Purpose: This study assessed cavities prepared in the enamel of primary teeth using Er:YAG laser. The rounding of the cavosurface margins and the angles of concavity at the base of the cuts were evaluated. Materials and Methods: Twelve exfoliated primary teeth were irradiated with Er:YAG laser emitting a wave length of 2.94 µm with a spot size of 0.70 mm. Radiation was perpendicularly applied for 10 s at a focal distance of 13 mm, with a pulse repetition rate of 10 Hz. The energy was set at either 200 mJ or 300 mJ. Cross-sectional views of the cut surfaces were examined in SEM micrographs (50X). All measurements of cavosurface angles and the angle of concavity were made using a modified cephalometric program. Results: The t-test analysis indicated differences in the occlusal and cervical cavosurface angles when the energy was modified: increased energy produced a cavity angle reduction. The occlusal vs cervical angle analysis showed no significant difference in cavities prepared with either energy level. Conclusion: Within the parameters of the present study, we concluded that there was a reduction in the concavity angle of the cavities when the laser energy was increased. The occlusal and cervical cavosurface angles were significantly different when the energy was increased.

Keywords: lasers, dental cavity preparation, primary teeth, Er:YAG laser irradiation, scanning electron microscopy, enamel