title: Cartilage degradation in temporomandibular joint induced by unilateral anterior crossbite prosthesis.
abstract: OBJECTIVE
  To investigate the pathological effects on temporomandibular joint cartilage of an experimentally created unilateral anterior crossbite prosthesis.
  
  
  METHODS
  Six-week-old female Sprague-Dawley rats were divided into experimental and control groups and further divided into three subgroups for three time points (n = 9). In experimental groups, the unilateral anterior crossbite was created by bonding two metal tubes on left maxillary and mandibular incisors. 2, 4, or 8 weeks after operation, the histomorphological changes and the expression changes of PCNA, COL II, aggrecan, MMP-3, MMP-9, MMP-13, and TIMP-1 in condylar cartilage were investigated by hematoxylin-eosin and toluidine blue staining, real-time PCR, and immunohistochemistry.
  
  
  RESULTS
  In experimental groups, decreasing in chondrocytes, cell-free areas, reduction in the thickness of hypertrophic layer, and loss of extracellular matrix were noticed. The expression level of PCNA was decreased at week 2 and week 4. The mRNA expression of COL II was decreased at 4 week and that of aggrecan was increased at 2 week but decreased at 4 and 8 week. The expression of MMP-9, MMP-13, and TIMP-1 was increased at 2-week and decreased at 4- and 8-week, while that of MMP-3 was increased at 4- and 8-week.
  
  
  CONCLUSIONS
  The present unilateral anterior crossbite prosthesis led to degradation of mandibular condylar cartilage.
authors.affiliation: Department of Oral Anatomy and Physiology and TMD, School of Stomatology, Fourth Military Medical University, Xi'an, China.
authors.forename: Y L
authors.initials: YL
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: M
authors.initials: M
authors.lastname: Zhang
authors.forename: L
authors.initials: L
authors.lastname: Lu
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.forename: M
authors.initials: M
authors.lastname: Guo
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.forename: M Q
authors.initials: MQ
authors.lastname: Wang
mesh_terms: D000818:Animals; D002356:Cartilage / Q000378:metabolism / Q000473:pathology; D002357:Cartilage Diseases / Q000209:etiology*; D005260:Female; D008310:Malocclusion / Q000150:complications*; D019736:Prostheses and Implants; D014176:Protein Biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013705:Temporomandibular Joint Disorders / Q000209:etiology*
keywords: MMPs; cartilage; osteoarthritis; temporomandibular disorder; temporomandibular joint