The aim of this study was to evaluate fracture resistance and failure pattern of endodontically treated premolars with simulated abfraction in various restorations. Thirty-two extracted two-rooted maxillary first premolars with same sizes and shapes were randomly divided into 4 groups (n=8) for different restorations types. The control group was endodontically treated without simulated abfraction and restored with resin composite at access opening. Groups 1 - 3 were simulated with abfraction, filled with resin composite, endodontically treated and then restored with different methods. Group 1 (RF) was restored with resin composite at access opening, group 2 (P/RF) was restored with fiber post and resin composite and group 3 (P/ZC) was restored with fiber post, resin composite and zirconium crown. The teeth then were placed into acrylic blocks with simulated PDL. The specimens were loaded at central fossae, 30° to long axis of the teeth until failure. The data were analyzed by one-way ANOVA and Scheffe test at a 95% level of confidence. The results showed that the fracture resistance of control group, groups RF and P/RF had not statistically significant difference (p>0.05), while the fracture resistance of group P/ZC was significantly higher than those of groups RF and P/RF (p