Bonding in direct composite restoration

Abstract

The bonding of direct composite restorations can be divided into two types: those that use phosphoric acid etching and those that use self-etching techniques. When phosphoric acid etching is applied to dentin, the demineralization of the untreated dentin surface goes deep, and the bonding resin does not fully penetrate the exposed collagen fiber layer. It has been confirmed that this results in deterioration of the collagen fiber layer in the long term. Among the self-etching adhesive materials, the two-step type exhibits excellent long-term bonding durability due to sufficient penetration of the bonding resin into the demineralized layer of the dentin surface, while the onestep type often has insufficient bonding to enamel, and selective enamel etching with phosphoric acid is generally recommended. Selective enamel etching with phosphoric acid is generally recommended. In order to form a durable adhesive layer, sufficient polymerization should be done. In cavity preparation, protection of the inner layer of caries dentin leads to pulp protection. The flowable resin composite liner is very effective in inhibiting gap formation in the cavity.