Purpose: to compare the efficacy of conventional and new retreatment instruments when removing gutta-percha root fillings in curved root canals.
N= 56 curved molar roots
Materials & Methods:
•Root canals with apical diameters no greater than a size 15-K file and with a curvature of 20–42° were selected.
•A film holder with stainless steel cube was attached to the device in order to ensure the orientation of the root.
•Canal preparation was done with profile .06 size 30 and obturated by W/V compaction.
•Retreatment technique: G1 (K + H files size 30), G2 (Profile size 30 ,06), G3(R-Endo retreatment) and G4 (ProTaper Universal retreatment files). •Eucalyptol was used as a solvent with all techniques.
•Bucco-lingual and proximal radiographs of the roots were exposed and the percentage area of the remaining material was calculated.
•More procedural errors were noted when using ProTaper.
Most highlighted Results:
- None of the techniques completely removed the root filling materials.
- Manual instruments and Protaper were significantly faster.
- Manual instruments had significant Complete removal of filling material.
In this laboratory study in curved molar roots, ProTaper Retreatment and R-Endo instruments were less effective in removing filling material from canal walls than manual and ProFile instruments.