Influence of dentinal adhesives and a prefabricated post on fracture resistance of silver amalgam cores

Purpose. Failures of silver amalgam cores for endodontically treated teeth have been attributed to the use of posts. The use of adhesive agents has been reported to improve the strength of silver amalgam restorations. The purpose of this study was to test the effects of two adhesive agents on the fracture resistance of silver amalgam cores with and without a post. Material and Methods. Sixty mandibular molars were restored with the use of silver amalgam, with or without one of the adhesive agents and/or a tapered prefabricated post. A universal testing machine, with a constant load rate of 0.5 mm/minute, was used to determine the force in kilograms at failure. Results. The use of either adhesive agent with silver amalgam significantly increased the force at failure, and neither adhesive agent was significantly better than the other. Silver amalgam with a post and without an adhesive agent had the least resistance to fracture. Conclusions. The results indicated that endodontically treated mandibular molars restored with silver amalgam are more resistant to fracture when an adhesive agent is used.