Microhardness, Structure, and Morphology of Primary Enamel after Phosphoric Acid, Self-Etching Adhesive, and Er:YAG Laser Etching

Figure 2

SEM micrographs of untreated (control) and conditioned surfaces of primary enamel. Group I (a, b, c) presented a smooth pattern with some enamel grooves. A traditional honeycomb etching pattern was observed when 35% phosphoric acid conditioning was employed (group II, d, e, f). Group III (g, h, i) exhibited rough zones and exposed prisms produced by self-etching agent. Exposed prisms and flakes, resulting in a rough scaly surface after Er:YAG laser irradiation at 15 J/cm² (j, k, l) and 19.1 J/cm² (m, n, o) (groups IV and V, resp.), microcracks, and small areas of enamel ablation (original magnifications, ×500, ×2500, ×7500); scale bar = 50 μm, 10 μm, and 2 μm.