Statement of problem: Techniques and recommendations for the restoration of endodontically treated teeth have changed from the use of custom cast metal post and core system to glass fiber-reinforced (GFRC) post and composite core system. Has this latest prefabricated glass fiber reinforced post and composite core system increased the fracture resistance of teeth and reduced the incidence of unrestorable root fractures. Purpose: The purpose of this study was to evaluate the incidence of root fracture and mode of failure of endodontically treated teeth restored with two different post and core systems. Material and Methods: Forty maxillary central incisors were randomly divided into two groups. (n=20). All teeth received endodontic treatment. First group was restored with custom cast post and core system. Second group was restored with glass fiber post and composite core system. In Both the groups posts were cemented with adhesive resin cement. Compressive load was applied at an angle of 130 to the long axis of teeth at a cross head speed of 1 mm/min until fracture occurred. Data were analyzed with student “t” test P<.001. Results: The mean value for fracture resistance was (331.4025) N in Group -I Custom cast Ni-Cr post and core and (237.0625) N in Group -II Glass fiber reinforced post and composite core system. Students “t” test shows the significant difference in fracture resistance of two groups. Conclusion: This study showed that the incidence of root fracture was significantly higher in custom cast Ni-Cr post and core system than glass fiber post and composite core system. A more favourable mode of failure was observed in teeth restored with Group II glass fiber post system. Key words:Post-and-core technique, glass fiber post, cast post and-core system, fracture resistance, endodontically treated teeth.

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Abstract:Cu-E glass fiber composites were developed with different vol. % of E-glass fiber (10, 20, 30 and 40 vol. %) by powder metallurgy route. Both as-received Cu and nanostructured Cu developed by milling as-received Cu powder for 20 h were used to develop various Cu-E-glass fiber composites. The effect of using as-received Cu powder and nanostructured Cu powder on the properties of the various Cu-E-glass fiber composites was analysed. The samples were sintered at 900 o C for 1 h in inert atmosphere. The results show good bonding between the matrix and the reinforcement and there is homogeneous distribution of the reinforcement in the matrix. . The hardness of the Cu-E-glass fiber composites was found to increase from 0.8GPa to 2.7GPa with increase in vol. % of the glass fiber in case of unmilled and from 1.2GPa to 2.9GPa for the milled Cu-E-glass fiber composites. The as-milled Cu-Eglass fiber composites shows better densification and sinterability compared to the unmilled Cu-E-glass fiber composites