title: The role of matrix metalloproteinases and cysteine-cathepsins on the progression of dentine erosion.
abstract: OBJECTIVE
  To evaluate in vitro the effect of the inhibition of endogenous dentinal enzymes (matrix metalloproteinases-MMPs and cysteine cathepsins-CCs) on dentine erosion.
  
  
  METHODS
  Dentine blocks (4mm×4mm×2mm) from sound human teeth were randomly divided into 7 groups (n=17) according to the treatment: MMP- and CC-inhibitor chlorhexidine digluconate (CHX, 10mM); MMP-inhibitor galardin (G, 0.2mM); specific cathepsin B inhibitor (CCB, 0.2mM); non-specific CC inhibitor (CCE-64, 0.5μM); fluoride (F, 1.23% NaF); placebo (P) and untreated (UT). Inhibitors were applied as gels once for 1min. Specimens were submitted to 5 days of pH cycling including the erosive challenge (Coke, pH 2.64, 90s/day) and remineralisation (artificial saliva). Demineralised organic surface loss was determined profilometrically. Demineralised organic matrix (DOM) was removed with collagenase and the profile was re-evaluated in the absence of collagen fibrils. The differences in profilometric results and DOM thickness among the groups were analysed with ANOVA and Tukey's test (p<0.05).
  
  
  RESULTS
  Loss of demineralised tissue (μm, mean±SD) was: CHX 8.4±1.7 b, G 8.6±1.9 b, CCB 9.6±1.4 a, CCE-64 9.9±1.3 a, F 9.9±1.7 a, P 10.9±2.2 a, UT 11.0±1.5 a. Loss of mineralised tissue was: CHX 15.4±2.2 b, G 16.0±1.8 b, CCB 17.6±2.4 a, CCE-64 17.6±2.0 a, F 17.3±2.8 a, P 19.1±2.1 a, UT 18.9±2.4 a. MMP-inhibitors significantly reduced organic matrix and mineral loss in comparison to all the other groups (p<0.05). No statistically significant differences were found in the thickness of the remaining DOM (p=0.845).
  
  
  CONCLUSIONS
  Dentine endogenous MMPs seem to be the main enzymes responsible for DOM loss and erosion.
authors.affiliation: Bauru School of Dentistry, University of São Paulo, Department of Oral Biology, 9-75 Al. Octávio Pinheiro Brisolla, Bauru, SP 17012-901, Brazil.
authors.forename: B L
authors.initials: BL
authors.lastname: Zarella
authors.affiliation: Bauru School of Dentistry, University of São Paulo, Department of Oral Biology, 9-75 Al. Octávio Pinheiro Brisolla, Bauru, SP 17012-901, Brazil.
authors.forename: C A B
authors.initials: CA
authors.lastname: Cardoso
authors.affiliation: Bauru School of Dentistry, University of São Paulo, Department of Oral Biology, 9-75 Al. Octávio Pinheiro Brisolla, Bauru, SP 17012-901, Brazil.
authors.forename: V T
authors.initials: VT
authors.lastname: Pelá
authors.affiliation: University of Sagrado Coração, Department of Dentistry, 10-50 Irmã Arminda ST, Bauru, SP 17011-160, Brazil.
authors.forename: M T
authors.initials: MT
authors.lastname: Kato
authors.affiliation: Institute of Dentistry, University of Oulu, and Medical Research Center Oulu, Oulu University Hospital, PO Box 5281, 90014 Oulu, Finland.
authors.forename: L
authors.initials: L
authors.lastname: Tjäderhane
authors.affiliation: Bauru School of Dentistry, University of São Paulo, Department of Oral Biology, 9-75 Al. Octávio Pinheiro Brisolla, Bauru, SP 17012-901, Brazil. Electronic address: mbuzalaf@fob.usp.br.
authors.forename: M A R
authors.initials: MA
authors.lastname: Buzalaf
mesh_terms: D002403:Cathepsins / Q000037:antagonists & inhibitors*; D002710:Chlorhexidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D003545:Cysteine / Q000037:antagonists & inhibitors*; D003804:Dentin / Q000187:drug effects; D004151:Dipeptides / Q000494:pharmacology*; D018450:Disease Progression; D006801:Humans; D066298:In Vitro Techniques; D061965:Matrix Metalloproteinase Inhibitors / Q000494:pharmacology*; D020782:Matrix Metalloproteinases / Q000502:physiology*; D008964:Molar, Third; D011897:Random Allocation; D012969:Sodium Fluoride / Q000494:pharmacology*; D014077:Tooth Erosion / Q000517:prevention & control*
chemical_list: D004151:Dipeptides; D061965:Matrix Metalloproteinase Inhibitors; C078131:N-(2(R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl)-L-tryptophan methylamide; D012969:Sodium Fluoride; D002403:Cathepsins; D020782:Matrix Metalloproteinases; D003545:Cysteine; C010882:chlorhexidine gluconate; D002710:Chlorhexidine
keywords: Cystein cathepsins; Dentine; Erosion; Inhibitors; Matrix metalloproteinases