Objective:
The aim of this study was to assess hybridization and push out bond strength of fiber post after endodontic retreatment.
Materials and methods:
10 freshly extracted human canines were collected having single root canal, samples were decoronated. Endodontic treatment was made to all samples. Samples were inserted into resin blocks. Then randomly divided in to: group I (control group) (5n) drilling to prepare post space followed by post cementation using total etch cement; while in group II (retreatment group) (5n) endodontic retreatment was made followed by drilling and post cementation as group one. Samples were sectioned into six sections of 1.5 mm thickness. Push-out test was performed using universal testing machine. Scanning of the root interface was made by SEM.
Results:
Group I showed significantly higher mean push-out bond strength (11.55 MPA) than Group II (7.93 MPA). Coronal (13.13 MPA) and middle root levels (9.62 MPA) showed significantly higher mean push-out bond strength than apical level (6.48 MPA). GI showed significantly higher mean push-out bond strength (16.06 MPA) than GII (10.19 MPA) at coronal level. At middle and apical levels; there were no significant difference.
SEM showed resin tags and hybridization within dentin in GI while in GII there was an ill-defined hybrid layer at interface.
Conclusions:
Endodontic retreatment showed significant adverse effect on fiber post push-out bond strength. Root level affected fiber post push-out bond strength only in endodontically treated teeth. Interface of the endodontically treated teeth showed hybrid layer while in endo-retreatment gaps and void were seen.