Sealer penetration: effect of separated file’s cross-section, taper and motion characteristics

Objectives The separated root canal instruments may affect the quality of root canal filling, hence the success of endodontic treatment. The aim of this study was to evaluate the effects of separated file fragments of nickel-titanium rotary systems with different cross-section, taper and motion characteristics on the apical sealer penetration in oval-shaped root canals via confocal laser scanning microscope (CLSM). Materials and methods Distal roots of 60 mandibular molars with oval-shaped root canals were randomly divided into 4 groups as follows: group 1, FlexMaster Nickel Titanium Rotary File System (NTRFS) (separated instrument: 30/.06); group 2, ProTaper Next NTRFS (X3); group 3, ProTaper Universal NTRFS (F3); group 4, Revo-S NTRFS (AS30/.06). Root canals were filled with gutta-percha and AH plus labelled with 0.1% rhodamine B using a warm vertical compaction technique. Each specimen was horizontally sectioned at 1st, 3rd and 5th mm from apical foramen. Amount of maximum and average penetration depths, penetration percentage and sealer penetrated area were measured and analysed with one-way repeated measures of ANOVA and the Bonferroni post hoc tests. p