title: Preparation and evaluation of a novel star-shaped polyacid-constructed dental glass-ionomer system.
abstract: OBJECTIVE
  The objective of this study was to synthesize and characterize novel star-shaped poly(acrylic acid-co-itaconic acid)s via chain-transfer radical polymerization technique, use these polyacids to formulate the resin-modified glass-ionomer cements, and evaluate the mechanical strengths of the formed cements
  
  
  METHODS
  The star-shaped poly(acrylic acid-co-itaconic acid)s were synthesized via a chain-transfer radical polymerization reaction using a newly synthesized star-shaped chain-transfer agent. The effects of MW, GM-tethering ratio, P/L ratio and aging on the compressive properties of the formed experimental cements were studied. Compressive, diametral tensile as well as flexural strengths were evaluated and compared to those of Fuji II and Fuji II LC cements.
  
  
  RESULTS
  The star-shaped polyacids showed significantly lower viscosities in water as compared to their linear counterparts. The cements formulated with these novel polyacids showed significantly improved mechanical strengths i.e., 49% in yield strength, 41% in modulus, 25% in CS, 20% in DTS and 36% in FS, higher than commercial Fuji II LC. After aging in water for 30 days, the compressive strengths of the experimental cements were significantly changed with an increase of 29% in YS, 19% in modulus as well as 23% in CS and a decrease of 5% in toughness, indicating that aging in water enhances the salt-bridge formation and increases brittleness.
  
  
  CONCLUSIONS
  A novel light-cured glass-ionomer cement system composed of the star-shaped poly(carboxylic acid)s has been developed via a cost-effective and time-efficient chain-transfer radical polymerization.
authors.affiliation: Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis, IN 46202, USA.
authors.forename: Leah
authors.initials: L
authors.lastname: Howard
authors.affiliation: Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis, IN 46202, USA.
authors.forename: Yiming
authors.initials: Y
authors.lastname: Weng
authors.affiliation: Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis, IN 46202, USA. Electronic address: dxie@iupui.edu.
authors.forename: Dong
authors.initials: D
authors.lastname: Xie
mesh_terms: D000143:Acids / Q000737:chemistry*; D005899:Glass Ionomer Cements; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000143:Acids; D005899:Glass Ionomer Cements
keywords: Compressive strength; Glass–ionomer cement, Synthesis; Poly(carboxylic acid); Star-shaped chain-transfer agent; Viscosity