title: Comparison of 2 canal preparation techniques in the induction of microcracks: a pilot study with cadaver mandibles.
abstract: BACKGROUND
  The purpose of this pilot study in a cadaver model was to compare 2 different shaping techniques regarding the induction of dentinal microcracks.
  
  
  METHODS
  Three lower incisors from each of 6 adult human cadaver skulls were randomly distributed into 3 groups: the control group (CG, no instrumentation), the GT group (GT Profile hand files; Dentsply Tulsa Dental, Tulsa, OK), and the WO group (WaveOne; Dentsply Tulsa Dental). In the GT group, manual shaping in a crown-down sequence with GT Profile hand files was performed. In the WO group, Primary WaveOne files were used to the working length. Teeth were separated from the mandibles by careful removal of soft tissue and bone under magnification. Roots were sectioned horizontally at 3, 6, and 9 mm from the apex using a low-speed saw. Color photographs at 2 magnifications (25× and 40×) were obtained. Three blinded examiners registered the presence of microcracks (yes/no), extension (incomplete/complete), direction (buccolingual/mesiodistal), and location. Data were analyzed with chi-square tests at P < .05.
  
  
  RESULTS
  Microcracks were found in 50% (CG and GT) and 66% (WO) of teeth at 3 mm, 16.6% (CG) and 33.3% (GT and WO) at 6 mm, and 16.6% in all 3 groups at 9 mm from the apex. There were no significant differences in the incidence of microcracks between all groups at 3 (P = .8), 6 (P = .8), or 9 mm (P = 1). All microcracks were incomplete, started at the pulpal wall, and had a buccolingual direction.
  
  
  CONCLUSIONS
  Within the limitations of this pilot study, a relationship between the shaping techniques (GT hand and WaveOne) and the incidence of microcracks could not be shown compared with uninstrumented controls.
authors.affiliation: Department of Endodontics, University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, California. Electronic address: aa@ana-arias.com.
authors.forename: Ana
authors.initials: A
authors.lastname: Arias
authors.affiliation: Department of Endodontics, University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, California.
authors.forename: Yoon H
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Department of Endodontics, University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, California.
authors.forename: Christine I
authors.initials: CI
authors.lastname: Peters
authors.affiliation: Department of Endodontics, University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, California.
authors.forename: Alan H
authors.initials: AH
authors.lastname: Gluskin
authors.affiliation: Department of Endodontics, University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, California.
authors.forename: Ove A
authors.initials: OA
authors.lastname: Peters
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging / Q000293:injuries*; D003804:Dentin / Q000000981:diagnostic imaging / Q000293:injuries*; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007180:Incisor / Q000000981:diagnostic imaging; D010781:Photography / Q000379:methods; D010865:Pilot Projects; D011859:Radiography; D011897:Random Allocation; D012388:Root Canal Irrigants / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods*; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D019227:Tooth Apex / Q000293:injuries
chemical_list: D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite
keywords: Cadaver mandible; GT hand; WaveOne; microcracks