title: Long-term stability of dentin matrix following treatment with various natural collagen cross-linkers.
abstract: OBJECTIVE
  Collagen disorganization is one of the main degradation patterns found in unsuccessful adhesive restorations. The hypothesis of this study was that pretreatment using natural collagen cross-linking agents rich in proanthocyanidin (PA) would improve mechanical properties and stability over time of the dentin collagen and, thus, confer a more resistant and lasting substrate for adhesive restorations.
  
  
  METHODS
  PA-based extracts, from grape seed (GSE), cocoa seed (CSE), cranberry (CRE), cinnamon (CNE) and açaí berry (ACE) were applied over the demineralized dentin. The apparent elastic modulus (E) of the treated dentin collagen was analyzed over a 12 month period. Specimens were immersed in the respective solution and E values were obtained by a micro-flexural test at baseline, 10, 30, 60, 120 and 240 min. Samples were stored in artificial saliva and re-tested after 3, 6 and 12 months. Data was analyzed using ANOVA and Tukey test.
  
  
  RESULTS
  GSE and CSE extracts showed a time-dependent effect and were able to improve [240 min (MPa): GSE = 108.96 ± 56.08;CSE = 59.21 ± 24.87] and stabilize the E of the organic matrix [12 months (MPa): GSE = 40.91 ± 19.69;CSE = 42.11 ± 13.46]. CRE and CNE extracts were able to maintain the E of collagen matrices constant over 12 months [CRE = 11.17 ± 7.22;CNE = 9,96 ± 6.11;MPa]. ACE (2.64 ± 1.22 MPa) and control groups immersed in neat distilled water (1.37 ± 0.69 MPa) and ethanol-water (0.95 ± 0.33 MPa) showed no effect over dentin organic matrix and enable their degradation and reduction of mechanical properties.
  
  
  CONCLUSIONS
  Some PA-based extracts were capable of improving and stabilizing collagen matrices through exogenous cross-links induction.
authors.affiliation: Department of Dental Materials, University of Sao Paulo, Av. Professor Lineu Prestes 2227, 0508-000 Sao Paulo, Brazil. carina@usp.br
authors.forename: Carina Strano
authors.initials: CS
authors.lastname: Castellan
authors.forename: Ana Karina
authors.initials: AK
authors.lastname: Bedran-Russo
authors.forename: Sachin
authors.initials: S
authors.lastname: Karol
authors.forename: Patrícia Nóbrega Rodrigues
authors.initials: PN
authors.lastname: Pereira
mesh_terms: D001688:Biological Products / Q000737:chemistry*; D032701:Biomimetics; D003094:Collagen / Q000737:chemistry* / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000737:chemistry*; D003738:Dental Cements / Q000737:chemistry / Q000378:metabolism; D003793:Dental Restoration, Permanent; D003804:Dentin / Q000737:chemistry* / Q000378:metabolism; D055119:Elastic Modulus; D010936:Plant Extracts / Q000737:chemistry; D044945:Proanthocyanidins / Q000737:chemistry; D012463:Saliva / Q000378:metabolism; D013997:Time Factors
chemical_list: D001688:Biological Products; D003432:Cross-Linking Reagents; D003738:Dental Cements; D010936:Plant Extracts; D044945:Proanthocyanidins; C013221:proanthocyanidin; D003094:Collagen