The aim of this study was to investigate the effect of one particular brand of post and core system (ER Post) consisted of different post and core materials on the fracture resistance of endodontically treated teeth. Fifty caries-free maxillary central incisors were randomly assigned to five groups (n=10). All teeth were sectioned at the cemento-enamel junction except for the teeth in the control group. Four experimental groups consisted of cast gold post-and-core group (GG), Heraplat post/cast gold core group (HG), titanium post/composite core (TC), and titanium post/cast gold core (TG). The control group (ETT) consisted of endodontically treated teeth without posts. All posts were cemented in the roots with zinc phosphate cement. Following thermal cycling (5000 cycles between 5 degrees C and 55 degrees C with a dwell time of 30 seconds) a static load was applied to 2 mm below the incisal edge on the palatal surface of each specimen until they were fractured. Fracture data obtained and statistically analyzed with one-way ANOVA and a Tukey's test (p
