Fiber Post & Core

Restoration of an endodontically treated tooth presents a challenge to the restorative dentist. The tooth to be restore has been hollowed out as part of the endodontic treatment. Depending on the degree of instrumentation, that tooth has lost a significant amount of structural support due to the endodontic access to treat the pulp chamber and root canals. When assessing an endodontically treated tooth for restorative treatment, it has to be assumed that good judgments have been made previously concerning the periodontal status of the tooth, the remaining tooth structure, and the prognosis of the endodontic treatment. The tooth to be restored should exhibit a good apical seal when evaluating the radiograph, and also exhibit no sensitivity to percussion or palpation, no exudates, no fistula, no apical sensitivity, and no active inflammation.

Bonding Agent:. Fiber posts are (optimally) placed using a bonding agent, followed by resin cement (preferably dual cure) and a composite for the core build-up. Brief exposure of light-cure energy from the occlusal aspect will initiate the cement catalysts. While polymerization will continue below the surface for a few minutes, the clinician can go directly to the placement of the core without waiting. This saves the few minutes you don't wait for the Civil Warera ZnPO4 cement to set. Those few minutes you save pay for the post itself. Bonding the post with a resin cement builds a monobloc of "dentin-type strength", thus elevating fiber posts to a higher plane than metal.

Micro-Retention Superior To Macro-Retention: Once viewed as heretical, etching of natural dental substrates has changed dentistry as much as anything has over the last 100 years. Creating micro-retentive surfaces is the safest, most conservative way to increase surface area and therefore increase retention. With metal posts and even some fiber posts, macro-retentive features were absolutely necessary for reliable retention. These macro-retentive features induce stress concentration in either the post or the tooth or both.14-15 Today, the best fiber posts are manufactured to provide a micro-retentive surface, one that doesn't require ridges and grooves for retention.

Minimally Invasive: Fiber posts are bonded and need only be seated to a depth of approximately one half of the root length, OR the equivalent of the length of the clinical or prosthetic crown.23 In contrast, with metal posts, increased insertion depth should equate to higher retention. However, this naturally threatens the apical seal, increases the risk of perforation and dislodgement of the gutta-percha, and worst of all, transfers stress apically to the narrowest, most vulnerable part of the tooth.

Tapered Is Now Better Than Parallel: when only metal posts existed, and prior to the ability to predictably bond to both the post channel and the post surface, it was determined in vitro that parallel metal prefabricated posts provided superior retention to tapered metal posts (except screw types) and that tapered metal posts demonstrated a propensity toward typical wedge-type activities (like splitting things in half). Also, in too many cases this parallel shape condemned me to sacrificing more dentin just to get some surface interface/adaptation. Fiber posts can be obtained in either parallel or tapered design. If one uses predictable bonding techniques, and fiber posts are bondable, the tapered design provides the additional benefit of conserving radicular dentin and reducing functional stresses towards the apex, and all of this without compromising strength.