title: The effect of proanthocyanidin-containing 10% phosphoric acid on bonding properties and MMP inhibition.
abstract: OBJECTIVE
  This study evaluated the effect of etching using 2% proanthocynidin-containing 10% phosphoric acid 2% PA/10% PhA vs. 35% phosphoric acid 35% PhA on immediate (IM) and 6-months (6M) resin-enamel microshear bond strength (μSBS), resin-dentin microtensile bond strength (μTBS), nanoleakage (NL) and as well as in situ MMP inhibition potential.
  
  
  METHODS
  The dentin surface of human were exposed and then etched using 35% phosphoric acid for 15s or 2% PA/10% phosphoric acid for 30s. After rinsing with water, the dentin was bonded with Single Bond Plus (3M ESPE) and composite build-ups were constructed, followed by polymerization. The teeth were sectioned and the bonds were testing for microtensile bond strength (μTBS) and by SEM for NL analysis at IM and 6M. For MMP activity, resin-dentin slices were prepared for in situ zymography, and analyzed under confocal microscopy. For μSBS, others teeth had flattened enamel surfaces etched according the experimental groups and prepared to microshear procedure. The specimens were tested IM and after 6M by microshear bond strength. The data were submitted to two-way repeated measures ANOVA and Tukey's test (α=0.05).
  
  
  RESULTS
  Acid-etching using the 2% PA/10% phosphoric acid did not lower the μTBS in IM (p>0.05) compared to the control 35% phosphoric acid group. However, after 6M, only the 2% PA/10% PhA etched dentin had remained stable the resin-dentin bond strength (p<0.05). Bonds made with 35% PhA showed significant increase in NL% after 6M (p<0.05). Dentin bonds made with 2% PA/10% phosphoric acid showed no increase in NL% after 6 months. The MMP activity within the resin-dentin interface was almost completely reduced after 2% PA/10% PhA etching, while the 35% PhA exhibited intense MMP activity. For μSBS, the type of etchant and the storage period did not affect the resin-enamel bond strengths (p>0.05).
  
  
  CONCLUSIONS
  Ten percent phosphoric acid containing 2% PA can produce stable resin-dentin and enamel-resin interfaces, without requiring additional steps in the bonding procedure. Future studies for longer evaluation time are required.
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, State University of Ponta Grossa, Paraná, Brazil; Department of Oral & Craniofacial Sciences, University of Missouri Kansas City, Kansas City, MO, USA.
authors.forename: Viviane
authors.initials: V
authors.lastname: Hass
authors.affiliation: Dentistry Academic Unit, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Issis
authors.initials: I
authors.lastname: Luque-Martinez
authors.affiliation: Department of Biomaterials, School of Dentistry, Universidad Val Paraíso, Valparaíso, Chile.
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Muñoz
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, State University of Ponta Grossa, Paraná, Brazil; Institute for Research in Dental Sciences, Faculty of Odontology, University of Chile, Chile.
authors.forename: Mario Felipe Gutierrez
authors.initials: MF
authors.lastname: Reyes
authors.affiliation: Department of Dental Materials, Piracicaba Dental School, Piracicaba, São Paulo, Brazil.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Abuna
authors.affiliation: Department of Dental Materials, Piracicaba Dental School, Piracicaba, São Paulo, Brazil.
authors.forename: Mario Alexandre Coelho
authors.initials: MA
authors.lastname: Sinhoreti
authors.affiliation: Department of Oral & Craniofacial Sciences, University of Missouri Kansas City, Kansas City, MO, USA.
authors.forename: Alex Yi
authors.initials: AY
authors.lastname: Liu
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, State University of Ponta Grossa, Paraná, Brazil.
authors.forename: Alessandro D
authors.initials: AD
authors.lastname: Loguercio
authors.affiliation: Department of Oral & Craniofacial Sciences, University of Missouri Kansas City, Kansas City, MO, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, State University of Ponta Grossa, Paraná, Brazil. Electronic address: reis_ale@hotmail.com.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Reis
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D017438:Bisphenol A-Glycidyl Methacrylate; D003763:Dental Leakage; D003804:Dentin / Q000737:chemistry* / Q000378:metabolism*; D057075:Enzyme Assays; D006801:Humans; D066298:In Vitro Techniques; D061965:Matrix Metalloproteinase Inhibitors / Q000494:pharmacology*; D008855:Microscopy, Electron, Scanning; D008964:Molar, Third; D010756:Phosphoric Acids / Q000737:chemistry* / Q000494:pharmacology*; D058105:Polymerization; D044945:Proanthocyanidins / Q000737:chemistry* / Q000494:pharmacology*; D033081:Shear Strength; D013718:Tensile Strength
chemical_list: D061965:Matrix Metalloproteinase Inhibitors; D010756:Phosphoric Acids; D044945:Proanthocyanidins; C115612:single bond; C013221:proanthocyanidin; D017438:Bisphenol A-Glycidyl Methacrylate
keywords: Acid etching; Crosslinking reagents; Demineralized dentin layer; Dentin collagen; MMPs; Proanthocyanidins