Picosecond laser ablation of dentine in endodontics

The interaction of picosecond laser radiation with human dental tissue was investigated in this study, in order to determine the ablation rates and th e surface characteristics of the dentine by using scanning electron microsc opy (SEM). Dentine ablation was performed by using tooth sections of differ ent thicknesses (0.5-2.0 mm). Dental tissue samples were irradiated in air with the fundamental wavelength and first harmonic of a regenerative amplif ier Nd:YAG laser system, at 1064 nm and 532 nm, respectively, with a pulse duration of 100 ps and a pulse repetition rate of 10 Hz. The results showed very clean craters surrounded by minimum melting of the surface of dentine when the 1064 nm pulses were used. in contrast, when the first harmonic 53 2 nm pulses were used, the SEM examinations revealed cracks and melting of dentine with irregular surface modification. Consequently, it seems that cl eaning and shaping of the foot canal walls during endodontic therapy with t he picosecond Nd:YAG laser application may be possible in the future. The, as yet unexplored, field of the picosecond laser interaction with hard dent al tissue is expected to be a potential alternative for powerful laser proc essing of biomedical structures.