In vitro comparison of different reciprocating systems used during endodontic retreatment.

The present study evaluated the effectiveness of two reciprocating systems for the removal of root-filling material during endodontic retreatment. One hundred extracted mandibular premolars were prepared and root-filled with gutta-percha and sealer. Root fillings were removed with K-files according to the following techniques: Group A--hand instrumentation; Group B--Endo-Gripper system driven by compressed air; Group C--INTRAmatic 29CH + INTRA-LUX 3LD driven by compressed air; Group D--Endo-Gripper system driven by electric engine; Group E--INTRAmatic 29CH + INTRA-LUX 3LD driven by electric engine. The amount of filling debris on root canal walls was assessed radiographically and analysed using Auto CAD 2000 software. One-way anova and Duncan's test revealed statistically significant differences only in the middle third (P = 0.01); the best results being reached in group D. The apical third displayed the greatest amount of filling material debris, regardless of the technique used.