## 1 Introduction
These novel materials offer advantages over all ceramic materials in terms of low brittleness, chipping resistance, wear resistance, and repairability [19]. However, the milled technique generates large amounts of waste material and requires a lot of raw materials. In addition, this technique can also lead to additional costs for milling tools [20]. The cost-effectiveness of 3D printing technology, the absence of resin material waste, and the production of more complex structures compared to the milling system are its advantages over the milling method [21]. Nowadays, the development of 3D printing technologies and materials has resulted in the emergence of new printable permanent composite resins that have been proposed for the production of indirect restorations [22; 23]. Color stability and surface roughness are key criteria in the dynamic oral environment for patient satisfaction and the aesthetic appearance of composite resins [24; 25]. However, various factors that have unfavorable effects on the roughness and color of dental materials, such as water sorption, inadequate polymerization, absorption of food or beverages, poor oral hygiene, and thermal processes in the oral environment, are limitations of composite materials [26; 27]. While color change requires the replacement of composite restorations, rough surfaces can lead to plaque adhesion, increasing the rate of gingivitis and secondary caries [28]. Thermocycling is a common artificial aging technique used to simulate the reaction of restorative material in the oral environment. The color and roughness of composite-based materials are affected by thermocycling [29; 30]. Additionally, it has been demonstrated that thermocycling followed by storage in staining solutions considerably alters the composite's optical characteristics which, in turn, influences the final aesthetic product [31; 32]. Today, studies compare the color stability and surface roughness of composite-based restorative materials produced by the subtractive manufacturing technique [33; 34; 35]. Three-dimensional printing technology and materials have also recently been frequently used in the production of permanent composite restorations. However, these materials are new, and laboratory and clinical data are needed [36; 37]. Furthermore, studies investigating the color stability and surface roughness of 3D printed permanent materials subject to thermocycling procedures and comparing them with milled materials are limited. Therefore, this study aimed to compare the color stability and surface roughness of 3D printed permanent composite resin with those of milled permanent composite materials and feldspathic glass ceramic after thermocycling, and the stainability of these materials was examined after immersion in coffee/distilled water. The first null (H\({}_{0}\)) hypothesis was that the color stability and surface roughness of the tested CAD/CAM restorative materials would not be affected by the type of material after thermocycling. The second null (H\({}_{0}\)) hypothesis was that the stainability of the tested CAD/CAM restorative materials would not be affected by the type of material after storage in coffee or distilled water.