title: Analysis of residual stress and hardness in regions of pre-manufactured and manual bends in fixation plates for maxillary advancement.
abstract: The aim of this study was to analyze, through Vickers hardness test and photoelasticity analysis, pre-bent areas, manually bent areas, and areas without bends of 10-mm advancement pre-bent titanium plates (Leibinger system). The work was divided into three groups: group I-region without bend, group II-region of 90° manual bend, and group III-region of 90° pre-fabricated bends. All the materials were evaluated through hardness analysis by the Vickers hardness test, stress analysis by residual images obtained in a polariscope, and photoelastic analysis by reflection during the manual bending. The data obtained from the hardness tests were statistically analyzed using ANOVA and Tukey's tests at a significance level of 5 %. The pre-bent plate (group III) showed hardness means statistically significantly higher (P < 0.05) than those of the other groups (I-region without bends, II-90° manually bent region). Through the study of photoelastic reflection, it was possible to identify that the stress gradually increased, reaching a pink color (1.81 δ / λ), as the bending was performed. A general analysis of the results showed that the bent plate region of pre-bent titanium presented the best results.
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dentistry of São José dos Campos, State University of São Paulo (UNESP), São José dos Campos, SP, Brazil.
authors.forename: Marcelo Marotta
authors.initials: MM
authors.lastname: Araújo
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dentistry of Piracicaba, State University of Campinas (UNICAMP), Av. Limeira, 901, PO Box 52, CEP 13414-903, Piracicaba, SP, Brazil. andrezzalauria@gmail.com.
authors.forename: Andrezza
authors.initials: A
authors.lastname: Lauria
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dentistry of Piracicaba, State University of Campinas (UNICAMP), Av. Limeira, 901, PO Box 52, CEP 13414-903, Piracicaba, SP, Brazil.
authors.forename: Marcelo Breno Meneses
authors.initials: MB
authors.lastname: Mendes
authors.affiliation: Department of Materials, School of Engineering of Guaratinguetá, State University of São Paulo (UNESP), Guaratinguetá, SP, Brazil.
authors.forename: Ana Paula Rosifini Alves
authors.initials: AP
authors.lastname: Claro
authors.affiliation: Department of Orthodontics, School of Dentistry, University of Taubaté, Taubaté, SP, Brazil.
authors.forename: Cristiane Aparecida de Assis
authors.initials: CA
authors.lastname: Claro
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dentistry of Piracicaba, State University of Campinas (UNICAMP), Piracicaba, SP, Brazil.
authors.forename: Roger William Fernandes
authors.initials: RW
authors.lastname: Moreira
mesh_terms: D001860:Bone Plates; D004548:Elasticity; D006244:Hardness; D008422:Materials Testing; D008437:Maxilla / Q000601:surgery*; D063166:Maxillary Osteotomy / Q000009:adverse effects; D013314:Stress, Mechanical; D014025:Titanium
chemical_list: D014025:Titanium
keywords: Bone plates; Hardness testing; Maxillary osteotomy