title: Collagen cross-linkers on dentin bonding: Stability of the adhesive interfaces, degree of conversion of the adhesive, cytotoxicity and in situ MMP inhibition.
abstract: To investigate the effect of collagen cross-links on the stability of adhesive properties, the degree of conversion within the hybrid layer, cytotoxicity and the inhibition potential of the MMPs' activity.
  
  
  
  The dentin surfaces of human molars were acid-etched and treated with primers containing: 6.5wt% proanthocyanidin, UVA-activated 0.1wt% riboflavin, 5wt% glutaraldehyde and distilled water for 60s. Following, dentin was bonded with Adper Single Bond Plus and Tetric N-Bond; and restored with resin composite. The samples were sectioned into resin-dentin "sticks" and tested for microtensile bond strength (μTBS) after immediate (IM) and 18-month (18M) periods. Bonded sticks at each period were used to evaluate nanoleakage and the degree of conversion (DC) under micro-Raman spectroscopy. The enzimatic activity (P1L10 cross-linkers, P1L22 MMPs' activities) in the hybrid layer was evaluated under confocal microscopy. The culture cell (NIH 3T3 fibroblast cell line) and MTT assay were performed to transdentinal cytotoxicity evaluation. Data from all tests were submitted to appropriate statistical analysis (α=0.05).
  
  
  
  All cross-linking primers reduced the degradation of μTBS compared with the control group after 18M (p>0.05). The DC was not affected (p>0.213). The NL increased after 18M for all experimental groups, except for proanthocyanidin with Single Bond Plus (p>0.05). All of the cross-link agents reduced the MMPs' activity, although this inhibition was more pronounced by PA. The cytotoxicity assay revealed reduced cell viability only for glutaraldehyde (p<0.001).
  
  
  
  Cross-linking primers used in clinically relevant minimized the time degradation of the μTBS without jeopardizing the adhesive polymerization, as well as reduced the collagenolytic activity of MMPs. Glutaraldeyde reduced cell viability significantly and should be avoided for clinical use.
authors.affiliation: Department of Postgraduate Program in Dentistry, CEUMA University, São Luis, MA, Brazil.
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 Virginia
authors.initials: IV
authors.lastname: Luque-Martinez
authors.affiliation: Institute for Research in Dental Sciences, Faculty of Odontology, University of Chile, Chile.
authors.forename: Mario Felipe
authors.initials: MF
authors.lastname: Gutierrez
authors.affiliation: Department of Dentistry, University Center of Triangulo, Uberlandia, Brazil.
authors.forename: Camila Guimarães
authors.initials: CG
authors.lastname: Moreira
authors.affiliation: Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
authors.forename: Valéria Bisinoto
authors.initials: VB
authors.lastname: Gotti
authors.affiliation: School of Dentistry, Federal University of Ceará, Fortaleza, CE, Brazil.
authors.forename: Victor Pinheiro
authors.initials: VP
authors.lastname: Feitosa
authors.affiliation: Biomaterials Department, King's College London Dental Institute, London, UK; Department of Operative Dentistry and Endodontology, University of Marburg, Marburg, Germany.
authors.forename: Garrit
authors.initials: G
authors.lastname: Koller
authors.affiliation: Department of Postgraduate Program in Dentistry, CEUMA University, São Luis, MA, Brazil.
authors.forename: Michel Fleith
authors.initials: MF
authors.lastname: Otuki
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, State University of Ponta Grossa, PR, Brazil. Electronic address: aloguercio@hotmail.com.
authors.forename: Alessandro D
authors.initials: AD
authors.lastname: Loguercio
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, State University of Ponta Grossa, PR, Brazil.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Reis
mesh_terms: D000134:Acid Etching, Dental; D003094:Collagen; D001840:Dental Bonding; D003738:Dental Cements; D003763:Dental Leakage; D003804:Dentin; D017220:Dentin-Bonding Agents; D006801:Humans; D008422:Materials Testing; D019279:Resin Cements; D013314:Stress, Mechanical; D013718:Tensile Strength
chemical_list: D003738:Dental Cements; D017220:Dentin-Bonding Agents; D019279:Resin Cements; D003094:Collagen
keywords: Dental bonding; Dentin collagen; Glutaraldehyde; Proanthocyanidin; Riboflavin