Synthesis and preparation of novel 4-arm star-shape poly(carboxylic acid)s for improved light-cured glass-ionomer cements.
OBJECTIVE
The objective of this study was to synthesize and characterize novel 4-arm star-shape poly(acrylic acid)s (poly(AA)s) via atom-transfer radical polymerization (ATRP) technique, tether in situ light-curable methacrylate functionalities onto the poly(AA) backbone, use these star-shape poly(AA)s to formulate the light-cured glass-ionomer cements (LCGICs), and evaluate the mechanical strengths of the formed cements.


METHODS
The 4-arm poly(AA)s were synthesized using ATRP and tethered with either 2-isocyanatoethyl methacrylate (IEM) or glycidyl methacrylate (GM). The polymers were formulated with 2-hydroxyethyl methacrylte (HEMA) or methacryloyl beta-alanine (MBA), water, initiators, and Fuji II LC filler. Compressive strength (CS) was used as a tool to evaluate the formed cements. The specimens were conditioned in distilled water at 37 degrees C for 24h prior to testing.


RESULTS
The 4-arm poly(AA) showed a lower viscosity as compared to its linear counterpart. Both IEM-tethered and GM-tethered 4-arm poly(AA) constructed LCGICs showed significantly high mechanical strengths. Both types of co-monomer and grafting agent dramatically affected the mechanical strengths. The MBA-containing poly(AA) cements exhibited much higher CS than the HEMA-containing cements. The IEM-tethered poly(AA) cements showed much higher CS and DTS than the GM-tethered cements.


CONCLUSIONS
This study developed a novel light-curable 4-arm star-shape poly(AA) system. The system was 13% in CS, 178% in DTS and 123% in FS, compared to Fuji II LC.
Xie
Dong
D
Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis, IN 46202, USA. dxie@iupui.edu
Park
Jong-Gu
JG
Zhao
Jun
J
D000180:Acrylic Resins / Q000138:chemical synthesis* / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry; D019245:Compressive Strength; D003799:Dental Stress Analysis; D004852:Epoxy Compounds / Q000737:chemistry; D005609:Free Radicals / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000138:chemical synthesis* / Q000737:chemistry; D017953:Isocyanates / Q000737:chemistry; D008027:Light; D008422:Materials Testing; D008689:Methacrylates / Q000138:chemical synthesis / Q000737:chemistry; D008968:Molecular Conformation; D008970:Molecular Weight; D044367:Phase Transition; D018583:Pliability; D012117:Resins, Synthetic / Q000737:chemistry; D013718:Tensile Strength; D014783:Viscosity; D015091:beta-Alanine / Q000737:chemistry
D000180:Acrylic Resins; D002264:Carboxylic Acids; D004852:Epoxy Compounds; D005609:Free Radicals; C079765:Fuji II LC cement; D005899:Glass Ionomer Cements; D017953:Isocyanates; D008689:Methacrylates; D012117:Resins, Synthetic; D015091:beta-Alanine; C006903:carbopol 940; C005044:hydroxyethyl methacrylate; C029845:2-isocyanatoethyl methacrylate; C007870:glycidyl methacrylate