Retentive capability of luting materials to fiber reinforced post at cement/radicular dentin interface.

This study was concerned with the evaluation of retentive capability of the luting materials namely; adhesive composite resin and glass ionomer cements along the bonded length of fiber re¬inforced posts with radicular dentin. As well as, characterization of the type of the bond at cement/ dentin interface. Ten single rooted maxil1ary anterior teeth free of defects were decapitated. An endodontic me¬chanical preparation was performed followed by post space preparation of 9 mm length. Five root canals were acid etched, adhesive resin was applied to dentin substrate and then the posts were luted with light cured composite resin. The other five root canals were irrigated by 2.5% NaOCI and then posts were luted by glass ionomer cements. Each root was cut transversely to obtain three speci¬mens; ccrvical, middle and apical sections of 3 mm thickness each. For SEM study; two roots wcre decapitated, endodontically prepared and then post holes were drilled. One of the root canal of these roots was acid etched and the other one was irrigated with 2.5% NaOCI. Both roots were sectioned longitudinally and photomicrographed at X 1500. Also, two specimens luted with the two in¬vestigated cements were photomicrographed after dislodgement of the posts by mechanical testing. Generally, both luting materials showed significant difference of the retention bonding strength among their three sections of the roots. The cervical section recorded the highest significant value while the apical section recorded the least significant value. Luting with glass ionomer cement showed higher significant retention strength values in middle and apical sections when compared with the corresponding ones luted with adhesive resin composite cement but comparison of the cer¬vical sections of both groups showed higher insignificant difference. SEM study of acid etched den¬tin surface showed widened dentinal tubules and severe rugosity and an adhesive failure was evident after mechanical testing of posts luted with adhesive composite resin cement suggesting mechanical H1terlocking attachment of this cement to radicular dentin. Meanwhile. more solid dentin and narrow onfices of the dentinal tubules was observed after irrigation with 2.5% NaOCI and a cohesive failure of the glass ionomer cement after mechanical testing suggesting stronger chemical bonding to the dentin substrate.King Saud Universit