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The STUDIA UNIVERSITATIS BABEŞ-BOLYAI issue article summary
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Abstract: The surface morphology of two composites (glass ionomer cements), and of their constituent inorganic and organic phases was investigated by atomic force microscopy (AFM), in tapping mode. The inorganic phase consists of a blend of inorganic powders, which was realized from surface active glasses. The organic phase contains either B1 copolymer or T1 copolymer, in the same weight percentage in water, with 3% tartaric acid. The two composites, noted B1 and T1, were made of the same inorganic powder blend, and the organic phase, containing either B1 or T1 copolymer. AFM imaging, namely height and phase-detection imaging with high resolution and contrast, was improved by monitoring the force of tapping of AFM probe on the sample surface. Morphological and structural analysis of investigated surfaces shows micro- and nanoparticles of inorganic powders embedded within the nano- and microdomains of copolymers. For B1 composite, it is observed a surface enrichment in B1 copolymer, against T1 composite. The surface of B1 and T1 composites was investigated both in native state and after polishing and glossing. The composites were measured in air and after 24 h or 7 days in artificial saliva. No essential topographical changes occurred to their surfaces, exposed about 24 h in saliva, independent of the used advanced processing methods for composite surfaces. The glossing leads to a stable surface of composites, both in air and after 24 h or even after 7 days exposed in saliva. However, after 7 days in saliva, the surface roughness is substantially increased for the T1 composite compared to B1 composite. Thus, B1 copolymer appears to be more stable in saliva than T1 copolymer. These data demonstrate that morphological and surface roughness analysis of both native surfaces and of enriched surfaces with polymers is important in determining the surface organization and the stability of composites in different environmental conditions. |
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