Evaluation of post and cores in the laboratory: rationale for developing a fatigue test and preliminary results

Prosthetic treatment failures related to the biomechanical deficiencies of post and cores still represent a problem of clinical significance. To overcome the difficulties of clinical studies, numerous in vitro methods were developed to address specific properties of post-and-core restorations. Most of them, however, were based on an oversimplified mechanical testing of the restored tooth. Experience proved that the fatigue of restorative materials was a primordial factor in clinical failures. Therefore, special devices were built that stimulate the physiological masticatory cycle. Tests performed with adhesive post-and-core systems seem to indicate that materials placed in the tooth should have physical properties as close as possible to those of natural tissues. New carbon-epoxy posts appear to offer a promising solution for restoring the endodontically treated tooth.