title: Solubility study of phytochemical cross-linking agents on dentin stiffness.
abstract: OBJECTIVE
  The effects of interactions between cross-linking proanthocyanidins (PA) in polar solvents and type-I collagen of demineralized dentin were investigated.
  
  
  METHODS
  Three PA-rich extracts, two from grape seed (GSEP and GSES) and one from cocoa (COE), were dissolved (water, ethanol:water and acetone:water) and analyzed for their ability to increase the modulus of elasticity of demineralized dentin. Sound dentin beams (0.5mmx1.7mmx7mm) were fully demineralized and divided into 12 groups according to the type of cross-linking agent and solvents used. Specimens were immersed in the respective solutions and tested at baseline, 10, 30, 60, 120 and 240min.
  
  
  RESULTS
  The elastic modulus (EM) of dentin was significantly increased by the PA treatment regardless of time (p<0.05 for all times). The extracts showed different solubility in different solvents. GSEP showed the highest increase in EM when diluted in distilled water and acetone at all exposure times. Both GSEs showed superior results when diluted in distilled water and after 4h of treatment, while COE produced strongest enhancement when dissolved in ethanol:water.
  
  
  CONCLUSIONS
  The results indicates that herbal extraction process and other pharmacognostic parameters have an important influence on extract solubility as well as constitution and, consequently, on the PA-dentin matrix interaction.
authors.affiliation: Department of Dental Materials, University of Sao Paulo, Avenida Prof. Lineu Prestes 2227, Cidade Universitaria, 05508-000 Sao Paulo, Brazil. carina@usp.br <carina@usp.br>
authors.forename: Carina Strano
authors.initials: CS
authors.lastname: Castellan
authors.forename: Patricia N R
authors.initials: PN
authors.lastname: Pereira
authors.forename: Grace
authors.initials: G
authors.lastname: Viana
authors.forename: Shao-Nong
authors.initials: SN
authors.lastname: Chen
authors.forename: Guido F
authors.initials: GF
authors.lastname: Pauli
authors.forename: Ana Karina
authors.initials: AK
authors.lastname: Bedran-Russo
mesh_terms: D024042:Collagen Type I / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D003799:Dental Stress Analysis; D003804:Dentin / Q000737:chemistry* / Q000473:pathology; D055119:Elastic Modulus; D006801:Humans; D008422:Materials Testing; D010936:Plant Extracts / Q000737:chemistry*; D044945:Proanthocyanidins / Q000737:chemistry*; D012995:Solubility; D017001:Tooth Demineralization
chemical_list: D024042:Collagen Type I; D003432:Cross-Linking Reagents; D010936:Plant Extracts; D044945:Proanthocyanidins