Evidence-based concepts and procedures for bonded inlays and onlays. Part I. Historical perspectives and clinical rationale for a biosubstitutive approach.

This first article in the series (Part I) aims to present an updated rationale and treatment approach for indirect adhesive posterior restorations based on the best scientific and long-term clinical evidence available. The proposed treatment concept relies on the basic ideas of (1) the placement of an adhesive base/liner (Dual Bonding [DB] and Cavity Design Optimization [CDO]) and, when needed, (2) a simultaneous relocation of deep cervical margins (Cervical Margin Relocation [CMR]), prior to (3) impression taking to ensure a more conservative preparation and easier-to-follow clinical steps, and the use of (4) a highly filled, light-curing restorative material for the cementation (Controlled Adhesive Cementation [CAC]), together with restoration insertion facilitation, the application of sonic/ultrasonic energy, and/or material heating. The suggested clinical protocol will help the practitioner to eliminate the most frequently experienced difficulties relating to the preparation, isolation, impression taking and cementation of tooth-colored inlays and onlays. This protocol can be applied to both ceramics and composites as no material has been proven to be the most feasible or reliable in all clinical indications regarding its physicochemical and handling characteristics. For the time being, however, we have to regard such indirect restorations as a biosubstitution due to the monolithic nature of the restoration, with still very imperfect replication of the specific natural dentin-enamel assemblage.