Effect of cyclic impact loading on the surface properties of flowable resin composites

The aim of this study was to examine the effect of cyclic impact loading (CIL) on the surface properties of flowable resin composites for posterior restorations. Cavities were filled with one of four flowable resin composites —Clearfil Majesty LV, Estelite Flow Quick, Beautifil Flow Plus F00, or Unifil Loflow Plus— and photo-polymerized. Clearfil Majesty was used as a control. Specimens were subjected to in vitro CIL testing with a mechanical loading device. The CIL-generated defect in the resin composite was scanned and traced at 10,000, 20,000, 30,000, and 40,000 cycles with a profilometer (n=5). An image scanner and computer program were used to calculate the mean defect depth on each resin composite restoration. Data were statistically analyzed with ANOVA and the post-hoc Tukey test. All tested flowable resin composites showed more surface degradation than the control after 40,000 CIL cycles.