Effect of polyacid aqueous solutions on photocuring of polymerizable components of resin-modified glass ionomer cements.
OBJECTIVE
Resin-modified glass ionomer cements (RMGI) are hybrid materials prepared by incorporation of polymerizable components (typically 2-hydroxyethyl methacrylate (HEMA) with possible addition of multifunctional methacrylates) into a conventional acid-base mixture (a polymeric acid with powdered calcium fluoro-aluminosilicate glasses). During setting, the photopolymerization process and the acid-base reaction affect each other. The aim of this work was to examine the effect of a 45% aqueous solution of poly(acrylic acid) (PAA) and the liquid component of a commercial glass ionomer cement on HEMA and triethyleneglycol dimethacrylate (TEGDMA) photopolymerization.


METHODS
The polymerization was initiated by 2,2-dimethoxy-2-phenylacetophenone (DMPA) and camphorquinone (CQ)/coinitiator system. The reaction course was monitored under Ar and air by isothermal differential scanning calorimetry.


RESULTS
The main effect of addition of polyacid solution (PAA and commercial) up to 10wt% to HEMA on the polymerization initiated with DMPA was earlier onset of autoacceleration. For the process initiated by the CQ-based system, the addition of 5wt% of PAA solution strongly accelerated the polymerization and increased the conversion, both in Ar atmosphere as well as in air. TEGDMA photopolymerization was not influenced or slightly retarded by the presence of 3wt% of PAA solution (the upper limit of solubility), depending on the initiating system used.


CONCLUSIONS
Under initiation conditions used in curing of commercial dental products (CQ-based two component initiating system), the presence of polyacid-aqueous solution in HEMA-based photocurable component increases markedly the polymerization rate and the conversion both in Ar atmosphere as well as in air. This result contributes to a characterization of the setting process of RMGIs.
Andrzejewska
Ewa
E
Institute of Chemical Technology and Engineering, Poznan University of Technology, Pl. M. Sklodowskiej-Curie 2, 60-965 Poznan, Poland. ewa.andrzejewska@put.poznan.pl
Andrzejewski
Maciej
M
Socha
Elzbieta
E
Zych-Tomkowiak
Dorota
D
D000180:Acrylic Resins; D000814:Aniline Compounds; D005899:Glass Ionomer Cements / Q000737:chemistry* / Q000528:radiation effects*; D008027:Light; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry / Q000528:radiation effects; D015394:Molecular Structure; D011092:Polyethylene Glycols / Q000737:chemistry / Q000528:radiation effects; D011108:Polymers / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry / Q000528:radiation effects; D013729:Terpenes; D013997:Time Factors; D014867:Water
D000180:Acrylic Resins; D000814:Aniline Compounds; D005899:Glass Ionomer Cements; D008689:Methacrylates; D011108:Polymers; D011109:Polymethacrylic Acids; D013729:Terpenes; D014867:Water; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; C048339:camphoroquinone; C006903:carbopol 940; C005044:hydroxyethyl methacrylate; C050795:N,N-dimethyl-4-anisidine