Surface topography and mechanical properties of flax fibres modified glass ionomer restorative materials

Abstract

Objectives: Regardless of the excellent adhesive and biological properties of glass ionomer cements (GICs), their poor mechanical properties and abrasion resistance limit their application to non-load bearing areas. This study aimed to investigate the effect of flax fibres incorporation on surface and mechanical properties of GIC filling materials.

Methods: Short chopped flax fibres were randomly incorporated into GIC at 0, 0.5, 1, 2.5, 5 and 25 wt%. Surface hardness, distribution of different phases, stiffness map, phase separation and uniformity of the material were investigated.

Results: Addition of flax fibres produced no significant change in Vicker hardness number of GIC. Qualitative imaging using atomic force microscopy showed the presence of a single phase in GIC, while biphasic structure was observed for flax fibres modified GICs (FFMGICs). For all tested formulations, the flax fibres, however, were uniformly distributed and well integrated within the GIC matrix without any visible interfacial separation. Incorporation of flax fibres was associated with a significant increase in surface roughness and stiffness. The roughness values obtained for all tested formulations, however, are far below the threshold values for bacterial adhesion and plaque accumulation.

Conclusions: Flax fibres modified GICs could be potentially used in high stress bearing areas.