canal preparation with stainless steel K-files and hand protaper files(in vitrostudy).
  
  
  METHODS
  Sixty extracted mandibular premo-lar teeth are randomly selected and embedded in an acrylic tube filled with autopolymerizing resin. A baseline image of the apical surface of each specimen was recorded under a digital microscope (80×). The cervical and middle thirds of all samples were flared with #2 and #1 Gates-Glidden (GG) drills, and a second image was recorded. The teeth were randomly divided into four groups of 15 teeth each according to the file type (hand K-file and hand-protaper) and working length (WL) (instrumented at WL and 1 mm less than WL). Final image after dye penetration and photomicrograph of the apical root surface were digitally recorded.
  
  
  RESULTS
  Maximum numbers of cracks were observed with hand protaper files compared with hand K-file at the WL and 1 mm short of WL. Chi-square testing revealed a highly significant effect of WL on crack formation at WL and 1 mm short of WL (p = 0.000).
  
  
  CONCLUSIONS
  Minimum numbers of cracks at WL and 1 mm short of WL were observed with hand K-file and maximum with hand protaper files.
  Soni D, Raisingani D, Mathur R, Madan N, Visnoi S. Incidence of Apical Crack Initiation during Canal Preparation using Hand Stainless Steel (K-File) and Hand NiTi (Protaper) Files. Int J Clin Pediatr Dent 2016;9(4):303-307.
authors.affiliation: Student, Department of Conservative Dentistry and Endodontic Mahatma Gandhi Dental College and Hospital, Jaipur, Rajasthan India.
authors.forename: Dileep
authors.initials: D
authors.lastname: Soni
authors.affiliation: Postgraduate Student, Department of Conservative Dentistry and Endodontic Mahatma Gandhi Dental College and Hospital, Jaipur, Rajasthan India.
authors.forename: Deepak
authors.initials: D
authors.lastname: Raisingani
authors.affiliation: Senior Lecturer, Department of Conservative Dentistry and Endodontic Mahatma Gandhi Dental College and Hospital, Jaipur, Rajasthan India.
authors.forename: Rachit
authors.initials: R
authors.lastname: Mathur
authors.affiliation: Professor and Head, Department of Conservative Dentistry and Endodontic Mahatma Gandhi Dental College and Hospital, Jaipur, Rajasthan India.
authors.forename: Nidha
authors.initials: N
authors.lastname: Madan
authors.affiliation: Senior Lecturer, Department of Conservative Dentistry and Endodontic Mahatma Gandhi Dental College and Hospital, Jaipur, Rajasthan India.
authors.forename: Suchita
authors.initials: S
authors.lastname: Visnoi
keywords: Cracks; Instrumentation; Root canal preparation; Vertical root fracture; Working length.