The Effect Of Casting And Masticatory Simulation On Strain And Misfit Of Implant-supported Metal Frameworks

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The influence of casting and masticatory simulation on marginal misfit and strain in multiple implant-supported prostheses was evaluated. Three-unit screw retained fixed dental prosthesis (FDP) and screw retained full-arch fixed dental prosthesis (FAFDP) frameworks were made using calcinable or overcasted cylinders on conical dental implant abutment. Four groups were obtained according to the cylinder and prosthesis type (n = 10). Frameworks were casted in CoCr alloy and subjected to strain gauge analyses and marginal misfit measurements before and after 10(6) mechanical cycles (2 Hz/280 N). Results were submitted to ANOVA, Tukey's HSD and Pearson correlation test (alpha = 0.05). No difference was found on misfit among all groups and times (p > 0.05). Overcasted frameworks showed higher strain than the calcinable ones (FDP Initial p = 0.0047; Final p = 0.0004; FAFDP Initial p = 0.0476; Final p = 0.0115). The masticatory simulation did not influence strain (p > 0.05). No correlation was observed between strain and misfit (r = 0.24; p > 0.05). In conclusion, the marginal misfit value in the overcasted full-arch frameworks was higher than clinical acceptable data. It proved that overcasted method is not an ideal method for full-arch prosthesis. Overcasted frameworks generate higher strain upon the system. The masticatory simulation had no influence on misfit and strain of multiple prostheses. (C) 2016 Elsevier B.V. All rights reserved.62746751Sao Paulo Research Foundation (FAPESP) [2011/02841-7, 2011/03032-5]National Council for Scientific and Technological Development (CNPq) [132946/2011-4]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq