Effect of XP-Endo Finisher Rotary File on Removal of Smear Layer on the Root Canal Wall Using Different Rotary Files and Different Irrigants (An Ex- vivo Study)

Abstract

Objective: To evaluate the efficacy of XP- endo finisher (XPF) in removing the residual smear layer as a final step following the use of the One Curve and 2Shape files.
 Methods: Sixty extracted maxillary first molar teeth with (MB) root curvature within (10-25°) were selected, and only (MB) roots were used in this study. After that, the teeth were divided randomly according to the type of file used for canal preparation into two main groups (1 and 2). Then the main groups were divided into three subgroups (A, B, and C). In subgroups A1, B1, and C1, the 2Shape file was used for canal preparation; in subgroups A2, B2, and C2, the One Curve file was used. In subgroups A1 and A2, NaOCl was used during instrumentation and XPF to improve the residual smear layer removal with EDTA. In subgroups B1 and B2, NaOCl was used during instrumentation, and EDTA was used for 1 min to remove the residual smear layer. In subgroups C1 and C2, normal saline was used during instrumentation and with XPF. Then the roots were linearly sectioned into two parts. The coronal, middle, and apical thirds were quantified for the remaining smear layer under the scanning electron microscope (SEM). The Kruskal–Wallis- test and Mann- Whitney U test were used to measure the subgroups' differences. All tests were performed at the significant (p < 0.05) level.
 Results: The subgroup C1 had the highest mean score and lowest efficiency in removing the residual smear layer. The result showed that the subgroup A2 exhibited the best residual smear layer removal effectiveness. Significant differences were observed between subgroups A1 and A2 (p < 0.05). At the same time, there were significant differences between subgroups B1 and B2 (p < 0.05), and subgroups A2 and B2 exhibited significant differences from C2 (p < 0.05). Furthermore, significant differences were observed when subgroups C1 and C2 were compared to all the other subgroups (p < 0.05). 
 Conclusions: Using the One Curve file with NaOCl during instrumentation and using XPF to improve the residual smear layer removal with EDTA exhibited the best efficacy for removing the residual smear layer.