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Figure 1. SEM images of fractured interfaces in dentin bonded with Fuji VII. Similar results were observed with the other GICs. (A) Dentin side of a representative beam fractured along the GIC-dentin interface. Despite the presence of artifactual cracks (arrow), numerous spherical bodies (pointer) could be seen within the fractured GIC. IL, intermediate layer; D, dentin. (B) Corresponding GIC side of fractured beam in (A), showing presence of similar spherical bodies (pointers). (C) High-magnification view contrasts the difference between spherical bodies (S) and angular fluoro-aluminosilicate glass (FASG) fillers (F). The spaces (asterisk) between the matrix and the spherical bodies are a result of shrinkage of the matrix (M) during specimen preparation of conventional SEM. (D) High-magnification view of (A), showing a partially fractured, hollow spherical body with evidence of brittle fracture (pointer) observed in the walls of the fractured eggshell-like structure. (E) When GIC beams were fractured 3 mm away from the GIC-dentin interface, only air-voids (pointer) could be identified. No spherical body could be seen. M, polyalkenoate matrix; G, FASG filler; arrow, dehydration crack.
