Curing kinetics of visible light curing dental resin composites investigated by dielectric analysis (DEA)

Light transmittance and polymerization kinetics of amorphous calcium phosphate composites

“…For early phase of the polymerization, two assumptions can be made: that the monomer concentration remains constant and that all of the present free radicals are in fact the radicalized initiator. Such simplification yields a constant polymerization rate, which is linearly dependent on the concentration of the radicalized initiator [39]. Although this approximation is not valid for longtime ranges through which we performed linear fitting (7-20 s, Table 2), a good fit throughout the whole range means that the slope remained the same as in the earliest stage of polymerization where the approximation holds.…”

Electrochemical impedance spectroscopy (EIS): An efficiency method to monitor resin curing processes

“…However, DSC results are easy to be affected by other heat-related events, such as solvent evaporation [14]. DEA analysis, based on variation of dielectric properties (such as dielectric constant and dielectric loss factor) of a sample, is highly affected by ions movement and dipoles alignment [15]. Although DEA analysis is more sensitive to small variation of sample properties in studying the curing degree, it requires plenty of preliminary experiments to ensure accuracy [12,16].…”

Dielectric analysis of depth dependent curing behavior of dental resin composites

“…With the help of the absorption depth a proper definition of the "depth of cure" becomes possible as the three fold of the absorption depth where the light intensity is attenuated to 5% of its initial value. The linear increase of ion viscosity with time justifies the assumption of the kinetics model of the curing process that a remarkable amount of the CQ is "instantaneously" activated in this layer [39]. It indicates the existence of an undisturbed chain growth (UCG) during the first seconds of the polymerization until the polymer chains reach a length that either allows for cross-linking with neighboring chains or transition to the glassy state.…”

“…Above this critical degree of polymerization, the viscosity increases with M 3,4 . Simultaneously, the polymerization process slows down due to a significant viscosity increase enhanced by gelation and cross-linking, respectively [39,46].…”

“…It has been shown that the ion viscosity is suitable to characterize the influence of resin compositions as well as curing conditions on the polymerization process of VLC composites. For many VLC composites the ion viscosity data shows a linear time dependency, and thus it is feasible to derive kinetic parameters [39].…”