Mixed Class V restorations: the potential of a dentine bonding agent.

The marginal micromorphology and seal of mixed Class V restorations (i.e. restorations with margins located 50 per cent in dentine and 50 per cent in enamel) using Scotchbond VLC or Scotchbond 2 bonded to dentine in conventional and saucer-shaped cavities were evaluated. The four operative systems tested included a two-step incremental filling technique using the light-curing composite Silux, two direct inlay techniques using Silar or Silux as a luting cement and an inlay technique utilizing a Ca(OH)2 liner. All restoration types showed poor marginal adaptation in dentine irrespective of cavity design and bonding agent used. The inlay technique, tested in seven different variations, did not optimize marginal adaptation. Cavity lining with the Ca(OH)2 base material adversely affected dentine bonding. In mixed Class V restorations, marginal adaptation at the dentinal cavosurface line angle continues to pose a problem.