Stress distribution analysis of mandibular protocol confectioned by the conventional system and cad/cam, ranging type, number and inclination of the implants

Author(s)

Cristian Sbardelotto

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC)
• Defense date: 2016-01-19

Examining board members

Renata Cristina Silveira Rodrigues Ferracioli; Rogério Margonar; Ricardo Faria Ribeiro

• Advisor: Renata Cristina Silveira Rodrigues Ferracioli

Abstract

The implant-supported fixed dental prostheses have been used to rehabilitate edentulous patients as it fulfills not only functional aspects but also esthetic questions. Literature shows that there is no consensus about the best configuration to distribute stress to the implants and surrounding tissues. The objective of this study was to compare the stress generated at the boneimplant interface of implant-supported mandibular dentures by a digital image correlation method (DIC). Two different configurations were analyzed for the implants quantity and position (4 or 5 implants), different connections [external hexagon (EH) and Cone Morse (CM)] and bars for implant-supported fixed prosthesis obtained by conventional casting and machined by CAD/CAM system. Models were prepared from polyurethane and implants (3.75x11mm) were divided in 8 groups: G1 (5 implants/EH/CAD-CAM), G2 (5 Implants/CM/CAD-CAM), G3 (5 Implants/EH/Conventional) , G4 (5 Implants/CM/Conventional), G5 (4 Implants/EH/CAD-CAM), G6 (4 Implants/CM/CAD-CAM) G7 (4 Implants/EH/Conventional) and G8 (4 Implants/CM/Conventional). DIC analysis were quantitative and qualitatively made with a 250N load at first molar central fossa, which were established in different regions of interest for analysis as C1 (cervical 1) and A1 (apical 1) to distal to the last implant, C2 (cervical 2) and A2 (apical) for mesial region to the last implant. Statistically significant differences were found for number of implants in all regions examined [C1 (p=0.002), A1 (p=0.01), C2 (p=0.001) and A2 (p=0.004)], for connections differences were found in the C2 region (p <0.05) and for the bar region at A2 (p=0.003). According to the results it can be concluded that the prosthesis with four implants showed a higher stress at the apical regions, there was no significant difference in the concentration of stress for EH and CM connections, except for the C2 region, where there was a higher concentration of stress for CM connection, and comparing bars obtained methods, conventional bars showed a higher concentration of stresses in prosthesis with 5 implants. (AU)

• FAPESP's process: 14/12927-4 - Analysis of stress distribution in mandibular protocol made by the conventional system and CAD/CAM, varying type, number and inclination of the implants
• Grantee: Cristian Sbardelotto
• Support Opportunities: Scholarships in Brazil - Master