title: A new acrylic-based fluoride-releasing cement as a potential orthodontic bonding agent.
abstract: OBJECTIVE
  To develop a fluoride-releasing, acrylic-based 'easy on, easy off' bracket cement as a potential orthodontic bonding agent.
  
  
  METHODS
  Three experimental cements were prepared in powder/liquid forms by mixing different ratios of methylmethacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA) to form the liquid (L) and sodium fluoride (NaF) and polymethylmethacrylate (PMMA) to form the powder (P). The resultant materials were tested for setting characteristics, fluoride release, hardness, strength, shear bond strength (SBS) and adhesive remnant index in comparison with resin composite and glass ionomer, which were used as control materials. The data were analyzed using ANOVA and the Kruskal-Wallis and Mann-Whitney tests.
  
  
  RESULTS
  The experimental groups had satisfactory setting characteristics. Fluoride release of the group containing P (10% NaF, 90% PMMA) and L (60% MMA and 40% HEMA) was similar to that of glass ionomer. When experimental materials were stored in water for 7 days, their hardness was reduced and stabilized at a value lower than those for composite and PMMA. Strength was only slightly affected by water storage. The SBSs of the experimental groups were considered clinically acceptable at both 30 min and 1 month. The group containing P (10% NaF, 90% PMMA) and L (90% MMA and 10% HEMA) had a higher mean SBS than the other two experimental groups. At 1 month, there were significantly less adhesive remnants observed on the surface of enamel after debonding for the experimental groups compared with the composite.
  
  
  CONCLUSIONS
  The new cement could potentially be useful as an orthodontic bonding agent.
authors.affiliation: Capital Medical University, Beijing, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Su
authors.forename: Yuxing
authors.initials: Y
authors.lastname: Bai
authors.forename: Song
authors.initials: S
authors.lastname: Li
authors.forename: Omar T
authors.initials: OT
authors.lastname: Al-Naimi
authors.forename: John F
authors.initials: JF
authors.lastname: McCabe
mesh_terms: D000180:Acrylic Resins; D000704:Analysis of Variance; D002152:Calorimetry, Differential Scanning; D002327:Cariostatic Agents / Q000008:administration & dosage / Q000032:analysis; D017005:Dental Debonding; D003799:Dental Stress Analysis; D005459:Fluorides / Q000008:administration & dosage / Q000032:analysis; D006244:Hardness; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D008689:Methacrylates; D016910:Orthodontic Brackets; D019279:Resin Cements / Q000737:chemistry*; D033081:Shear Strength; D018709:Statistics, Nonparametric
chemical_list: D000180:Acrylic Resins; D002327:Cariostatic Agents; D008689:Methacrylates; D019279:Resin Cements; C005044:hydroxyethyl methacrylate; D005459:Fluorides