Comparative Study of Retention of Fiber- Reinforced Post Retention At Middle and Cervical Thirds of Root Canal Cemented by Different Luting Cements

The purpose of this study was to compare regional bond strength at middle and cervical thirds of the root canal among glass fiber-reinforced composite (FRC) endodontic posts luted with different cements, using the push-out test. To compare the performance (retention) of two types of luting cements polycarboxylat cement and Glass ionomer cement used to cement translucent fibre post. and To compare the result of the push-out test at different storage times;1 week ,1month and 2 months. Sixty caries-free, recently extracted single-rooted human teeth with straight root canals will be used in this study, The Roots endodontically instrumented canals were at a working length of 0.5 mm from the apex by means of conventional instruments for hand use (Dentsply, Switzerland) up to size 35.then root canal filling was performed followed by post space preparation up to 8mm including cervical and middle one third of root canal then the fibre post was cemented into canal post space then the root was sectioned to get cervical (4 mm in length) and middle (4 mm in length) thirds ,these thirds were examined by push out test to get values of retention of fiber post inside these canal thirds .The results of this study showed that there was no significant differences between push out bond strength between fiber post and root at cervical third as compared with middle third when using polycarboxylate cement to cement the fiber post to the canal walls but there was highly significant differences between push out bond strength between fiber post and root at cervical third as compared with middle third when using glass ionomer cement also the results showed that the glass ionomer cement. The results also shwed that the push out bond strength for GIC was higher than that of PCC and that the push out retention of GIC incrases with time,while no such changes occur with PCC.