Polymerisation of restorative dental composites: influence on physical, mechanical and chemical properties at various setting depths

To appraise influence of polymerisation of restorative dental composites on physical, mechanical and chemical properties at various setting depths. The cylindrical samples (5 mm diameter, 2.5 mm height, and n = 6) of microhybrid and nanohybrid composites were fabricated. Nanohardness was performed from the surface to the core of the sample in stages, i.e., stage 1–5. Additional chemical and physical characterisations of the study materials were performed. Differences in nanohardness, and W_sl and W_sp values were evaluated using analysis of variance (P ≤ 0.05). Nanohardness was significantly affected between stages of dental composites (P < 0.001). Only Nanohybrid™ composite exhibited nearly same formation ratio of double bonds into polymeric carbon–carbon single bonds at different stages. The Nanohybrid™ composite exhibited lowest W_sl and W_sp parameters. Nanohybrid™ may have the potential to survive a harsh oral environment for a longer time compared with other composites.