Thesis & Dissertations

This study was conducted to compare the fracture resistance of structurally compromised teeth restored by different lengths of fiber posts. Materials and methods: Thirty two freshly extracted sound mandibular premolars of approximate sizes were mounted centrally and vertically in 12 x 12 x 20 mm acrylic block. Then, decoronated 2 mm above the cemento-enamel junction and their root canals were treated endodontically. Teeth were randomly classified into four main groups (n= 8). For all groups, post holes were prepared (group A; post hole less than the crown length (3 mm), group B; post hole equal to the crown length (5 mm), group C; post hole half of the root length (7 mm), group D; post hole 2/3 of the root length (9 mm). Posts were cemented using self-adhesive resin cement. The coronal core portion were built with a light-cured core composite for all samples, using core former. A 0.5 mm finish line was prepared at the cemento-enamel junction with ferrule of 2 mm to receive a metal coping. Compressive load was applied at crosshead speed of 0.5 mm/min, parallel to long axis of the tooth until failure with a universal testing machine. Results: Viewing the mean of fracture resistance and fracture mode between studied groups (Newton) , Group D scored the highest fracture resistance values (2670 ± 597.37) followed by Group A (2668 ±316.67) and Group B (2609 ±523.15). Group C scored the lowest fracture resistance values (2517 ±464.35). One-way ANOVA revealed no significant difference between groups (P=0.913). Chi-square test also revealed no signicant differences in restoring possibility between the studied groups. (P=0.212). Conclusions: 1- There is no significant difference in fracture resistance between tested fiber post lengths. 2- Teeth can be restored by a post that has a length less than the crown length to avoid drilling drawbacks. Key words: fiber post, length of fiber post, fracture resistance.