An overview of dentin conditioning and its effect on bond strength

Abstract

Given the inherent qualities of this medium, particularly when contrasted to enamel bonding, bonding to dentin is considered to be a less dependable approach. Further, when dentin is reduced, a sizable amount of cutting detritus coats the dentin's exterior, forming the smear layer. A steep decrease in interfacial adhesion over time has been attributed to the collagen web's inadequate resin impregnation as a result of the dentinal surface preparation with strong acidic agents like phosphoric acid, which left a zone of vulnerable collagen at the root of the hybrid smear layer. Self-etching priming agents that comprise acidic, non-cleansing, polymerizing monomers cause demineralization of the surface and encapsulate the collagen fibers and hydroxyapatite crystals while dissolving the smear layer or incorporating it into the adhesion interface. The concurrent occurrence of dentinal demineralization and monomeric penetration prevents collagen from buckling and shields an exposed collagen web. There may be a drawback to including the smear layer in the hybrid layer, according to certain investigations. Adhesion issues could arise even though the smear layer is reinforced with impregnated resin. To achieve dependable, robust resin-dentin connections, such defects may need to be removed by integrating a distinct etching process because they can reduce the resistance and longevity of the conjugated smear layer. In relation to a traditional bonding system, is has been discovered that removing the smear layer with 0.5 M ethylene diamine tetra-acetic acid (EDTA) before applying a self-etching primer result in greater bond strengths. Even though this approach integrates the smear layer within the adhesion interface, the pre-conditioning of dentin with just an acidic primer is highly convincing and merits additional exploration for the streamlined total-etching systems.