Influence of cervical preflaring on apical file size determination

By Pecora J, Capelli A

Date: 01/2005
Journal: IEJ


Purpose: To investigate the influence of cervical preflaring with different instruments (Gates-Glidden drills, Quantec Flare series instruments and LA Axxess burs) on the first file that binds at working length (WL) in maxillary central incisors.

  • N= 40 maxillary central incisors.


  • Forty human maxillary central incisors with complete root formation were used.
  • access cavity were prepared, size #06 K file used to determine WL 1 shorter than the apex.
  • the teeth were divided into 4 groups according to the preflaring technique (G1: no preflaring, G2: Gates Glidden sizes 90, 100, 130, G3: Quantec Flare series instruments, G4: LA Axxess burs) the preflaring in the experimental groups was performed in the cervical and middle thirds.
  • the size of initial file in each canal was determined, starting with size 08 files with passive movements followed by larger instruments until the WL was reached.
  • The apical region was then observed under a stereoscopic magnifier, images were recorded digitally and the differences between root canal and maximum file diameters were evaluated

Most highlighted Results:

  • Significant differences were found between experimental groups regarding anatomical diameter at the WL and the first file to bind in the canal.
  • The major discrepancy was found when no preflaring was performed (0.151 mm average). The LA Axxess burs produced the smallest differences between anatomical diameter and first file to bind (0.016 mm average).

Clinical Significance:

 the importance of preflaring to accurately determine the size of initial file.

weakness: using one tooth type, the number of examiners were not specified.