title: Disease and functional loading effect on the structural conformation and mechanical properties of the mandibular condyle in a transgenic rheumatoid arthritis murine model: an experimental study.
abstract: The aim of the present study was to investigate the effect of rheumatoid arthritis (RA) and functional loading through diet modification on the structural conformation and the mechanical properties of the mandibular condyle in a transgenic mouse model and compare to healthy littermates.
  
  
  
  Four-week-old hybrid male mice from mixed background CBAxC57BL/6 were used. Four groups of animals were formed consisting of five animals each, either presenting RA (transgenic line hTNF 197), or wild-type (control), half receiving ordinary (hard) diet and half receiving soft diet within each category. Following sacrifice, resin-embedded and metallographically polished condylar specimens were evaluated employing scanning electron microscopy/ Energy dispersive x-ray spectroscopy and also tested for mechanical properties, through Vickers microhardness (HV100) measurements.
  
  
  
  The multivariable analysis revealed significantly lower HV100 values for the RA groups after adjusting for diet (β = -10; 95% confidence interval: -16, -4; P = 0.001), while functional loading through diet modification did not appear as a significant predictor of the outcome.
  
  
  
  There was evidence of compromised mechanical properties of the mandibular condylar bone for the diseased animals, whereas no association between functional loading and mechanical properties of the condyle could be established.
authors.affiliation: Department of Oral Technology, School of Dentistry, University of Bonn, Germany, Departments of.|Orthodontics and.|Dental Biomaterials, School of Dentistry, University of Athens, Greece, and.
authors.forename: Despina
authors.initials: D
authors.lastname: Koletsi
authors.affiliation: Clinic of Orthodontics and Paediatric Dentistry, Center of Dental Medicine, University of Zurich, Switzerland theodore.eliades@zzm.uzh.ch.
authors.forename: Theodore
authors.initials: T
authors.lastname: Eliades
authors.affiliation: Dental Biomaterials, School of Dentistry, University of Athens, Greece, and.
authors.forename: Spiros
authors.initials: S
authors.lastname: Zinelis
authors.affiliation: Department of Oral Technology, School of Dentistry, University of Bonn, Germany, Departments of.
authors.forename: Christoph
authors.initials: C
authors.lastname: Bourauel
authors.affiliation: Dental Biomaterials, School of Dentistry, University of Athens, Greece, and.
authors.forename: George
authors.initials: G
authors.lastname: Eliades
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000473:pathology / Q000503:physiopathology*; D001172:Arthritis, Rheumatoid / Q000473:pathology / Q000503:physiopathology*; D004032:Diet; D006244:Hardness; D006245:Hardness Tests / Q000379:methods; D008297:Male; D008335:Mandibular Condyle / Q000503:physiopathology* / Q000648:ultrastructure; D008822:Mice, Transgenic; D008855:Microscopy, Electron, Scanning; D016474:Weight-Bearing / Q000502:physiology