PubMed ID (PMID): 20617225Pagine 350-352, Lingua: IngleseDe Oliveira, José Luiz G. / Martins, Leandro Moura / Sanada, Jefesson / De Oliveira, Pedro Cesar G. / Do Valle, Accácio L.This study evaluated the effect of framework design on the fracture resistance of metal-ceramic implant-supported crowns. Screw-retained molar crowns with a screw access hole composed of metal or porcelain were compared to a cement-retained crown (control). For each group (n = 10), five crowns were subjected to dynamic loading (1,200,000 3 100 N 3 2 Hz at 37°C). Afterward, all specimens were loaded to failure using a universal testing machine. Significant differences could be established between the cement- and screw-retained groups (P = .05), but no difference was found between the screw-retained groups and the specimens subjected to dynamic loading. Occlusal discontinuity of screw-retained crowns affects their resistance, and the metallic support on the screw access hole did not reinforce the crowns.
