الفهرس 
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Abstract
This in-vitro study was performed to evaluate the influence of individually-formed and prefabricated fiber post on the fracture resistance of structurally compromised teeth. Sixty freshly extracted human single rooted upper central incisor teeth with single canal were selected. The external surfaces of anatomically similar roots of selected teeth with fully developed apices were cleaned of soft tissue and calculus using hand scaler. Teeth were mounted in standardized self-cured cylindrical acrylic blocks. To standardize the root canal length for this study, the coronal portion of each tooth was sectioned 13±1 mm coronally from the root apex with a 0.15 diamond wafer blade in an Isomet slow speed saw under water. All root canals were prepared using step back technique, obturated with gutta-percha cones and a resin sealer (AH-26) using lateral condensation technique. After 24 h, gutta-percha were removed from each root canal to a point 5 mm from the apex using gates-glidden with rubber stopper leaving specimens with 8.0 mm post space length. Specimens were divided into control and experimental group (n=30) according to reinforcement of the root canal dentin with composite resin. Each group was further subdivided according post type used (n=15); individually formed and prefabricated fiber posts. A dual-polymerizing resin luting agent was used for post cementation, Composite cores and complete cast crowns were fabricated for each specimen using conventional technique. Each specimen was subjected to fracture resistance in an Instron testing machine with cross head speed 0.5 mm/min. The data indicate that individually formed posts with reinforced root canal had higher mean fracture strength (414.50±22.09 MPa), and the lower mean fracture strength (372.57±25.66 MPa) was found for prefabricated post in root canal without reinforcement. Regardless of the root canal reinforcement, individually formed posts had the highest fracture strength, and the prefabricated posts had the lowest fracture strength.