Five year survival of posterior adhesive bridges. Influence of bonding systems and tooth preparation

The present study reports the final analysis of a randomized controlled clinical trial in which different designs of posterior resin-bonded bridges were evaluated for a period of at least 5 years. The operational hypothesis was that the bonding system and the preparation design used in posterior resin-bonded bridges have an influence on the survival and clinical functioning of these restorations. Survival in this study was defined at two levels: (1) 'primary' survival (survival without any debonding), and (2) 'functional' survival (survival including loss of retention on one occasion and successful rebonding of the original resin-bonded bridge without further debonding). Preparation of grooves in abutment teeth for posterior resin-bonded bridges appeared to be beneficial to their chance of survival. Resin-bonded bridges placed in the maxilla have a better prognosis than those made in the mandible. The bonding systems used in this study (etching/Clearfil F2, sand blasting/Panavia EX and silica-coating/Microfill Pontic C) appear to have no influence on the chance of failure with regards to the 'primary' survival. In rebonded posterior resin-bonded bridges, the bonding system silica coating/Microfill Pontic C was more retentive than the other systems tested.