Polymerization kinetics of resin-based restorative materials

The kinetics and mechanism of cure of resin-based restorative materials have been investigated by incorporating into commercial materials additional amounts of inhibitor, initiator, and accelerator. The polymerization was monitored by IR spectroscopy, viscosity measurements, and an oscillating rheometer. The rate of initiation of the polymerization was found to be first order with respect to the initiator and accelerator concentration. The inhibitor was found to be responsible for the induction period during which no polymerization occurred. The duration of this period was proportional to the inhibitor concentration. It was also found that the efficiency of the inhibitor affected the difference between the initial and final set times so that with one particularly effective inhibitor a "snap-set" behavior could be obtained.