title: Effect of ultraviolet A-induced crosslinking on dentin collagen matrix.
abstract: OBJECTIVE
  The aim of this study was to evaluate the effect of using UVA-induced crosslinking with or without riboflavin as photosensitizers on degradation of dentin matrix by dentin proteases.
  
  
  METHODS
  Demineralized dentin specimens (0.4×3×6 mm(3), n=10/group) were subjected to: (RP1), 0.1% riboflavin-5 phosphate/UVA for 1 min; (RP5), 0.1% riboflavin-5 phosphate/UVA for 5 min; (R1), 0.1% riboflavin/UVA for 1 min; (R5), 0.1% riboflavin-UVA for 5 min; (UV1), UVA for 1 min; (UV5), UVA for 5 min. Specimens were incubated in 1 mL zinc and calcium containing media for 1 day and 1 week. An untreated group served as control (CM). After incubation, the loss of dry mass of samples was measured and aliquots of media were analyzed for the release of C-terminal fragment telopeptide (ICTP vs. CTX) of collagen to evaluate for cathepsin K (CA-K) and total matrix metalloproteinase (MMP)-mediated degradation. Data were analyzed using repeated measures ANOVA at α=0.05.
  
  
  RESULTS
  Although UVA radiation alone reduced dentin degradation, UVA-activated riboflavin or riboflavin-5 phosphate inhibited MMP and CA-K activities more than UVA alone. The effects of crosslinking were more pronounced in 7-day samples; only with CA-K were the effects of crosslinking with or without photosensitizer significantly different from controls in 1-day samples.
  
  
  CONCLUSIONS
  The use of bioactive forms (RP) or longer treatment time did not result with better effect. The use of UVA crosslinking reduces dentin matrix degradation, especially with photosensitizers.
authors: Finnish Doctoral Program in Oral Sciences (FINDOS), University of Turku, Institute of Dentistry, Turku, Finland; Adhesive Dentistry Research Group, Institute of Dentistry, University of Turku, Turku, Finland. Electronic address: dirose@utu.fi.
authors: Roda
authors: R
authors: Seseogullari-Dirihan
authors: Institute of Dentistry, University of Oulu, and Medical Research Center, Oulu University Hospital and University of Oulu, Oulu, Finland; Department of Oral and Maxillofacial Diseases, University of Helsinki, and Helsinki University Hospital, Helsinki, Finland.
authors: Leo
authors: L
authors: Tjäderhane
authors: School of Dentistry, Georgia Regents University, Augusta, GA, USA.
authors: David H
authors: DH
authors: Pashley
authors: Adhesive Dentistry Research Group, Institute of Dentistry, University of Turku, Turku, Finland; Institute of Dentistry, University of Turku, Turku University Hospital, TYKS, University of Turku, Kiinamyllynkatu 4-8, 20520, Turku, Finland.
authors: Arzu
authors: A
authors: Tezvergil-Mutluay
mesh_terms: D002403:Cathepsins / Q000378:metabolism; D024043:Collagen Type II / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D003804:Dentin / Q000187:drug effects / Q000528:radiation effects*; D008422:Materials Testing; D020782:Matrix Metalloproteinases / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism; D017319:Photosensitizing Agents / Q000494:pharmacology*; D012256:Riboflavin / Q000494:pharmacology*; D013499:Surface Properties; D014466:Ultraviolet Rays
chemical_list: C000590554:C-terminal cross-linking telopeptide of type II collagen, human; D024043:Collagen Type II; D003432:Cross-Linking Reagents; D010446:Peptide Fragments; D017319:Photosensitizing Agents; D002403:Cathepsins; D020782:Matrix Metalloproteinases; D012256:Riboflavin
keywords: Collagen matrices; Crosslinking; Dentin; Riboflavin