The interaction of picosecond laser radiation with human dental tissue
was investigated in this study, in order to determine the ablation rates
and the surface characteristics of the dentine by using scanning
electron microscopy (SEM). Dentine ablation was performed by using tooth
sections of different thicknesses (0.5-2.0 mm). Dental tissue samples
were irradiated in air with the fundamental wavelength and first
harmonic of a regenerative amplifier 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 532 nm pulses
were used, the SEM examinations revealed cracks and melting of dentine
with irregular surface modification. Consequently, it seems that
cleaning and shaping of the foot canal walls during endodontic therapy
with the picosecond Nd:YAG laser application may be possible in the
future. The, as yet unexplored, field of the picosecond laser
interaction with hard dental tissue is expected to be a potential
alternative for powerful laser processing of biomedical structures