| Autor: |
Pimentel AC; 1 Department of Implantology at the University of Santo Amaro, São Paulo, Brazil., Manzi MR; 2 School of Dentistry, Department of Oral and Maxillofacial Surgery and Traumatology, University of São Paulo (USP), São Paulo, SP, Brazil., Polo CI; 2 School of Dentistry, Department of Oral and Maxillofacial Surgery and Traumatology, University of São Paulo (USP), São Paulo, SP, Brazil., Sendyk CL; 3 Prosthodontics, University of São Paulo (USP), São Paulo, Brazil., da Graça Naclério-Homem M; 4 University of São Paulo (USP), São Paulo, Brazil., Sendyk WR; State University of Campinas (UNICAMP); Graduate Program in Implant Dentistry at the University of Santo Amaro (UNISA), São Paulo, Brazil. |
| Abstrakt: |
The aim of this study was to evaluate the stress distribution of different retention systems (screwed, cemented, and mixed) in 5-unit implant-supported fixed partial dentures through the photoelasticity method. Twenty standardized titanium suprastructures were manufactured, of which 5 were screw retained, 5 were cement retained, and 10 were mixed (with an alternating sequence of abutments), each supported by 5 external hexagon (4.0 mm × 11.5 mm) implants. A circular polariscope was used, and an axial compressive load of 100 N was applied on a universal testing machine. The results were photographed and qualitatively analyzed. We observed the formation of isochromatic fringes as a result of the stresses generated around the implant after installation of the different suprastructures and after the application of a compressive axial load of 100 N. We conclude that a lack of passive adaptation was observed in all suprastructures with the formation of low-magnitude stress in some implants. When cemented and mixed suprastructures were subjected to a compressive load, they displayed lower levels of stress distribution and lower intensity fringes compared to the screwed prosthesis. |
