Significance of the use of two rotary systems and hand file in endodontic retreatment

الملخص EN

The aim of this study was to evaluate the efficacy of R-Endo and ProTaper Universal rotary retreatment instruments compared with Hedstrom files for removal of ActiV GP during root canal retreatment.

Sixty extracted human single-canal mandibular premolars were decoronated to obtain 16 mm long root segment.

The root canals were instrumented with a crowndown technique using 0.06 taper Endosequence files to size 40.

The roots were randomly assigned according to obturation material into two groups (n=30); group I were filled with ActiV GP and group II with laterally compacted gutta-percha and AH Plus sealer.

Further division of each group into 3 subgroups (A, B and C) was performed 6 month later according to retreatment technique: R-Endo, ProTaper Universal and Hedstrom files, respectively.

All techniques were used with the solvent Guttasolv.

The amount of filling material remaining on root canal walls was assessed radiographically from two directions: mesiodistal and buccolingual.

Total canal area, area of the cervical, middle and apical thirds, and area of remaining filling material from both directions were outlined and calculated using Image-Pro Plus, version 6 computer software.

Statistical analysis of remaining filling material within each third of the canals was performed by the Kruskal–Wallis and Mann-Whitney U tests.

The two rotary nickel-titanium instruments left significantly less remaining filling materials than hand instruments (p< 0.05).

Canals obturated with gutta-percha / AH Plus showed significantly cleaner walls after its removal by either ProTaper or H files (p< 0.05).

None of the retreatment techniques (instruments) employed for the removal of root fillings was totally effective, especially in the apical third of the root canal.