Evaluation of modern post and core systems by testing the mechanical fatique resistance

Introduction: Prosthetic treatment failures related to the mechanical deficiencies of post and core systems still represent a problem of clinical significance and justify the researches orientated through the increasing of their performances and clinical longevity. The fatigue resistance tests represent an essential research tool because it simulate the repetitive cyclic way of the occlusal forces and replace the clinical tests that are time consuming.The aim of this study was to compare the behavior of different types of post and core systems when subjected to a cyclic loading test. Materials and method: Forty upper central incisors were endodontically treated and mounted in acrylic blocks. After anatomic crowns were removed, the teeth were reconstructed with carbon fiber, ceramic and titanium posts. In the control group, no posts were used. The crown build-up was made with composite resin and covered with metal crowns. An intermittent load was applied at an angle of 45 degrees to the long axis of the tooth at a frequency of 1,3 loads per second. The Kaplan-Meier analysis of the results obtained after 400.000 cycles showed that the survival rates for all experimental groups was lower than that of the control group, and the survival rate of carbon fiber group was higher than that of titanium and zirconium group. Conclusions: Fiber posts reduce the risk of root fracture and is the best choice in reconstruction of endodontically treated teeth. Keywords: Post-and-core, fatigue resistance