Posterior acid-etch bridge--a modified retentive design

This article reviews the recent literature on clinical trial studies of acid-etch bridges. Due to long-term retention problems, acid-etch bridges are not as yet considered among the permanent types of bridge prosthesis. When failure of acid-etch bridges occurs, the weak link seems to be the enamel-resin junction rather than the metal-resin junction. A modified posterior acid-etch bridge design is described in detail. This design, which incorporates a major retention-promoting component, is meant to improve long-term retention of posterior acid-etch bridges. Cast projections are added to the bridge design. These fit loosely into slot cavities made in the abutment teeth. Following bridge cementation, the slot cavities are restored with posterior composite. As a result, the cast metal projections are locked into the abutment teeth. This added retention device will maximize the long-term retention of posterior acid-etch bridges.