Influence of custom adaptation on the characteristics of fiber posts

In this in vitro study, 3 experiments were conducted to evaluate the influence of customizing the apical portion on the characteristics of fiber posts. In the first experiment, 4 fiber posts were submitted to different custom adaptations (no customization, industrial shaping tool, diamond bur, or paper disc) and were observed with a scanning electron microscope to evaluate the micromorphologic changes. In the second experiment, 60 posts of different sizes were divided into 6 groups (n = 10): 0 (No. 0.5), 1 (No. 1), 2 (No. 2), 3 (No. 3), 4 (No. 4), and 5 (paper disc-remodeled No. 4). The posts were submitted to a 3-point bending test. In the third experiment, the crowns of 20 extracted, healthy permanent human canines were removed, and the teeth were endodontically treated, embedded in acrylic resin, and divided into 2 groups (n = 10): I (control), No. 4 posts cemented into post spaces prepared with a No. 4 drill; and II (test), remodeled No. 4 posts cemented into root spaces prepared with No. 2 and 4 drills. The posts were cemented with self-adhesive dual resin cement, and the specimens received direct resin crowns. Fracture strength was measured with a universal testing machine at 45 degrees until fracture. Results were submitted to analysis of variance (P ≤ 0.05). Customization of fiber posts with diamond burs or paper discs produced acceptable micromorphologic changes. Custom adaptation of fiber posts reduced their flexural strength, which remained at acceptable values. Teeth restored with customized fiber posts had greater fracture strength than those restored with intact posts. The results of this study indicated that post remodeling is a safe means to facilitate adaptation to root walls and preserve tooth structure.