title: Fractographic analysis of 2.0-mm plates with a screw locking system in simulated fractures of the mandibular body.
abstract: OBJECTIVE
  The purpose of the present study was to analyze the fractured plates from 2 brands of 2.0-mm locking fixation systems submitted to axial linear load testing.
  
  
  METHODS
  Four aluminum hemimandibles with linear sectioning to simulate a mandibular body fracture were used as a substrate and fixed with 2 fixation techniques from 2 national brands: Tóride and Traumec. The techniques were as follows: one 4-hole plate, with four 6-mm screws in the tension zone, and one 4-hole plate, with four 10-mm screws in the compression zone; and one 4-hole plate, with four 6-mm holes in the neutral zone. The hemimandibles were submitted to vertical linear load tests using an Instron 4411 mechanical test machine. The system was submitted to the test until complete failure had occurred. Next, a topographic analysis of the surface of the plates was performed using a stereomicroscope and an electronic scanning microscope. The samples were evaluated using different magnifications, and images were obtained.
  
  
  RESULTS
  The surface of the fracture analyzed in scanning electron microscopy demonstrated a ductile-type fracture, usually found in the traction test bodies of ductile materials, such as titanium. No evidence of failure was observed in any fracture surface from a change in the structure or composition of the material.
  
  
  CONCLUSIONS
  The plates were fractured by a ductile rupture mechanism, as expected, suggesting that the manufacturing of the national brand name plates used in the present study has been under adequate quality control, with no structural changes produced by the manufacturing process that could compromise their function.
authors.affiliation: Postgraduate Student (PhD Degree), Department of Oral and Maxillofacial Surgery, Piracicaba Dental School, State University of Campinas-UNICAMP, Piracicaba, São Paulo, Brazil. Electronic address: raquelcorreiademedeiros@gmail.com.
authors.forename: Raquel Correia
authors.initials: RC
authors.lastname: de Medeiros
authors.affiliation: Postgraduate Student (PhD Degree), Department of Oral and Maxillofacial Surgery, Piracicaba Dental School, State University of Campinas-UNICAMP, Piracicaba, São Paulo, Brazil.
authors.forename: Andrezza
authors.initials: A
authors.lastname: Lauria de Moura
authors.affiliation: Postgraduate Student (MsD degree), Department of Oral and Maxillofacial Surgery, Piracicaba Dental School, State University of Campinas-UNICAMP, Piracicaba, São Paulo, Brazil.
authors.forename: Danillo Costa
authors.initials: DC
authors.lastname: Rodrigues
authors.affiliation: Postgraduate Student (PhD Degree), Department of Oral and Maxillofacial Surgery, Piracicaba Dental School, State University of Campinas-UNICAMP, Piracicaba, São Paulo, Brazil.
authors.forename: Marcelo Breno
authors.initials: MB
authors.lastname: Menezes Mendes
authors.affiliation: Adjunct Professor, Department of Oral and Maxillofacial Surgery, University of Passo Fundo, Paraná, Brazil.
authors.forename: Renato
authors.initials: R
authors.lastname: Sawazaki
authors.affiliation: Adjunct Professor, Department of Oral and Maxillofacial Surgery, Piracicaba Dental School, State University of Campinas-UNICAMP, Piracicaba, São Paulo, Brazil.
authors.forename: Roger William
authors.initials: RW
authors.lastname: Fernandes Moreira
mesh_terms: D000497:Alloys / Q000737:chemistry; D017607:Aluminum Compounds / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry; D001860:Bone Plates; D001863:Bone Screws; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000379:methods*; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006801:Humans; D008337:Mandibular Fractures / Q000601:surgery*; D055595:Mechanical Phenomena; D008855:Microscopy, Electron, Scanning; D008953:Models, Anatomic; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
chemical_list: D000497:Alloys; D017607:Aluminum Compounds; D001672:Biocompatible Materials; D014025:Titanium