Analysis of stress distribution in rehabilitation with morse taper implants in the posterior region of maxilla: study by nonlinear 3D-FEA

Author(s)

Cleidiel Aparecido Araujo Lemos

• Document type: Master's Dissertation
• Press: Araçatuba. 2016-02-19.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Odontologia. Araçatuba
• Defense date: 2016-02-16
• Advisor: Eduardo Piza Pellizzer

Abstract

This project aimed to evaluate the stress on single and splinted implant-supported fixed prostheses over morse taper implants in the posterior region of the maxilla, varying the length of the implants and prosthetic fixation, by three-dimensional nonlinear finite element method. Twelve three-dimensional models were simulated with Rhinoceros 3D 4.0 software (NURBS Modeling for Windows, USA) and SolidWorks 2011 software (SolidWorks Corp, USA). The bone portion was obtained by use of InVesalius software (CTI, São Paulo, Brasil). Each model presented a section of bone of the maxillary posterior region in the form of a type III bone block (cortical and trabecular), with the presence of three morse tapper type implants with 4,0mm in diameter and different lenghts (7,0mm, 8,5mm, 10mm, 11,5mm) placed 1mm below at cortical bone surface supporting prostheses of three elements with metal-ceramic crowns. In chapter 1 was considered models varying the fixation systems (screw-retained x cement-retained), and the splinting (single-unit prostheses x splinted prosthesis), while in Chapter 2 was considered only single-unit prostheses varying the fixation systems (screw-retained x cement-retained), and the length of the implants (7.0mm, 8.5mm, 10mm and 11.5mm). The three-dimensional models were exported to pre- and post- processing in the FEMAP v.11.0 software (Siemens Product Lifecycle Management Software Inc. USA) for mesh generation, restrictions and configuration of load of 400N axial and 200N oblique (45º) applied at each dental cusp. The analysis was performad by NEiNastran 11 software (Noran Engineering, Inc., EUA) and results were displayed using von Mises tension maps and Maximum Principal Stress tension maps that were individualized for each proposed model as necessary. The Chapter 1 results showed that cement-retained prostheses showed better biomechanical behavior compared with the screw-retained prosthesis, mainly in oblique loading in implant/component region, as well as bone tissue. The splinted crowns favored the stress distribution between the implants/components in the both fixation systems. However, it was found advantage in reducing tensions only in screw-retained prostheses in the oblique loading in relation to bone tissue analysis. The results of Chapter 2 cement-retained prostheses showed better stress distribution in the cortical bone when compared to the screw-retained prostheses. Short implants (7 mm) showed greater stress in the implants/components, and larger area of traction stresses in the cortical bone with significant difference in the screw-retained prostheses. Thus, it can be concluded that cement-retained prostheses were more favorable for stress distribution in implant/component region and the bone tissue. However, the splinted crowns favoring the stress distribution only in the bone tissue for screw-retained prostheses. Short implants (7 mm) showed worse biomechanical behavior, especially in screwed prostheses. (AU)

• FAPESP's process: 14/02490-8 - Analysis of stress distribution in rehabilitation with Morse taper implants in the posterior region of maxila: study by nonlinear 3D-FEA
• Grantee: Cleidiel Aparecido Araujo Lemos
• Support Opportunities: Scholarships in Brazil - Master