title: Effect of proanthocyanidin incorporation into dental adhesive resin on resin-dentine bond strength.
abstract: OBJECTIVE
  This study evaluated the effect of proanthocyanidin (PA) incorporation into experimental dental adhesives on resin-dentine bond strength.
  
  
  METHODS
  Four experimental hydrophilic adhesives containing different PA concentrations were prepared by combining 50wt% resin comonomer mixtures with 50wt% ethanol. Proanthocyanidin was added to the ethanol-solvated resin to yield three adhesives with PA concentrations of 1.0, 2.0 and 3.0wt%, respectively. A PA-free adhesive served as the control. Flat dentine surfaces from 40 extracted third molars were etched with 32% phosphoric acid. The specimens were randomly assigned to one of the four adhesive groups. Two layers of one of the four experimental adhesives were applied to the etched dentine and light-cured for 20s. Composite build-ups were performed using Filtek Z250 (3M ESPE). After storage in distilled water at 37°C for 24h, twenty-four bonded teeth were sectioned into 0.9 mm×0.9 mm beams and stressed to failure under tension for bond strength testing. Bond strength data were evaluated by one-way ANOVA and Tukey's test (α=0.05). Interfacial nanoleakage was examined in the remaining teeth using a field-emission scanning electron microscope and analysed using the Chi-square test (α=0.05).
  
  
  RESULTS
  No significant difference in bond strength was found amongst PA-free, 1% and 2% PA adhesives. However, incorporation of 3% PA into the adhesive significantly lowered bond strength as demonstrated by a greater number of adhesive failures and more extensive nanoleakage along the bonded interface.
  
  
  CONCLUSIONS
  Incorporation of 2% proanthocyanidin into dental adhesives has no adverse effect on dentine bond strength.
  
  
  CONCLUSIONS
  The addition of proanthocyanidin to an experimental adhesive has no adverse effect on the immediate resin-dentine bond strength when the concentration of proanthocyanidin in the adhesive is less than or equal to 2%.
authors.affiliation: Paediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital, 34 Hospital Road, Pokfulam, Hong Kong SAR, China.
authors.forename: D J
authors.initials: DJ
authors.lastname: Epasinghe
authors.forename: C K Y
authors.initials: CK
authors.lastname: Yiu
authors.forename: M F
authors.initials: MF
authors.lastname: Burrow
authors.forename: F R
authors.initials: FR
authors.lastname: Tay
authors.forename: N M
authors.initials: NM
authors.lastname: King
mesh_terms: D010129:4-Aminobenzoic Acid / Q000737:chemistry; D000134:Acid Etching, Dental / Q000379:methods; D000268:Adhesiveness; D000975:Antioxidants / Q000737:chemistry*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods*; D003763:Dental Leakage / Q000145:classification; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure*; D000431:Ethanol / Q000737:chemistry; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D010756:Phosphoric Acids / Q000737:chemistry; D044945:Proanthocyanidins / Q000737:chemistry*; D019279:Resin Cements / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013314:Stress, Mechanical; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000975:Antioxidants; D003188:Composite Resins; D003432:Cross-Linking Reagents; C444701:Filtek Z250; D008689:Methacrylates; D010756:Phosphoric Acids; D044945:Proanthocyanidins; D019279:Resin Cements; D012997:Solvents; D014867:Water; C013221:proanthocyanidin; D000431:Ethanol; D017438:Bisphenol A-Glycidyl Methacrylate; C026575:2-hydroxyethyl methacrylate phosphate; C005044:hydroxyethyl methacrylate; C030242:phosphoric acid; D010129:4-Aminobenzoic Acid