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Computational and Mathematical Methods in Medicine
Volume 2012, Article ID 816481, 6 pages
Research Article

In Vitro Evaluation of Ferrule Effect and Depth of Post Insertion on Fracture Resistance of Fiber Posts

Department of Oral Health, University of Rome Tor Vergata, Viale Oxford, 00100 Rome, Italy

Received 10 October 2012; Accepted 5 November 2012

Academic Editor: Carlo Cattani

Copyright © 2012 R. Schiavetti and G. Sannino. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Purpose. The analysis of the complex model of fiber post and ferrule is given and studied in this paper. A novel approach and a solution to the evaluation of stress of post and core system within the ferrule effect are proposed. Methods. Sixty freshly extracted premolars were selected for the study. The following experimental groups were therefore defined ( ): (1) 5 mm, (2) 7 mm, (3) 9 mm, (4) ferrule-5 mm, (5) ferrule-7 mm, and (6) ferrule-9 mm. Preshaping drills (C) were used to prepare the root canals at 5, 7, and 9 mm in depth. In specimens of groups 3–6 a circumferential collar of tooth structure of 2 mm in height. Fluorocore 2 core build-up material (I) was used for fiber post luting. With the same material, a buildup of 2 mm in height was created. A controlled compressive load (crosshead speed: 0.75 mm/min) was applied by means of a stainless steel stylus (Ø 1 mm) at the coronal end of the post extruding out of the root. Results. In all the tests the level of significance was set at . Significantly higher fracture strengths were measured in the presence of a ferrule effect. In groups 1, 2, and 3 (ferrule group), the mean fracture values were, respectively, 163,8 N, 270,9 N, and 254,7 N. These data are higher and statistically significantly different when compared with the three groups 4, 5, and 6 (no-ferrule group), in which the values obtained were, respectively, 40,5 N, 41,7 N, and 44,9 N. Conclusion. The ferrule effect in the endodontically treated teeth positively affects the fracture strength of the fiber post. Conversely, post depth insertion did not affect the resistance to fracture.