Fig. 3.

Bonding of a pre-fabricated fiber post and a resin cement to a post space represents the classic secondary monoblock depicted in the restorative and endodontic literature. Although there is ample evidence in the literature to support the use of fiber posts for improving the fracture resistance of endodontically treated teeth, a case is illustrated showing that fiber posts do not necessarily strengthen roots and that crown fracture may still occur after the use of fiber posts. A. A radiograph of a retained root (tooth 21; pointer) with an incomplete root filling, a fractured fiber post containing radiopaque fibers, and horizontal root fracture along the gingival margin. B. A photograph of the fractured crown with a ceramometal crown and the coronal portion of the fractured fiber post (pointer). In this particular case, the presence of eccentric masticatory forces caused by the absence of molar tooth support and the possible pre-existence of a cervical abfraction lesion (see tooth 20) probably accounted for the failure of the fiber post-supported tooth.