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Figure 2. FE-ESEM images of fractured interfaces in dentin bonded with Fuji IX GP. The fractured specimens were examined wet and without further coating. (A) Similar to the conventional SEM images, the dentin sides of fractured beams examined in a FE-ESEM showed similar spherical bodies (arrows) closely adapted to the adjacent polyalkenoate matrix. At these very small vacuums, no cracks were seen in the fractured GIC. (B) A small crack (pointer) began to appear in the polyalkenoate matrix, adjacent to a spherical body, as the vapor pressure was reduced to 5.4 Torr. (C) Shrinkage of the polyalkenoate matrix resulted in irreversible separation of the latter from the spherical bodies, even after the vapor pressure was returned to 5.6 Torr. A fractured spherical body revealed the presence of a solid core that was probably due to the retention of water within the eggshell-like structure. (D) Fractured unbonded Fuji IX GP (control) showed the absence of spherical bodies within the polyalkenoate matrix. Only air-voids (arrows) could be observed. (E) EDX analysis of Fuji IX GP-bonded dentin that was fractured along the GIC-dentin interface and examined with FE-ESEM. The elemental composition included Ca and P within the polyalkenoate matrix and Si in the spherical bodies and FASG fillers.
