Characterisation of resin composite structure and collagen assembly at nanometre to micrometre length scales

UoM administered thesis: Phd


from collagen samples seeded on silicon wafer using advance imaging techniques: Atomic Force Microscopy (AFM) and Kelvin Probe Force microscopy (KPFM). The samples were then divided in 5 groups of 8 specimens and submitted to the effects of dental chemical agents (citric acid, phosphoric acid, phosphoric acid/chlorhexidine, chlorhexidine, HEMA/TEGDMA). After each agent, the same area of the fibrils was reassessed. Important reductions in height, and electrical surface potential were detected. Therefore, it was concluded that chemical agents induce changes on the structure of collagen type I.
Moreover, topographic maps at different dimension were obtained from polished and brushed samples from three different resin-composites using AFM. Using Matlab routines, arithmetical mean height (Sa), root mean square height (Sq) and maximum height (Sz) were obtained at incremental size areas. It was observed a non-linear increase of surface roughness at higher dimensions. These observations suggest that to successfully characterise surface roughness of dental materials is essential measuring and report Sa, Sq and Sz at both, small and large areas and to standardise procedures.


Original languageEnglish
Award date2019