Table 1.

Materials used in this study

Material	Composition	Lot no.	Company
AdheSe Universal (self-etch adhesive)	Methacrylates (67 wt%), water, ethanol (25 wt%), highly dispersed silicon dioxide (4 wt%), initiators, and stabilizers (4 wt%)	W97834	Ivoclar Vivadent, Schaan, Liechtenstein
Tetric EvoFlow Bulk Fill, shade IVA (TEF, flowable bulk-fill composite)	Dimethacrylates (28 wt%), barium glass, ytterbium trifluoride and copolymers (71 wt%), additives, initiators, stabilizers and pigments (<1.0 wt%); total inorganic filler content of 68.2 wt%, inorganic filler particle size ranging between 0.1 μm and 30 μm	W95972	Ivoclar Vivadent, Schaan, Liechtenstein
Tetric EvoCeram Bulk Fill, shade IVA (TBF, hybrid bulk-fill composite)	Dimethacrylates (19.7 wt%), prepolymer (17.0 wt%), barium glass filler, ytterbium trifluoride, mixed oxide (62 wt%), additives, initiators, stabilizers, pigments (< 1.0 wt%)	W93586	Ivoclar Vivadent, Schaan, Liechtenstein
SDR flow+, shade universal (SDR, flowable bulk-fill composite)	Modified urethane dimethacrylate resin, TEGDMA, polymerizable dimethacrylate resin polymerizable trimethacrylate resin, camphorquinone (CQ) photoinitiator, ethyl-4(dimethylamino)benzoate photoaccelerator, butylated hydroxyl toluene (BHT), fluorescent agent and UV stabilizer, fillers (70.5 wt%): barium-alumino-fluoro-borosilicate glass, strontium alumino-fluoro-silicate glass, ytterbium trifluoride glass, silicon dioxide; inorganic filler particle size ranging from 20 nm to 10 μm	1807000856	Dentsply DeTrey GmbH, Konstanz, Germany
Glass beads (added to the flowable composites)	SiO2 (72.50 wt%), Na2O (13.00 wt%), CaO (9.06 wt%), MgO (4.22 wt%), Al2O3 (0.58 wt%), diameter: 40–70 μm	Art. no. 5211	Sigmund Lindner GmbH, Warmensteinach, Germany