Mojtaba Mahmoudi1, Ali Reza Saidi2, Parviz Amini3, Maryam Alsadat Hashemipour4. 1. Doctoral student, Department of Mechanical Engineering, School of Engineering, Shahid Bahonar University of Kerman, Kerman, Iran. 2. Professor, Department of Mechanical Engineering, School of Engineering, Shahid Bahonar University of Kerman, Kerman, Iran. Electronic address: saidi@uk.ac.ir. 3. Associate Professor, Department of Prosthodontics, Kerman Oral and Dental Diseases Research Center, Kerman University of Medical Science, Kerman, Iran. 4. Associate Professor, Department of Oral Medicine, Kerman Oral and Dental Diseases Research Center, Kerman University of Medical Science, Kerman, Iran.
Abstract
STATEMENT OF PROBLEM: In post-and-core crown restorations, the use of flexible posts concentrates stresses at the dentin and the use of stiff posts concentrates stresses at the interfaces. A class of inhomogeneous materials (called functionally graded materials) has been proposed for posts to resolve the weaknesses of both flexible and rigid posts. PURPOSE: The purpose of this in vitro study was to design an inhomogeneous post and investigate its influence on the stress distribution of post-and-core crown restorations. MATERIAL AND METHODS: An extracted tooth was mounted, sectioned, and photographed to create a 3-dimensional model of the first premolar tooth. The post-and-core crown restoration was modeled with and without a ferrule. The surrounding tissues of the mandibular tooth, periodontal ligament, and cortical and trabecular bones were modeled. Fiber-reinforced composite (FRC), metallic, and inhomogeneous posts were investigated by finite element analysis and the stress distribution results compared. RESULTS: FRC posts resulted in the highest maximum tensile stress (MTS) at the remaining dentin (90.4 to 93.2 MPa), while inhomogeneous posts graded by index n=10 (FGM10) caused the lowest MTS, both with and without a ferrule (72.3 to 74.8 MPa). CONCLUSIONS: The use of FRC posts concentrated more MTS at the dentin and less MTS at the dentin-adhesive interface than metallic posts. Inhomogeneous posts (FGM10) resolved the weaknesses of both flexible and rigid posts by simultaneously reducing stresses at the dentin and interface. The ferrule effect resulted in fewer dentin and interface stresses.
STATEMENT OF PROBLEM: In post-and-core crown restorations, the use of flexible posts concentrates stresses at the dentin and the use of stiff posts concentrates stresses at the interfaces. A class of inhomogeneous materials (called functionally graded materials) has been proposed for posts to resolve the weaknesses of both flexible and rigid posts. PURPOSE: The purpose of this in vitro study was to design an inhomogeneous post and investigate its influence on the stress distribution of post-and-core crown restorations. MATERIAL AND METHODS: An extracted tooth was mounted, sectioned, and photographed to create a 3-dimensional model of the first premolar tooth. The post-and-core crown restoration was modeled with and without a ferrule. The surrounding tissues of the mandibular tooth, periodontal ligament, and cortical and trabecular bones were modeled. Fiber-reinforced composite (FRC), metallic, and inhomogeneous posts were investigated by finite element analysis and the stress distribution results compared. RESULTS: FRC posts resulted in the highest maximum tensile stress (MTS) at the remaining dentin (90.4 to 93.2 MPa), while inhomogeneous posts graded by index n=10 (FGM10) caused the lowest MTS, both with and without a ferrule (72.3 to 74.8 MPa). CONCLUSIONS: The use of FRC posts concentrated more MTS at the dentin and less MTS at the dentin-adhesive interface than metallic posts. Inhomogeneous posts (FGM10) resolved the weaknesses of both flexible and rigid posts by simultaneously reducing stresses at the dentin and interface. The ferrule effect resulted in fewer dentin and interface stresses.
Authors: Raphaël Richert; Philip Robinson; Gilbert Viguie; Jean-Christophe Farges; Maxime Ducret Journal: Biomed Res Int Date: 2018-06-07 Impact factor: 3.411
Authors: Alexandru Dan Popescu; Dragoș Laurențiu Popa; Andreea Gabriela Nicola; Ionela Teodora Dascălu; Cristian Petcu; Tiberiu Tircă; Mihaela Jana Tuculina; Horia Mocanu; Adela Nicoleta Staicu; Lelia Mihaela Gheorghiță Journal: Int J Environ Res Public Health Date: 2022-07-22 Impact factor: 4.614