Background: Resin-based restorative materials have significantly evolved over the past decades and are widely used in dental practice to satisfy increasing esthetic demands. However, maintaining colour stability in the constantly changing oral environment remains a critical factor affecting their clinical longevity and continues to be a persistent challenge for these materials.

Material and methods: A total of 72 samples (n = 18) of microhybrid resin composite restorative material (Prime Dental Products, India) were prepared using a customized Teflon mold. Each specimen measured 10 mm in length, 10 mm in width, and 2 mm in thickness. The samples were randomly divided into four groups as follows: Group I: Control group (Artificial saliva) Group II: Oral B (non-alcohol–based mouthwash) Group III: Listerine (alcohol-based mouthwash) Group IV: Hexidine (chlorhexidine gluconate–based mouthwash) each group consisted of 18 samples. After the immersion procedure, values for each sample were recorded. The color differences were assessed using the CIE Lab* color space parameters: ΔL* (white–black), Δa* (red–green), and Δb* (blue–yellow). The overall color change (ΔE*ab) was calculated using the following formula.

Results: ΔE values differed significantly among all groups except Oral B and Hexidine, which showed no significant difference. Listerine showed the highest staining (mean ΔE = 5.208), followed by Hexidine (3.14) and Oral B (3.03).