The effect of curing light distance on the effectiveness of cure of bulk-fill resin-based composites / Rana Abdelbaset Lotfy Diab

Objectives: To investigate the effect of different curing light distances on the surface hardness (SH) and the effectiveness of cure of bulk-fill resin-based composites (RBCs). Methodology: Two bulk-fill RBCs (Tetric N Ceram® Bulk Fill [TN] and Filtek™ Bulk Fill [FK]) were evaluated. Cylindrical RBC specimens of 5 mm diameter and 4 mm height were fabricated using black Perspex® acrylic moulds. Photopolymerization of the RBC specimens was carried out at different light-curing distances (0 mm, 2 mm, 4 mm, 6 mm and 8 mm) and stored for 24 hours at 37°C in 100% relative humidity. The SH (n=12) of the top and bottom surfaces of each specimen was assessed using a Knoop hardness micro-indentation tester. The bottom to top SH values were calculated to obtain the hardness ratio (HR) for each specimen. HR of the two bulk-fill RBCs were compared. Results: Data were analysed using one-way ANOVA and Tukey’s post hoc test (α