With Buonocore's discovery in 1955, the face of restorative was changed from a purely mechanical retention concept to a adhesion to tooth structure concept. This not only improved the restorations but also increased the longevity of the teeth.active and is complex in composition and morphologic structure. To be successful, dentin-bonding systems must adhere and remain sealed in the presence of dentinal fluids, vital tissues and a porous non-uniform substrate.The dentin bonding agents are applied to the deepest surface of the cavity, which is etched thereby increasing the penetration of bonding agent. Hence the biocompatibility consideration of dentin bonding agent is important.The dentin bonding agent besides bonding of composites can be utilized in bonding of metal indirect resin-bonded inlay, onlay, crown or veneer; as amalgam bonding agent; prevention and treatment of hypersensitivity, in establishing apical and coronal seal of the root along with resin and pulp capping.