Purpose: The objective of the present study was to investigate the usefulness of high-output Erbium:Yttrium,Aluminum, Garnet (Er:YAG) laser in pulp cavity perforation, chamber roof removal, and root canal orifice enlargement. Materials and Methods: Seventy extracted human incisors without curvature were used. Using an Er:YAG laser system (2940 nm, Smart 2940D, DEKA; Florence, Italy), chamber roof removal and root canal orifice enlargement were performed. A total of 14 subgroups, including two control groups, were formed. The following three laser application tips were used: mirror, sapphire, and spear-shaped sapphire (spear). Laser output was set at either 5 or 7 W. Time required for dental tissue removal was measured and statistically analyzed using Kruskal- Wallis and Fishers PLSD tests. After laser application, x-ray imaging, stereomicroscopy, and scanning electron microscopy were performed. Results: In teeth without crowns, the time required for root canal orifice enlargement was clearly shorter with the mirror tip. In teeth with crowns, the root canal was enlarged almost up to the apical third of the root, and when using the mirror tip, a V-shaped hole was created. In teeth without crowns, a U-shaped hole was made almost up to the center of the root. SEM showed hardly any smear layer on the cut surface of the root canal wall. Conclusion: Root canal preparation should be carried out by applying high-output Er:YAG laser using a spear tip.
Keywords: Er:YAG laser, root canal preparation, perforation into pulp chamber, treatment time, SEM, superimposition