Verification of remaining filling materials in flattened/oval-shaped root canals after use of several endodontic retreatment protocols

This study verified of remaining filling materials in flattened/oval-shaped root canals after use of several endodontic retreatment protocols. Material and methods: Seventy human mandibular incisors were selected. Sixty specimens received crown-apex preparation performed by ProTaper Next® system andwere filled with hybrid Tagger technique with gutta-percha and AH Plus®. Ten specimens were left unprepared (Control Group). The specimens were randomly distributed in six groups, according the different retreatment protocols: G1 – Clearsonic® + ProTaper Universal Retreatment® + Reciproc®; G2 – Reciproc®; G3 – Clearsonic® + ProTaper Universal Retreatment®; G4 – Clearsonic® + Reciproc®; G5 – Oscillatory EndoEze® + Manual files; G6 – ProTaper Universal Retreatment®. Presence of root canal filling material residual were evaluated using Scanning Electron Microscopy. The relative differences of remaining filling materials between the groups and root thirds were determined by Kolmogorov-Smirnov and Levene tests followed by Tukey post hoc test. The level of significance was set at α = 5%. Results: Regarding the presence residual, G1 (Clearsonic® + ProTaper Universal Retreatment® + Reciproc®), G2 (Reciproc®), G3(Clearsonic® + ProTaper Universal Retreatment®) and G6 (ProTaper Universal Retreatment®) protocols presented a lower amount (p<0.05). The highest values (p<0.05) of remaining filling materials were presented in the G5 (Oscillatory EndoEze® + Manual files) protocol. Intermediate values (p<0.05) were presented by G4 (Clearsonic® + Reciproc®) protocol. Conclusion: The endodontic retreatment protocols no showed effectiveness for complete removal of remaining sealing material from flattened/oval-shaped root canals.