Effects of two amine reducing agents on the degree of conversion and physical properties of an unfilled light-cured resin
1993; Elsevier BV; Volume: 9; Issue: 4 Linguagem: Inglês
10.1016/0109-5641(93)90069-3
ISSN1879-0097
AutoresKazuhiro Yoshida, E.H. Greener,
Tópico(s)Dental materials and restorations
ResumoThe influence of varying concentrations of two amine reducing agents commonly used in commercial light-cured composites, N,N-dimethyl-p-toluidine (DMPT) and 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA), on the degree of conversion (DC), Knoop hardness, and compressive and transverse strengths of an unfilled light-cured resin was investigated. The DC obtained from employing two different internal standard peaks, carbonyl (C=O) at 1730 cm−1 and urethane (N-H) at 3350 cm−1, was compared. The resin consisted of 50 wt% triethyleneglycol dimethacrylate (TEGDMA) and 50 wt% 1,6-bis (methacryloxy-2-ethoxycarbonylamino)-2,4,4-trimethylhexane (UDMA) activated with 0.5 mol% camphorquinone (CQ) and varying concentrations of either DMPT or DMAEMA. The DC calculated by use of either C=O or N-H absorption peak as an internal reference showed similar values. For both amines, the physical properties were directly related to DC and appeared to reach maximal values at an amine/CQ molar ratio of 4.0. The DC, however, appeared to reach a maximum at an amine/CQ molar ratio of 3.0. Generally, for the same amine/CQ molar ratios, the polymers formulated with DMAEMA, had greater DCs and better physical properties than those formulated with DMPT.
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