title: Effect of increased exposure times on amount of residual monomer released from single-step self-etch adhesives.
abstract: BACKGROUND
  The aim of this study was to evaluate the effect of increased exposure times on the amount of residual Bis-GMA, TEGDMA, HEMA and UDMA released from single-step self-etch adhesive systems.
  
  
  METHODS
  Two adhesive systems were used. The adhesives were applied to bovine dentin surface according to the manufacturer's instructions and were polymerized using an LED curing unit for 10, 20 and 40 seconds (n = 5). After polymerization, the specimens were stored in 75% ethanol-water solution (6 mL). Residual monomers (Bis-GMA, TEGDMA, UDMA and HEMA) that were eluted from the adhesives (after 10 minutes, 1 hour, 1 day, 7 days and 30 days) were analyzed by high-performance liquid chromatography (HPLC). The data were analyzed using 1-way analysis of variance and Tukey HSD tests.
  
  
  RESULTS
  Among the time periods, the highest amount of released residual monomers from adhesives was observed in the 10th minute. There were statistically significant differences regarding released Bis-GMA, UDMA, HEMA and TEGDMA between the adhesive systems (p&lt;0.05). There were no significant differences among the 10, 20 and 40 second polymerization times according to their effect on residual monomer release from adhesives (p&gt;0.05).
  
  
  CONCLUSIONS
  Increasing the polymerization time did not have an effect on residual monomer release from single-step self-etch adhesives.
authors.affiliation: Department of Pediatric Dentistry, Faculty of Dentistry, Sifa University, Izmir - Turkey.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Altunsoy
authors.affiliation: Department of Pediatric Dentistry, Faculty of Dentistry, Selcuk University, Konya - Turkey.
authors.forename: Murat Selim
authors.initials: MS
authors.lastname: Botsali
authors.affiliation: Faculty of Chemistry, Karadeniz Technical University, Trabzon - Turkey.
authors.forename: Gonca
authors.initials: G
authors.lastname: Tosun
authors.affiliation: Faculty of Chemistry, Karadeniz Technical University, Trabzon - Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Yasar
mesh_terms: D000269:Adhesives / Q000737:chemistry*; D000818:Animals; D002417:Cattle; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003804:Dentin / Q000737:chemistry; D008422:Materials Testing; D008689:Methacrylates / Q000032:analysis* / Q000737:chemistry*; D013997:Time Factors
chemical_list: D000269:Adhesives; D003188:Composite Resins; D008689:Methacrylates