title: Do the monomers release from the composite resins after artificial aging?
abstract: OBJECTIVE
  The aim of this study is to measure the effect of thermal cycling on the amount of monomer released from three different composite materials by HPLC analysis method.
  
  
  METHODS
  Three different composite materials, inlay composite, posterior composite and micro-hybrid composite were used. Sixty cylinder specimens each with a dimension of approximately 1 cm width and 3 mm depth, were prepared before experiments were carried out. Inlay composite material was polymerized according to manufacturers' instructions. Thermal cycling device was used to simulate thermal differences which occur in the mouth media. Monomers were analyzed using HPLC technic after thermal cycling process. The amount of ethoxylated Bis-GMA and urethane dimethacrylate (UDMA) in inlay composite material, the amount of ethoxylated Bis-GMA in posterior composite material, the amount of ethoxylated Bis-GMA and triethyleneglycol dimethacrylate (TEGDMA) in micro-hybrid composite material were investigated.
  
  
  RESULTS
  Monomer release of thermal cycles levels showed a linear increase in UDMA and TEGDMA (P < 0.05). In terms of thermal cycles levels, Bis-EMA released from posterior composite showed a cubic change (P < 0.001).
  
  
  CONCLUSIONS
  It was observed that use of additional polymerization processes might have positive effect on the decrease of residual monomer. In the light of the results, we suggest that indirect composite resins have more outstanding features than direct composite resins in terms of biocompatibility.
authors: Department of Pediatric Dentistry, Faculty of Dentistry, Ishik University, Erbil, Iraq.
authors: Ugur
authors: U
authors: Tokay
authors: Alp Erdin
authors: AE
authors: Koyuturk
authors: Abdurrahman
authors: A
authors: Aksoy
authors: Bilal
authors: B
authors: Ozmen
mesh_terms: D002678:Chimera; D002851:Chromatography, High Pressure Liquid; D003188:Composite Resins / Q000528:radiation effects*; D008422:Materials Testing; D008689:Methacrylates / Q000032:analysis*
chemical_list: D003188:Composite Resins; D008689:Methacrylates
keywords: HPLC; aging; composite resins; monomer; thermal cycling