Pietro Ausiello1, Stefano Ciaramella2, Massimo Martorelli2, Antonio Lanzotti2, Fernando Zarone3, David C Watts4, Antonio Gloria5. 1. School of Dentistry - University of Naples Federico II, Italy. Electronic address: pietro.ausiello@unina.it. 2. Department of Industrial Engineering, Fraunhofer JL IDEAS - University of Naples Federico II, Italy. 3. School of Dentistry - University of Naples Federico II, Italy. 4. School of Medical Sciences and Photon Science Institute, University of Manchester, United Kingdom. 5. Institute of Polymers, Composites and Biomaterials - National Research Council of Italy, Naples, Italy.
Abstract
OBJECTIVE: To assess the effect of a ferrule design with specific post material-shape combinations on the mechanical behavior of post-restored canine teeth. METHODS: Micro-CT scan images of an intact canine were used to create a 3-D tessellated CAD model, from which the shapes of dentin, pulp and enamel were obtained and geometric models of post-endodontically restored teeth were created. Two types of 15mm post were evaluated: a quartz fiber post with conical-tapered shape, and a carbon (C) fiber post with conical-cylindrical shape. The abutment was created around the coronal portion of the posts and 0.1mm cement was added between prepared crown and abutment. Cement was also added between the post and root canal and a 0.25mm periodontal ligament was modeled around the root. Four models were analysed by Finite Element (FE) Analysis: with/without a ferrule for both types of post material and shape. A load of 50N was applied at 45° to the longitudinal axis of the tooth, acting on the palatal surface of the crown. The maximum normal stress criterion was adopted as a measure of potential damage. RESULTS: Models without a ferrule showed greater stresses (16.3MPa) than those for models with a ferrule (9.2MPa). With a ferrule, stress was uniformly distributed along the abutment and the root, with no critical stress concentration. In all models, the highest stresses were in the palatal wall of the root. Models with the C-fiber post had higher stress than models with the quartz fiber posts. The most uniform stress distribution was with the combination of ferrule and quartz fiber post. SIGNIFICANCE: The FE analysis confirmed a beneficial ferrule effect with the combination of ferrule and quartz fiber post, with tapered shape, affording no critical stress concentrations within the restored system. Crown
OBJECTIVE: To assess the effect of a ferrule design with specific post material-shape combinations on the mechanical behavior of post-restored canine teeth. METHODS: Micro-CT scan images of an intact canine were used to create a 3-D tessellated CAD model, from which the shapes of dentin, pulp and enamel were obtained and geometric models of post-endodontically restored teeth were created. Two types of 15mm post were evaluated: a quartz fiber post with conical-tapered shape, and a carbon (C) fiber post with conical-cylindrical shape. The abutment was created around the coronal portion of the posts and 0.1mm cement was added between prepared crown and abutment. Cement was also added between the post and root canal and a 0.25mm periodontal ligament was modeled around the root. Four models were analysed by Finite Element (FE) Analysis: with/without a ferrule for both types of post material and shape. A load of 50N was applied at 45° to the longitudinal axis of the tooth, acting on the palatal surface of the crown. The maximum normal stress criterion was adopted as a measure of potential damage. RESULTS: Models without a ferrule showed greater stresses (16.3MPa) than those for models with a ferrule (9.2MPa). With a ferrule, stress was uniformly distributed along the abutment and the root, with no critical stress concentration. In all models, the highest stresses were in the palatal wall of the root. Models with the C-fiber post had higher stress than models with the quartz fiber posts. The most uniform stress distribution was with the combination of ferrule and quartz fiber post. SIGNIFICANCE: The FE analysis confirmed a beneficial ferrule effect with the combination of ferrule and quartz fiber post, with tapered shape, affording no critical stress concentrations within the restored system. Crown
Authors: João Paulo Mendes Tribst; Amanda Maria de Oliveira Dal Piva; Roberto Lo Giudice; Alexandre Luiz Souto Borges; Marco Antonio Bottino; Ettore Epifania; Pietro Ausiello Journal: Int J Environ Res Public Health Date: 2020-06-05 Impact factor: 3.390