In restorative dentistry, enamel-dentin adhesives are used to achieve a strong bond between a composite filling material and dental hard tissues (dentin and enamel). Adhesion to enamel requires etching with an acid resulting in selective demineralisation of prismatic and interprismatic enamel. Micromechanical interlocking is then obtained by in situ polymerisation of a methacrylate based resin in the acid-induced porosity (Figure 1). For adhesion to dentin the smear layer produced during cavity preparation has to be removed by acid-etch treatment, which results in the case of the total-etch-technique in the creation of a 3 to 5 μm deep demineralized zone in the dentin surface. Collagen fibrils are nearly completely denuded of hydroxyapatite, and form a microretentive interpenetrated polymer network of applied methacrylate based monomers. This interlock was described first by Nakabayashi and commonly referred to as “hybrid layer”.
展开▼
