title: Mass spectrometry analysis of gingival crevicular fluid in the presence of external root resorption.
abstract: BACKGROUND
  In this study, we used liquid chromatography-mass spectrometry (LC-MS) to investigate the differences in the composition of gingival crevicular fluid between resorbing deciduous molars and nonresorbing permanent teeth. The main goal was to identify novel biomarkers associated with root resorption.
  
  
  METHODS
  Eleven children (4 boys, 7 girls) in the mixed dentition were selected to participate in this split-mouth design study, in which a deciduous second molar with radiographic evidence of root resorption served as the experimental site, and the permanent first molar on the contralateral quadrant was the control site. Gingival crevicular fluid was collected using absorbing strips. A total of 22 samples (11 root resorption, 11 control) were each analyzed with 1-dimensional LC-MS. The remaining samples were then pooled across the 11 patients and analyzed by 2-dimensional LC-MS. The output files were converted to mascot generic format, which can be used to perform protein identification with conventional search engines.
  
  
  RESULTS
  The 2-dimensional LC-MS protocol was able to identify 2789 and 2421 proteins in the control and resorption pooled samples, respectively. In this population, we detected significantly upregulated and downregulated proteins in the teeth with root resorption. Interestingly, many of these proteins are characteristically found in exosomes.
  
  
  CONCLUSIONS
  We identified novel proteins that might prove to be useful biomarkers of root resorption, individually or as part of a panel.
authors.affiliation: Assistant professor, Department of Orthodontics, College of Dentistry, University of Florida, Gainesville, Fla. Electronic address: wrody@dental.ufl.edu.
authors.forename: Wellington J
authors.initials: WJ
authors.lastname: Rody
authors.affiliation: Associate professor, Department of Orthodontics, College of Dentistry, and Department of Anatomy and Cell Biology, College of Medicine, University of Florida, Gainesville, Fla.
authors.forename: L Shannon
authors.initials: LS
authors.lastname: Holliday
authors.affiliation: Associate professor, Department of Periodontology, College of Dentistry, University of Florida, Gainesville, Fla.
authors.forename: Kevin P
authors.initials: KP
authors.lastname: McHugh
authors.affiliation: Associate professor, Department of Periodontology, College of Dentistry, University of Florida, Gainesville, Fla.
authors.forename: Shannon M
authors.initials: SM
authors.lastname: Wallet
authors.affiliation: Bioinformatics specialist, Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Victor
authors.initials: V
authors.lastname: Spicer
authors.affiliation: Assistant professor, Department of Internal Medicine, University of Manitoba; senior scientist, Manitoba Center for Proteomics and Systems Biology, Winnipeg Manitoba, Canada.
authors.forename: Oleg
authors.initials: O
authors.lastname: Krokhin
mesh_terms: D000418:Albumins / Q000032:analysis; D015415:Biomarkers / Q000032:analysis; D002648:Child; D002853:Chromatography, Liquid / Q000379:methods; D003818:Dentition, Mixed; D005260:Female; D005883:Gingival Crevicular Fluid / Q000737:chemistry*; D006801:Humans; D008297:Male; D008963:Molar / Q000378:metabolism; D011506:Proteins / Q000032:analysis; D012391:Root Resorption / Q000378:metabolism*; D053719:Tandem Mass Spectrometry / Q000379:methods; D014080:Tooth Exfoliation / Q000378:metabolism; D014094:Tooth, Deciduous / Q000378:metabolism
chemical_list: D000418:Albumins; D015415:Biomarkers; D011506:Proteins