Resin materials are important because they achieve similar appearance compared to natural teeth, But unfortunately These substances are likely to be discolored with long-term exposure to oral environment , The methodology used in the present study was in accordance with previous researches that used spectrophotometry and the CIE L*a*b* coordinate system, Most color determination studies in dentistry use the CIE L*a*b* system, and this system is almost exclusively based on color research in dentistry around the world. The color perception in the CIE system depends on the eye's sensation in three different colors (red, green, and blue). When the light reflects, it recieves and stimulates these receptors, and the result is sending three signals to the brain that determine whether the color is bright or dark red, green, yellow or blue.  After evaluating the color measurement process through direct vision and using digital devices, the amount of color change that can be observed when comparing teeth within the oral environment is determined by 3,7 according to the standards of the United States of Public Health Services (USPHS) . this study was performed for a long-term staining protocol of 28 days because this time of exposure should simulate around 2 years of clinical exposure to the staining agents (24 h in vitro corresponds to about 1 month in vivo), which is considered sufficient for a long-term staining susceptibility evaluation.In this study coffee presented a significant staining capacity regardless of the composite resin. The results of the present investigation showed significant differences in discoloration between the different groups. Several studies concerned with the staining of the restorations resulting from the colorants contained in the oxidizing pollutants, and the color changes of the resin restorations were evaluated after being immersed in various dyed liquids. Coffee, tea , red wine and soft drink, and fruit juices  The most common studied pigmentation factors. The pigmentation caused by these fluids varies according to composition and properties of the resin materials.Reports have shown that both coffee and soft drinks caused a clear color change to the composite resin samples seven days after being immersed in solutions. As shown in this study with ΔE > 3.3 after week and 28 days but all materials showed acceptable values after 24 hours of immersed. From a clinical point of view, these factors that have a pronounced effect on the color stability of laboratory samples can also cause clinical color change, but the change in resin color will be clinically slower due to the continuous effect resulting from saliva and oral care procedures for patients.  The properties of the restoration surface have a significant effect on the color stability of the composite resin. Surface roughness is one of the causes of external pigmentation and is closely related to the size of the filling particles used and the finishing and polishing system used. In this study no finishing or polishing were applied to the samples this might explain the high values of discoloration after week and 28 days as studies have reported that the restoration surface resulted from the use of polyester strips is exposed to the largest amount of color change, due to the fact that the outer layer of Restoration is hampered by its diffusion compared to the restoration mass. So removing this layer of resin during The finishing and polishing process will increase the staining resistance and thus achieve greater color stability for the restoration.  discoloration of the resin materials is due to internal and external reasons. internal discoloration includes change in the color of the resin itself, such as the change of the resin matrix or filling material or the interface between them. Therefore, the structure of the resin matrix and the properties of the fillers has a clear influence on the color stability of the restoration as well as the accelerators and inhibitors of the reaction. As for the external pigmentation, it results from the absorption of colourants from the external environment. They differ according to the oral health of patients, as well as their food habits, drink and smoking. Monomeers properties affect the color stability of the resin restorations, and most studies have shown that this is directly related to the hydrophilic and hydrophobic monomeers  and water absorption properties.  Water absorption has many harmful effects on the resin mold, as it causes it to swell due to moisture, entrainment and dissolution, or oxidation, and all of this leads to penetration of the pigmented factors within it in addition to the influence of its transparency. The chemical composition of admira fusion x-tra is made of silicon oxide which forms both glass fillers and ceramic resin matrix that caused less water absorption and includes high color stability because It is synthesized through a solution and gelation process (sol-gel process) from multifunctional urethane and thioether(meth)acrylate alkoxysilanes. in addition to surface hardness and durability. .The use of UDMA reduces the occurrence of pigmentation compared to the more common Bis-GMA . Arikawa H et a 2007 showed that it is affected by the size and shape of the filling particles and the loading ratio. Our results are in correspond with recent studies which reported higher discoloration for conventional nanohybrid to new nanohybrid ormocer ones.