Morphological study on the capability of Er : YAG laser irradiation for root canal preparation

Objective: The purpose of this study was to evaluate morphologically the ca pability of Er:YAG laser irradiation for root canal preparation in vitro. B ackground Data: There have been no reports on root canal preparation using Er:YAG laser irradiation. Methods: Forty extracted human teeth were divided randomly into two groups of 20. Laser irradiation was performed using thre e different sizes of fiber tips at the two different parameters (G 1, 2 Hz and 136-184 mJ/pulse; G 2, 2 Hz and 170-230 mJ/pulse). After laser irradiat ion, the teeth were bisected longitudinally and observed by stereoscopy and field emission-scanning electron microscopy (FE-SEM), The time required fo r preparation in each group was recorded and the achievement degree of root canal preparation was scored according to our criteria. Statistical analys is of the times was performed using one-way analysis of variance (ANOVA), A value of p < 0.01 was considered significant. Results: Root canals were pr epared using laser irradiation at 50% of teeth in G 1 and 40% in G 2, Remna nt pulp tissue after laser irradiation was observed at 30% of teeth in G 1, but not recognized in G 2. Irradiated areas were scale-like and clean, but rough and irregular by FE-SEM, The statistical analysis revealed that the time required for preparation at high energies was significantly shorter co mpared with that at low energies (p < 0.01), Conclusion: These results sugg est that Er:YAG lasr irradiation is capable of root canal preparation if ap propriate parameters are selected.