## 1 Introduction  
Resin composites are widely used in restorative dentistry due to their aesthetic appeal and favorable mechanical and physical properties, making them preferred material for direct restoration [1]. Recently, a new class of flowable composites, termed highly filled flowable or injectable resin composites, has been developed to improve mechanical performance. These composites, with increased filler loading, demonstrate superior physical and mechanical properties compared to conventional flowable composites, making them particularly suitable for posterior restorations [2]. Additionally, their smaller filler particle size enables a highly polished, aesthetically pleasing finish, making them ideal for anterior restorations [3]. In restorative dentistry, the color of the material plays a critical role in determining the overall esthetic outcome, especially in the anterior region, where appearance is highly prioritized. In addition to mechanical properties for durability in high-stress areaslike the posterior teeth, the selection of restorative materials must also consider esthetic properties to ensure effectiveness. Color mismatch and discoloration are among the most common reasons for the replacement of dental restorations. Therefore, selecting materials with high color stability not only enhances the aesthetic outcome but also extends the functional lifespan of the restorations [4]. The potential for discoloration over time is a key consideration, as exposure to commonly consumed colored foods and beverages can affect the material's color and translucency [5]. Consequently, color stability is a key attribute of restorative materials, guiding both clinicians and patients in the selection process. Aging of composite materials involves various factors, including exposure to acidic beverages, which can significantly impact their mechanical properties, such as microhardness and roughness. Acidic beverages, like coffee, tea, and red wine, can erode the surface of composite resins, leading to increased roughness and decreased microhardness. These changes in the surface properties can subsequently influence the material's susceptibility to discoloration [6, 7]. This emphasis on color stability has prompted studies in which various resin composites are immersed in common beverages to assess their resistance to discoloration. Numerous investigations have been conducted to evaluate the color stability of resin composites when exposed to different beverages [8, 9, 10, 11]. Most studies include common beverages, such as coffee, Coca-Cola, red wine, and tea, to evaluate their impact on the color stability of resin composites [11, 12, 13, 14, 15, 16]. It has been consistently observed that these beverages affect the color stability of the materials. A study by [PERSON] and colleagues in 2023 found that different types of composite resins significantly influence color stability. They found that injectable composites exhibited better color stability than conventional composites following immersion [11]. However, daily toothbrushing, especially with whitening toothpaste, may also affect the color of restorations. Despite this, limited data exist on how different composite resin responds to brushing with whitening and daily-use toothpastes and how this interaction affects the color of restorations over time [11, 17]. This study aims to fill this gap by using a unique methodology, including the immersion of samples in red wine and the use of two distinct types of toothpaste. Red wine was chosen due to its widespread consumption and high pigmentation potential, making it suitable for evaluating the discoloration resistance of composite resins. The null hypotheses were (1) the type of composite resin will not exhibit different levels of red wine staining, and (2) whitening and daily dentifrices do not differ in their efficacy to reduce red wine staining on composite resins.