View larger version (136K):
[in a new window]
|
Figure 2. Representative TEM photomicrographs and SEM fractographs of the RMGI adhesive applied to dentin by the experimental surface treatments. Important microstructural features have been identified: unaffected dentin (Ud); dentin tubule (T); hybrid layer (Hy); gel-phase (G-P); matrix in RMGI (M); glass particle in RMGI (Gp). (A1,A2) Non-demineralized and unstained specimen of the untreated group revealing a thin, 0.5-µm, hybrid layer and absence of the gel-phase. (A3) Fractured dentin side after µTBS testing, showing a typical adhesive failure pattern characterized by the furrows from a bur-cut smear layer. (B1,B2) Non-demineralized and unstained specimen of the polyalkenoic acid group, revealing an underlying thin, 0.5-µm, hybrid layer covered by the gel-phase, and heterogeneously distributed hydroxyapatite crystals within the hybrid layer. (B3) Fractured dentin side after µTBS testing, showing a typical mixed failure pattern characterized by adhesive debonding on the right side and cohesive failure of the RMGI on the left side. Notice the typical porous appearance of fractured RMGIs. (C1,C2) Non-demineralized and unstained specimen of the exp-SE group, revealing a thin, 0.5-µm, hybrid layer, absence of the gel-phase, and heterogeneously distributed hydroxyapatite crystals within the hybrid layer. (C3) Fractured dentin side after µTBS testing, showing a typical mixed failure pattern. (D1,D2) Non-demineralized and unstained specimen of the phosphoric acid group, unveiling a 5-µm-thick hybrid layer and absence of the gel-phase or hydroxyapatite crystals within the hybrid layer. (D3) Fractured dentin side after µTBS testing, showing a typical cohesive failure in RMGI.
|
