title: Qualitative Analysis of Collagen Fibers in Oral Submucous Fibrosis using Picrosirius Red Stain and Polarising Microscope.
abstract: BACKGROUND
  Oral Submucous Fibrosis (OSMF) is an oral potentially malignant condition caused predominantly by areca nut chewing. Early recognition with accurate staging of the disease and appropriate treatment planning is of utmost importance to prevent the malignant transformation and to improve the quality of life of the patient. Picrosirius red stain is specific for collagen and enhances its birefringence under polarising light producing different colours in different stages of the disease.
  
  
  OBJECTIVE
  To compare the clinical and functional staging with histopathologic staging methods used to assess the severity of OSMF and to perform a qualitative analysis of the collagen fibres in various histopathologic stages of OSMF using picrosirius red stain and polarising microscope.
  
  
  METHODS
  It is a retrospective study done on archival samples. The study sample included a total of 30 cases which was divided into two groups. Group I comprised of 20 OSMF samples and Group II comprised of 10 normal tissue samples. Clinical, functional and histopathological staging was performed for all OSMF samples. Comparative analysis between clinical and functional stages with the histopathological staging was done using chi square test. Picrosirius red- stained sections of OSMF were analysed using polarising microscopy to evaluate the qualitative changes in the collagen fibers.
  
  
  METHODS
  Descriptive data which includes frequency and percentages were calculated for each group. Categorical data were analysed by chi-square test. A p-value of 0.05 or less was considered statistically significant.
  
  
  RESULTS
  Comparative analysis between clinical and functional stages with the histopathological staging revealed a significant correlation (p < 0.05) between the functional and histopathological stage. Enhanced birefringence of the collagen fibers due to picrosirius red stain yielded characteristic prominent polarising colours in different stages of OSMF.
  
  
  CONCLUSIONS
  Comparison of functional staging with histopathologic grading is more reliable in determining the severity of the disease than the clinical staging. Production of characteristic polarising colours by various stages of picrosirius red stained sections of OSMF substantiates the use of picrosirius red stain and polarising microscope as a tool in assessing the severity of this condition thereby aiding in better treatment planning.
authors.affiliation: Reader, Department of Oral Pathology and Microbiology, Thai Moogambigai Dental College and Hospital , Chennai, India .
authors.forename: T
authors.initials: T
authors.lastname: Radhika
authors.affiliation: Former Undergraduate Student, Faculty of Dental Sciences, Sri Ramachandra University , Chennai, India .
authors.forename: Preethi
authors.initials: P
authors.lastname: Sekaran
authors.affiliation: Professor and Head, Department of Oral Pathology and Microbiology, Faculty of Dental Sciences, Sri Ramachandra University , Chennai, India .
authors.forename: Malathi
authors.initials: M
authors.lastname: Narasimhan
keywords: Clinical; Functional; Histopathological staging; Polarising microscopy