Return to the resin -modified glass-ionomer cement sandwich technique

One of the critical goals of adhesive dentistry is torestore the peripheral seal of dentin that is interrupted when enamel is lost as a result of developmental sequelae, trauma, caries or operative intervention such as preparatory excision. For coronal lesions the exposed strata may be bounded by dentin, enamel or both. Manufacturers continue to work vigorously on resin formulations that will restore this peripheral seal with operative ease and absolute durability. Enamel Bond The bond between resin and enamel is generally satisfactory. Most clinicians report that it is possible to achieve seemingly impeccable margins at the visible cavosurfaces when restoring posterior teeth with a direct composite-resin technique. Clinical experience, however, reveals that these resin–tooth interfaces deteriorate as they age. More pertinently, in vitro studies have revealed the formidable challenge of achieving a predictable seal at the proximal margins when toothcoloured restorations are used.