Several studies have been conducted to investigate the production of cross-linker compounds. These compounds have been shown to promote collagen cross-linking, preventing collagen molecules from loosening. The cross-linkers seek to create more interfibrillar and intrafibrillar collagen cross-links. Increased cross-linking can enhance dentin strength and stiffness by limiting collagen collapse. Additionally, prolonged application of cross-linkers resulted in protease suppression via permanent alterations in dentin structures. The universal matrix is composed of hydrophilic HEMA, and hydrophobic decandiol methacrylate (D3MA), and intermediate (bis-GMA) monomers. This mix of characteristics enables universal adhesives to bridge the hole between the hydrophilic tooth substrate and the hydrophobic resin restorative under a wide range of surface conditions. The clinical outcome of resin composite restorations is dependent on the efficiency and longevity of the adhesive interface. Adhesion to tooth structure ought to provide retentive strength, a marginal seal, being feasible to establish, and clinically durable. The authors advocate the micro-tensile bond strength test (µTBS) as a reliable indicator of dental composite retention, especially following durability challenges. Micro testing produces more uniform bond strength values due to lesser and smaller imperfections at the bonded interface. Recent adhesive systems provide strong initial adhesion, but weaken significantly over time. Incomplete penetration of adhesive monomers results in partly exposed collagen fibrils at the base of the hybrid layer within both etch-and-rinse and self-etching adhesives. Poorly penetrated zones lead to nano-leakage and poor mechanical characteristics at resin-dentin interface.