Fracture resistance of endodontically treated roots after restoration

This study evaluated the shear strength resistance of endodontically treate d roots that were restored by two different techniques. Twenty-seven recent ly extracted single-rooted teeth with similar anatomic characteristics were sectioned to obtain the same length for all specimens. Group I (GI) consis ted of 14 roots restored with cast post-core (nickel-chromium alloy) and ce mented using zinc phosphate cement; group II (GII) consisted of 13 roots re stored with steel prefabricated posts (FKG(R)) cemented with zinc phosphate cement and rotated with caution for anchorage. The crown portion of this g roup was made using a hybrid composite resin (Prisma APH(R)). Results showe d that on all specimens of GI the fracture occurred in the cervical root st ructure while in GII the composite resin fractured in all specimens. Statis tical analysis showed a significantly higher resistance to fracture for GI than GII. The specimens were sectioned longitudinally for stereoscopic micr oscope analysis (63x) and did not show fracture lines in the dentin anchora ge post area for any of the specimens.