Nd:YAG laser effects on the occlusal surface of premolars.

PURPOSE: To evaluate with the scanning electron microscope (SEM) the effects of a pulsed Nd: YAG laser on the occlusal surface of human premolars in vitro. MATERIALS AND METHODS: Twenty normal premolars extracted for orthodontic reasons were used and separated in two groups. Group 1 received the irradiation at 2.0 watts, repetition rate of 20 Hz and 124.3 J/cm2 of energy density during 3 minutes, on the occlusal fissure. Group 2 received the laser irradiation in only half of the fissure. RESULTS: The SEM analysis revealed that in the case of shallow fissures the sealing was total but in narrow and deep fissure the sealing was partial or was in complete.