title: HPLC analysis of HEMA released from two different adhesive systems.
abstract: OBJECTIVE
  The aim of this study was to evaluate in vitro elution of 2-Hydroxyethyl methacrylate (HEMA) from two different adhesive systems, used in two dual polymerized resin cements for bonding of ceramic restoration by high performance liquid chromatography (HPLC).
  
  
  METHODS
  Twenty freshly extracted caries and restoration free molar teeth used in this study. Standardized Class I preparations were prepared in all teeth. A lithium disilicate based (IPS Empress Esthetic; Ivoclar) ceramic inlays were cemented with one of the dual polymerized resin cements (RelyX ARC; 3M ESPE or Nexus 2; Kerr) that have two different adhesive systems (Single Bond; 3M ESPE, Optibond Solo Plus; Kerr). After cementation, specimens were stored in 75% ethanol solution. HPLC was used to analyze the amount of HEMA in the solution (after 10 min, 1 h, 24 h, 3, 7, 14, and 21 days). Two-way analysis of variance and Tukey HSD tests were used to evaluate the results (p < 0.05).
  
  
  RESULTS
  There were statistically significant differences between adhesive systems according to the amount of released HEMA (p < 0.01) and also among time periods (p < 0.01). The amount of HEMA eluted from Optibond Solo Plus was significantly higher than Single Bond. The total amount of monomers was the highest after 21 days (p < 0.01).
  
  
  CONCLUSIONS
  In the case of adhesive systems, Optibond Solo Plus showed the highest amount of HEMA. The amount of HEMA eluted from adhesive systems influenced by the time.
authors.affiliation: Department of Prosthodontics, Karadeniz Technical University, Trabzon, Turkey.
authors.forename: Subutay Han
authors.initials: SH
authors.lastname: Altintas
authors.affiliation: Department of Prosthodontics, School of Dentistry, Gaziantep University, Gaziantep, Turkey.
authors.forename: Aslihan
authors.initials: A
authors.lastname: Usumez
mesh_terms: D002138:Calibration; D002516:Ceramics / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D003731:Dental Caries / Q000378:metabolism; D003764:Dental Materials / Q000032:analysis*; D000431:Ethanol / Q000737:chemistry; D006801:Humans; D016014:Linear Models; D008689:Methacrylates / Q000032:analysis*; D012996:Solutions; D012997:Solvents; D014014:Tissue Adhesives / Q000032:analysis*
chemical_list: D003764:Dental Materials; D008689:Methacrylates; D012996:Solutions; D012997:Solvents; D014014:Tissue Adhesives; D000431:Ethanol; C005044:hydroxyethyl methacrylate