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Previous issue date: 2015-03-09 / This study aimed to evaluate "in vitro" possible changes on prosthetic retaining screws on implants with platform external hexagon, this because the loosening this component is very common in clinical dentistry practice. Were assessed screws of UCLA's pillars of titanium Neodent? brand and 3i BIOMET? and of titanium with surface treated with tungsten carbide Neodent? brand. Two techniques of utilization of the screws were compared, the technique I, recommended by the manufacturer with only the definitive torque, and the technique II , utilized in broad scale in Brazil where multiple torques are applied in the same screw simulating the clinical steps, up to definitive installation. The initial weight of all the screws (T0) was registered, in the screws of technique I, it was given definitive torque (32N.cm to Neodent? and 20N.cm to 3i BIOMET?) submitted to mechanical cycling and the final weight (TF) registered. In the screws of technique II have been applied opening and closing cycles, and their weights registered (T1, T2 and T3) before applying the definitive torque and mechanical cycling after the final weight has been registered (TF). The morphologies and the surface compositions of the screws were evaluated using SEM and EDS at each time. The results showed significant weight loss in the three screws groups, of technique I (p< 0.005 for uncoated Neodent?, p = 0.001 for coated Neodent? and p < 0.001 to 3i BIOMET?) and on one step of the uncoated Neodent? group and two steps of the other two groups of technique II (p <0.001 for all groups), and comparing the final weight of the screws of the two techniques, only the uncoated Neodent? screws of the technique I, showed significantly higher values than the screws, of the technique II (p = 0.021 for uncoated Neodent?, p = 0.089 for coated Neodent? and p = 0.095 to 3i BIOMET?), as well as SEM showed less permanent deformation for the technique I of these screws. EDS showed no major changes in the surface compositions. Therefore, the use of the definitive screw only at time of final torque would not necessarily minimize problems regarding to the loosening the retaining screws of implant supported prostheses. / O presente estudo teve como objetivo avaliar ?in vitro? poss?veis altera??es em parafusos de reten??o de pr?teses sobre implantes com plataforma hex?gono interno, pois o afrouxamento deste componente ? muito frequente na pr?tica cl?nica odontol?gica. Foram avaliados parafusos de pilares UCLA de tit?nio da marca Neodent? e 3i BIOMET? e de tit?nio com superf?cie tratada com carboneto de tungst?nio da marca Neodent?. Duas t?cnicas de utiliza??o dos parafusos foram comparadas, a t?cnica I, recomendada pelo fabricante com apenas o torque definitivo, e a t?cnica II, procedimento que ? comumente realizado pelos profissionais no Brasil, onde s?o aplicados m?ltiplos torques no mesmo parafuso, simulando as etapas cl?nicas at? a instala??o definitiva. Foi registrado o peso inicial de todos os parafusos (T0), nos parafusos da t?cnica I foi dado torque definitivo (32N.cm para Neodent? e 20N.cm para 3i BIOMET?), submetidos a ciclagem mec?nica e registrado o peso final (TF). Nos parafusos da t?cnica II foram aplicados ciclos de abertura e fechamento e seus pesos registrados (T1, T2 e T3) antes da aplica??o do torque definitivo e ciclagem mec?nica, ap?s o peso final foi registrado (TF). As morfologias e as composi??es de superf?cie dos parafusos foram avaliadas atrav?s de MEV e EDS em cada tempo. Os resultados evidenciaram perda significativa de peso nos tr?s grupos de parafusos da t?cnica I (p<0,001 para Neodent? sem revestimento, p=0,001 para Neodent? com revestimento e p<0,001 para 3i BIOMET?), e em uma das etapas do grupo Neodent sem cobertura e duas etapas dos outros dois grupos da t?cnica II (p<0,001 para todos os grupos), sendo que comparando o peso final dos parafusos das duas t?cnicas, apenas os parafusos Neodent? sem revestimento da t?cnica I apresentaram valores significativamente maiores que os parafusos da t?cnica II, (p=0,021 para Neodent? sem revestimento, p=0,089 para Neodent? com revestimento e p=0,095 para 3i BIOMET?), do mesmo modo a MEV evidenciou menor deforma??o permanente para a t?cnica I desses parafusos. EDS n?o apresentou grandes altera??es nas composi??es de superf?cie. Portanto, a utiliza??o do parafuso definitivo apenas no momento do torque final n?o minimizar? necessariamente problemas com rela??o ao afrouxamento de parafusos de reten??o de pr?teses implanto suportadas.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/6241 |
| Date | 09 March 2015 |
| Creators | Souza, Elbio Costa |
| Contributors | Mota, Eduardo Gon?alves |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Odontologia, PUCRS, Brasil, Faculdade de Odontologia |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | -8096554818733665164, 600, 600, 600, 4673435736271820140, -2070498469879244349 |
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