The objective of this controlled clinical trial is to evaluate the clinical performance of restorative material "SI-R21204 resin composite" versus a "nano-hybrid resin com-posite" materials for Class I and Class II cavities that needs to be restored in per-manent teeth. Giomers are a new group of anhydrous resin based direct adhesive restorative materials based on the filler technology (PRG) to form a stable phase of glass ionomer in the restorative. These materials have both advantages of glass ionomers namely, fluoride release and recharge, and resin composites with excellent optical and mechanical properties. PRG fillers are fabricated by acid-base reaction of glass particles and polyacrylic acid in the presence of water and forms wet silicous hydrogel. S-PRG filler particles exhibit a three-layer structure where the glass core is enveloped by a stable glass-ionomer hydrogel. This hydrogel is surrounded by the "reforming phase," which provides structural protection for the hydrogel. These materials with S-PRG technology therefore, differ from polyacid modified composite resins because the glass ionomer hydrogel forms only after water uptake by the compomer resin matrix after polymerization. The chemistry of Giomer materials facilitates fluoride ion release with the potential for a lower incidence of recurrent caries that was accepted as a major factor to retreat a resin restoration. Limited number of studies is available on their fluoride release, and polishability, as well as clinical survival. The study will be carried out as a prospective study, with assessment of the restorationsafter three year.