Abstract
The present study evaluated the dynamic viscoelastic behavior of commercially available dental composites by a Split Hopkinson pressure bar (SHPB) test machine. Five commercially available composite resins — namely, two conventional hybrid composites (FiltekTM Z100, Z100; FiltekTM Z250, Z250) , a packable composite (FiltekTM P60, P60) , a flowable composite (FiltekTM Flow, FL) , and a nanofill composite (FiltekTM Supreme, SU) — were evaluated. By means of SHPB technique, the dynamic stress-strain curve, storage modulus, and loss tangent of the five dental composites were calculated. All specimens exhibited a nonlinear stress-strain curve in the loading process, which resulted not only from the viscoelasticity — but also from the plasticity — of matrix. In terms of storage modulus, no significant differences were exhibited among the five dental composites (p>0.05) . In terms of loss tangent, Z100 showed a significantly higher value than P60, FL, and SU (p<0.05) . Within the limitations of this investigation using SHPB, it was indicated that the loss tangent increased with increasing filler content.
