Clinical evaluation of five adhesive systems: three-year results.

Five dentine adhesive systems (four resin-based dentine bonding agents and one polyacid-modified composite resin) were evaluated clinically in non-undercut Class V 'abrasion' lesions. The loss rate of restorations varied from 26 per cent to 95 per cent at three years among the five systems. Products which bonded to dentine via the hybrid layer were markedly more retentive than those which were designed to bond chemically. The two products which attempted to achieve bonding between their carboxyl groups and dentinal calcium were hydrophilic, which probably contributed to their lack of success.