title: Stereomicroscopic evaluation of dentinal defects induced by new rotary system: "ProTaper NEXT".
abstract: BACKGROUND
  The objective of this study was to evaluate dentinal defects formed by new rotary system - Protaper next™ (PTN).
  
  
  METHODS
  Sixty single-rooted premolars were selected. All specimens were decoronated and divided into four groups, each group having 15 specimens. Group I specimens were prepared by Hand K-files (Mani), Group II with ProTaper Universal (PT; Dentsply Maillefer), Group III with Hero Shaper (HS; Micro-Mega, Besancon, France), and Group IV with PTN (Dentsply Maillefer). Roots of each specimen were sectioned at 3, 6, and 9mm from the apex and were then viewed under a stereomicroscope to evaluate presence or absence of dentinal defects.
  
  
  RESULTS
  In roots prepared with hand files (HFs) showed lowest percentage of dentinal defects (6.7%); whereas in roots prepared with PT, HS, and PTN it was 40, 66.7, and 26.7%, respectively. There was significant difference between the HS group and the PTN group (P < 0.05).
  
  
  CONCLUSIONS
  All rotary files induced defects in root dentin, whereas the hand instruments induced minimal defects.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vidya Shikshan Prasarak Mandal's Dental College and Research Centre, Nagpur, Maharashtra, India.
authors.forename: Deepa Deepak
authors.initials: DD
authors.lastname: Shori
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vidya Shikshan Prasarak Mandal's Dental College and Research Centre, Nagpur, Maharashtra, India.
authors.forename: Pratima Ramakrishna
authors.initials: PR
authors.lastname: Shenoi
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vidya Shikshan Prasarak Mandal's Dental College and Research Centre, Nagpur, Maharashtra, India.
authors.forename: Arshia R
authors.initials: AR
authors.lastname: Baig
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vidya Shikshan Prasarak Mandal's Dental College and Research Centre, Nagpur, Maharashtra, India.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Kubde
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vidya Shikshan Prasarak Mandal's Dental College and Research Centre, Nagpur, Maharashtra, India.
authors.forename: Chetana
authors.initials: C
authors.lastname: Makade
authors.affiliation: Private Practitioner, Raipur, Chattisgarh, India.
authors.forename: Swapnil
authors.initials: S
authors.lastname: Pandey
keywords: Dentinal defects; NiTi instruments; ProTaper next™ rotary system; hand files; root canal preparations