Laser and ultrasound selective preparation of hard dental tissues

For the purpose of dentin micro-selective treatment the thermal ablation and photoablation accomplished by Er:YAG laser radiation, and preparation of tissue by ultrasonic round ball tip, and also by the classical dental drilling machine using diamond round bur, were executed. The laser energy used in the experiment was 75 mJ, and 40 mJ yielding in the interaction radiation intensity 97.5 kW/cm(2) and 130 MW/cm(2), for laser working in free-running (FR) and Q-switched mode (Q), respectively. The lengths of the interacting pulses were 200 mu s (FR) and 80 ns (Q) for these two regimes. Four various cavities prepared by these methods differs in shape, roughness of inner surface, and by the smear layer removal.