title: Temporomandibular joint fibrocartilage degeneration from unilateral dental splints.
abstract: OBJECTIVE
  The objective of this study was to determine the extent to which altered loading in the temporomandibular joint (TMJ), as might be associated with a malocclusion, drives degeneration of articulating surfaces in the TMJ. We therefore sought to quantify the effects of altered joint loading on the mechanical properties and biochemical content and distribution of TMJ fibrocartilage in the rabbit.
  
  
  METHODS
  Altered TMJ loading was induced with a 1mm splint placed unilaterally over the maxillary and mandibular molars for 6 weeks. At that time, TMJ fibrocartilage was assessed by compression testing, biochemical content (collagen, glycosaminoglycan (GAG), DNA) and distribution (histology), for both the TMJ disc and the condylar fibrocartilage.
  
  
  RESULTS
  There were no changes in the TMJ disc for any of the parameters tested. The condylar fibrocartilage from the splinted animals was significantly stiffer and the DNA content was significantly lower than that in control animals. There was significant remodeling in the condylar fibrocartilage layers as manifested by a change in GAG and collagen II distribution and a loss of defined cell layers.
  
  
  CONCLUSIONS
  A connection between the compressive properties of TMJ condylar fibrocartilage after 6 weeks of splinting and the changes in histology was observed. These results suggest a change in joint loading leads to condylar damage, which may contribute to pain associated with at least some forms of TMJ disease.
authors.affiliation: Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Henderson
authors.affiliation: Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Jesse R
authors.initials: JR
authors.lastname: Lowe
authors.affiliation: Department of Oral Biology, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Mauro A
authors.initials: MA
authors.lastname: Tudares
authors.affiliation: Department of Anesthesiology, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Gold
authors.affiliation: Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Oral Biology, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA. Electronic address: aja19@pitt.edu.
authors.forename: Alejandro J
authors.initials: AJ
authors.lastname: Almarza
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D003094:Collagen / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D003799:Dental Stress Analysis; D005260:Female; D051445:Fibrocartilage / Q000378:metabolism / Q000503:physiopathology*; D006025:Glycosaminoglycans / Q000378:metabolism; D066298:In Vitro Techniques; D011817:Rabbits; D013165:Splints / Q000009:adverse effects*; D013705:Temporomandibular Joint Disorders / Q000378:metabolism / Q000503:physiopathology*
chemical_list: D006025:Glycosaminoglycans; D003094:Collagen; D004247:DNA
keywords: Fibrocartilage degeneration; Temporomandibular joint; Unilateral dental splint