title: Correlation between vertical misfits and stresses over implants from castable frameworks made of different alloys.
abstract: This study aims to investigate a possible correlation between vertical misfits and the stresses transmitted to implants from one-piece casted frameworks fabricated with 3 different materials: commercially pure titanium, cobalt chromium alloy, and nickel chromium titanium alloy. Twelve frameworks simulating screw-retained prosthesis were fabricated from a master cast with 5 implants. Each framework was screwed (20 Ncm) over a metal cast and the vertical mesial and distal misfits were measured using an optical microscope. The stresses transmitted to the implants were measured in a third model by a quantitative photoelastic analysis. Stress and vertical misfit data were statistically analyzed by ANOVA and least significant difference tests and the correlation tests were performed using Pearson Correlation Test (α = 0.05). Mean and standard deviation values of vertical misfit and stress over implants are presented, respectively: commercially pure titanium (29.09 ± 13.24 μm and 11.38 ± 9.23 kPa), cobalt chromium alloy (27.05 ± 10.30 μm and 15.83 ± 9.30 kPa), nickel chromium titanium alloy (24.95 ± 11.14 μm and 16.39 ± 9.51 kPa). There were no significant differences for vertical misfit (P = 0.285). Regarding the stress analysis, there were significant differences between commercially pure titanium, cobalt chromium alloy, and nickel chromium titanium alloy (P = 0.035), with the lowest values for the commercially pure titanium. It may be concluded that stress over implants was affected by different procedures and materials for framework production.
authors.affiliation: *Department of Dentistry, School of Dentistry, Federal University of Rio Grande do Norte-UFRN, Natal, Rio Grande do Norte, †Department of Dental Implants of Latin American Institute for Dental Research and Education-ILAPEO, Curitiba, Paraná, ‡Department of Dentistry, School of Dentistry, State University of Rio Grande do Norte, Caicó, Rio Grande do Norte, §Department of Fixed Prosthodontics, Occlusion and Dental Materials, School of Dentistry, Federal University of Uberlândia-UFU, Uberlândia, Minas Gerais, and ∥Department of Dental Materials and Prosthesis, School of Dentistry of Ribeirão Preto, University of São Paulo-USP, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Gustavo Augusto Seabra
authors.initials: GA
authors.lastname: Barbosa
authors.forename: Sérgio Rocha
authors.initials: SR
authors.lastname: Bernardes
authors.forename: Danilo Gonzaga Bernardo
authors.initials: DG
authors.lastname: de França
authors.forename: Flávio Domingues
authors.initials: FD
authors.lastname: das Neves
authors.forename: Maria da Glória Chiarello
authors.initials: Mda G
authors.lastname: de Mattos
authors.forename: Ricardo Faria
authors.initials: RF
authors.lastname: Ribeiro
mesh_terms: D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D002858:Chromium Alloys / Q000737:chemistry; D003035:Cobalt / Q000737:chemistry; D000044:Dental Abutments; D003722:Dental Alloys / Q000737:chemistry; D003735:Dental Casting Technique; D019094:Dental Prosthesis, Implant-Supported; D004548:Elasticity; D006801:Humans; D008334:Mandible / Q000033:anatomy & histology* / Q000502:physiology; D011474:Prosthesis Design / Q000379:methods*; D014025:Titanium / Q000737:chemistry
chemical_list: D002858:Chromium Alloys; D003722:Dental Alloys; D003035:Cobalt; D014025:Titanium