Fracture resistance of teeth with bonded amalgams.

Breaking strength of the cusps of molars with MOD amalgam and composite restorations was measured with an Instron. Bonding of the amalgam and composite restorations with adhesives increased the resistance of the cusps to fracture, however, the cusp strength was not returned to that of intact, unprepared teeth. The relative effectiveness of the bonding agents with amalgam was C&B Metabond > Amalgambond > Panavia EX. Reinforcement by amalgam bonding was similar to or less than reinforcement with the composite restorations depending on the adhesive used.