Luting agents for ceramic and polymeric inlays and onlays

The requirements for luting agents for ceramic and polymeric inlays and onlays are reviewed and discussed. The current overriding consideration seems to be the chemical adhesion of the restoration to tooth substance and this is challenged as being an overambitious goal. The systems in use are principally the dual cure resin based cements and these have some disadvantages such as restricted and slow cure, chemical degradation and, most importantly, shrinkage on setting. This shrinkage, when the material is used in conjunction with a dentine bonding agent, is almost certain to guarantee the rupture of any bond formed. It is suggested that the objectives of the luting agent should be rethought with reference back to the well established principles of cast metal restorations.