Case Study: Management of Failing Maxillary Bridgework

Whilst appropriately prescribed and maintained bridgework is likely to provide good clinical service, it will ultimately fail. Survival rates for conventional fixed dental prostheses (FDPs) vary in the literature, with an estimated 5- and 10-year survival of 93.8% and 89.2%, respectively,¹ and 15-year survival reported at 68−74%.^2,3 Complication rates over a 5-year observational period are 15.7%,¹ with the most frequent complications being biological, such as caries and loss of pulp vitality.^1,4 An earlier study supported these findings, with the two most commonly reported complications as caries (18% of abutments) and need for endodontic treatment (11% of abutments).⁵

This particular case highlights an additional risk factor − an increased number of units and, more significantly, abutment teeth, within the bridge. A bridge of greater than four units is considered to be at increased risk of failure, and use of three or more abutments reduces survival by almost half.^6,7 Despite this, additional abutment teeth are often incorporated into bridge design where one or more abutments are considered suboptimal. This, however, is a false economy, as bridge survival is dictated by the most compromised tooth. Many such bridges will fail as a result of partial de-cementation and decay − whilst it is often difficult to know whether abutment de-cementation preceded the caries or not, it has been suggested that this loss of the marginal seal is a common cause of catastrophic caries beneath bridges.⁸