The effect of instrument type and preflaring on apical file size determination.

Abstract

AIM: The aim of this study was to investigate the effect of instrument type (K-files and Lightspeed (LS) instruments) and the impact of preflaring on the first file size that binds at working length (WL) in a range of canal types of varying sizes and curvatures. METHODOLOGY: One hundred and twenty-one canals from 60 extracted intact human maxillary and mandibular premolars and molars were utilized. After standard access cavities, a size 6 K-file was inserted into each canal until the tip of the file was visible outside the apical foramen. WL were set 0.5 mm short of these measurements. Each canal was sized using consecutively larger K-files and hand-held LS instruments until one bound at WL...