Objectives: The purposes of this study were to investigate the effect of Er:YAG laser to remove debris near the apical seats in root canals and to evaluate the efficacy of a fiberscope for the assessment of remnant debris on the root canal wall in vitro.
Summary background data: There has been no report to evaluate residual debris in root canals after Er:YAG laser irradiation using a fiberscope.
Methods: After cleansing and shaping by a one step back method with the alternative irrigation of hydrogen peroxide and sodium hypochlorite solution, 80 extracted single root human teeth with straight canals were randomly divided into four groups. The teeth of groups 1, 2, and 3 were irradiated by Er:YAG laser at the parameters of 1 W, 2 W, and 3 W, respectively. Group 4 was comprised of control specimens that were not lased. After laser irradiation, the remnant debris on the apical portions of all root canals was evaluated by fiberscopy. The teeth were then bisected longitudinally, and the specimens were observed by stereoscopy and scanning electron microscopy (SEM). The degree of remaining debris on the apical seats was scored.
Results: The degree of remaining debris observed by fiberscopy coincided with the results by SEM. There was no significant difference between groups 1 and 4, and also between groups 2 and 4, but the remaining debris in group 3 was significantly decreased after Er:YAG laser irradiation compared with that in group 4 (p < 0.01).
Conclusions: These results suggest that Er:YAG laser irradiation is effective for removal of debris near the apical seats and that a fiberscope is useful for the evaluation of the remaining debris near the apical seats of intact teeth.