title: Evaluation of UDMA's potential as a substitute for Bis-GMA in orthodontic adhesives.
abstract: OBJECTIVE
  To investigate the effect of UDMA %, of a range of filled UDMA:TEGDMA resins, on viscosity, degree of conversion and shear bond strength. Furthermore, to compare between model filled and unfilled UDMA adhesives, and clinically used orthodontic adhesives on these properties.
  
  
  METHODS
  Four filled and four unfilled resins with a UDMA to TEGDMA weight ratio 50:50, 60:40, 70:30, 80:20 were formulated, tested and compared to the Bis-GMA control Transbond XT. The properties investigated were: viscosity (rotational viscometry), degree of conversion (DC) (FT-IR) and bond strength (shear bond strength test). One-way ANOVA and Tukey post hoc test was used to statistically analyze the data for viscosity and DC% while the non-parametric Kruskal-Wallis and Mann-Whitney U-test was used for the shear bond strength values.
  
  
  RESULTS
  For SBS a comparable bond strength was obtained between the U80:T20(F) adhesive and the control Transbond XT (27.1 and 30.1 respectively). There was no significant difference between the U70:T30 adhesive and the control. Transbond XT (43.1%) had a significantly lower DC% than all the UDMA based adhesives. Furthermore, there was no significant difference between the DC% means of the various UDMA resins. There was a significant decrease in the viscosity for both filled and unfilled groups, as the TEGDMA concentration was increased.
  
  
  CONCLUSIONS
  The results indicate that adhesives formulated with UDMA and TEGDMA monomers, could produce resins with comparable viscosities to the Bis-GMA control, Transbond XT. Adhesives formulated with high UDMA %, can be used to produce resins with greater viscosity and increased bond strength, potentially without affecting their degree of conversion.
authors.affiliation: Biomaterials Research Group, School of Dentistry, The University of Manchester, UK.
authors.forename: Alexia E
authors.initials: AE
authors.lastname: Papakonstantinou
authors.forename: Theodore
authors.initials: T
authors.lastname: Eliades
authors.forename: Francesco
authors.initials: F
authors.lastname: Cellesi
authors.forename: David C
authors.initials: DC
authors.lastname: Watts
authors.forename: Nick
authors.initials: N
authors.lastname: Silikas
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D001840:Dental Bonding; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D009967:Orthodontic Appliances; D011092:Polyethylene Glycols / Q000737:chemistry; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry*; D019279:Resin Cements / Q000737:chemistry*; D012212:Rheology / Q000295:instrumentation; D033081:Shear Strength; D012821:Silanes / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013729:Terpenes / Q000737:chemistry; D014783:Viscosity
chemical_list: D008689:Methacrylates; D011109:Polymethacrylic Acids; D011140:Polyurethanes; D019279:Resin Cements; D012821:Silanes; D013729:Terpenes; C477790:Transbond XT; C029824:urethane dimethacrylate luting resin; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C048339:camphoroquinone; C049840:2-(dimethylamino)ethyl methacrylate
keywords: Adhesives; Bis-GMA; Degree of conversion; Orthodontics; Rheology; Shear bond strength; Transbond; UDMA