title: Influence of hydroxyethyl acrylamide addition to dental adhesive resin.
abstract: OBJECTIVE
  to determine the physicochemical properties of experimental adhesive resins containing hydroxyethyl acrylamide.
  
  
  METHODS
  Three groups of experimental resin were formulated, GHEAA33% (33.3wt% HEAA+66.6wt% BisGMA), GHEAA50% (50wt% HEAA+50wt% BisGMA), and GHEAA-FREE (33.3wt% HEMA+66.6wt% of BisGMA). The polymerization process of each adhesive resin group, as well as for the homopolymers, BisGMA, HEMA, HEAA, HEMA* without EDAB, and HEAA* without EDAB, was characterized through differential scanning calorimetry (DSC). Elution of monomers was evaluated by (1)H NMR. Dynamic mechanical analysis (DMA) was used to collect the glass transition temperature (Tg), the storage modulus (E') and the reticulation degree (ρ). Flexural strength was calculated by three-point bending test with 0.75mm/min. Softening in solvent was calculated through hardness before and after immersion in water or ethanol.
  
  
  RESULTS
  GHEAA50%, GHEAA33%, GHEAA-FREE presented higher polymerization rate ( [Formula: see text] , 12.3 and 5.3mmolg(-1)s(-1), respectively) than homopolymers HEMA, HEMA* and HEAA*. Group with HEAA presented higher degree of conversion (GHEAA50%=64.07%>GHEAA33%=55.82%>GHEAA-FREE=49.02%; p=0.008) All groups presented low elution of monomers (p>0.05). The values of E' were higher on GHEAA33% than GHEAA-FREE (p=0.034). Tg and flexural strength values of GHEAA-FREE were higher than acrylamide groups (p=0.022 and p<0.001, respectively). Hardness varied from 27.05 to 34.78 for water and from 63.27 to 68.51 for ethanol with no difference for ρ values.
  
  
  CONCLUSIONS
  The addition of HEAA increased the materials reactivity and, consequently, improved the maximum rate of polymerization, degree of conversion and the storage modulus of experimental adhesive resin.
authors.affiliation: Dental Materials Laboratory, School of Dentistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Stéfani Becker
authors.initials: SB
authors.lastname: Rodrigues
authors.affiliation: Dental Materials Laboratory, School of Dentistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. Electronic address: fabricio.collares@ufrgs.br.
authors.forename: Fabrício Mezzomo
authors.initials: FM
authors.lastname: Collares
authors.affiliation: Dental Materials Laboratory, School of Dentistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Vicente Castelo Branco
authors.initials: VC
authors.lastname: Leitune
authors.affiliation: Restorative Dentistry, School of Dentistry, Federal Fluminense University, Niterói, RJ, Brazil; Nucleus for Dental Biomaterials Research, School of Dentistry, Veiga de Almeida University, Rio de Janeiro, RJ, Brazil.
authors.forename: Luis Felipe Jochims
authors.initials: LF
authors.lastname: Schneider
authors.affiliation: School of Materials Engineering, Universidade Federal de Pelotas, Pelotas, RS, Brazil.
authors.forename: Fabrício Aulo
authors.initials: FA
authors.lastname: Ogliari
authors.affiliation: Organic Chemistry Department, Chemistry Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Cesar Liberato
authors.initials: CL
authors.lastname: Petzhold
authors.affiliation: Dental Materials Laboratory, School of Dentistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Susana Maria Werner
authors.initials: SM
authors.lastname: Samuel
mesh_terms: D020106:Acrylamide / Q000737:chemistry*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry*; D002164:Camphor / Q000031:analogs & derivatives / Q000737:chemistry; D003738:Dental Cements / Q000737:chemistry*; D055119:Elastic Modulus; D009682:Magnetic Resonance Spectroscopy; D008689:Methacrylates / Q000737:chemistry*; D058105:Polymerization; D012117:Resins, Synthetic / Q000737:chemistry*; D013696:Temperature; D014783:Viscosity; D062366:para-Aminobenzoates / Q000737:chemistry
chemical_list: D003738:Dental Cements; D008689:Methacrylates; D012117:Resins, Synthetic; D062366:para-Aminobenzoates; D020106:Acrylamide; D017438:Bisphenol A-Glycidyl Methacrylate; C005044:hydroxyethyl methacrylate; D002164:Camphor; C030747:ethyl 4-dimethylaminobenzoate; C553149:camphorquinone
keywords: Acrylamides; Adhesion; Degree of conversion; Hydroxyethyl methacrylate