Mechanical properties of a resin-modified glass-ionomer cement reinforced with short-glass fiber flowable resin composites.

Purpose: To evaluate the improvement of selected mechanical properties of a resin-modified glass-ionomer cement (RMGIC) with a discontinuous short E glass fiber flowable resin composites (GFRRC) to be used in load-bearing areas of permanent teeth.

Methods: Experimental materials were prepared using two different weight proportions, 7 wt% (1.75% E glass fibers) and 25 wt% (6.25% E glass fibers) of a GFRRC into an RMGIC matrix. Flexural strength was evaluated in 0- and 24-hour hydration periods, and fracture toughness was assessed after 24 hours. The internal microstructure of fractured samples was evaluated using a scanning electron microscope.

Results: The addition of 25% of GFRRC was more effective in strengthening RMGIC than the introduction of only 7% GFRRC. Hydration periods did not show any significant statistical difference (P> 0.05). SEM micrographs of experimental materials' fractured surfaces revealed pull-out and fractured fibers; the presence of the matrix attached to fibers indicates great fiber-matrix adhesion. Within the limitations of the study, the results revealed that reinforcing RMGIC with discontinuous short E glass fiber flowable resin composites (GFRRC) improved significantly the flexural strength and modestly enhanced fracture toughness.

Clinical significance: The current study results are promising for the future of resin-modified glass-ionomer as a viable permanent restorative material in stress-bearing areas for permanent teeth after the reinforcement with short E glass fiber flowable resin composites as a source of discontinuous short glass fibers.