Subsurface morphologic changes of ND:YAG laser-etched enamel

Background and Objective Etching the enamel surface with a Nd:YAG dental laser produces impact craters with cavities, micropores, and microfissures. This in vitro SEM study examined laser‐etched enamel to determine the pattern and extent of subsurface changes. Study Design/Materials and Methods The facial surface of 10 maxillary central incisor teeth were coated with a black initiator and laser‐etched with a pulsed Nd:YAG laser (1.06λ, 75 mJ, 15 Hz, 320 μm fiber, 94 J/cm2 fluence). The facial surface of five teeth were plastic‐embedded under a low vacuum, then demineralized in 10% formic acid. The other teeth were split inciso‐apically. All samples were prepared for SEM. Results Examination of the plastic impressions showed a delicate interlacing pattern of thin partitions and small knob‐like expansions. Examination of the split teeth showed the penetration of microfissures into the enamel estimated at 10 μm. Conclusion These subsurface alterations may provide space for the infiltration and mechanical retention of dental resin. Lasers Surg. Med. 21:193–197, 1997. © 1997 Wiley‐Liss, Inc.