Artículos de revistas
Influence Of Diamondlike Carbon Coating Of Screws On Axial Tightening Force And Stress Distribution On Overdenture Bar Frameworks With Different Fit Levels And Materials
Registro en:
Influence Of Diamondlike Carbon Coating Of Screws On Axial Tightening Force And Stress Distribution On Overdenture Bar Frameworks With Different Fit Levels And Materials. Quintessence Publishing Co Inc, v. 30, p. 1019-1027 SEP-OCT-2015.
0882-2786
WOS:000367251300004
Autor
Fernandes dos Santos
Mateus Bertolini; Bacchi
Atais; Xediek Consani
Rafael Leonardo; Correr-Sobrinho
Lourenco
Institución
Resumen
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Purpose: The aim of this study was to evaluate the axial tightening force applied by conventional and diamondlike carbon (DLC)-coated screws and to verify, through three-dimensional finite element analysis (FEA), the stress distribution caused by different framework materials and prosthetic screws in overdenture frameworks with different misfit levels. Materials and Methods: The axial tightening force applied by the screw was evaluated by means of a titanium matrix connected to a load cell. Conventional titanium or DLC-coated screws were tightened with a digital torque wrench, and the load values were recorded. The values were applied in an FEA to a bar-clip attachment system connected to two 4.0 x 11-mm external-hexagon titanium implants placed in an anterior edentulous arch. DLC-coated and conventional screws were modeled with their respective axial forces obtained on the experimental evaluation for three bar framework materials (titanium, nickel-chromium, and cobalt-chromium) and three levels of misfit (100, 150, and 200 mu m). Von Mises stresses for prosthetic components and maximum principal stress and microstrains (maximum principal strains) for bone tissue were measured. Results: The mean force applied by the conventional screw was 25.55 N (+/- 1.78); the prosthetic screw coated with a DLC layer applied a mean force of 31.44 N (+/- 2.11), a statistically significant difference. In the FEA, the DLC screw led to higher stresses on the framework; however, the prosthetic screw suffered lower stress. No influence of screw type was seen in the bone tissue. Conclusion: Titanium frameworks reduced the stress transmitted to the bone tissue and the bar framework but had no influence on the screws. Higher misfit values resulted in an increased stress/strain in bone tissue and bar framework, which was not the case for retention screws. 30 5
1019 1027 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) FAPESP [2012/19374-5]