Adhesive bonding--some clinical considerations.

Over the last decade the development of adhesives has moved from the classic concept of three-step bonding towards the introduction of more user-friendly, simplified systems. Current adhesive systems can be grouped into three categories: etch and rinse adhesives, self-etch materials and glass ionomers. Published data indicate that the three-step etch and rinse systems form the gold standard in durability, with the two-step self-etch materials approaching that standard, and the glass ionomers, although clinically reliable, are limited by their physical properties. However, a major shortcoming of bonded restorations is their unreliable durability in vivo. One of the most important factors influencing bond durability is hydrolysis, which affects all adhesive systems. Two important aspects of this process involve water uptake in the adhesive resin and thinning or disappearance of collagen fibrils from within the hybrid zone. Techniques to improve the stability of the adhesive bond and prolong the clinical life of adhesive restorations are discussed.