Effect of filling in the stress distribution and fracture resistance of premolars weakened

• Grant number: 11/09104-8
• Support type: Regular Research Grants
• Duration: November 01, 2011 - October 31, 2013
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal researcher: Alexandre Luiz Souto Borges
• Grantee: Alexandre Luiz Souto Borges
• Home Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil
• Assoc. researchers: Ana Carolina de Oliveira Souza ; Tathy Aparecida Xavier

Abstract

This study will evaluate in vitro the influence of the base in the distribution of stress in endodontically treated premolars with cusp weakened filled with composite and glass ionomer and restored with ceramic inlays or indirect resin composite, by flexural strength test and also by finite element analysis 3D method. Forty-nine human premolars will be selected and randomly separated into 7 groups: G1- intact teeth; G2-inlay without restorative material; G3-inlay without restorative material and undermined cusps, G4-filling with glass ionomer resin inlay + indirect (Signum), G5-filling with glass ionomer + ceramic inlay (e.max Press) G6 - filling with composite resin inlay + indirect (Signum) and G7-filling with composite resin inlay + ceramic (e.max Press). All teeth receive endodontic treatment and the dentinal support will be removed to the G2 until G6 by wheel-shaped and spherical diamond burs in the buccal and lingual occlusal box. The preparation of inlays will be standardized by a pantograph device, shaped and sent to laboratory for the preparation of indirect restorations. The restorations are cemented using resin cement, dual Variolink II (Ivoclair Vivadent) and stored in distilled water at 37 °C for 24 hours. Each specimen shall be subjected to a universal testing machine (EMIC, DL200MF) with speed 1mm/min. The fracture strength data will be subjected to analysis of variance two-factor and Tukey test (5% of significance). For the finite element analysis (FEA) will be obtained 3D models of anatomical structures. Three designs will be generated on STL format images for the mathematical simulation software for Rhinoceros 4.0 and exported to Ansys 12.0, which is hosting the pre and post processing of the hypotheses to be tested. (AU)