title: Collagen in histologic stages of oral submucous fibrosis: A polarizing microscopic study.
abstract: BACKGROUND
  Oral submucous fibrosis (OSF) is a precancerous condition in which there is excessive deposition of collagen in connective tissue. The purpose of present study was to compare changes in birefringence of collagen fibers in histopathological stages of OSF.
  
  
  METHODS
  Collagen in connective tissue of 91 cases of OSF was studied by staining 5 μm thick sections with picrosirius red. The polarization colors of thin (0.8 μm or less) and thick (1.6-2 μm) collagen fibers were recorded.
  
  
  RESULTS
  The birefringence of thin collagen fibers showed no difference in both histopathological connective tissue stages and degrees of epithelial dysplasia. The polarization colors of thick collagen fibers showed a gradual change from predominantly yellow-orange to greenish-yellow in advancing connective tissue stages and degrees of epithelial dysplasia.
  
  
  CONCLUSIONS
  The results of present study show a significant change in birefringence of collagen between connective tissue stages and between mild, moderate to severe degree of epithelial dysplasia. This change in birefringence colors and arrangement of collagen fibers may give an implication of impending neoplastic change in OSF.
authors.affiliation: Department of Oral Pathology, Sri Siddhartha Dental College and Hospital, Agalakote, Tumkur, India.
authors.forename: Kokila
authors.initials: K
authors.lastname: Ganganna
authors.forename: Pushparaja
authors.initials: P
authors.lastname: Shetty
authors.forename: Sarosh Edulji
authors.initials: SE
authors.lastname: Shroff