title: A first study on the usefulness of matrix metalloproteinase 9 from dentinal fluid to indicate pulp inflammation.
abstract: BACKGROUND
  Pulpal diagnostics might be improved by using molecular markers found in dentinal fluid. In the current pilot study, we tested whether matrix metallopeptidase 9 (MMP-9) levels in dentinal fluid were detectable and differed between pulps from symptomatic teeth diagnosed with irreversible pulpitis and healthy counterparts.
  
  
  METHODS
  Thirty-one patients participated; 19 were diagnosed with irreversible pulpitis, and 12 were in need of replacement of a filling close to the pulp space in a clinically healthy tooth. Dentinal fluid was collected during a period of 2 minutes from dentin cavities by using folded polyvinylidene difluoride (PVDF) membranes, which were then transferred to microcentrifugation tubes containing physiologic saline solution. Total MMP-9 levels in these solutions were assessed by using a human MMP-9 fluorescent assay, detection limit 0.25 ng/mL. MMP-9 levels between groups were compared by using Mann-Whitney U test (alpha <0.05).
  
  
  RESULTS
  Three specimens from the symptomatic teeth were not included because coronal pulps proved to be necrotic on access. Dentinal fluid samples from symptomatic teeth had significantly higher MMP-9 levels than those from clinically healthy counterparts (P < .05). However, merely 7 of the 16 pulpitis samples contained detectable levels of MMP-9. None of the clinically healthy control specimens contained any detectable amounts of MMP-9.
  
  
  CONCLUSIONS
  With a sensitive assay, it was possible to detect an enzyme linked with pulp tissue destruction (MMP-9) in dentinal fluid. However, the collection method needs to be improved to provide predictable fluid yields. Longitudinal studies should be performed to assess the predictive value of molecular markers in dentinal fluid on pulpal pathosis.
authors.affiliation: Division of Preventive Dentistry, Periodontology, and Cariology, University of Zürich Center of Dental Medicine, Zürich, Switzerland. matthias.zehnder@zzmk.uzh.ch
authors.forename: Matthias
authors.initials: M
authors.lastname: Zehnder
authors.forename: Florian J
authors.initials: FJ
authors.lastname: Wegehaupt
authors.forename: Thomas
authors.initials: T
authors.lastname: Attin
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D019234:Dentinal Fluid / Q000201:enzymology*; D005260:Female; D006801:Humans; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008875:Middle Aged; D010865:Pilot Projects; D011671:Pulpitis / Q000175:diagnosis / Q000201:enzymology*; D012016:Reference Values; D016037:Single-Blind Method; D018709:Statistics, Nonparametric; D055815:Young Adult
chemical_list: D015415:Biomarkers; D020780:Matrix Metalloproteinase 9