title: Influence of 2-hydroxyethyl methacrylate concentration on polymer network of adhesive resin.
abstract: OBJECTIVE
  To evaluate the effect of variations in 2-hydroxyethyl methacrylate (HEMA) concentrations in an experimental comonomer blend on degree of conversion, water sorption, solubility, and ultimate tensile strength of adhesive resin.
  
  
  METHODS
  The effect of HEMA content (0, 15, 30, and 50%wt - control, G15, G30, and G50 groups, respectively) was tested in an experimental comonomer blend of bis-GMA, bis-EMA, TEG-DMA, and HEMA. The degree of conversion, polymerization rate, ultimate tensile strength, water sorption, and solubility of the adhesive resin blends were determined.
  
  
  RESULTS
  At 40 s of light activation time, groups G30 and G50 showed a decrease of 30% and 61%, respectively, in degree of conversion compared to control. Water sorption and solubility differed for all groups, and was statistically higher in G50. For ultimate tensile strength, the control and G15 groups showed statistically higher values than the other groups (p < 0.05).
  
  
  CONCLUSIONS
  Higher HEMA content increases dental adhesive resin degradation.
authors: Conservative Dentistry Department, School of Dentistry, Federal University of Rio Grande do Sul, RS, Brazil. fabriciodonto@gmail.com
authors: Fabrício Mezzomo
authors: FM
authors: Collares
authors: Fabrício Aulo
authors: FA
authors: Ogliari
authors: César Henrique
authors: CH
authors: Zanchi
authors: Cesar Liberato
authors: CL
authors: Petzhold
authors: Evandro
authors: E
authors: Piva
authors: Susana Maria Werner
authors: SM
authors: Samuel