title: Evaluation of the apical adaptation performance of various root canal instruments.
abstract: OBJECTIVE
  The aim of this study was to evaluate the apical root canal adaptation performance of various root canal instruments.
  
  
  METHODS
  A total of 40 freshly extracted single-rooted mandibular incisors were used in this study. Coroner parts of all teeth were removed from cemento-enamel junction and root canal of each tooth was explored with a size 8 K-file until the tip of the file was just visible at the apex. Working lengths (WLs) were determined as 1 mm short of these measurements. ProTaper, K-file, profile and hedstroem files were inserted into the root canals of 10 teeth to the WL following the flaring of the coronal and middle thirds. Instruments were fixed in the root canals with acrylic resin. The apical 1 mm of each root tip was ground on wet sandpaper to expose the canal and the instrument at the WL and the apical region of each tooth was examined under stereomicroscope. The stereoscopic images of the teeth were digitized and analyzed with software in order to determine the differences between the areas of root canals and file tips. Result data were analyzed using the one-way analysis of variance test (P = 0.05).
  
  
  RESULTS
  There were no significant differences between apical file/root canal areas of the evaluated instruments (P > 0.05).
  
  
  CONCLUSIONS
  None of the evaluated instruments performed a perfect adaptation with the apical root canal surface at the WL in mandibular incisors. Therefore, total removal of the debris from the apical canal surface may not be achieved when these filing instruments are used.
authors: Department of Endodontics, Faculty of Dentistry, Karadeniz Technical University, Trabzon, Turkiye.
authors: K Tolga
authors: KT
authors: Ceyhanli
authors: Department of Restorative Dentistry, Faculty of Dentistry, Ege University, Izmir, Turkiye.
authors: Murat
authors: M
authors: Turkun
authors: Department of Endodontics, Faculty of Dentistry, Ege University, Izmir, Turkiye.
authors: Necdet
authors: N
authors: Erdilek
authors: Department of Restorative Dentistry, Faculty of Dentistry, Ege University, Izmir, Turkiye.
authors: Cem
authors: C
authors: Peskersoy
authors: Department of Biostatistics and Medical Informatics, Faculty of Medicine, Izmir, Turkiye.
authors: Timur
authors: T
authors: Kose
keywords: Apical adaptation; ProFile; ProTaper; hand instruments; stereomicroscope