In this work, we studied the effects of C0(2), Nd:YAG and diode lasers on the enamel and dentin of deciduous human teeth. After the irradiations, the samples were duly prepared and set up on metallic bases, covered with gold and examined in the scanning electron microscope. The results showed that the irradiation with the C0(2) mode locked laser with 1.0 W power caused melting and irregularities with small cavities on the surface of the enamel. The irradiated area on the dentin surface appeared circular and well delimited, containing blocks of dentin and cracks. By using the pulsed Nd:YAG laser with 1.0 W mean power and 10 Hz frequency, the enamel surface presented granules of molten enamel, with a typical melting look. The irradiated dentin surface presented a cavity with a margin elevated with granules and holes, and its bottom presented dentinary tubules with globules of melted dentin. Irradiation with the mode locked of diode laser with 1.0 W mean power, showed the formation of a melted and evenly resolidified enamel surface, and the dentin surface presented a block of melted dentin with adjacent regions of normal dentin, evidently with a relatively smooth surface.