A novel comonomer-free light-cured glass-ionomer cement for reduced cytotoxicity and enhanced mechanical strength.
OBJECTIVE
The objective of this study was to develop a novel comonomer-free light-cured glass-ionomer system based on the 4-arm star-shape poly(acrylic acid). The mechanical strengths and in vitro cytotoxicity of the formed system were evaluated and compared with those of several representative commercial glass-ionomer cements.


METHODS
The 4-arm poly(acrylic acid) was synthesized using ATRP and tethered with glycidyl methacrylate (GM). The GM-tethered polymer was formulated with water, photo-initiators, and Fuji II LC filler. Fuji II, Fuji II LC and Vitremer were used for comparison. Compressive strength (CS) and MTT assay were used as tools to evaluate the mechanical strengths and in vitro cytotoxicity of the cements, respectively.


RESULTS
The experimental cement exhibited significantly high compressive, diametral tensile and flexural strengths as compared to commercial glass-ionomer cements, Fuji II, Fuji II LC and Vitremer. The effects of polymer/water (P/W) ratio, GM-grafting ratio, glass powder/polymer liquid (P/L) ratio and aging in water on strengths were significant. Similar to conventional glass-ionomer cement Fuji II, the eluates from the experimental cement showed little in vitro cytotoxicity to Balb/c mouse fibroblast cells, as compared to Fuji II LC and Vitremer that contain HEMA as a comonomer.


CONCLUSIONS
It appears that this novel comonomer-free light-cured glass-ionomer cement will be a promising dental restorative because it demonstrated significantly improved mechanical strengths and almost no in vitro cytotoxicity as compared to current commercial light-cured glass-ionomer cements.
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
Yang
Youyun
Y
Zhao
Jun
J
Park
Jong-Gu
JG
Zhang
Jian-Ting
JT
D000180:Acrylic Resins; D000704:Analysis of Variance; D000818:Animals; D002478:Cells, Cultured; D003188:Composite Resins; D019245:Compressive Strength; D003799:Dental Stress Analysis; D005347:Fibroblasts / Q000187:drug effects; D005899:Glass Ionomer Cements / Q000138:chemical synthesis* / Q000737:chemistry* / Q000633:toxicity; D005989:Glycerides; D008027:Light; D009682:Magnetic Resonance Spectroscopy; D008422:Materials Testing; D008689:Methacrylates; D051379:Mice; D008807:Mice, Inbred BALB C; D015394:Molecular Structure; D044367:Phase Transition; D018583:Pliability; D012117:Resins, Synthetic; D017550:Spectroscopy, Fourier Transform Infrared; D013718:Tensile Strength; D014783:Viscosity
D000180:Acrylic Resins; D003188:Composite Resins; C079765:Fuji II LC cement; D005899:Glass Ionomer Cements; D005989:Glycerides; D008689:Methacrylates; D012117:Resins, Synthetic; C084550:Vitremer; C006903:carbopol 940; C069750:glyceryl methacrylate