In vitro effect of XP‑Endo finisher on the amount of residual debris and smear layer on the root canal walls

Abstract

Background: A successful endodontic treatment depends on efficient cleaning and shaping and
effective irrigation of root canals. The irrigating solution may not be effective in some areas in the
canal. The manufacturer of XP‑Endo finisher claims that it can effectively clean the root canals with
complex morphology. This study aimed to assess the effect of XP‑Endo finisher on the amount of
residual debris and smear layer on the root canal walls of mandibular second premolars.
Materials and Methods: In this In vitro study Fifty extracted mandibular second premolars with a root
curvature <20° were collected. Root canals were prepared using BioRaCe rotary system. The root canals
were in contact with the file and different irrigating solutions for 1 min. The teeth were then randomly
divided into four experimental (n = 10) and one positive control group as follows: (1) XPF + saline,
(2) XPF + ethylenediaminetetraacetic acid (EDTA), (3) XPF + sodium hypochlorite (NaOCl),
(4) XPF + EDTA + NaOCl and (control) EDTA + NaOCl. The teeth were longitudinally sectioned
into two halves and the amount of debris and smear layer remaining in the coronal, middle, and apical
thirds of the roots was quantified and scored under an electron microscope. The Kruskal–Wallis test
was used to compare the groups, and P < 0.05 was considered statistically significant.
Results: The highest mean amount of residual debris (2.9 ± 1.13) was noted in XPF + saline
group (P < 0.05). XPF + saline and XPF + NaOCl (3.8 ± 0.60) had the lowest efficacy for smear layer
removal (P < 0.05) with no significant within‑group difference. No significant difference was noted
between Groups 2, 3, and 4 with the positive control group regarding debris removal. Groups 2
and 4 had no significant difference with the positive control group regarding smear layer removal.
Conclusion: Use of XP‑Endo finisher has no superiority to the standard protocol for the use of
irrigating solutions (EDTA + NaOCl) for debris and smear layer removal, but in some cases, such
as second appointment of regeneration treatment we cannot use NaOCl because of its destructive
effects on stem cells; thus, we can benefit from the synergistic effects of XPF and EDTA for better
smear layer removal.
Key Words: Debris, root canal, smear layer