Scanning Electron Microscopy Study on Enamel Etching with Nd:YAG Laser and Phosphoric Acid

The effect of a neodymium:yttrium–aluminum–garnet (Nd:YAG 1.064 nm) laser was compared to acid etching on the human enamel surface. Twenty extracted teeth revealed morphological changes on the enamel surface under SEM microscopy. There was great morphological differences in the enamel surface caused by these two methods. With acid etching the enamel surface presents clean prisms and with laser application a melted recrystallized lava surface can be seen. We analyzed several groups of teeth (Groups I-A, I-B, I-C, and Group II). Group II presented the best results with 32% phosphoric acid etching and Nd:YAG laser etching at 2.0 W, 15 Hz, 133 mJ/pulse, and 165.4 J/cm² of energy density, applied for 60 sec. The degree of enamel penetration varied among groups.