Comparative Evaluation of the Surface Hardness of Monochrome Composite and Conventional Composite after Immersion in Food-simulating Liquids: An In Vitro Study

in the composite resin, which were able to produce red to yellow color as ambient light diffuses within the composite resin. 3he drastic conditions in the oral cavity, such as fluctuations in temperature and pH, a wide range of masticatory forces, and IntroductIonFor several reasons, dental clinicians always favor composite resins as the direct restorative material of choice.They have good esthetics and require conservative tooth preparation.They set in an adequately short time, bond to the tooth structure, giving it greater strength, are of reasonable cost, and offer a range of mechanical properties that make them fit various dental applications. 1ental clinicians prefer dental practices that grant the implementation of simplified protocols to decrease chair time and technique sensitivity.Because color selection is a difficult process and dependent on positional and individual differences in natural teeth environmental and operator factors, a trend to streamline shade selection has resulted in new composite resins based on the "wide color matching" concept.These provide shades that include an expansive scale of natural teeth colors to minimize the shade-matching variability and decrease the composite shades required in inventory. 1,2 Lately, a single-shade universal (monochrome) resin composite was developed, apparently capable of matching all Vita classical shades (Vita, Vita Zahnfabrik, Bad Säckingen, Germany), from A1 to D4, without the need for adding dyes or pigments.This capability was attained by incorporating equally sized 260 nm spherical fillers