title: Is the inactivation of dentin proteases by crosslinkers reversible?
abstract: Inactivation of dentin proteases by crosslinkers has been suggested as a way to prevent the degradation of dentin collagen in the hybrid layer. However, it is not known if the inhibition is reversible. The aim of this study was to evaluate the inactivation effect of various crosslinkers on dentin protease activity over a period of 6 months.
  
  
  
  Demineralized dentin beams (1×2×6mm, n=10/group) were treated with (1) 1% glutaraldehyde (GA1), (2) 5% glutaraldehyde (GA5), (3) 1% grape seed extract (GS1), (4) 5% grape seed extract (GS5), (5) 10% sumac berry extract (S), (6) 20μM curcumin (CR20), and (7) 200μM curcumin (CR200) for 5min. Untreated beams served as control. The beams were incubated up to 6 months and incubation media were used to analyze solubilized telopeptide (ICTP and CTX) fragments as indicators of MMP- and cathepsin K-mediated degradation after 1, 3 and 6 months of incubation. The relative MMP activity of dentin beams was tested using a generic MMP assay. Data were analyzed using repeated-measures ANOVA, α=0.05.
  
  
  
  All treated groups showed significant decrease in CTX release (32.2-469.5pg/mg dentin) and ICTP (1.8-47.6ng/mg dentin) fragments during the first month of incubation compared to control (1159pg/mg and 72.9ng/mg dentin, respectively). GA5, GS5 and CR200 maintained their inhibitory effect during 6-month incubation. The results were confirmed by dry mass loss and relative MMP activity following 6 months.
  
  
  
  The results of this study indicate that the long-term effect is both crosslinker and dose dependent.
authors.affiliation: Finnish Doctoral Program in Oral Sciences (FINDOS), University of Turku, Institute of Dentistry, Turku, Finland; Department of Restorative Dentistry, and Cariology, and Adhesive Dentistry Research Group, Institute of Dentistry, University of Turku, Finland. Electronic address: dirose@utu.fi.
authors.forename: Roda
authors.initials: R
authors.lastname: Seseogullari-Dirihan
authors.affiliation: Department of Restorative Dentistry, and Cariology, and Adhesive Dentistry Research Group, Institute of Dentistry, University of Turku, Finland; Turku University Hospital, TYKS, University of Turku, Turku, Finland.
authors.forename: Mustafa Murat
authors.initials: MM
authors.lastname: Mutluay
authors.affiliation: School of Dentistry, Georgia Regents University, Augusta, GA, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Pashley
authors.affiliation: Department of Restorative Dentistry, and Cariology, and Adhesive Dentistry Research Group, Institute of Dentistry, University of Turku, Finland; Turku University Hospital, TYKS, University of Turku, Turku, Finland.
authors.forename: Arzu
authors.initials: A
authors.lastname: Tezvergil-Mutluay
mesh_terms: D003094:Collagen; D003804:Dentin / Q000201:enzymology*; D005976:Glutaral; D020782:Matrix Metalloproteinases; D010447:Peptide Hydrolases / Q000378:metabolism*
chemical_list: D003094:Collagen; D010447:Peptide Hydrolases; D020782:Matrix Metalloproteinases; D005976:Glutaral
keywords: Crosslinkers; Cysteine cathepsins; Degradation; Dentin; Matrix metalloproteinases