title: [The responses of the microvasculature of the periodontal ligament to horizontal force].
abstract: OBJECTIVE
  The purpose of this study is to examine the responses of the microvasculature in periodontal ligament(PDL) to horizontal force.
  
  
  METHODS
  Using ink injections and celloidin embed, serial sections were cut, then observed by light micrascope, quantitative analysis was conducted by the picture-analysis instrument. Vascular corrosion casts were prepared and examined by scanning electron microscopy. The forth premolars of dogs were pulled by 200 g force in a mesial direction for two hours, and the pressure effects in different positions were demonstrated.
  
  
  RESULTS
  The section area of the microvasculature per unit PDL area is obvious larger on the tension sides than on the pressure sides. There is not an obvious distinction on the pressure sides between the experiment groups and control groups. However, there are clear distinctions in the one-third of cervical, and apical segment on the tension sides between the experiment groups and control groups.
  
  
  CONCLUSIONS
  The microvascular changes in PDL had importance to the cushioning effect of PDL when a teeth received a kind of force in a short-time.
authors.affiliation: Affiliated Stomatology Hospital of China Medical University, Shenyang 110002.
authors.forename: Y
authors.initials: Y
authors.lastname: He
authors.forename: J
authors.initials: J
authors.lastname: Xu
authors.forename: Y
authors.initials: Y
authors.lastname: Deng
mesh_terms: D000818:Animals; D004285:Dogs; D008833:Microcirculation; D008855:Microscopy, Electron, Scanning; D010513:Periodontal Ligament / Q000098:blood supply* / Q000648:ultrastructure; D013314:Stress, Mechanical