Purpose: to quantify the amount of remaining gutta-percha/sealer on the walls of root canals when two engine-driven instruments (Quantec and ProFile) and two hand instruments (K-file and Hedström file) were used to remove these materials.
N= 100 extracted mandibular premolars (single canal)
Materials & Methods:
•Teeth were prepared using a modified step-back, flare technique and obturated with the lateral condensation technique and Tubli-seal sealer. •Retreatment technique: 0.5 mL orange oil solvent was introduced in each canal to soften the gutta-percha and a size 15 K-file was inserted until it reached the working length.
• samples were divided randomly into: G1:K files sizes (15-45), G2 Hedstrom file (15-45), G3 Quantec LX rotary instruments sizes 1–10 (45 tip) and G4 ProFile .04.
• After repreparation with the test instruments, the specimens were cut transversally at the cervical, middle and apical thirds with steel discs and the three sections were split longitudinally.
•The amount of residual debris on the canal walls in each section was examined using a stereomicroscope.
•The amount of apically extruded debris and the time required for treatment were also recorded by stopwatch.
Most highlighted Results:
- In all groups, the cervical and middle thirds demonstrated no debris.
- No statistically significant difference was found between the two groups for incidence of debris,
- There was a statistically significant difference between the four groups with the Hedström group less length of canal wall with remaining obturation and less time than the Quantec group.
- Six instruments fractured in the Quantec group, four in the ProFile group.
The results showed that overall, all instruments may leave filling material inside the root canal. During retreatment there is a risk of instrument breakage, especially rotary instruments.