aim of this study was to compare the efficacy of the Nd:YAG laser,
ultrasound, the ProTaper Universal system (Dentsply Maillefer,
Ballaigues, Switzerland), and the CanalBrush (Coltene Whaledent,
Langenau, Germany) methods for the removal of the smear layer from the
apical third of root canals.
distal root canals from extracted human mandibular first molars were
instrumented up to ProTaper Universal F5 and divided randomly into 5
groups (n = 10) according to the following final irrigation
agitation techniques: no agitation (control), ProTaper Universal file,
ultrasound, CanalBrush, and Nd:YAG laser. Specimens were observed under a
scanning electron microscope. The presence of the smear layer was
evaluated using a 3-grade scoring system. The data were analyzed with
Cohen kappa, Kruskal-Wallis, and Mann-Whitney U tests. A level of significance of .05 was adopted.
ultrasound group performed significantly better than the rest of the
groups; 56.6% of the specimens revealed no smear layer, 44.4% showed the
presence of a moderate smear layer, and no heavy smear layers were
observed. In the Nd:YAG laser group, 30% of the specimens presented with
no smear layer, 70% showed the presence of a moderate smear layer, and
no heavy smear layers were observed. In contrast, a heavy smear layer
was observed on the surfaces of the root canals in the CanalBrush
(23.4%), ProTaper Universal (13.4%), and control (86.6%) groups.
Statistically significant differences were observed (P < .05).
of the agitation methods completely removed the smear layer. However,
the ultrasound method performed significantly better followed by the
Nd:YAG laser, the CanalBrush, and the ProTaper Universal system.
Agitation of the irrigant improved smear layer removal in the apical
third of the canal.