Aim: The current study aimed to compare, bond strength exhibited by root fillings made with gutta-percha/AH Plus after instrumenting oval root canals with different file systems.

Material and Methods: 60 recently extracted mandibular premolars exhibiting oval canals were selected for the study. These samples were randomly divided into 3 groups (n=20) for instrumentation: Group 1: Self-Adjusting File, Group 2: WaveOne and Group 3: Protaper NEXT. Post instrumentation, the samples were obturated with gutta-percha and AH Plus, and the sealer was allowed to set for 7 days. The teeth were then prepared for micro push-out assessment using 1.0 mm-thick root slices. Loading was performed with a universal testing machine at a speed of 0.5 mm/min. The load at which push-out occurred was registered and statistical analysis was done using one-way analysis of variance and Tukey’s post hoc test.

Results: Bond strength of root fillings in specimens instrumented with SAF were significantly higher (p<0.01) compared to WO and PTN instrumentation at coronal, middle and apical thirds. The bond strength of SAF instrumented samples was higher in coronal by 40% and 35% and the apical thirds by 30% and 25% compared to those instrumented by WO and PTN, respectively. No difference was found between the other two groups.

Conclusion: Gutta-percha/AH Plus root fillings exhibited higher bond strength in oval canals instrumented by the SAF System, as compared to WaveOne or Protaper NEXT.

Key Words: AH Plus, Gutta-percha, Protaper NEXT, Push-out bond strength, SAF, Self-Adjusting File, WaveOne.