Incidence of Vertical Root Fracture at the Apical Third of the Root Canal System after Preparation with Newer NiTi Rotary Files and Hand Files at Different Working Lengths
Abstract: Introduction Vertical root fracture (VRF) is considered one of the most unfavorable complications in root canal treatment which may lead to tooth extraction. The aim of the study was to compare the incidence of generation of dentinal defects in the apical third of human extracted teeth after canal preparations with new rotary files (Vortex blue rotary file and HyFlex CM file) at differen... read moret instrumentation lengths after hand filing vs. hand filing only (K-Flexofile). At different levels, the assessment of the defects was evaluated using a stereomicroscope using a cold light source. Materials and Methods One hundred and twenty anterior teeth (maxillary and mandibular) were mounted in resin blocks with simulated periodontal ligaments after examination and exclusion of cracked teeth. The teeth were randomly divided into six groups (N = 20). Group 1: Control group (no preparation). Group 2: Hand file to working length using Stainless steel K-Flexofile (Dentsply Maillefer, Ballaigues, Switzerland). Group 3: Hand file to working length and Vortex Blue rotary file (Dentsply, Tulsa, OK) to working length. Group 4: Hand file to working length and Vortex Blue rotary file to -2 mm of the working length. Group 5: Hand file to working length and HyFlex CM file (Coltène Whaledent, Cuyahoga Falls, OH, USA) to the working length. Group 6: Hand file to working length and HyFlex CM file to -2 mm of the working length. Specimens were sectioned horizontally at 2 mm from the apex and dentinal microcracks were observed under a stereomicroscope. The differences between groups were determined by Fisher's exact test. Results The control group did not show any dentinal defects. However, there was no significant difference between the rotary groups and hand filing group in terms of presence of complete root fracture (p = 1) or any root fracture (p = .076). Conclusion Within the limitations of this study, it was concluded that canal preparation with hand files or rotary files could induce dentinal defects. There was no significant difference between groups in terms of crack formation.
Thesis (M.S.)--Tufts University, 2018.
Submitted to the School of Dental Medicine.
Advisor: Robert Amato.
Committee: Gerard Kugel, Britta Magnuson, and Matthew Finkelman.
Keyword: Dentistry.read less