This study aimed to evaluate the nanomechanical surface properties and water uptake
of a flowable short-fiber-reinforced composite (SFRC) using various restorative techniques
in order to assess its potential as a standalone restorative material. Nanoindentation
and compressive creep testing were employed to characterize material performance.
Three resin composites were examined: a flowable SFRC (everX Flow), a bulk-fill particulate
filler composite (PFC), and a conventional PFC. Five experimental groups were established
based on the restorative technique: layered PFC, layered SFRC, bulk SFRC, bulk PFC,
and a bi-structure combining SFRC and PFC. Ninety standardized specimens (n = 18/group)
were fabricated. Static and creep nanoindentation tests were conducted to assess surface
properties, and water uptake was measured over a 30-day period. Data were analyzed
using one-way ANOVA and Bonferroni post hoc tests. Nanoindentation revealed significant
differences in hardness, with bulk PFC exhibiting the lowest values (p < 0.001). Creep
testing indicated changes in modulus and viscosity following water storage. Notably,
bulk SFRC showed the lowest water absorption (p < 0.001). Overall, bulk-applied SFRC
demonstrated favorable nanomechanical properties and reduced water uptake, demonstrating
its suitability as a standalone restorative material. Further clinical investigations
are recommended to validate its long-term performance.
