MECHANICAL BEHAVIOR AND SHRINKAGE STRESS OF FIBER REINFORCED FLOW COMPOSITE

Objective: To evaluate the mechanical properties of a newly developed flowable bulk-fill composite with fibers as a dispersed phase.
Methods: experimental EverX Flow (GC corporation) (EXF), one conventional bulk-fill composite without fibers (Filtek, 3M (FBF)), and one flowable bulk composite without fibers (SureFil, Dentsply (SRD)) were tested. Samples were light-cured with Elipar DeepCure LED device (3M) and polymerization stress and volumetric shrinkage were evaluated. Samples were characterized in terms of flexural strength (ISO 4049), fracture toughness (ISO 207951) and Vickers hardness. EXF microstructure was characterized by SEM, as well as the fractured samples. Data were submitted to One-Way Anova and independent t test (α=0.05).
Results: FBF showed statistically higher Vickers hardness and flexural strength than EXF and SDR, while EXF showed higher values than SDR. However, EXF showed statistically higher KIC than FBF and SDR, and samples broken parts remained attached after fracture. Polymerization stress and volumetric shrinkage of the three composites were not significantly different.
Conclusion: Experimental fiber-reinforced flowable bulk-fill composite has a significantly higher fracture toughness values than non-reinforced bulk-fill composites. The obtained results provide evidence for its potential use as a restorative material in stress bearing areas.