title: [Comparison of the effectiveness of two types of filter papers on gingival crevicular fluid collection].
abstract: OBJECTIVE
  To compare the effectiveness of whatman3MM chromatographic filter paper and whatman3# qualitative filter paper on gingival crevicular fluid collection and protein extraction,in order to provide the evidence of using appropriate filter paper for collection of gingival crevicular fluid in clinical researches.
  
  
  METHODS
  Whatman3MM chromatographic filter paper was used in group A and whatman3# qualitative filter paper in group B. Both types of filter papers were clipped into 2mm±8mm strips, then added into 15 incremental volumes of the fuchsine solution with serum, respectively, and each volume was repeated for 4 times. The length of infiltration on each filter paper was measured. Both groups were added into 5 incremental volumes of normal human serum separately and each volume was repeated for five times. The concentration of total protein in the extraction liquid of each group was measured. Both two groups were added into 5 incremental concentrations of 1μL normal human serum which were diluted to the corresponding multiples with 0.9% NaCl solution, and each concentration was repeated for 5 times. SPSS17.0 software package was used to conduct statistical analysis.
  
  
  RESULTS
  The linear relation between the length of infiltration and volume of the solution were good and significant difference (P<0.05) was found between the two groups. With the exception of 0.1μL,the lengths of infiltration in group A were all larger than that in group B. No significant difference (P>0.05) was found in two groups when considering the protein extraction yield.
  
  
  CONCLUSIONS
  The two filter papers were both effective to measure the volume of gingival crevicular fluid which was collected according to its infiltration length on the paper. When there was a large volume of gingival crevicular fluid, Whatman3# qualitative filter paper was more applicable than whatman3MM chromatographic filter paper. However, no significant difference was found between the two filter papers in consideration of protein extraction.
authors.affiliation: Department of Prosthodontics, Shanghai Jiao Tong University School of Medicine, Shanghai, China. he_yan_ping@hotmail.com
authors.forename: Yan-ping
authors.initials: YP
authors.lastname: He
authors.forename: Ming
authors.initials: M
authors.lastname: Xie
authors.forename: Ting
authors.initials: T
authors.lastname: Jiao
authors.forename: Li-ping
authors.initials: LP
authors.lastname: Chen
mesh_terms: D005883:Gingival Crevicular Fluid; D006801:Humans; D013048:Specimen Handling