Figure 1. Five specimens of a single-shade nano-hybrid composite (Omnichroma) and a conventional nano-hybrid composite (Filtek™ Z250 XT) were prepared according to ISO 4049:2019 standards. The specimens were marked and carefully handled. Each specimen was immersed in water in a separate container at 37 ± 2 °C in an oven for one week, maintaining a vertical position.
