The study compares four different procedures of selective preparation of hard dental tissues: ablation by Er:YAG laser radiation (with long and short pulses), preparation by an ultrasound extension with a ball and a classical dental drill. In the long pulses the authors employed interaction energy of 40mJ, duration of the pulse 200 μs and interaction intensity 62kW/cm2; in short pulses the energy was 20mJ, pulse duration 100ns and interaction energy 62kW/cm2. The laser methods were compared with the ultrasound preparation (Sonixflex cariex TV, D – Sonicsys micro) and with the classical preparation. The longitudinal sections through the dentin and the samples of ivory were evaluated after the creation of cavity and administration of the filling by means of electron scanning microscope.

        Key words: dentin – ivory – Er:YAG laser – ultrasound –preparation