title: [The ultrastructure changes of nerve fibers in pressure side of periodontal ligament during orthodontic tooth movement in rats].
abstract: OBJECTIVE
  To observe the ultrastructure changes of nerve fibers in pressure side of periodontal ligament during orthodontic tooth movement (OTM) in rats.
  
  
  METHODS
  The left maxillary of fifteen rats molar was moved mesially by an appliance for 2 days, 1 week, 2 weeks and 3 weeks. The ultrastructure changes of nerve fibers in pressure side of the periodontal ligament in rats were observed with electron microscope.
  
  
  RESULTS
  The thick myelinated axon was degenerated after 2 days of OTM and not recovered after 3 weeks of OTM; the number of thin unmyelinated axons was increased after 2 days of OTM. It reached a maximum after 1 week of OTM and recovered after 3 weeks of OTM. Only part of thin unmyelinated was slightly degenerated. At the same time, some of the thin myelinated axons were slightly degenerated and partly demyelinated.
  
  
  CONCLUSIONS
  The nerve fibers were involved in periodontal tissue remodelling.
authors.affiliation: Department of Stomatology, Special Hospital of Guangdong Provincial Military Command, Guangzhou 510500, China.
authors.forename: C
authors.initials: C
authors.lastname: Fan
authors.forename: Y
authors.initials: Y
authors.lastname: Duan
authors.forename: X
authors.initials: X
authors.lastname: Li
mesh_terms: D000818:Animals; D008297:Male; D008854:Microscopy, Electron; D009412:Nerve Fibers / Q000648:ultrastructure*; D009970:Orthodontics; D010513:Periodontal Ligament / Q000648:ultrastructure*; D011312:Pressure; D051381:Rats; D017207:Rats, Sprague-Dawley; D014087:Tooth Movement Techniques