Aim: Evaluate the efficacy of the combined use of XP shaper and finisher in cleaning simulated internal root resorption defects in comparison to the conventional passive ultrasonic irrigation using stereomicroscope.
Materials and methods: The root canals of 90 freshly extracted human mandibular premolars were prepared using Protaper up to F4 and the teeth were split longitudinally and semicircular cavities (simulated internal root resorption cavities) were prepared in the canal wall on each half of the roots, then randomly assigned into two experimental groups (n=40) according to the cleaning technique groups (A) cleaned using passive ultrasonic irrigation , group (B) cleaned using XP-endo shaper followed by XP-endo finisher , five specimens were assigned to serve as negative control and five more were assigned to serve as positive control. Colored gelatin material (CGM) was prepared and applied into the semicircular cavities except for the negative control which did not receive (CGM). The root halves were reassembled creating a circular simulated resorption cavity within the root canal. Specimens were cleaned according to the group they were assigned to except for the positive control which did not receive any further treatment. All the specimens were disassembled and the residual CGM was examined under a stereomicroscope at 10x magnification and calculated as percentage of residual CGM to total area of the IRR cavity by using image analysis software and the data were statistically analyzed with one- way ANOVA test and significance level was set at P> 0.05.
Results: None of the tested methods could completely remove the CGM from the simulated IRR cavities. Group B showed lower mean percentage of residual CGM than did group A
(P> 0.041).
Concussion: within the limitations of this study XP-endo shaper followed by XP-endo finisher was more effective in cleaning inaccessible internal root resorption defects than PUI.