title: Mechanical and microstructural properties of fixation systems used in oral and maxillofacial surgery.
abstract: OBJECTIVE
  This paper aims to evaluate in vitro the mechanical and microstructural properties of internal fixation systems used in oral and maxillofacial surgeries.
  
  
  METHODS
  Four brands of internal fixation systems (screws and 4-hole straight plates) were selected and assigned to four groups: G1 Leibinger®, G2 Tóride®, G3 Engimplan®, and G4 Medartis®. The systems were submitted to Vickers hardness testing, metallographic and interstitial elements chemical composition analyses. Data were submitted to ANOVA and Tukey's test for statistical analysis.
  
  
  RESULTS
  Plates in groups 1, 2, and 3 showed similar microstructure and mechanical properties, different from those in G4 revealing larger grains. In all groups, the screws showed similar microstructure, with uniform arrangement and size of grains; the screws showed higher hardness values than those observed for the plates.
  
  
  CONCLUSIONS
  The results indicate that all materials tested are adequate for use in oral maxillofacial surgeries.
authors.affiliation: Department of Oral Diagnosis, Oral and Maxillofacial Surgery Division, Piracicaba Dental School CP 52, State University of Campinas-UNICAMP, 13.414-903, Piracicaba, SP, Brazil. marcelobreno@yahoo.com.br.
authors.forename: Marcelo Breno Meneses
authors.initials: MB
authors.lastname: Mendes
authors.affiliation: Department of Oral Diagnosis, Oral and Maxillofacial Surgery Division, Piracicaba Dental School CP 52, State University of Campinas-UNICAMP, 13.414-903, Piracicaba, SP, Brazil.
authors.forename: Raquel Correia de
authors.initials: RC
authors.lastname: Medeiros
authors.affiliation: Department of Oral Diagnosis, Oral and Maxillofacial Surgery Division, Piracicaba Dental School CP 52, State University of Campinas-UNICAMP, 13.414-903, Piracicaba, SP, Brazil.
authors.forename: Andrezza
authors.initials: A
authors.lastname: Lauria
authors.affiliation: Department of Oral Diagnosis, Oral and Maxillofacial Surgery Division, Piracicaba Dental School CP 52, State University of Campinas-UNICAMP, 13.414-903, Piracicaba, SP, Brazil.
authors.forename: Érica
authors.initials: É
authors.lastname: Marchiori
authors.affiliation: Temporary Substitute Professor of Oral and Maxillofacial Surgery, University of Passo Fundo, Rio Grande do Sul, Brazil.
authors.forename: Renato
authors.initials: R
authors.lastname: Sawazaki
authors.affiliation: Department of Manufacturing and Materials Engineering, State University of Campinas-UNICAMP, CP 6122, 13.083-970, Campinas, SP, Brazil.
authors.forename: Éder Sócrates Najar
authors.initials: ÉS
authors.lastname: Lopes
authors.affiliation: Department of Oral Diagnosis, Oral and Maxillofacial Surgery Division, Piracicaba Dental School CP 52, State University of Campinas-UNICAMP, 13.414-903, Piracicaba, SP, Brazil.
authors.forename: Roger William Fernandes
authors.initials: RW
authors.lastname: Moreira
mesh_terms: D001860:Bone Plates; D001863:Bone Screws; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006245:Hardness Tests; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D009584:Nitrogen / Q000032:analysis; D061848:Optical Imaging; D019647:Oral Surgical Procedures / Q000295:instrumentation*; D010100:Oxygen / Q000032:analysis
chemical_list: D009584:Nitrogen; D010100:Oxygen
keywords: Chemical composition; Metallography; Stable internal fixation; Vickers hardness