title: Injured condylar cartilage leads to traumatic temporomandibular joint ankylosis.
abstract: OBJECTIVE
  The exact mechanisms of traumatic temporomandibular joint ankylosis (TTMJA) are largely unknown. In this study, we explore the role of injured condylar cartilage in the development of TTMJA.
  
  
  METHODS
  One-month-old male mice were divided into two groups. In group 1, condylar cartilage was partially removed in the right joint using a small scissors to induce ankylosis. In group 2, condylar cartilage was completely removed in the same right joint using a small scissors to induce ankylosis. The phenotypes were observed using gross observation, micro-computed tomography scans and histological examination.
  
  
  RESULTS
  The results revealed a great deal of ectopic cartilage and bone formation in the right periarticular region in all mice in group 1, whereas there was only a small amount of ectopic cartilage present in 26.7% of the mice in group 2. Additionally, there was stronger expression of FGF9 and weaker expression of OPN in the right temporomandibular joint region in group 2 at 7 days after surgery.
  
  
  CONCLUSIONS
  These results suggest that the injured cartilage, not the injured bone, plays a crucial role in the development of TTMJA. In addition, it offers a useful TTMJA animal model to study the molecular mechanisms of TTMJA based on the gene manipulation technology, such as gene knock-out and knock-in as well as transgenic or gene mutation.
authors.affiliation: Department of Oral & Cranio-maxillofacial Science, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, No.639 Zhizaoju Road, Shanghai 200011, China. Electronic address: daijiewen@163.com.
authors.forename: Jiewen
authors.initials: J
authors.lastname: Dai
authors.affiliation: Department of Oral & Cranio-maxillofacial Science, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, No.639 Zhizaoju Road, Shanghai 200011, China.
authors.forename: Ningjuan
authors.initials: N
authors.lastname: Ouyang
authors.affiliation: Department of Oral & Cranio-maxillofacial Science, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, No.639 Zhizaoju Road, Shanghai 200011, China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Oral and Maxillofacial Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China.
authors.forename: Li
authors.initials: L
authors.lastname: Huang
authors.affiliation: Department of Oral & Cranio-maxillofacial Science, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, No.639 Zhizaoju Road, Shanghai 200011, China. Electronic address: maxillofacsurg@163.com.
authors.forename: Guofang
authors.initials: G
authors.lastname: Shen
mesh_terms: D000818:Animals; D000844:Ankylosis / Q000209:etiology*; D002356:Cartilage / Q000293:injuries*; D008297:Male; D008335:Mandibular Condyle / Q000601:surgery; D051379:Mice; D013704:Temporomandibular Joint / Q000473:pathology; D013705:Temporomandibular Joint Disorders / Q000209:etiology*; D055114:X-Ray Microtomography
keywords: Condylar cartilage; Temporomandibular joint ankylosis; Traumatic